help with rear pistons

[gtkid2]

so I tore everything apart... any tips on removing the pistons? I sprayed PB blaster on the brake line, but it won't come loose...don't want to strip it! also when I pulled the pistons/boots away from the body, it was and still is completely filled with this brown-ish powder... what is it? any tips appreciated... thanks!

[First opel 1981]

Originally Posted by gtkid2 so I tore everything apart... any tips on removing the pistons? I sprayed PB blaster on the brake line, but it won't come loose...don't want to strip it! also when I pulled the pistons/boots away from the body, it was and still is completely filled with this brown-ish powder... what is it? any tips appreciated... thanks!

I just pulled mine apart last weekend. Its pretty easy if you don't have a lot of attachment to the internals of the wheel cylinder. It's a pretty simple unit, really.
You have a metal piece in each end. Behind those are rubber cups and inbetween the rubber cups is a spring.
I just tapped them all from one side through to the other. Nothing was damaged but I am replacing the cups anyhow since they are cheap (get 5/8).

The brown powder is brake fluid infused oxidation. There is a good chance that your wheel cylinders are toast if you have a lot of that powder.
New wheel cylinders are less than $30 at the parts store I go to (knechts).

[hrcollinsjr]

Originally Posted by gtkid2 so I tore everything apart... any tips on removing the pistons? I sprayed PB blaster on the brake line, but it won't come loose...don't want to strip it! also when I pulled the pistons/boots away from the body, it was and still is completely filled with this brown-ish powder... what is it? any tips appreciated... thanks!

You really need a line or flare nut wrench, same thing different name, to remove the brake line fittings. Toss the wheel cylinders and get new. As a last resort you can use pliers of some type on the brake line fittings. Remember the fittings have a hole in the middle and over clamping with pliers can ruin the fitting for reuse.

Flare-nut wrench, tube wrench or line wrench: used for gripping the nuts on the ends of tubes. It is similar to a box-end wrench but, instead of encircling the nut completely, it has a narrow opening just wide enough to allow the wrench to fit over the tube. This allows for maximum contact on plumbing nuts, which are typically softer metals and therefore more prone to damage from open-ended wrenches.

Harold

[gtkid2]

I'm going to check and see if any local shops have one of those wrenches. and that stinks about the pistons, but I guess buying new adds some security. Thanks!

[guyopel]

Yes , Brake parts and W/Cyls. are cheaper than Sheet metal any day.

[First opel 1981]

If you ever want to replace the wheel cylinder cups (before you have to replace a wheel cylinder) the Raybestos part number for 5/8 cups is WCC2530
It is a box of 10 so you will have a few to spare.

[kwilford]

Rebuilding rear wheel cylinders is fairly practical, UNLESS the pistons are corroded as they are hard to come by (they were at one time part of a standard rebuild kit, but not so much anymore), or if the cylinders themselves are pitted more than just slightly. From what is described above, those wheel cylinders are toast.
JM2CW

[First opel 1981]

Originally Posted by kwilford Rebuilding rear wheel cylinders is fairly practical, UNLESS the pistons are corroded as they are hard to come by (they were at one time part of a standard rebuild kit, but not so much anymore), or if the cylinders themselves are pitted more than just slightly. From what is described above, those wheel cylinders are toast. JM2CW

Correct, you are.
Replacing the cups is best done as a preventive measure and not a corrective one, unless your pistons and wheel cylinder bore are in excellent shape.

Maybe someday someone will take a lathe and cut a bunch of wheel cylinder pistons someday. Of course as long as the wheel cylinders are still being sold new, there isn't really a need.

[gtkid2]

well I ordered the pistons (surprisingly enough my local auto story has them!) and I'm still trying to find a line wrench...

[kwilford]

Originally Posted by gtkid2 well I ordered the pistons (surprisingly enough my local auto story has them!) and I'm still trying to find a line wrench...

ANY decent tool store that carries wrenches should have a flare-nut wrench, either individually or as a set. You need a 10 mm version IIRC.

[sawdust]

Originally Posted by kwilford ANY decent tool store that carries wrenches should have a flare-nut wrench, either individually or as a set. You need a 10 mm version IIRC.

Just saw a set of three (3) at menards for about $15. Didnot look to see if they were metric

[gtkid2]

I bought a set for $12 at advance auto... new pistons make me wonder why i considered rebuilding the old ones

rear brakes almost done now... oh and did I mention line wrenches are my new best friend?