Rear Brakes Locking Up!

[import racer]

So last week my rear brakes started locking up,not sure why.I replaced the caliper,rotor and pads a couple of months ago on the driver's side to pass inspection.Everything was fine after that,so don't know why they are locking up,think I need to clean them with brake fluid but to cold out to work on them.Anyone have an idea what's going on with them.

[lostforawhile]

your proportioning valve is going bad, it limits rear pressure to prevent the rears from locking before the front, it also has the residual pressure valves built into it. I doubt it's the master as the brakes are split diagonally, left front,right rear, etc, so a front and a back brake would be locking or dragging

[Dr_Snooz]

Also do a visual inspection of the brakes themselves. Check for rust and wear, and re-grease all the sliding and pivot points as necessary. It's possible to have a backing plate go bad and do funky things with the rear brakes, so be aware of that too.

[import racer]

Would the pads cause a problem,the ones on the car were semi met and the one i changed were replaced with honda ones.

[import racer]

bump!

[import racer]

Seems like only one is locking up,the one i didn't replace.

[VIPER1988]

If its only one I doubt it would be the prop valve. More likely the caliper or the rubber line to the caliper.

[lostforawhile]

If its only one I doubt it would be the prop valve. More likely the caliper or the rubber line to the caliper.

well there is a residual pressure valve for each rear brake built into the proportioning valve

[VIPER1988]

Never said it wasn't a possibility. Just that caliper or hose are more likely. Especially if its the original 25 year old hoses. They collapse on the inside and hold the pressure in the caliper.

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[lostforawhile]

I would have gotten rid of those hoses years ago, not safe to trust a 25 year old brake hose

[VIPER1988]

Agreed. These days you can find braided steel lines cheaper than regular rubber lines. I think I paid around 70$ for the whole set.

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[Dr_Snooz]

Also do a visual inspection of the brakes themselves. Check for rust and wear, and re-grease all the sliding and pivot points as necessary. It's possible to have a backing plate go bad and do funky things with the rear brakes, so be aware of that too.

This fool thinks you have rear drums. LOL

I don't think your mismatched pads are helping things. The hydraulic system is designed to supply even pressure throughout. With one set of pads grabbing more aggressively than the other, expect one side to lock up sooner than the other. Pads are cheap so start there and work your way toward more expensive stuff.

[gyates93]

This fool thinks you have rear drums. LOL

I don't think your mismatched pads are helping things. The hydraulic system is designed to supply even pressure throughout. With one set of pads grabbing more aggressively than the other, expect one side to lock up sooner than the other. Pads are cheap so start there and work your way toward more expensive stuff.

I agree here, I would never replace brakes on one side of an axle without doing the same part on the other side, that's just asking for trouble.

Otherwise I would look at the calipers and make sure they slide properly and the pistons are not seized or anything, then look at the proportioning valve.

[Fixedit]

Did an SEi rear disc swap on my 86 LXi, new master cylinder, calipers, pads rotors etc., and installed the 4040 prop valve from the donor SEi.

Left front caliper drags intermittently. Prop valve leaks out of the weep hole. Prop valve seems quite suspect. Grabbed a 3540 prop valve from a 3g prelude 2.0si, think I’ll be alright using that in place of the 4040?

[ShiRen]

Probably. I think that you would be fine with any prop valve that works, beggars can't be choosers

[conozo]

I don't think anyone could tell the difference except for that race car driver you hire to race your car on a track during the weekends.