All 4 wheel cylinders leaking

[kevin_tbird]

All four of my wheel cylinders are leaking. I have completely new lines and hoses and a rebuilt master cylinder. Two of the wheel cylinders were rebuilt and two are new. The only twist is that I rebuilt the system about 6 or 7 years ago and then got distracted and am only now getting around to finishing the job. Should I expect them all to seal up over the next day or so or will I need to pull and refurbish all four wheel cylinders?

[jopizz]

Once they leak they are usually toast. You may be able to rebuild them but if they were sitting for that long it's easier just to replace them.

[jax]

Wheel Cylinders

X2.

It's much less time consuming to replace than it is to rebuild. I rebuilt the cylinders on many old pickups and cars. Some where along the way, I found it easier, and sometimes more cost effective to just replace them.

[simplyconnected]

It's easy to tell you to spend $40+. But I'm cheap as ****, and I love this kind of work.

Leave your lines and cylinders in place, and pull the guts out of each cylinder. Feel inside the bores for a ridge of rubber from the cups. This is normally why they leak.

There may be more to this story. If you mixed DOT-3 with DOT-5 brake fluids, the cups will deteriorate (and so will your brake switch). If true, buy rebuild kits or new cylinders and flush the system with alcohol.

Inspect the rubber cups in your hand. Pull on them and search for cracks or chips. If the cylinders are not rusty and the cups look good, you only need to sand the cylinder bores, using your finger (very wet with brake fluid). I use 250-grit wet/dry paper in strips. You don't need much. Just work it back and forth until the inside feels smooth. There is no need to stone with a hone. Those cups have a LOT of room inside the bores. They will hold like new when you're done.

Of course, if the inside of a cylinder is pitted with rust voids, replace it. I have had brand new cylinders leak because the cups weren't seated properly. A quick look inside and re-assemble wet, usually fixes them.

I once found a rear cylinder (oem) on my '64 Tempest that had no hydraulic hole. After drilling through the casting, the cylinder worked just fine. - Dave