I've done a lot of brake jobs in my day, but my truck is still making life much harder than anything I have ever encountered.

After all the brake problems from my last post, things got worse. My left front completely locked up. I ended up replacing both calipers. I've bled almost 32oz through the system starting w/ the right front and then left and my pedal is still WAY too soft. I've gone as many as 5 brake pumping/bleeding cycles w/ no air on each side and still no luck.

If by some strange way I got air in the master cylinder, is there a way to bleed it while it is still in the truck, or does it have to be removed?

 

To get all the air out,you are going to have to bleed "ALL" the calipers,starting at the right rear,left rear,right front,left front.

 

Are you sure what your feeling is air in the line. If you have a caliper or pads that isnt sliding it will give you that mushy feel too....Rob

 

I didn't catch the previous link, but did you do any service to the system before the bleeding air problem?

If you did brakes and compressed fluid back into the system from the caliper, it can flip over a "hat" valve located in the ABS valve system(box). After flipping this seal it is just about impossible to get it to reverse again. You might end up having to replace the ABS valve.

This will feel like a mushy pedal too.

To eliminate the mushy feeling, bleed normally, then having someone depress the brake pedal. Attatch locking pliers or brake line clamps to the soft lines at all 4 corners, or the rear diff brake hose if it has drums. Then reapply the brake pedal and it should feel like a rock. If not the air is in the master. If it is like a rock, remove the clamps one at a time and you will feel a drop in the pedal when you find the problem corner.

Check for air as well, check for a misalligned caliper, not sliding, warped brake pads, etc.

This should at least narrow it down.

 

What do you mean a pad "not sliding?" I don't think I've ever heard of this. Are you saying that the mushiness is from the pad flexing in the caliper guide?

I did not compress the pistons in the calipers like you are describing. I had no mushiness till I changed front calipers.
Clamping flex lines doesn't hurt them? That just sounds like a bad idea. Are you sure about that?
If clamping is ok, and the pedal is mushy, can the master cylinder be bled in the truck?

 

a brake hose thats on the way out will give that "mushy"feeling also..tends to fill up like a balloon and not do much my old '89 F-250 did the same thing..left front...just something else to watch for...zap!

 

First the pad needs to be able to move in the caliper bridge(thats the part that bolts to the spindle/knuckle). Next the caliper needs to slide free on the caliper to bridge slider/bolts. This is a commonly overlooked step. Use a high quality caliper slider lube....not brake quiet.

Next, it is ok to pinch the lines with brake line clamps. There is a tool specifically for this that will not damage the soft brake lines. In a pinch locking pliers will work....if you're worried about damage put duct tape on the plier faces to prevent damage fromthe plier teeth. You can also check fo a worn soft line by appling clamps at both ends of the soft line, removing the higher one first. If the pedal drops when the top clamp is removed, you have a line that is expanding.

Don't rule out a warped brake pad either, I've seen at least a hundred of them.

 

Thanks CO. Good info.

I wonder if my problem was actually from the rear. I've had problems on all 4 corners, but the biggest mystery was the right rear drum overheating burning the shoe. I backed off the adjusters so much in the rear that it made the pedal feel mushy. After a lot of driving and multiple back-ups, I think the adjusters have pushed the shoes out. The strange thing is that the rt drum is not overheating anymore... for now.

 

any time

 

Stupid question...you do have the new calipers installed on the proper sides, right? Bleeder valves facing up?

 

Yes. Thanks for asking though. Sometimes it's the easiest things that make for big problems.

Overall my brakes seem better, but the rt rear drum still gets hotter than the left. At least it isn't burning anymore.

 

Thoroghly check the side that is overheating..it may be bound up somehow. It can be something as simple as the e-brake cable sticking as not to release that side or a wheel cylinder that is half froze up. Tap the brake shoes with the drum off. It should move side to side. Including at the wheel cylinder. Then check the e-brake cable....they freeze up easy.