westhurmond

Brake pedal seems to have a lot of travel and are a little spongy. They makes a SHHHH sound when pressing on them. They work. Truck stops, but maybe not as responsive as my other cars. We replaced ALL of the brakes fluid. Previous looked like coffe now its nice and clean. I notice some sludge at bottom of master cyinder (why is it stil there). All 4 brakes bled clean with no air or issues (Two bottles of fluid later). There don't appear to be any leaks. Pads and shoes looked fairly new, disc and drums seemed good. Brake pedal returns to its position nicely after applying brakes. Why is there so much travel? Why can't I "stop on a dime"?

And I have a question that probably is dumb to most of you...When the wheel is off and I am looking at the front or rear brakes should I be able to see the calipers moving when someone presses the brake? Same for drums? I would think the brake is at a resting position when the car is off and in park. Pressing the brake should make the calipers grab the disc/ shoes push out against the drum? And both shoes should move outward? I was able to see the movement on my rear, but only one shoe moved. I couldn't detect any movement in front.

Thanks!

88xlt

As far as the disc brakes in front, they ride pretty close so you may not detect any movement. As far as the drum brakes in the rear, the shoe that moves easiest will probably move with the drum off. When the drum is on, the easiest moving shoe will apply slightly ahead of the other shoe but they should work properly. That's my take on that.

It's hard to say for sure what your problem is with the sound and excess pedal travel.

raski

Try adjusting the rear drum brakes. You want a slight drag. The drums have a huge affect on the pedak height. If they are spongy, you still have air trapped. If the pedal sinks to the floor, look at a bypassing master cylinder. You might see some movement when the brakes are applied. Also, the boosters on these trucks fail often and will produce a hissing sound when leaking.. After you shut down the engine, wait about five minutes. With the engine off, pump the brakes. You should get about 3-5 power assisted pumps before the pedal goes hard. If you do not get that, the booster or check valve is leaking.

Steve83

The fronts will only move as much as they retracted after their last application. There are no retractor springs on the calipers, so the only thing that pulls the shoes back is the rubber dust boot between the caliper & piston. IOW: not enough to see.

The rear has springs, but they're NOT identical even if the mechanism was perfectly balanced (and it ISN'T), so one piston will move more-easily than the other (usually the primary/front).

And since both front & rear brakes are rarely maintained correctly, none of them move as smoothly & reliably as they should. Did you ever clean & grease yours? That may be why the pedal has so much travel.

If you want to understand more, read all the front disk, rear drum, & vacuum booster captions in this album:
https://www.supermotors.net/registry/2742/12739-4