Rear brakes are grabbing when driving. Don't have to apply brakes just grab without notice then stop and rolls fine. I've looking inside everything looks ok, I did replace one back drum. Also replaced all brake hose's flushed and bleed system. Did some research looks to be a back plate problem? Anyone have similar problems, thoughts - ideas to fix.

 

Pull the drums off and have someone press on pedal while you watch the movement of shoes . spring is probably in wrong or something binding ?

 

Small shoe to the front. Springs like this. Make sure there isn't oil seepage from an axle seal.

 

Replaced springs and wheels cylinders as needed about a year ago. Everything has worked fine till a few days ago. In last few days I have gone thur both front and rear brakes with drum off, springs look fine and correct. Replaced 2 broken self adjustment cables, front wheel bearings, 1 rear drum, flushed and bleed brakes. After all this I test drove truck today. Everything was fine for the first few miles and then the rear brakes start to grab again for a couple minutes then let go and fine again. Sounds like metal on metal like before replacing everything but shoes are fine.

From research I have done it sounds like the backing plate is bad. I guess question is how can I tell it is the backing plate for sure and where can I get new ones if bad. I'am guess if shoes toed in towards truck the plate is bad.(Have not checked that yet) Looked quickly online for new backing plates, napa has some but no year make or model specified. Also read where they can be repaired by welding the high spots. No sure how that works but if you have any experience with that let me know.

Popping drums off again tomorrow, if you have any ideas of what to look for let me know. I will check the springs again but pretty sure they are in correct and not binding. Thanks!

 

Thanks for the pic! Everything is just like pic with no seal leak in the rear. Had leak in front so I replaced both inner seals when I did bearings. Small shoe towards the front. ( Made that mistake before, big mess) I like the ford blue on the shoes!

 

you can fix your backing plates , with a grinder and welder seen it done along time ago at a gas station i worked at .

 

Been doing some research and almost sure backing plate needs good cleaning on high spots and more grease. Brought one of those small packets and may not have gotten enough on. Hope I don't have to weld but if I have to I have to.

Read an article where welded/filled in the grooves and used backing plate edge as a height/level gauge. Don't have any more brake grease but have some anti -seize some people use with good results. Should have looked at backing plate closer, did't realize how important they are for good brake operation. Another lesson learned.

Going to get started on brakes, thanks for the help especially on xmas. Any other tips or tricks please post I'll be checking back from time to time. It's chilly outside and I will need a warm up break.

Hope your having a good xmas and got all the truck goodies you where wishing for!

 

The backing plate can wear where the shoe rides on it. Do you have a pic of yours? Backing plates just do not go "bad" other than wear. The wear is very very easy to fix if you have a ridge on it. Takes just a few minutes each.

Where do you live?

 

Sorry and thanks but can't do a pic right now. Backing plate looks to be in good shape other than a few minor grooves on 2 high spots. I did notice the self adjusting cable was loose. Made me wonder if wheel cylinder might be sticking a little. (Rebuilt or replace all 4 just over a year ago) I took it off and was in good shape except there was a little sludge/dirty fluid in it. Got it cleaned up and ready to go back on. I'am going to grind the minor in perfections off (Carefully) the 2 high spots and put back together. Then have to look at the other rear brake. I live in Atlanta Ga. (Doraville)

 

Do you have power brakes? ANy work to master or power brake booster recent?

Any sign of grease on rear shoes?

Does not sound like a backing plate issue to me, how about pushrod adj for brakes?

 

Think I found the problem, looked closer at the high spots and the one on bottom front of plate was grooved pretty bad. I just welded and I'am going back in a few minutes to grind. I do have power brakes but only thing I did was replace the master cylinder about a year ago. No signs of grease on rear but front passenger side needed a new seal. Replaced both seals and bearings on the front.

 

You can use any wheel bearing grease , it doesn't get hot or anything just need to only put a little on contact area .

 

Everything back together, test drove and problems is still there. Took wheel and drum off everything looks fine except real hot. Drum was not stuck, came off easy. Not sure what to look at next, any ideas ? Thanks.

 

Is your brake lines close to exhaust or other source of high heat?

 

Just replaced rear brake hose a couple of days, is about 2 inches from exhaust but sure it's not the problem.

Noticed the E-Brake was sticking some so I disconnected it, problem is still there. Only 2 things I have not changed or checked is the master cylinder and the rear drum on the drivers side, passenger side has been replaced. I'am running out of ideas other than to get new master cylinder and another drum.

I still have original brake lines but no leaks and fluid seem to flow good when I bleed-flushed system. Any thoughts or ideas welcome, I'am stumped.