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Discussion Starter #1 (Edited)
Any information or experiences from BB members about disassembling the brake Booster on an Alfa Spider? I am thiking of having the brake booster halfs chrome plated, but am somewhat put off by the idea of spliting the booster can and then getting it back together successfully after the plating is done. Any thoughts on this or past experiences from anyone? I have successfully split Jaguar boosters but they usually have a band clamp securing the 2 halfs. This indented containment set up on the Alfa booster looks intimidating. This project is not worth ruining a good booster over.

The hood latch bracket and spring are at the plating shop right now being chrome plated.

Robert Hill in Memphis, TN
 

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Have done it

Got exactly the same "Looking" booster on my 1974 Spider Junior. Split it in half and put back together with no issues. Only issue I came up against is there is a seal on the "back" half that seals against the rubber gland. This seal was cast onto the back half during manufacture. I replaced the seal with a removable seal type from a Alfa 33 (common in New Zealand). Yours may be different being a later car but if you split it and decided not to go any further reassembly is easy. Hope this helps. Mark
 

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No experience with the Spider booster, but I do know that the crimped area of the shells typically seal against the outer diameter of the rubber diaphragm. So if you distort those areas too much while prying the crimps open and then bending them back on reassembly, you might wind up with a vacuum leak. There are also springs inside that need to be compressed to bring the shells together. You'll need a way to keep the shells clamped together while you re-crimp them together. Please document your work if you go ahead with this and good luck!
 

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Since it's coming out anyway you can polish the aluminum pedal box and paint the booster gloss black. That's what I did and it looks pretty good.
 

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My '73 has a cad-plated booster from the factory. It's the only one I've seen. It needs to be replated or I might just paint it black.
 

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My worry would be that once you have the bits nicely chrome plated, re-crimping the dimples would cause the brittle plating to crack. I like Kcabpilot's approach of just painting the sucker.
 

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Discussion Starter #7 (Edited)
""My worry would be that once you have the bits nicely chrome plated, re-crimping the dimples would cause the brittle plating to crack""

I have had a nagging bad feeling about attempting this chrome plating job on the booster can, but I think Alfajay has just nailed it. I had never considered that re-assembling the joker might result in ruining the palting job. If I went to that much trouble and expense and then ended up with a hatchet job, I don't think I could stand it. Alfajay, I am going to take your advice and strip and paint the extra booster I bought off Mike R's totaled Quad. It has been previously and poorly repainted, but since it is off already I should be able to get a good result on striping and repainting it black before substituting it for my old rusty booster. Thanks for some really sound advice! I am actually relieved not to be getting into what may easily have become a quagmire.

I was already planning on sanding and polishing the booster/pedal cast aluminum mount as kcabpilot suggests. If I end up with as good a result as his engine compartment indicates, it will be good enough. I already have new complete hydraulics sittting on the shelf along with stainless steel braded flex hoses, and all this will go on the car at the same time as the replacement booster.


Robert
 

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""My worry would be that once you have the bits nicely chrome plated, re-crimping the dimples would cause the brittle plating to crack""

I have had a nagging bad feeling about attempting this chrome plating job on the booster can, but I think Alfajay has just nailed it. I had never considered that re-assembling the joker might result in ruining the palting job...
Instead of plating you could try what I did. After I had mine rebuilt, I stripped the booster to bear metal, polished it up until nice and shiny, then used a little red paint inside the script for accent, and then clear coated the whole thing. Not as bright as chrome plate or polished aluminum, a little more subdued and goes nicely with other polished bits. No worry about the chrome cracking or blueing. If the master cylinder leaks, clean it really well, a little bit of sanding to blend the edges of the paint, and hit it with some clear again. Looks great against the pedal box mount on the firewall too.
 

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to disassemble a brake booster surely you don't pry open those tabs (they will just get weaker and weaker and break off, and these things are overhauled by shops all the time!), but instead you somehow lock the bottom part of the servo in a vise and turn the top piece (well this is how it works on a TR6 Triumph and the boosters look pretty similar - to quote the TR6 people: "The servo canister has two half-shells that are joined by bringing the half-shells together and then twisting slightly so that the lip of the rear half-shell is locked under tabs on the front half-shell. The outer edge of the rubber diaphragm is locked between the two half-shells at this joint to both secure it as well as seal the half-shells. So, all that is needed is a way to grasp the two half shells and rotate them a few degrees.) The problem arises in trying to turn it to open it since the seal will be well and truly "sealed stuck!" between the 2 halves - but it should be do-able.
That way you can chrome the 2 halves, as putting it back requires no bending of tabs, but just a simple turn till it locks together again....no cracked chrome.
Hot rodders chrome these the whole time
 

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When my booster went bad about a month ago I looked for a replacement. Rebuild kits are available for cars up to '69 but not after so, although I never attempted disassembly, I assumed it wasn't possible or practical. It doesn't look to me that they are manufactured with disassembly and rebuild in mind. After all, this is the first time in my life that I have ever experienced failure of a brake booster - they just don't break down.
 

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Discussion Starter #11
My personal belief is that years of a leaking master cylinder into the booster, or replacing a leaking master cylinder and failing to suck out or otherwise remove the old leaked fluid in the booster; these are the reasons boosters go bad. Cannot prove it, just a gut feeling.

Robert
 

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Well, FWIW, I did have a leaky master many years ago and I did suck a lot of brake fluid out of that booster way back then. I probably should have taken it apart just to see if I could determine whether it was the diaphragm or control valve that failed but I'm at that age where I look around and see all of the junk I've been collecting and holding onto for no good reason and figured there's no point so I just tossed it.

It's funny but when it went bad I suddenly realized that I had no idea how the darn things even work, so I Goolgled it and read up on the subject. Pretty simple really but like I said, I've never had one go bad before. Honestly, I don't even KNOW anyone who has had one go bad. Except of course myself (as of now) :rolleyes:
 

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Mine is inoperable as well. At some point I'll replace the booster but right now I get by with a strong leg.
 

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to disassemble a brake booster surely you don't pry open those tabs (they will just get weaker and weaker and break off, and these things are overhauled by shops all the time!), but instead you somehow lock the bottom part of the servo in a vise and turn the top piece (well this is how it works on a TR6 Triumph and the boosters look pretty similar - to quote the TR6 people: "The servo canister has two half-shells that are joined by bringing the half-shells together and then twisting slightly so that the lip of the rear half-shell is locked under tabs on the front half-shell. The outer edge of the rubber diaphragm is locked between the two half-shells at this joint to both secure it as well as seal the half-shells. So, all that is needed is a way to grasp the two half shells and rotate them a few degrees.) The problem arises in trying to turn it to open it since the seal will be well and truly "sealed stuck!" between the 2 halves - but it should be do-able.
That way you can chrome the 2 halves, as putting it back requires no bending of tabs, but just a simple turn till it locks together again....no cracked chrome.
Hot rodders chrome these the whole time
spiderserie4: I have a 73 Spider with a bad diaphragm. I made special holding & turning tools so I could put it in my hydraulic press and twist it apart. Not as easy as you
described but I got it apart. But I can not find a source to buy a new diaphragm. If you know of a supplier would you share that supplier with me? Injector (aka Tom
Du Jardin)?
.
 
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