Touchy brake problem!

[see ten]

I've driven vehicles that didn't want to stop, but now I've got one that wants to throw you through the windshield when you barely press the brake pedal! I've never seen one so touchy! Any ideas on what to do to make it a bit more manageable.

[joedoozer]

Rear drum brakes? Disc brake calipers are self adjusting. When brakes are applied the piston squeezes out, and the O-ring around it flexes slightly. When the brakes are let off, the O-ring flexes back. This is the "self adjusting" part. Drum brakes generally speaking are not self adjusting. And directly effect brake pedal height. And the way they work, wedging themselves against the anchor. If the rear brakes are adjusted up nice and tight, that will give you a very high brake pedal, and could cause them to grab.

I would take the drums off, and look at the brake shoes and the drums. See if there is any weird wear patterns. Look at the surface of the drum. Have they been resurfaced recently? Also cheaper brake shoes made of a softer material can be quite grabby too.

Long winded but I would start with backing off the rear brakes a bit. Since that is the easiest fix. If that lowers the pedal, but they are still grabbing. I would pull the drums and make sure everything looks good inside.

[see ten]

I was swapping the wheels out today and didn't even think to pull the drums. I did check the pads up front and they looked good to go. It sounds like pulling the drums and having a lookie lou is going to be a good starting point. The brakes are grabbing so bad that when I drive with the window down you can hear the tires just all but locking up.

[joedoozer]

Pop the little rubber thing out in the backing plate. And use a flat tip screwdriver to turn the adjuster. With it jacked up spin the tire. You should hear the brakes rub slightly. But not grab. The tire should spin 1 1/2 turns or so when spun by hand. You don't need to pull the drums yet.

[gintaras]

Can someone shed some light on my brake problem?

The problem is that my brakes are inconsistent.. most of the time they feel fine, but sometimes the rears lock up, this is mostly in slower stop and go traffic, like when you are waiting your turn in a line of cars at a stopsign or stoplight. Normal driving on the highway or a normal road with very few stops and the brakes feel just fine.. but get a lot of action in stop and go traffic and the rears lock up sometimes.

[ZombieWeinerDog]

Originally Posted by gintaras

Can someone shed some light on my brake problem?

The problem is that my brakes are inconsistent.. most of the time they feel fine, but sometimes the rears lock up, this is mostly in slower stop and go traffic, like when you are waiting your turn in a line of cars at a stopsign or stoplight. Normal driving on the highway or a normal road with very few stops and the brakes feel just fine.. but get a lot of action in stop and go traffic and the rears lock up sometimes.

happens to me sometimes

[68gmsee]

Originally Posted by see ten

I've driven vehicles that didn't want to stop, but now I've got one that wants to throw you through the windshield when you barely press the brake pedal! I've never seen one so touchy! Any ideas on what to do to make it a bit more manageable.

First, have you replaced the brakes shoes? These days, the manufacturers add metal filings (bronze?) and in some cases they are very "grabby". As joedoozer mentioned, they're made to wedge themselves against the drum surface and if they are grabby they will lock up. I've had couple of instances in the last 5-10 yrs where it's happened to me.

Second, make sure that everything is in the right place on your rear drums. I'd compare pictures that have been posted just to make sure.

Last, the booster, if you have one, could be defective.

[68gmsee]

Originally Posted by gintaras

Can someone shed some light on my brake problem?

The problem is that my brakes are inconsistent.. most of the time they feel fine, but sometimes the rears lock up, this is mostly in slower stop and go traffic, like when you are waiting your turn in a line of cars at a stopsign or stoplight. Normal driving on the highway or a normal road with very few stops and the brakes feel just fine.. but get a lot of action in stop and go traffic and the rears lock up sometimes.

In your case, if it started when you replaced the brakes I'd say the same things need to be checked. If it's something that gradually started or nothing was changed prior to the problem, then the first thing I'd do is replace the rear rubber hose on top of the rear axle.

They get swelled from the inside and allow fluid in one direction because of the hydraulic pressure but restrict it on the return cycle where it's just "spring" tension that retracts them. The fluid slowly trickles back and eventually can lock them up permanently. That also happened to me.

[see ten]

Well...This is a thread that's been brought up from the dead! My problem turned out to be none of the above suggested ailments.

I've got a seeping rear axle seal that's causing fluid to get on the shoes of the drivers side. I can spray some brake parts cleaner on the shoes and it's fine for a while...and then it starts again.

I'll get to it eventually! This truck gets driven the least out of the six vehicles we own so it's pretty low on the priority list of things to fix.

[68gmsee]

Originally Posted by see ten

Well...This is a thread that's been brought up from the dead! My problem turned out to be none of the above suggested ailments.

I've got a seeping rear axle seal that's causing fluid to get on the shoes of the drivers side. I can spray some brake parts cleaner on the shoes and it's fine for a while...and then it starts again. ...

Just noticed the dates.... But, you're wrong on none of the above. I did mention "grabby" brakes...

and if they are grabby they will lock up.

[69GMCLonghorn]

See Ten, I have the exact same problem with mine. The only thing is I've replaced the seals twice, and did the brakes 3 times, on 3/4 ton axles, which are a BEEATCH! They're leaking again. Time to take it to someone with more brains and time than I have.

[see ten]

Sir...Nowhere did you mention that a leaking wheel seal could be the cause of my ills. But yes they are "grabby".

[special-K]

I never saw this thread before and if I did I would have suggested a leaky seal.Rear drums are as self adjusting as calipers.Calipers are more likely to bind than a wheel cylinder.