A few weeks ago, a wheel cylinder on the rear blew the seal and fluid started leaking out fast. I replaced the cylinder, bled the line and all was fine.

Saturday, the pedal suddenly started to feel strange while I was driving home and by the time I got home I had to pump the brakes to stop. I checked the fluid level in the MC and it was fine. I had heard that the MC sometimes fails after a brake leak that causes the pedal to drop to the floor because the piston moves to a spot in the bore where it doesn't normally go (where corrosion builds up)and damages the piston seal. Also, my symptoms of no fluid loss or leaks but the pedal goes to floor and can be "pumped up" to get a brief period of braking also pointed to a bad MC.

There were no places locally that had a new MC assembly (MC + reservoir) in stock. There was only a reman MC without reservoir. I bought that and replaced it yesterday. I bled the brakes at all four corners. After I took it out for a test drive, same thing, the pedal can be pushed to the floor and pumped up briefly. I re-bled all the wheels again, there was no additional air that came out.

The only conclusion I can come to is that the reman MC is bad. I have had reman parts be bad out of the box before. Rare, but it has happened.

What do you think? Am I missing something?

Steve

 

Did you adjust the rear brakes after installing the new shoes?

 

New shoes were installed 2 months ago on both rear wheels and they were adjusted. I had to replace the new shoes on the wheel which blew the seal on the cylinder because they were soaked with brake fluid. The brakes worked fine after the wheel cylinder fix and new shoes so I doubt that's the problem, but I'll check the adjustment again just in case.

Steve

 

You should always replace hydraulics and brakes in pairs.

What about the booster? With engine off, pump up and hold the pedal, start the engine, the pedal should go down near the floor.

Did you inspect and re attach the vacuum hose and check valve?

 

Yes check the adjustment. When my mechanic replaced my cylinders and whatnot he didnt tighten the shoes up and my pedal went right to the floor. After bringing it back to have him readjust he said they were "tighter than he liked but he adjusted them" and low and behold my pedal was back to normal. Additionally, I tightened them up even more at home and now pedal is much firmer and better. How many clicks does it take until your parking brake is engaged? Should be 4 clicks or around there. If it is higher your shoes are sitting way too far from the drum

 

Well, last night I fixed it. It did turn out to be the rear brakes, but not like I expected.

I had a set of Wagner shoes I bought 2 years ago and never installed. In January I had a local shop install them during the state inspection. Everything worked fine. About 10 days ago I was driving out of the work parking lot and when I hit the brakes there was a loud bang and the pedal sank down. I left the car at work and got a ride home. the next day I took the drum off and fluid had leaked out of the wheel cylinder. The front shoe had the lining come off completely from the backer. This allowed the piston to come out of the bore enough to expose part of the seal and the seal blew. This was the first time I had seen the lining come off the backer, but I chalked it up to a fluke. I bought a set of shoes at NAPA and a new wheel cylinder and fixed it. Everything was fine until Saturday night when the brakes started feeling funny and by the time I got home I had to pump the brakes at every stop. Classic symptoms of a sudden MC failure (which I had many times on other cars). So I replaced the MC and it didn't help.

After the suggestions on the forum, I looked at the rear wheel where the shoe lining had come off and all was ok, including the adjustment.

However, when I removed the other drum, I saw that BOTH shoes had the lining come off the backer.

I replaced the two shoes with new ones from the NAPA set I had bought 10 days ago. After adjusting the shoes, the brakes work fine now.

I find it highly unusual that 3 of the 4 brake shoes had the lining come off after being installed only 2 months. Maybe there was a defect in the bonding process.

Anyways, all's well that ends well.

Thanks for the help.

Steve

 

Yup, As I learned from the forum, the rear drum brakes have a GREAT impact on pedal feel. More than you would imagine. Thats just the way it is!

 

Great it's fixed, and a reminder, replace brakes in axle sets! Do both sides at the same time!
Any chance you still have the receipt for the Wagner shoes?

 

I bought the shoes from Rock Auto, so I may be able to bring up the old order online. I'll probably just "eat the loss" for now. I might Email Wagner and describe what happened to see what they say.

Steve

 

That Chinese brake shoe glue must be some awful stuff.