1984 Trans AM - rear brake wheel cylinder
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From: Windsor, On
Car: 1984 Trans AM
Engine: 305
Transmission: 700-4r
Axle/Gears: 3.23
1984 Trans AM - rear brake wheel cylinder
i am replacing the brake shoes & rebuilding leaking wheel cylinder.
The rebuild kit Dorman 35886 is supposed to be the correct one. Only the caps that attach to spring unit fit.
Sometime, along the way, the wheel cylinder design were changed by GM to a new style with "pistons".
The wheel cylinders on my 1972 Buick GS (sold) had units that where loose & removable from the cylinder & u had to reinsert & then connect to the brake shoe.
Anyone familiar with the change?
UPDATE
I reordered the same 35886 & will double check if I made a error. I know the spring included will not work properly but to that is ok.
Will let u know next wee after parts arrive.
The rebuild kit Dorman 35886 is supposed to be the correct one. Only the caps that attach to spring unit fit.
Sometime, along the way, the wheel cylinder design were changed by GM to a new style with "pistons".
The wheel cylinders on my 1972 Buick GS (sold) had units that where loose & removable from the cylinder & u had to reinsert & then connect to the brake shoe.
Anyone familiar with the change?
UPDATE
I reordered the same 35886 & will double check if I made a error. I know the spring included will not work properly but to that is ok.
Will let u know next wee after parts arrive.
Last edited by 72buickgs; Apr 10, 2026 at 08:25 PM.
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Car: '83 Firebird (T/A Clone)
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Re: 1984 Trans AM - rear brake wheel cylinder
That's a mystery to me. I replaced the wheel cylinders in mine (the rear-end is a '84) and just bought them from AutoZone. Everything fit like it was supposed to...
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Re: 1984 Trans AM - rear brake wheel cylinder
Never heard of "wheel cylinder design were changed by GM". Which is of course NOT to say that it didn't happen; only, I've never seen or heard of any such thing. For one thing, GM is LONG out of the business of redesigning brakes for 1984 vehicles.
Might well be that the replacement mfrs & rebuilders have an "updated" design though. I haven't seen anything like that butt I haven't worked on any drum brakes lately either.
All the ones I've ever seen have the usual pistons inside the WC and the little link pieces that stick in from the outside that push on the shoes. Sounds like maybe the "kit" you have, has those 2 pieces combined into one? If so, then as long as it's reasonably close to the same length as the original setup, can't see how it would really make all that much difference.
Might well be that the replacement mfrs & rebuilders have an "updated" design though. I haven't seen anything like that butt I haven't worked on any drum brakes lately either.
All the ones I've ever seen have the usual pistons inside the WC and the little link pieces that stick in from the outside that push on the shoes. Sounds like maybe the "kit" you have, has those 2 pieces combined into one? If so, then as long as it's reasonably close to the same length as the original setup, can't see how it would really make all that much difference.
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