What's new
CK5
Register an account today to become a member! Once signed in, you'll be able to participate on this site by adding your own topics and posts, as well as connect with other members.

Crazy Brake Problem

I haven't measured the thickness of the drums to see if there still in specs, I just figured I would replace them since they have 150,000 miles on them. They are not scarred up but I'm sure they have worn quite a bit.
 
in 150k, im sure theyve been machined at least once.. some drums can take 2 or 3 machinings, and some cant be machined at all (ie: focus drums).. drums for our trucks are what, 20 bucks each?
 
I have replaced just about everything (not the drums or hard lines along the frame) on my rear brakes including the mc and p. valve. And I still get a little bit of air out of the right rear. I'll bleed and the peddle will become stiff. Then pump it a few times and it becomes mushy, then bleed the wheel cylinder and I get air. It pissed me off for a month solid, but now I just deal with mushy breaks. I can't figure it out.
 
go buy some speed bleeders at pep boys they help a lot and you can do work by yourself. they are basically bleedscrews that have a one way valve inside. i found my proportioning valve was leaking when i pumped up the brakes and fluid dripped out of it. if you look at the part where the rear line comes out you'll see the hardline is actually coming out of a bigger nut. the leak was coming out of the bigger nut. to fix this i put jb weild on the net screwed it in and then put all the lines back on. are you positive your mc is not defective, i got a bad one my first time. open the top and pump the pedal a bunch of times really fast to mix in the air if there is any and see if any bubbles are coming to the surface of the mc resivore. if they are thats not good i think that would mean its no good. make sure your not bottoming out the mc either, if you have been doing that it may be broken. also check all the fittings anf make sure there tight. are you sure you got the right master cylender too? at pep boys they had three to choose from and they couldnt tell me wich one to use. buy speed bleeders theyre ten dollars but im thankfull i bought mine.
 
I have checked everything on the brake system and can't find a leak anywhere. Unfortunately, I'm to the point of just replacing parts until the problem is fixed. Ordered a new proportioning valve from LMC that should be here in a few days. If that doesn't fix the problem I really don't know where to look next. I'm getting ready to lift the truck and put bigger tires on it but I want the brakes working right before I do that.

Next time I'm at the auto parts store I'm going to pick up the self bleeders. Girlfriend is complaining about a sore leg from pumping my brake pedal so much over the last week. /forums/images/graemlins/rotfl.gif

Thnaks for all the help. I'll post when I replace the proportioning valve and let everybody know what happens.

Any other suggestions, let me know.

Thanks.
 
The proportioning valve I ordered from LMC arrived today. Hopefully I will have time to put it on saturday, but if not I will get it done sunday.

I'll let everybody know if this fixes the problem. Thanks for all the help and suggestions. If anyone else thinks of anything let me know.
 
/forums/images/graemlins/angryfire.gif I just replaced the proportioning valve and still have the same problem. /forums/images/graemlins/angryfire.gif

Now the only thing that hasn't been replaced in the rear brake system is the hard line that starts at the proportioning valve, runs down the frame, and ends at the rear rubber hose. I guess thats the next thing I'll try unless somebody can give me any more suggestions.

Please respond with any ideas.

Thanks.
 
did you try those speed bleeders? if not mabey the old bleeder you are using is leaking. how much air comes out? is it just a little that comes out the right rear? how long untill it stopps? one pump? are you bleeding by holding the pedal and opening?only one side leaks air right? make sure the new hard line you put in is tight. if there is bubbles coming out of both sides continuously the hard line from the proportioning valve could be the problem but i dont think it could only affect one brake drum only.
 
OK, I'll add my opinion. After reading through this post (considerable length) I think the most likely problem is incorrectly adjusted brakes. When initially adjusted (and the wheel off the ground) the drums should be slightly dragging on the shoes. You should be able to hear the brakes contacting the drums. A little too much adjustment is generally OK as this will go away as the new brakes "seat" to the drums.
 
The Excuse.

In the beginning, I was just getting air out of the left rear. I had already replaced the hard line to this wheel so I went ahead and replaced the hard line to the right rear also because it was cheap and easy. Once I replaced the right hard line, I started getting air out of both sides. The only theory I have for this is maybe the left side was flowing better than the right so the air would get pushed to the left. I haven't gotten the speed bleeders yet but both wheel cylinders are new and came with new bleeders. Also, I can get all of the air out, pump the pedal 5 or 6 times, and than the pedal will get mushy again and when I rebleed air comes out. When I bleed, I have someone holding pressure on the pedal while I open the bleeder.

Mouse.

I have adjusted the brake shoes already to where they just started dragging the drum. Although having the brakes out of adjustment can cause a low pedal, can it cause air to get into the system? I can't figure it out because no fluid leaks out, only air leaking in.

All help and suggestions greatly appreciated.

Thanks.
 
when the pedal is firm im assuming all air has been bled. after this does air come out the first pump or does it take a while befor the air shows up. im telling you speedbleeders make things so easy. if you put a tube on the end of them you can save the fluid that comes out. it should still be good since its prety fresh. if it takes a while before the bubbles show up i would gues they are farther up in the system. try getting it firm then pushing hard on the brakes this will make fluid leak from your air leak. be sure to wipe off all fittings before this so you will know where its coming from. when i was doing this i left a little bit of fluid in the hole on the bleeder screws so i could tell if air was being sucking in from them but i made sure the threads arround them were dry. pushing the pedal down hard should make enough fluid leak out so you could see it. you replaces the rubber rear line right?
 
You must log in or register to reply here.

Latest Posts

Top Bottom