Brake failure

[denisgav]

Hello everyone. I have a 220k 1994 Corolla with I have come across a couple problems recently. It all started about a week ago when I decided to change my rear brake shoes. The old ones turned out to be all cracked and everything but were generally in pretty good shape in terms of wear. Anyways I put the new shoes in (my first brake job) and tightened up the e brake cable and went for a test drive. I walked away extremely satisfied, the e brake worked perfect which was my main reason for changing the shoes in the first place. Basically the whole thing worked perfectly until 2 days later. I was driving for about 8 miles when my brake pedal suddenly fell through to the floor (or pretty close) at first I even thought I hit the clutch pedal! anyways after pumping the pedal a few times my pedal feel returned about 70% and after another maybe 10 seconds braking power was lost again until I pumped the pedal. So lucky for me my destination was a 1/4 mile away so I parked and checked the fluid level; it was at the max mark, then I check the wheels/drums and they were REALLY hot. Also the driver’s side drum had a faint smell of brake fluid. Anyways about an hour later I went for a short drive and the brakes worked fine so an hour after that I drove the 8 miles home and about 1/8 of a mile from home same thing happened; brake pedal basically goes almost down to the floor until pumped. My thoughts were that the new shoes were constantly rubbing and the old fluid overheated and caused failure so I flushed the system and put new fluid in and adjusted the shoes "in" with the click adjuster bolt. Oh and I had a really hard time getting the drums of to begin with. That and I loosened the e brake cable just in case. So the next morning I drive about 5 miles without using the brakes pulled over to check that the drums were not heating up anymore (they weren’t) so I thought I had fixed it. Well 3 days later (last night) I was experiencing the rear brake stickiness again. Basically when I was just moving from a stop where I had used the e brake to secure the car, I could literally feel that the rear brakes were stopping the car pretty aggressively and sure enough after a few more miles my brake pedal fell through so I poured water on the drums and they started to let off lots of steam, even after like 10 bottles! So I limped to my friends house at 12:00 AM and jacked my car for a look. Again the drums really didn't want to come off and once we did get them off my friends dad inspected them and could find anything wrong with my installation. The conclusion that we came to was that the auto adjustor for the shoes makes the shoes too tight and they rub. So I’m thinking maybe this is cause for the fluid to overheat and boil, causing the pedal to fall through. Any ideas? The pedal fell has gotten much worse since I bled the system 3 days ago so that may be an indicator. Did a test this morning for 5 miles and the drums were just below lukewarm… Any help would be greatly appreciated.

[maxwedge]

Tough to help on this from our desks, but the brake adjustment should just let the drum spin freely, too tight and you will lock up the shoes and all gets real hot. make sure the wheel cylinders aren't rusted up internally and not releasing the brakes.

[vgames33]

You are correct, the sticking brakes are overheating the fluid and causing the brakes to fail. I've had it happen before. Scary stuff.

Are you sure your brake cables are releasing all the way? Try just leaving the car in gear with no e-brake for a few days and see if you have any troubles. The adjusters can't really over tighten themselves. As long as the shoes are installed correctly, the cables or a stuck wheel cylinder are the only options I can think of.

[Black Lotus]

Originally Posted by maxwedge

Tough to help on this from our desks, but the brake adjustment should just let the drum spin freely, too tight and you will lock up the shoes and all gets real hot. make sure the wheel cylinders aren't rusted up internally and not releasing the brakes.

This.
+110
Rebuild or replace the wheel cylinders.
And since you probably cooked the return springs, replace them too.
Review the condition of your "new" shoes.
Review the condition of your drums again.

[Blt2Lst]

If the brake pedal goes to the floor and there are no external leaks, your master cylinder is probably bad. I doubt that you boiled the fluid but flushing with new brake fluid should be done when replacing the brake pads and shoes.
Also, as mentioned, make sure the rear wheel cylinders are not frozen. You should probably replace the wheel cylinders anyway for good measure.
If your rear brakes were adjusted to tight, you would smell the shoes burning after a while.