MATTSRED

So here is the deal Front Disc. Rear Drums. and when driving and braking the rear seems to sometimes stick and or grinding noise. I know how to check brakes and i did today and there fine appropriate thickness and no glazing, cracks, Etc. so what would cause the grinding/ bad brake performance??

bigarms23

try adjusting your proportion valve

MATTSRED

yes i was thinking that but i had never messed with it and dont have a clue about it.... but will look into that thanks.

GVOLCRunner

Its not your LSPV unless its gone bad, which I seriously doubt. If your LSPV was out of whack your back end would either LOCK up everytime you put on the brakes or you would notice nothing back there at all.

The LSPV works by reducing the pressure from the brake booster as disk brakes require a good bit more "power" than drum, so if an equal amount of force was applied front and back your back end would always lock up.

Sticking might be a stuck valve, but if it is a bad valve "adjusting" wont do anything.

1. Flush your lines
2. Bleed your lines

You can inspect our fluid to see how nasty it is.. maybe you have some jun in there?

After that, have you checked to see if the drum brakes themsleves are not going bad? Sometimes the springs break or wear out? Do you have bad brake performace up front?

the fact is, about 70 percent of your brake power comes from the front. Unless you were weighed down, or in a SUDDEN stop situation you might now even notice your back breaks. Your front do far more work. So if you are noticing a serious brake performance issue, it could be something relating to the entire brake system.

Say, weak or bad brake booster? Weak, leaking master cylinder? You said you checked pad left? How about pulling them off to see if they are even? Maybe a stuck piston?


You mentioned "sticking" is that from the rear or front? Id flush all your lines, gt the old stuff out...make sure no crud/air/water is in the lines.

Grinding, from front or back? Well I could go on, more info would be helpful.

Just to let you know, I was redoing my entire brake system and the new drums were on back order so all I did was bypass the back. Ran on just the front 2 brakes, which everything was new. I noticed VERY little difference. I didnt drive it much, stuck to the motorcycle but all im saying is I doubt the serious performance issue is coming from back alone.

Unless its sticking.. dragging back drums would def. be a bummer and affect your accel and gas milage...but it didnt sound like that.


Im noticing some typo's, it appears the batterys in my keyboard are going. Sorry.

MATTSRED

Ya that's a lot of stuff i misinterpreted..the fact that my whole brake system could be wack...

but the grinding i mostly hear from the rear.

i plan on flushing everything and cleaning the bad dust from the drums to see if that is my issue.

GVOLCRunner

grinding. Like gears? Becuase, by the very nature of drums..unless somethings broken in there...you might her a Swoosh of the shoe not leaving..but grinding...me thinks backend? You got enough gear oil back there? you checked?

Dont breath that dust AT ALL. it could and probably is asbestos

You need a mask on. That stuff causes nasty cancer/

drew303

Could you elaborate on your definetion of bad performance?

Typically you won't notice much of a performance drop when you're rears arent pulling their weight in the work because they don't do much anyway. You can experience pulsating from warped or off-center drums tho. But the noise ... I'd check the adjusting rods. They easily get stuck/corroded and cause some weird behavior.

The parking brake cable adjusts the shoes outward to stay close to the walls of the drum, this can get gunked up or overtighten causing shoe drag.

But this is all speculation, it could be any number of issues. And your sure it's the brakes?

GVOLCRunner

Just to let you know. I redid my entire brake system for about 400.
New everything. I'm so glad I did. When I pulled my front calipers off, each one had a stuck piston. Yea, no wonder it was like trying to stop a tank.

RustyBucket_4x4

I have a grinding noise from rear brakes.the grinding shifts from right to left sometimes.its not always constant.all this after repairing all the brakes.I cant believe noone has a solution.Ineed input too.

abd9810

Had same problem with wifes car turned out to be the brake pad formula/compound. Changed to a different compound per toyota tsb which called for a semi-copper-mettalic pad. Could be a similar problem. The grinding noise was absolutly scary as hell and was very irregular, but was smoooth as silk after making the change.