New brake stuff, EMERGENCY !Rear wheels locking up, brake pedal too firm

[86-accord-lxi]

:rant: I installed a new master cylinder, booster, front brake hoses, new rear wheel cylinders, drums and shoes. I bench bled the master cylinder before installation, and I bled the brakes at all 4's . Now the rear wheels keep locking up, I backed the adjuster all the way down, and they worked fine,
But after about 10 minutes of driving they lock up again. I have been through this about 3 or 4 times now. The first time the adjuster was too tight, But the last 2 or 3 times the adjuster is backed all the way down and they still do it. The brake pedal is way too hard. :wtf: I need to drive this car tomorrow morning with no problems, What could be the problem here ? All the brake parts are clean, I don't understand why they keep locking up. When they lock up, It's not sudden, They just start to drag and eventually the car won't move. Please help, I think I might sell this car very soon .

[Soundy]

So don't step on the brakes. Brakes are for pussies :)

[86-accord-lxi]

So don't step on the brakes. Brakes are for pussies
Ha ha ,Yeah , But The car won't even move. It's like the parking brake is on, But it's not. Seriously though, I don't know why they do this. I need help.
Has anyone else experienced this problem ?

[86-accord-lxi]

Ok, I just went outside started the car, moved it back in the driveway, Then moved it up in thee driveway and It works just fine now. :wtf: Although, The pedal is still a little too firm. So, It seems that the rear brakes are overheating ? What would cause that ? Most all the brake system is new, The fluid is new, I don't get it. I need to get this problem solved by tonight.
Please, If any of you have had the same experience and solved it, I need your advice.

[T-Funk]

which adjuster did you back down?
on the drums or in the car?

[Whistler225]

ok, I'm no brake expert, but Sundays are really slow around here, and the person I asked to look at the thread logged off before he got my message, so I will put in my two cents. That's about all it's worth.

It sounds like your master cylinder is sending pressure into your rear brake lines constantly. I don't know what would cause this, although since you also replaced your booster, I would start with the brake pedal linkage and make sure it is properly aligned, etc. I think the booster effects the entire master cylinder, so you should be able to eliminate it as a culprit, unless your front brakes are actually dragging and you don't know it. But if it is just the rear brakes, then it's gotta be your master cylinder somehow. If the brake pedal is hard, it's because you're already braking and there is pressure in the brake lines. So, if you apply more pressure to the brake, that means that when you let off, the pressure isn't being released. That's why it builds gradually. I dunno....I do know that I've bought master cylinders that were bad out of the box, but it's usually a situation where I had no brakes after the install, not too much.

Sorry man, I know it isn't very helpful. It just sounds to me like the problem is probably up front somewhere.

[Whistler225]

there's an adjuster in the car? lol....see, like I said, I'm certainly no expert....listen to T-Funk before me....

[A20A1]

It sounds like what happens when the car is not running... I know if the car is off and you press the brake it will get hard and will lock up. Then you turn the ignition and the pressure goes back to normal. Same with the steering wheel locking up if the key isn't turned... I dunno what turning the igntion does to the brakes other then the connection with the brake booster... but then people say they remove the booster and the brakes work fine so I don't know what to say.

I'm not a brake person.


Did you use the right type of fluid?

[T-Funk]

well the one in the car is used to change what point the ebrake engages, so as your rears wear i think you tighten it, so you dont have to pull the ebrake up too far

i would assume if you had it really tight and then put on brand new shoes it might engage without even being up at all
but i could be wrong, plus it has nothing to do with the brake pedal being so firm

[b8er]

i would also check your fuild, iv heard of guys using oil and stuff instead of actually brake fulid and it boils up andyour lines streched out and its just all bad if you use the wring fluid, i would say flush your whole brake fuild lines and put in some brand new stuff, and even if that doesnt fix it you can check it off the list

[Oldblueaccord]

:rant: I installed a new master cylinder, booster, front brake hoses, new rear wheel cylinders, drums and shoes. I bench bled the master cylinder before installation, and I bled the brakes at all 4's . Now the rear wheels keep locking up, I backed the adjuster all the way down, and they worked fine,
But after about 10 minutes of driving they lock up again. I have been through this about 3 or 4 times now. The first time the adjuster was too tight, But the last 2 or 3 times the adjuster is backed all the way down and they still do it. The brake pedal is way too hard. :wtf: I need to drive this car tomorrow morning with no problems, What could be the problem here ? All the brake parts are clean, I don't understand why they keep locking up. When they lock up, It's not sudden, They just start to drag and eventually the car won't move. Please help, I think I might sell this car very soon .


Its when you installed the MC. The push rod needs to have to correct adjustment or the pressure will build over time. Whats wierd is that usually its the fronts that do it first not the rears.

I dont knoe what the adjustment is see if you can look it up in the book.

wp

[Pico]

Is the booster you installed New or Rebuilt?
it's possible that you may have a defective booster or the check valve
for the booster has gone bad.
Another thing there may be air in the portioning valve causing your rear brake to lock up.
check those out first and good luck.

[86-accord-lxi]

I backed the adjuster inside the drum and shoe assembly all the way down (where the shoes are as far inward, away from the drums as they can be)
The e brake fully engages at around 9-10 clicks, Which it says 7-11 clicks in the chiltons manual. After letting the car sit for awhile, The brakes work just fine. But then they start to seize up in the rear and the pedal gets hard after like 10 minutes of driving. The pushrod was supposed to be pre-adjusted.
And If I have to adjust it, I'll have to buy a special $50 pushrod tool from honda. I used prestone dot 4 brake fluid. The master cylinder and booster and re-mans with lifetime warranty.

[Whistler225]

I dunno about LXI's, but my LX brake fluid reservoir calls for DOT 3 fluid, not DOT 4....I don't know if that would make a difference. it still sounds to me like something is up with your master cylinder. The fact that it's just the rear brakes, to me would mean that the MC is sending pressure through those lines constantly. That would explain why it takes 10 minutes for them to lock up, and why they return to normal after the car sits.
My ebrake only pulls up about 3 clicks, and I don't have any problems with my brakes...
I hope you find it man....

[Soundy]

Don't these cars use a proportioning valve - that dooflinky that splits one MC output to left-front and right-rear wheels, and the other MC output to right-front and left-rear?

[86-accord-lxi]

Well, With everyones help and suggestions, I have come to the conclusion that the master cylinder pushrod is adjusted too long. It says in the manual if the pushrod is too long, It causes the master cylinder compensating ports to be blocked off, eventually causing brake drag (exactly my problem). If the pushrod is too short, It causes excessive brake travel and a groaning noise may be noticed from the power booster. So, after I eat dinner (which I am doing as I type this) I am going to go adjust the pushrod. This should solve the problem. The troubleshooting is like this :
Remove master cylinder reservoir cover
Have an assistant depress the brake pedal 3/8" to 1/2"
Watch for fluid movement in the master cylinder
If fluid movement is seen after depressing the pedal 3/8" to 1/2"
This indicates proper pushrod adjustment.
If the pedal travels 1/2" or more before fluid movement is noticed,
The pushrod is too short. If nothing happens no matter how far the pedal is depressed, the pushrod is too long (which is my case)
To adjust the pushrods length, remove the master cylinder from the vehicle.
Turn the adjusting nut in to shorten the pushrod, or out to lengthen the pushrod.
Install the master cylinder and recheck pushrod length.
I'll adjust and and let you guys know what happens.
Thanks for all your help and suggestions !

[Whistler225]

cool deal man....let us know.

[Oldblueaccord]

Yeah reason why I said that is I had a friend with an intergra did the same thing only the fronts would lock after about 7-10 miles. I finally sent him to my favortie Honda mechanic and he set it up for him. He had a leaky MC and done it himself.


I set the rear brakes very close to the drum. Just so you can wiggle it on. It gives your brake pedal a nice high and hard feel which I perfer. I might have 5 clicks till it holds OK when I first do it. Of course it falls outta adjustment in about 3 months so I adjust them when I change the oil.


wp

[86-accord-lxi]

I adjusted the pushrod on the brake booster, Then beld the brakes.
They aren't locking anymore, But the pedal is slightly mushy for my likeing.
I will have to mess with the adjuster some more, And bleed the brakes again.
I drove around for 40 minutes last night and they seem fine, just slightly mushy though.

[Whistler225]

That's great man! Glad you figured out what it was. Nothing worse than wondering how the heck you're going to get to work in the morning.

[86-accord-lxi]

Yeah, Only thing is, Now the pedal is too mushy.

[Whistler225]

well, have you readjusted the rear brakes back out yet? Now that you've got the pushrod adjusted, you might try that....You gotta have them as close as they will get without actually rubbing the drum (although if you have self adjusting rear drum brakes, you could do this without taking the wheels back off. Just put the car somewhere you have room to back it up about 50 feet or so, put it in reverse, back up at a fair pace (not too fast, but not too slow....I know that's vague sorry), and then apply the brake firmly. Repeat. This is kind of a redneck method, but it usually works with self-adjusters).