Please Help Break Problems

[82fj60bigblue]

The breaks on my 82 fj60 are getting stuck on. The longer I drive the harderthey clamp down. I have already replaced the master cylinder and both front callipers. When I crack one of the bleaders loos it shoots out fluid and lets loose of the callipers. Please Help this is driving me nuts!

 

[Jan-78FJ40]

The breaks on my 82 fj60 are getting stuck on. The longer I drive the harderthey clamp down. I have already replaced the master cylinder and both front callipers. When I crack one of the bleaders loos it shoots out fluid and lets loose of the callipers. Please Help this is driving me nuts!

What did you replace the master with? new, rebuilt, napa, aisin...?
this sounds like a master problem.

You also need to check the booster and the pedal. Does the pedal come back when you depress it? How does the booster look? There are some checks for it described in the FSM.
cheers,
J

 

[Mark W]

Almost certainly a problem with the adjustment of the pushrod between the booster and the M/C... or the pedal pushrod and the Booster.... make sure you have at least a nominal amount of freeplay in each.

This is a common mistake on adjustment.


Mark...

 

[82fj60bigblue]

I replaced the master with Schucks unit the truck was doing the same thing before I replaced it so I took the original out and took it apart. It had alot of crap in it so I decided to replace it. Then the problem was still there so I reserched and it sounded like sticking calipers so I replaced them too.

Now I am getting really frusterated. I will check the adjustment next. Yes the petal comes back and I will take a closer look at the booster. Thankyou for your help I will let you know how it goes.

 

[82fj60bigblue]

I forgot to mention that after I bleed them they work fine at first but then build up pressure. It is like they let the fluid go to the calipers but not back to the master.

 

[mudnyreye]

Check your metal lines on your axles/frame. Any crimp or blockage would cause the sytom which you are describing.

 

[ntsqd]

It is also common for aged flex hoses to develop "flaps" in them that can act like check valves. Brakes will work fine, for the first use. After that they will drag or won't release. Usually they'll bleed down over time.

So how old are the hoses? If you're not sure I'd say that it is time to replace them.

 

[Mace]

Do as Mark Says and check the pushrod and the pedal adjustment.

99% of the time that is the answer.

 

[slcfj62]

Is it all four wheels, or just some of them (which wheels have hot/warm rotors/drums)? There is also that load proportioning valve on the top of the back axle.

 

[82fj60bigblue]

My hoses look like the original ones so that sounds like the culprit. I checked the petal and the adjustment is good. I took the porportioning valve apart it had a bunch of dirt in it so I cleaned it out and that didn't fix it either. I blew all the lines out and it still had the problem. I will try the rubber lines now, because it is only the front brakes that are having the problem.

 

[snowakii]

Peddle push rod adjustment. Not just that the peddle comes back. It is the free-play when the peddle is in the returned position. Err on the sloppy side rahter than trying to get the firmest peddle possible. Check the FSM for the correct amount of free-play and resting position.

How do I know? I was adjusting mine to accomodate a tow-brake and the peddle felt great on the tight side of FSM spec, but the brakes acted like you describe. Would have to lift the peddle further with my foot after it came back what looked to be fully back.

Steve

 

[Mark W]

I have heard of brake lines deteriotating... third and fourth hnd internet reports.... but in over 15 years of running the shop... I have never seen it.... not inthe years of hobiest involv,emt prior to that... so... it may be... but do not assume that is a likely problem.

Did you actually verify that you have freeplaqy... I do not mean the pedal returning... I mean freeplay in both pushrods... you have to remove the master to check the one between there and the booster.


Mark...

 

[82fj60bigblue]

How do you check the one between the master and booster? The petal has freeplay but I dont understand how you check the other one. Also the breaks will return to notmal after sitting for a while I dont know if that helps. It seems that the more youuse them the worse it gets till they are clamped on full. Sorry I'm new to this site can someone explain how to get to the FSM.

 

[ntsqd]

The freeplay adjustment is a freebie, so definitely make sure that is correct first.
The FSM probably has a procedure for the m/c to booster freeplay, but generally you want to measure the push-rod's length sticking out of the booster from the m/c mounting surface and it should be slightly shorter than the depth of the hole in the back of the m/c from it's mating mount surface.

I have had two rubber hoses do the flapper trick over the years, so when I read/hear of this sort of problem it is on my list of possibilities. I wouldn't change them just to change them, but if they don't look good (cracks, excessively oxidized, etc.) or grow excessively under pressure then changing them is not a bad idea.

 

[Mark W]

I have had two rubber hoses do the flapper trick over the years, so when I read/hear of this sort of problem it is on my list of possibilities. I wouldn't change them just to change them, but if they don't look good (cracks, excessively oxidized, etc.) or grow excessively under pressure then changing them is not a bad idea.

Can't argue with that


Mark...

 

[ntsqd]

It is interesting that I've had it happen twice because it isn't all that common.

 

[82fj60bigblue]

The hoses looked horrible, I am going to pickup the new ones now. $12.50 from napa. I will also chech the rod adjustment. then I will put it back togeather and let you all know how it went. I'm crossing my fingers, I'm supposed to go wheelin tomorrow.

 

[alaska60]

almost certainly a problem with the adjustment of the pushrod between the booster and the m/c... Or the pedal pushrod and the booster.... Make sure you have at least a nominal amount of freeplay in each.

This is a common mistake on adjustment.


Mark...

xxxxxxxxxxxx2222222222222!

 

[82fj60bigblue]

Ok its finally fixed. I had to mess with the rod adjustment a little but it works, I am pretty sureit was the rubber hoses. Thanks to everyone for the help.