No funky background music, no constant talking, just pure engineering, you dont need much else do you, just the right amount of narration to explain things then let the viewer enjoy, brilliant episode again 👍
This is the most enjoyable channel i've ever seen. The calmness, precision and good tips relax me like no other. Amazing work, keep cool ! best regards from Hungary :)
One year on from this episode release it’s now my turn to overhaul my rear booster. What an episode and so thankful that you created this one. Top job Jethro
You’re either born engineer or a born producer, I’m not sure which, but your videos are always educational, soothing and make me want to restore cars to the end of my days. 👍
@@JethroBronner Whilst watching this video, part of my brain was occupied thinking how fear can stem from ignorance. You have explained this repair wonderfully and it is always such a pleasure to view your work. I am sure that many of your viewers will feel the same as I. Brake boosters demystified in one easy lesson! Thanks Jethro, you are a Star mate!
Jethro that was a master class on rebuilding and restoring a brake booster. I doubt I could keep all the parts in order, but I'm glad that you can! Always a pleasure to stop by and see what you are up to!
That's why we should have explosion drawings for these multi-part devices, best with old stock numbers pointing at each part, too, to be able gooogling numbers instead of pics ......
Hello, I have a Hillman Hunter 77 with this brake system and with this video I just understood how the remote brake works. Thank you very much and greetings from Perú
Brake fluid being drawn into an engine (in small quantities) isn't a horrible thing. Many, many moons ago, my high school physics teacher owned a car repair shop. I was having trouble with carbon build-up on the valves, so he showed me how to mix up a 50/50 mixture of brake fluid and auto transmission fluid and poured down the carbs- it really cleaned up the cylinders!
Thanks so much for making this video. I’ve just watched it for a second time and used it as a guide while rebuilding both the boosters on my ‘73 Super. One of the little air valves was really stuck but I read online that if you blanked off the end of the cylinder you could pump it full of grease to push the piston out. It worked a treat!
Only perfection is good enough for Jethro, another piece of art! Good luck with your business, and remember we all watch the other cartubers too, so a little less perfection is good enough for is 2. Not that i don't appreciate your hard work, but you gotta watch yourself sometimes. Best of luck
I've always looked at brake boosters as a monolithic unserviceable lump, and in some cars they are. This was quite educational, I've never seen one with a removeable band.
Even the ones with bent tin to keep everything together are repairable/rebuildable. Learnt that in Middle East where my T1N 212 Sprinter had a total booster failure: the fixer got it bent open, cut a new diaphragm out of plain rubber and put it back together. I still drive with it confidently 10 years after, even with a low km parts-car spare in the cellar meanwhile. Never touch a working system, and repair the non-working ones properly once need be. I gotta learn to metal-plate like Jethro does it - these Mercedes Boosters are black matte on bare steel and turn into crumbly brownish once You spill a first drop of brake fluid on those.
@@manfredschmalbach9023 We've all had to do emergency repairs, and that sounds like the guy knew what he was doing. My best effort was fixing a broken heater hose stub by jamming a cork in it. I managed to get to a tiny town, asked for a cork at the local general store and borrowed a knife to pare it into shape. It was still there when I sold the car - a Ford ZD Fairlane - to my cousin two years later.
@@shedtime_au Have a friend with a heavily changed, even more used Yamaha 650 XS; she's third owner and the thing meanwhile has unbelievable 470 k km - she got it with 50 tkm in its fourth year 1979 from the second owner, changed it to her liking from ape-hanger to step-seat to better brakes to whatever else plus a Leopard paint she did herself (artsy painter, airbrush artist and hyperrealism-airbrusher beneath 12 other artsy fartsy skillz ...) and has used it ever since - wasn't even unregistered for a winter in 43 years. We were on a tour somewhere in Syria back in the days while it still was an adventure and not yet idiocy when her rev meter shaft-inlet (engine side) broke off - there's oil behind it, and it started spilling. She stopped it with her thumb, burnt herself good, grabbed a couple pine branch stumps in a hurry, the only thing resembling a cork or filler piece within her reach with the thumb on the leak, tried some of 'em and put the one in that fitted best. We cut the excess with a swiss knife's saw after it swelled absolutely tight. That was 1993 or so ... since then, the engine was opened once and bigger pistons with new rings were put in after honing, and some minor other stuff, the deleted starter motor was put in again for her sixtieth birthday and shit like that - the pine bung still is in there, she says she feels her engine and does not need a rev counter, she had in the bum .... The emergency compromise usually is the longest lasting solution.
Nicely done Jethro. At least its serviceable, most brake boosters are a sealed unserviceable unit and I would imagine that a replacement unit for this car would be unobtanium.
9:25 - I had to re-watch the explanation of how a vacuum booster works - not because it wasn't clear, but because I was distracted by wondering "Is that a Montblanc 145 in burgundy?"...
If only things still were made to be this serviceable. I had never given much though before on how a booster really works, but I think I understand it now. Quite interesting and well put together!
Jethro.... good to see you today.. this booster tutorial was excellent. I learned a few thing today... Not sure the Alfa hand book went to that extent on the subject....very nice..
@@JethroBronner These boosters were after-market parts fitted by dealers, right? So, Alfa wasn't even supposed to take these into their manuals I reckon. I had a couple Bertones back in the days (LHD though, obviously, as a Bavarian😁) and all came from Italy without boosters. Otherwise I found Alfa manuals pretty usable compared to Fiat or Peugeot manuals. Cheers!
Just watched a '67 Duetto Spider auctioned off online. It went for AU56,000 which, considering it was in fairly average condition, was a bit of an eye-opener. Oh, and you've inspired this old Alfa fanatic to re-enter the fray. Later this week I'll be taking delivery of a 2003 147 Ti 5-speed. It's not as cool as a Duetto but I'm a pensioner, so have to work with what I can afford. It has 88,600km on the clock and needs a crank sensor, an alternator, a cambelt set (7 years!) and some serious clearcoat correction. But at AU$2,200 I just couldn't pass it up.
fantastic episode and like others comments i love the fact you dont have rave music playing all the way through. its so relaxing watching you and i love that you can hear your spanners clanking as you work .. awesome cant wait for the next .. respect from the uk
Just got around to watching this one. It appears to be what we in America call a "hydrovac" booster, actuated by hydraulic pressure instead of just a pushrod from the pedal. There is one on my 1962 Ford F-600 truck project! I sent mine out to be restored. it was worth $400 to save me time hunting for parts! I made a video on the history and basic operation of the unit over on my other channel Duluth Junction Workshop. Over here they were most common on medium duty commercial trucks as well as luxury cars, so it's very interesting to see the same setup on a sports car! I have to imagine they had to use a hydrovac due to space limitations. Cheers!
Just rewatched this as I reassembled the first of my two boosters. So useful to double check the order and orientation of all of the parts. Such an informative video. Thanks so much Jethro!
Thank you very much for your video, I've been waiting for it for a long time. It's the only video on the internet that explains how to reconstruct a bonaldi, fantastic!
Perfect timing Jethro, I have just stripped both of the boosters for my 1973 2000 GTV and am about to clean and reassemble them. Thanks for the video! I have the rebuild kits from Classic Alfa - when I bought those in 2019 they were also available from Highwood and Alfastop. They include the diaphragm, seals, gaskets, bolt lock plates and the 90 deg hose. 15+ years ago I had both sleeved in stainless but one diaphragm had now split and both boosters were leaking slightly into the vacuum chamber. There was quite a lot of crystalized brake fluid in the air valve. I have also just rebuilt the double circuit master cylinder, honed with a new set of seals. My fingers will be well crossed when I put it all back together again :) Early in my ownership of the car I had trouble with the rear brakes being slow to release, which turned out to be the small 90 degree rubber hose collapsing under vacuum. Took a while to find!
@@JethroBronner yep, bleeding can be a hassle with this version of the system. I have found that it helps to do a final bleed with the engine running so that the boosters are operating. I also added "speedbleeder" non-return nipples to the calipers, which made it a lot easier with one person. I will be interested to seeing how the bleed process goes with everything I'm replacing now...
@@markbattley8515 I have a 1977 UK RHD 2000 Spider, with all the joys of dual circuit brakes including twin Bonaldi brake servos. I pressure bleed through the brake reservoir cap but limit the pressure to around 12 psi which works for me. A word of warning if you use this method the flexible feed pipes from the bottom of the reservoir to the rigid brake pipes must be secured with good quality stainless steel hose clips- a lesson I learnt nearly 34 years ago now!
Excellent video, highest quality technical content and taking the angst-loaden mystery out of the brake-black-box. I really enjoy Your calm, music-, fake-suspension- and drama-free tech vids very much. I gotta learn how to metal-plate like You do it - that quality surface is way over any three layer paint "restoration" I ever tried with the outsides of crumbly-brownish booster housings. Thanks for sharing!
Fantastic work as always! Reassembly of the main unit rubber seal looked like a tedious task with a spring constantly fighting against you and a a shaft to line up...and a clamp to try slip on 😬
Clear and professional work as usual, I really enjoyed watching your video, useful tips and extreme precision in the cleaning and reassembling parts. I will wait for the next episode to learn something new. Thanks for your videos.
@23:57 - It was not mention but I feel I should state it here for everyone's benefit. There is a difference between a vacuum hose and a regular PCV hose. A vacuum hose is designed and reinforced in such a manner that the hose stays rigid and does not collapse under a vacuum. Although, the performance of the PCV hose might be satisfactory now. You may want to reconsider your choice for long term reliability and safety. Think about the condition and environment the hose will have to endure. The prolong exposure of high temperature will make the hose soft and supple and under the right circumstances the hose may collapse, leading to unsafe brake operation.
Alfas are the only cars I've ever heard of to have problems with vacuum brake boosters, at least as catastrophic as sucking brake fluid into cylinders :D
@@JethroBronner most old ones i’ve seen had them separate. 1960’ fiat 124 had a brake master cylinder bolt on to the booster. With it being a self contained unit operated by vaccum that just increases force on the pushrod
@@MrDoroh The Fiat 124 Coupe used a different brand of booster called Beditalia which I assume was made by Bendix in Italy. As you say ,the booster was attached to the end of the master cylinder. The later 105 Alfas from 1970 onwards had the same system as the Fiat 124, because by then Alfa had ditched the floor mounted pedals and mounted the pedals from the top . Right hand drive 105 cars kept the floor mounted pedals, so it was not possible to mount the booster at the end of the master cylinder.
@@EliteRock Yes it was hilarious to see the look of bafflement of the not so experienced mechanics, but the good mechanics always checked the vacuum line from the cylinder head to the brake booster, brake fluid there meant the engine was burning brake fluid, hence the white smoke
Jethro .. that’s a perfect rendition of how it’s done.. well executed.! The best bit was the leopard scarf rag.. too good to use , I would have been wearing it hehe.. Love to see your plating process...
@@JethroBronner good thing they are cheap. But yeah, it's crazy like service manuals used to show how to set up ignition timing and replace crankshaft bearings and now it's all "please go to authorised service".
During my college days in the mid 1970’s I bought a used 1969 Duetto Spyder. Correct me if I am wrong but I believe it had 2 Bonaldi boosters. Both leaked, constant spongy pedal and no one could repair it. Ended up removing the boosters and the pedal was finally firm but needed muscular legs to stop. Very dangerous. ATE calipers all around. Too bad I didn’t have access to your knowledge. The zinc plating looks very good, should have given it a dichromate dip for corrosion protection.
Yes the later 1750/2000 cars had duel circuit brakes, and had duel boosters. I'm very new to doing electroplating, so I'll look into that for my next batch, thank you!
you could probably manufacture a somewhat decent filter from an air silencer for pneumatic cylinders, by the lloks of it a 1/4'' cylinder silencer would do
On top of all right comments: did everyone notice the good taste "touch" of using a fontain pen to mark the lines of all those small parts, certainly a "Montblanc"? Justy amazing how Jethro is able to turns engineering into art!
My '67 Duetto did not have the booster. The big problem I ran into is the calipers were aluminum with chrome plated piston bores, and could not be just simply re-built if corroded. Once I got good calipers, the brakes were very good.
@@JethroBronner Renault used to use alloy calipers - I was surprised to find them on the front of a 1976 12 (not a Gordini or anything like that) I once owned. Under-rated/under-appreciated cars BTW.
Hi Jethro, I find your movies both entertaining and informative, thank you. However there is one area that I can't find anywhere and that is a repair of a 116 rear caliper. I know you specialise in 105's however can you give this a thought as no one else seems to want to cover this topic. Regards. Jim
Great video, thank you, and great channel too!. I finally fixed an old "juddery" brake problem on a 1966 GTV by rebuilding the servo/booster this year. But...like you, I had a broken red plastic spring perch, so had to re-assemble with the remnants... Could you let me know if/where you managed to buy that white one - thanks!
The white one came from my spares, I have a few boosters in parts that I keep around for this sort of thing. Whenever I see people selling Alfa parts I try buy old boosters.
Hello Jethro, really nice job on your Duetto. Your videos are so helpful for my restoration. As i watched this video I mentioned that on mine air valve the small spring is missing😢... obviously someone disabled in the past and lost this spring 😢. Could you give me some information of this particular spring? Greetings from Austria. Fabio
Hi Jethro! I join the complements for the excellent work you did in this video! I have a technical question for you, if you're so kind to help me. Is the spring you put on at 20:35 the one from the previous brake booster? I saw that the spring is not included in the repair kit (neither yours nor mine). Since I lost the old one, could you by any chance tell me the measurements of the spring you have so that I could get it somehow? Thank you very much!
As always simply fantastic. We all love your work. I don't have a deep stash of parts to pull spares from. What sources for booster parts do you know of. Is there a Bondi specialist supplier of components you know of or is there a kit from Classic Alfa or another supplier/ Thanks as always
For new service parts Classic Alfa carries what you'll usually need, and new boosters if you really can't repair an old one, I've linked their parts in the description of the video.
Hey Jethro you say very simple 🤣 but where did you find the explanation about how this booster works ? so good video again ... for a little bit more i would think i could do it myself 🤣🤣🤣
When I started rebuilding these I just took one apart to see how it worked, It's pretty self explanatory if you can follow the path of air and brake fluid in your head.
Great video with a question?? My US 1750 Berlina has two boosters so with that I would like to delete one of them 👍👌 any thoughts/suggestions on what needs to be done to accomplish this. TIA
