leaking brake

[carpenter_jai]

I had my rear brake assembly exposed to the elements for a while while my 95 was up on blocks to get the electrical sorted out. (I took the hub off to put it on my other car.) Now that most of it is fixed, I decided to test drive it. Turns out that I have a bad brake fluid leak. The brakes were depressed many times while the hub was off. I had to re-centre the shoes to get the hub back on, and that is when I noticed that it is leaking fluid from the wheel cylinder.

Does anyone know if I can readily exchange the cylinder alone to fix this kind of problem? Anyone know what it does and how it works? Once I fix this thing, I can drive my favourite car again! I'm pretty excited!

Jai

[91Caprice9c1]

Originally Posted by carpenter_jai

The brakes were depressed many times while the hub was off. I had to re-centre the shoes to get the hub back on, and that is when I noticed that it is leaking fluid from the wheel cylinder.

Does anyone know if I can readily exchange the cylinder alone to fix this kind of problem? Anyone know what it does and how it works? Once I fix this thing, I can drive my favourite car again! I'm pretty excited!

Jai

Jai,

The wheel cylinder pushes the shoes against the drum via hydraulic pressure developed in the master cylinder. The pistons inside your wheel cylinder were hyper extended. Wheel cylinders are spring loaded, and have more than twice the pieces of a brake caliper inside, albeit they are still very simple devices. They consist of the body, bleeder, a spring, two pistons, piston seals and outter dust boots. You can order new wheel cylinders, this is the safest bet, as I've had to replace about a dozen of them on my fleet.

There is no doubt that a good bit of air found its way into the system, and because our cars are diagnally split systems, you will have to at the very least bleed the offending corner and it's diagnal counter-part, but preferably bleed the whole system to err on the side of caution. Start at the front driver side wheel and work away from the master cylinder.

It is not required to replace wheel cylinders in pairs as it is when replacing pads, rotors, shoes and drums, but it is a good idea to pull the drum off the other side and inspect for leaks there also. Peel back the dust boots on both sides of the cylinder - if moisture is there, or if fluid comes pouring out, you know what to do - otherwise just seat the dust boot back into place.

-MechanicMatt

[carpenter_jai]

Sure enough, the wheel cylinder had a broken seal inside and just as Matt suggested, it was from hyper extending the brakes. I got new brake shoes, cylinders and fluid. All in all, to clean the drums and brake parts, install new parts, and bleed the lines only took a short while. I wish I had the fore sight to buy new brake lines as the old ones are pretty rusty.

Thanks for the help!

Jai