Sorry that reminds me of my granddad, when automatic transmissions where a new things someone had a car they couldn't start. They'd give it to him if he could fix it. He put the shifter into park, started it up and drove away. That's what you call penny wise, pound foolish.
Ivan, the Right Front definitely looked like it was moving. It’s only going to move a small amount because the trans is in park and the left is locked. Take another look at the video. Great diagnosis. Can’t wait for the repairs!!
Yes, I saw that. I was thinking about the brake line to the right front is shorter than the the rear left line and when he presses the brake the right front line may receive more pressure than the rear left when we consider the length of the two lines. anyway we need a physic teacher to explain that for us.
@@nimairikowa5650 when speaking of hydraulics there is no pressure difference. Any hydraulic connection will have the same pressure though out. A pressure difference can only happen when you have some sort f orifice.
@@RichardHilverts With the orifice you need flow as well. Without the flow, the pressure will equalize too. Here pressurizing the system with jammed broom does not create any flow (beside the few seconds when installing it).
Great diagnosis procedure! I did all the usual checks and fluid flush then concluded that the fault was in the ABS unit. I took the car for a drive on to a wet road deliberately braked heavily to get the ABS to operate and in doing so it cleared the fault of the sinking brake pedal. Cheers from Melbourne Australia. 😁👍
The way Ivan speaks and the way he goes about diagnosing things, is quite evident that he is not just a mechanic. He is a a true SCIENTIST. i hope he completes the Ph.d one day.
Ivan. There is a one way check valve.. the diagram you are showing us states it and you mentioned it.. the inlet valves are non return.. so with the return valve closed the wheel still builds pressure even with the "leak" in the system for the second wheel
Great reasoning stepping through this diagnostic! It seemed to me that the front right wheel was not really tight - it moved a bit. Trapped air or master cylinder leak were my first thoughts, before you went through the tests. Now I'm curious to see the results of the ABS replacement :-)
Thanks for the video. I had similar symptoms on a 2013 Mazda 3 with 2.0 Skyactiv engine at 154,000 miles. After reading the comments I went with the cheapest fix. A large bottle of DOT 3 brake fluid. I flushed the old brake fluid and then exercised the ABS system and for now the brake is back to normal. Previously it would sink on the first application. You could pump first and then brake and it wouldn't sink as much. We'll see how long this fix lasts.
Have encountered this problem a half dozen times at my shop here in Toronto. On 2 occasions the owners reported that the problem began immediately after an ABS event. Very interested to see how you tackle the repair. Personally have never needed to replace the hydraulic unit. Last unit I priced out OE was for a '10 Mazda 3 and if memory serves it was $1400 CAD. Thanks for all the effort you put into making content. Great work and keep them coming!!
Same exact issue here. 2010 Mazda 3, issue started after ABS engaged in rain. I basically had no brakes while the ABS was engaged, very dangerous. After, the pedal would go 70% to floor before brakes engaged.
Old brake fluid with a high moisture content could have caused sludge or corrosion inside the valve block. A good example why you should aways replace and flush brake fluid at least every couple years.
230,000 miles. 270,000 miles. 190,000 miles 250,000 miles. 150,000 miles. just some miles on cars I take care of. never changed the brake fluid never will. as far as im concerned this is up there with changing the blinker fluid. brake fluid absorbs water. so therefore it can be tested for its water content. the testers check the boiling point of the brake fluid as it gets more water in it the boiling point changes. $10 AMAZON. so $10 for a tester to check the fluid instead of wasting Time and $$$ changing fluid like banshee
@@sw7366 I live in the north east in the middle of the humidity. I ordered a brake fluid tested. Im going to guess it shows 18 year old brake fluid is OK. I'll make a video on it showing either way. this sounds more like a money grab by shops and a hook home mechanics got lured to.
@@bobspurloc I've seen many cars loose brakes from heavy braking due to vapour locks from heat boiling water in the fluid. I think you are dangerous because you refuse to believe there could ever be a problem. Your customers are trusting you to look after them and I hope none of them pay the price for your fixed thinking.
I like it when you open up modules and repair them... pretty sure that's not an option with a critical safety item like the ABS. Still, I'd love to see a teardown and the failures up close.
Hello Ivan, if you see this comment I’m reaching out to get your opinion. I live in Oregon and can’t simply drive to you. I have been trying to figure out a similar problem on my wife’s 2004 Honda Odyssey. The brake pedal when first applied, feels low and soft. You can feel that it IS applying the bake but not with force until maybe half way down. If I release the brake and re-apply it quickly, so basically just pump it once quickly, it firms up and feels great. Once we start driving again, and come up to the next stop light or sign it’s back to the same. It feels low and soft, pump it once quickly and it is firm and grabs at the normal pedal travel. When I pump the pedal and the brake firms up, it remains there until I release it. So I do not suspect a faulty master cylinder. The van does have ABS, is very well maintained. No leaks anywhere, has new brakes and rotors, I know that new brakes and rotors will cause the brakes to not seem to grab at first, until the pads and rotors wear into each other, but this issues has been there well before those were even replaced. Would you suspect a faulty ABS unit? Your input much appreciated!🤙
I'm currently working on a 06 Mazda 3s with the same exact symptoms. I think your video initially led me astray. The abs does nothing when the car is not running or not moving when running. Your brake pedal test was good, it showed you had diagonal tires that would turn with the brakes applied and diagonal tires that would not spin with brakes applied. If you had opened the bleeder on the left rear wheel and pumped the brakes you would have seen the pedal get progressively stiffer while at the same time very little fluid would have come out of the bleeder. Doing the same test with the right rear tire you would have noticed the pedal would go down with each pump and a large amount of fluid would have come out of the bleeder. During the first test the pedal gets hard because the half of the master cylinder controlling the right rear wheel and its diagonal is working and the fluid is trapped thus building pressure with each pump. During the second test neither half of the master cylinder can build pressure because the bleeder on the right rear is open and the chevron seals on the half of the master cylinder controlling the left rear wheel and its diagonal are leaking through and unable to move much fluid or build normal pressure. The abs system is not causing the half pedal issue.
Great video!, Exact same problem with my 2005 mazda 3. No bi-directional tool though and not worth proper service like this. Problem seems to come and go intermittently. Happened today. Exercised the ABS etc, no change, still doing it. Took a 1" wrench and a hammer and gave it a few gentle love taps in a non-damaging area to wake it up and maybe shake whatever valve is stuck, loose. All fixed.
Update: as it works out, although bumping it with a hammer may have fixed it, looks like it was temporary. Took it out on gravel and exercised the abs… problem is back. Dammit.
Awesome channel! Thanks for your clear-headed problem solving approach Ivan! Way entertaining and educational - Sesame Street for mechanics, engineers, and curious tinkerers of all ages. I think the answer to your pressure question is in the labeling of the components. The "Inlet valve with non-return valve". I'm not familiar with ABS but imagine pressure can't be dumped from either circuit until the outlet valve for that circuit is opened or the pedal is released. You or one of your viewers probably already posted the correct answer. But when you asked, I had to pause the video, look at the schematic, wonder the same thing, and raise my hand with my best guess. Keep up the great work!
My dad has same problem with his 2012 mazda 3 , i did exactly as your steps and the same diagnoses, thanks for your explanation with the diagram that made me understand , excelent video man👍
I've had a few of these problems and ends up having a sticky valve in the hcu. I would drive it on a gravel road or lot and activate the abs and try this few times and it would fix the concern. Also the rear caliper slider are bad for seizing in the bracket because of the corrosion under the slider boot. Good luck
I have the same car except 2007. ABS module will reset if you can get the ABS to activate (slam on the brakes on a dirt road - it may take a few tries). Pedal will be back to its former self. Then, gravity-bleed the brakes with a quart of brake fluid, repeat if necessary, it may take 2 or 3 quarts. It cured my ABS module problems.
My old brake fluid was quite sparkly when shining a flashlight through the clear bleed hose - I think those tiny metal particles were jamming the ABS module's valves.
Interesting video. I currently have what I thought was a stuck valve in the ABS HU on a 2006 Mazda 3 but after sending the unit off for testing and repair, it turns out it is a blockage inside the unit so after being quoted $2430 AUD by Mazda for a new one and not wanting a used one, I have ordered a new one from Japan for $580 AUD delivered.
What happened here was that, unlike my Mondeo which cycled the HCU valves just after pulling away after every start to remove the air from behind the ABS valves, this does not happen on this variant. Minute amount of air build up behind the ABS valves up after period time. The minute build up of air is not in the brake system until an ABS even takes place. Then you get the soft pedal feel. There is a special service function on the dealer tool to allow for sequential cycling of the valves to purge the air build up. Even though the pedal is soft the brakes still work. Just the feel is not very good. Great video.
Hi Ivan if its a Bosch 8 ESP unit it can be repaired. I had that unit on an Opel last week with the same complaint. It's a known issue on those modules.
I will look it up and maybe refurbish the old one. From my experience it is not a common problem. Usually occurs after a panic stop where the ABS valves are activated. Have seen it before only once on a Ford 👍
@@PineHollowAutoDiagnostics let me know if i can help, the company is in Holland. Maybe there's a company in the US that can repair it. If not send me a PM
Dont know if anyone mentioned it, but it looks and sounds like the front right is in fact NOT being braked. The car is in Park and so it is locked via both the differential (front left wheel) and the gearbox. The movement can’t travel anywhere. The rear is only a wheel that is not driven by the engine and so it is able to spin.
Interesting problem. I wonder if used ABS unit from scrap yard would fix it economically? Or take the original unit apart and just replace all seals, if possible? Wondering if too old brake fluid made the seals fail, if the fluid wasn't changed in recommended intervals?
A frozen caliper slide pin can cause a similar problem. If the caliper can't slide freely, as the pads wear the piston has to travel an extra distance to apply the brake. This will cause a low soft pedal. Sometimes to diag this problem if you release and press the pedal quickly a second time and if the pedal feels normal the problem is likely a sticking caliper slide. Very common in the northeast where salt is used on the road.
are the rear brakes drum? if it had a left rear wheel cylinder or if discs caliper was froze it would build pressure on the rf. hate to say it but anytime there's a brake problem its time to pull all the wheels and inspect everything. also checking pressures at the wheels and master cylinder outputs is extremely helpful. flexible hoses can be a problem too
Interesting one Ivan. The sound coming from the module is great! I can only imagine the internal leaky valve just spraying out in the wrong direction. Thinktool pros doing the good work! Would be cool to see a tear down of the faulty module too!
@@PineHollowAutoDiagnostics How's things going with the right to repair law over the pond Ivan ??. Hopefully they will outlaw this practice of making things unserviceable 😉🤞🤞. I bet there is a 1cent O Ring inside that unit that's split or worse case scenario a faulty solenoid valve, if we could open the darn thing it would probably be an easy fix. 😉😊
@@stephenjones9153 There is are technical reasons to not use bolts nor any similar easy to disassemble means. It is the same reason why many nickname the "fasteners" as "loseners". They tend to get lose on their own, when a slight error happens during assembly. Something you don't want on something that may kill all brakes at once. The way it is assembled makes it rather robust against errors not detectable at the end of line test. Plus there is not much reason to disassemble it anyway (maybe except investigating why it had failed). Most often the cause of one valve failing (corrosion, mess in the fluid,...) affects all the other the same way so makes them fail the same way soon too. So even when similar systems happen to be possible to disassemble, the good practice tells to replace all valves and the pump anyway. And with the whole system just being pressed/welded instead of bolted together, such new module gets cheaper than all the parts to replace separately if they had to be made "easy to replace". It just does not make financial sense to pay with each car for a "serviceable" unit, when it fails before the car gets scrspped in few percent cases.
@@annaplojharova1400 But that the whole point of mass production, make things as efficiently as possible to the lowest acceptable standard. I don't think end user safety is the primary factor.
@@MTLeopold Yes, but with still meeting certain safety requirements. The thing is, making it easy to disassemble would make it either below the minimum safety requirements (we know how Takata ended up with their cheaper airbags), or it would be so much more expensive than needing completely new unit when a valve fails in few percents of them over their lifetime (few percent chance times the $900 extra is less money than 100% of few 100's $ on each unit in a new cars when the few % of failures would cost "just", my guess, $300 for a ABS hydraulic rebuild kit). And that extra expense would go after the customers within the cost of every new car. Or that money would have to be saved by cutting corners elsewhere in the car.
We had one Volvo V70 with high concentration of water in brake fluid. Valve in the ABS block was stuck and there was zero braking in right rear corner. Brake pedal felt fine.
I have worked on a few cars where a stuck brake pad/caliper caused a similar condition to the one you have. It might be a good idea to double check the left rear brake caliper.
North Americans are notorious for NOT replacing their brake fluid on a regular basis and hence they spend more money on expensive components than other places in the world. Brake fluid is hydroscopic and that kills components if not replaced.
I had Mazda5 in past, once a week I will experience soft sinking pedal, car was stopping ok but it was not nice filling on the foot, my solution was go to gravely roads or parking lot speed up and bomb the brakes couple of times and will activate ABS and I got FIRM pedal, some other owners of mazda 3,5,6, or Ford Fusion with same problem will replace master cylinder and issue will persist, I think it's ABS module, one of valves stock open and oil will flow trough and create sinking pedal, they are super expensive new, you need go to dealer to reprogram or use and transfer old software part to new ABS body to avoid dealer visit, also if I had good scanner with ABS bleeding option, I would use that instead going on dirt road to play with ABS.
Nice diag,Ivan! That is definitely a rare problem. One that possibly had contaminated brake fluid as the cause. As far as why the right front wheel is still able to brake with adequate pressure: all I know is that in many modern systems, the abs unit doubles as a proportioning valve. It has to limit pressure applied to the rear wheels during braking or the rear brakes would lock up due the front wheel drive weight bias to the front and the vehicle’s inertia. So the hydraulic circuit has to be “separated” or divided by some means in order to control/limit force applied to the rear wheels. Perhaps out of pure ignorance, I would simply claim that the proportioning function of the abs unit has failed🙂 I’m curious though if at the moment the brake pedal goes hard, right before it fades, if adequate pressure IS actually applied to that left rear wheel, and then the fade is the fluid bleeding back into the right front portion of the system. You’d probably need a 2-man operation to test that theory! Lol!
Not so rare as there are companies that repair this fault, one such company is Injectronics in Australia. They have seen an increase in the issue in the last 2 years as the longer a vehicle sits undriven (like during lock downs) the more likely the valves stick.
Jeremy, Exactly right. Very nice Explanation. Definity is not seen often, But Brake fluid moisture contamination is most likely the culprit. Nice Job Ivan! Is there a check valve in that bleeder cup? I own one and have never used it for that bleeding procedure! I will now!
Fairly common problem actually on 1st and 2nd gen Mazda 3s. Bigger problem with those gen cars is the bleeder screws seizing in the rear calipers sooner than they should (steel bleeders in aluminum calipers, fronts also like to seize solid too) which makes regular brake fluid flushes sometimes impossible with caliper replacement.
Cool diag. I've ran into this on many cars and it's simply a caliper issue. Rear calipers on a lincoln mks stands out in my mind. Exact symptoms as far as what the pedal does here. Does the pedal pump up after a few quick stabs?
This video came as a glove. My 2004 Opel developed a similar symptom. I hope that is because a swelling brake line, because it started just after a suspension job. And the Bosch 5.3 ABS unit that it uses is impossible to find. Don’t remember if the Tech2 can command individual solenoids or just make a guided test to the solenoids.
The front brakes have a much larger piston in the caliper so a same amount of fluid pressure will have a much greater effect. That is also why when you panic break the rear of the car doesn't lock up and slide around you. With the brakes working properly you should not be able to spin any wheel with your foot or even a 6 foot breaker bar when clamped like that so the little movement you got was way too much out of the right front and that would also make the car pull hard to the left when braking so I wouldn't advise selling it like that either unless they tell the new owner exactly what is wrong with it and sell it as a broken vehicle.
During reasonably normal braking you wouldn't notice much difference except your pedal goes half down but improves some with a second pump. However in an emergency stop especially on gravel or on wet or icy pavement the right rear wheel will lock up leaving only the left front wheel doing anything close to normal braking. You will lose control of the vehicle. The abs system will do its best to try to compensate but with the brakes only working on two diagonal tires it has more than it can handle. The car needs a new master cylinder.
Impressive diag Ivan. Who would have thought that Brake/ABS faults would make for a good vid. Any chance of a "1 year on" vid on how the classic 2 wheeled Japanese stallion is performing?
Great analysis Ivan. I’m guessing the stiffness of the pedal half way down is a result of the accumulation of pressure from the other two functional wheels/lines causing back pressure through master cylinder? Just a wild guess.
I picked up an Autel scanner a few days ago. Oddly enough if doesn't give live misfire data on my ford focus. It does on my Toyota. The diagonal wheel wasn't completely locked up, as you could kinda move it with your foot. I think your notes said the out flow on the front wheel was closed shut, so it's possible it is braking some constantly. You could compare brake pad wear.
I'm having the same problem with a 2009 Mazda CX-9. Mom bought new, I drive now. I replace the Master Cyl 3 years ago and bled and bled and bled. Still had soft pedal. The booster just failed. I replaced the booster and the MC. Had all kinds of issues after bleeding...wheels locked. Brake lights wont turn off. I ended up disconnecting the ABS unit electrical cable. Mechanically...brakes are fine.
Ivan, will Thrush mufflers (red glass packs) pass PA safety inspection? I'm Emissions exempt (we do less than 1000 miles yearly). The original muffler shed its skin literally at the shop. Longggg story probably will do a vid on my channel when I replace system from CAT back on Monday LOL. Gotta get a new jack, my trolly dumped... Harbor freight time! I do my wrenching on a cobblestone street near Pittsburgh so I'm going with 8T bottle jacks, floor jacks are difficult ROFLMFAO!!
I believe I observed the R front wheel move when you were testing brake pressure. If the car was in park and the L front was locked the R wheel will only move a small amount.
Ivan.. Ivan... Ivan.. PLEASE PLEASE put safety boots on. You are in a garage where mechanical work is done, no matter what work, safety boots. Protects you from spillage and/or physical injury. Good video by the way...
I like those quick "outside the box" tests! What about running clean brake fluid through the ABS valves in the valve block to see if dirt and/ or debree come out. Of course if you don't hear the solenoid click, what about a wiring fault?
Just few minutes in, but right now I couldn't tell, so many things could be wrong. I would also point out that you don't want the rears locking before the front, the average driver would lose control if that happened (I saw that many time). In the mid-seventies, for some reason GM had their proportioning valve set up to lock the rears first in their sedans which cause multiple accidents I witnessed. With no knowledge at all, given those symptoms, it has to be the ABS pump/valve.
On ancient old timey cars (such as a Vauxhall back in the day, lol), that same pedal action would be indicative of the brake reservoir's (screw on) cap's vent being plugged solid with dirt, Isyn. lol
So I have a 2008 Mazda 3 Hatchback with only 67k miles which is amazing considering the car is 15 years old now. Thought it was in great shape given the age. Wrong. When I picked up the car the brake was going all the way to the floor! Super soft/spongy/squishy brakes that took forever to stop. Kinda scary! Took it in and had the rear brakes, rotors, and calipers replaced (front brakes were new). When the mechanic said the problem still wasn't fixed after all of that I was not happy. He checked the master cylinder and said it was new. They bled all the lines and confirmed nothing was leaking. So I figure its a problem with the ABS module. I read a few comments in different places talking about valves getting stuck and that may cause the spongy brakes. So you have to take your car out onto gravel road, speed up and hit the brakes hard to trigger the ABS. Do this about 5-10 times and it will get the valve unstuck. I did this last night and my brakes work so much better. It may not be a permanent fix but I am amazed at the difference! So try this before you drop 1000s on unnecessary crap. It may not work for you but worth a try to anyone with this problem.
i have a Mazda 3 from 2013, hatchback, with only 31k miles. It has the same issue right now. Official service concluded "its the ABS", without doing as much diagnostics as Ivan (they just exchange the brake fluid, everything else was fine, so that's their conclusion.). WHAT exactly is faulty in the ABS is none of their concern. The price of a new ABS they state as 2000€, and its not even on stock in Europe and they have no clue how long it would take to get it from Japan.... im taking it to a way more experienced service guy (unofficial) tomorrow, and let's see...
Are there individual wires to the ABS module to control each valve, or is the valve wiring all internal to the unit on a PCB? My point is, could it be a broken or shorted wire?
To answer the question on the front right wheel, you can’t just rely on that it’s building pressure. With the car being front wheel drive and the left tire locking up, I would test the car being off the ground and the car in Neutral otherwise the left tire is preventing the right from rotating due to the differential not being able rotate. I recommend retesting with the car in Neutral and then see if the front right still builds pressure. From the video to me it looked like it was freely rotating but stopped cause the slop in the diff/trans was taken up.
Great point Brittany! Yes that is definitely a variable. Interesting to note that the car didn't pull to the side during a test drive, so the front right wheel was receiving some pressure...
@@PineHollowAutoDiagnostics with the split system they are designed to minimize the amount of pull so that you can stop safely. but for it getting pressure im guessing that the blockage in the abs module is enough to keep the front right side from loosing all pressure.
It is certainly plausible that there was simply reduced brake force to the right front wheel. You *were* able to move it. The left front didn't budge at all.
When one of the inlet valves is stuck activated, it looks like it only allows flow out of that wheel’s brake line. That could explain why you are seeing one wheel in the diagonal being blocked, but the other one not. Just a thought.
I got an used ABS pump off of EBay and after installing, it had the ABS light CZME BACK ON, but with a diff set of codes. The mechanic said it didn’t need to be programmed because it came out of the same model car. The brakes work fine, but do you think the light is still on because he didn’t download and transfer program to replacement unit? Thanks!!
Maybe a valve that doesn't click is stuck in the activated position. If the inlet valve for the left rear is stuck in the activated position, it blocks fluid to the left rear wheel. If the outlet valve is in the closed position, pressure from the right front can't transfer to the left rear.
My 2003 Century did something like this, it was after I blew out and replaced a break line (and most of the brake system due everything being rust welded). At first I thought I did something, but the brakes worked fine, and abs came on fine, and then I just assumed that's how they work. That was 2 years ago.
You think with a scanner you would get some type of ABS code if one of the 4 wheels was not working because of it, what is the purpose of code if this issue would not set one.
Being a ford tech early 2006-2012ish fusion/Milan/ mkz style fords and 2012ish edges/ Lincoln mkx are very common for bad HCUs the cars have a recall for this to flush the fluid to dot 4. 19s54. Commonly after the recall the HCUs fail due to contaminated solids bec theres no way to totally flush all the old fluid out of it.
So, BP Gaming, if the flush is under recall and that causes the HCU to go bad, is HCU replacement covered by recall or warranty? Just curious (absolutely nothing against you, I've worked for a couple stealerships) and I know they'll do next to anything to not have to cover a repair.
It seemed to me that, at the start of your video when you were manually turning the tires with your foot, the right-front tire also turned...not as much as the left-rear tire but it did turn.
As someone else pointed out, car was in park. Being front wheel drive the transaxle pawl would have stopped the wheels from turning after a little movement. Hard to believe the car didn't skid on breaking but might have to get upto highway speed for that. Either way, it's broke, fix it.
Ivan, will you please do one extra check before you proceed, check the brake fluid quality, I had similar issue in my Mitsubishi lancer (long story short), the fluid was so degrading and caused similar issues. Check brake fluid quality If bad -> change the fluid completely including ABS BLEEDING.
I seem to recall some ABS units have a centering valve.. after working on brakes, if the brake light is ON, you depress and hold the pedal all the way to the floor, with engine running, and the valve is supposed to center itself. if the valve isnt centering, it could let one side pass fluid and not the other side.. wondering what the condition of the brake fluid looked like.,. if it was dark brown cruddy milkshake, it may have rusted a valve or jammed a valve.
and remember , people never change brake fluid until they fail.. I do a gradual fluid replacement.. I take a turkey baster and remove most of the fluid out of the reservoir, then top off with fresh fluid.. a month later, do the same thing, then once more a month later.. you end up with fairly clean fluid without having to bleed the entire system, and flush, then repeat. .
@@randy1ization You're doing a great job of keeping your master cylinder reservoir clean. The rest of the system is full of dirty, old, possibly water logged old brake fluid. Brake fluid is hygroscopic. It attracts and absorbs water. It also has a service life of 2-3 years, depending on operating conditions. That's why most manufacturers have been recommending periodic brake fluid flushes for approximately 40 years or more.
@@alantrimble2881 I would think that the fluid circulates thru the system and doesnt stay in the reservoir , if it did it would remain clean. and there would not be black gook on the inside walls of the reservoir . The reservoirs are very well sealed with the rubber top. so I doubt contamination and moisture is entering into it... does the fluid not circulate ? if not then I will change my brake fluid change procedure.
@@randy1ization brake fluid does not circulate like engine coolant. The pressure is applied on the fluid at the master cylinder and since a fluid is not compressible the pistons at the calipers move in response to the pressure. The fluid is fairly static or stationary.
I have a hyundai accent that has no ABS.. It's a front wheel drive car. When the car is jacked up and if you press the gas to let the wheels spin and then when I press the brake, the left front wheel will stop spinning while the right front wheel keeps spinning for an extra second or so. This seems to cause the car to shake when pressing the brakes while driving at high speed... What could be the problem here? Btw Brake pads look OK
We had a Ford Fusion come back four times for a dead half pedal after we did rear calipers. Never got to bottom of that one I think management sent him to a dealer.
A frozen caliper side pin would also cause a low brake pedal. If it was me i would start with the basic ,check all wheels make sure all the piston go in and all the side pins move freely. Check that all the pads are not stuck to the bracket as well.if all is good there i would bleed the hole system out making sure all wheels have good fluid pressure and flow. A bad hose could cause a wheel to still spin with the brakes applied.
@@alantrimble2881 the caliper binds and don't allow the piston to apply pressure evenly . Just in the same way if you have a drum brake system that way out of adjustments. Pedal travels frather
@@michaelpagliarini4785 No, that's not how a brake system works. If a caliper slide binds, the piston moves toward the rotor. It may retract a few thousandths of an inch when you release the pedal, but it pretty much stays in the same place it was when the pedal was applied. The same thing happens when the brake pads wear. Otherwise, the brake pedal travel would increase as the pads wear.
There maybe something wrong with the abs module but it is unlikely to be the problem. The first things to check would be bleed the brakes, then clamp of the flexy brake hoses one at a time and try the pedal to see if the pedal becomes firm. This will show which corner the problem lies. It is more likely caused by excessive piston travel due to frozen pads or guide pins.
All these people saying it's not the ABS module when you can clearly tell a solenoid is not working... Does appear however that the front right was locked by the transmission being in park and LF brake holding, not the RF brake?
@@PineHollowAutoDiagnostics 2:55 it appears that the wheel moved just enough to get locked by the transmission. You of course could feel it, not trying to say you're wrong at all, merely stating what it looks like on video. That theory would have lined up the mystery of the hydraulic diagram. But if you say the brake was holding, it was holding. I'm very curious if anyone will be able to answer your question about how RF brake was holding, I'm super curious myself. I enjoy your videos and learn from them. My method previous to this video was to block the output from the master cylinder and if it held pedal, bleed the abs and lines, verify no leaks, then condemn the ABS. Your technique will definitely be a huge time saver!
i've seen a few cars that had pedals that sank far down like it was a mushy brake pedal, but it was only because the brake pads were worn. i don't think the right front was locked, i believe you were at the max of its ability to spin with the other drive wheel being braked.
I agree with that,i heard a clunk when all the play went out of the diff. I think. but Ivan is probably right he usually is,And like Ivan said about most of us old mechanics i too said maybe the master cly seals leaking.I like the old style without ABS.but I'm old school,just one more thing to go wrong with a car,AND diagnosing WITHOUT A SCAN-TOOL,how would that be done,for the home enthusiast?My newest car is 1995 Honda,so don't have that issue yet.If i do my a NEW CAR you can bet I'll by a descent scanner,like Ivan showed the other day.BUT scanners are only as good as the operator,right IVAN? KNOWLEDGE IS POWER.
I'd start with the loose brake shoes, 1998 Toyota Camry with abs had same problem, pedal went to near floor with no abs light, tightened passenger rear and pedal was fine. Currently have air in one wheel that creates spongy pedal and abs light but brakes work well
@@robertoruiz7069 It's easy to just unhook they lines and bypass the ABS and just rought the lines directly, just like the old vehicles. I don't know if it's legal, but you can do it.
Does it not have a proportioning valve that be giving that front wheel more pressure thus holding that bias pressure back from bleeding out the rear circuit abs valve ...
I would check the left rear brake caliper. The piston might have been turned and pushed back in too far. Causing the caliper piston to not adjust to the brake pads.
RF "brake holding": You made quite a significant error in the diagnostic. You have the trans in P, so the diff cage is locked. The LF brake works, so the RF gets simply stuck via the diff, parking lock and the LF brake. You may see tye wheel was not really stuck completely, it moved a bit before it stuck. That little motion was the play in the drivetrain, with working brake it won't move even a bit, so that means the RF brake was released... The correct procedure would obviously be either having the car in N, or more careful evaluation of what happens - treat even the slightest movement as the brake not working. Then everything matches pretty well again...
If the ABS module is prohibitively too expensive to replace, you can delete it from braking system. You will lose ABS and active handling but you gain full braking power.
EXPLANATION why the front right brake is slightly braking..Actually its not. This is the backlash between the parking pin and the tooths it engages. Because the car is in Park the Differential case is locked by the parking pin. Also the left front brake is properly holding, this means the left side gear in the Differential is hold from moving thru the driveshaft. This means the two spider(pinion) gears cant move, and the left side gear also cant move(because left front brake holds okay) , which will also lock the opposite - the right side gear. If car was in Neutral - front right would spins also.
Mine was the same way. I turned the DSC button off, and the brake pedal went back to normal. Unfortunately, this is an "automatic feature," so you have to remember to turn it off each and every time you start the car. I wouldn't normally settle for something this janky, but I've seen way too many videos on this subject to look a gift horse in the mouth.
