88 runner 3.0

Heres the issue:
Brake pedal gets harder to push and the front brakes are binding up more and more the longer i drive. once its had time to sit and cool down it is fine again.

What I've done:
replaced both calipers and pads up front and bleed the system. Replaced the booster.


Other issues that may have merit :
Front bearings making humming noise and suspect that it may be heating the calipers enough to boil fluid....just a theory.


So my thoughts on what the next step should be is either wheel bearings or MC rebuild...??? or anything else you can think of

 

Go ahead and do both. Neither is very costly.

 

Could try replacing soft lines from hard lines to calipers, too. Maybe split internally, acting like a one-way valve? Is that remotely possible?

 

had the same prob in my 93... could never figure it out, till one day I had no brakes at all... turned out to be the master for me.

 

I doubt this is the cause for heat generation. Have you jacked up the front wheels and checked the wheels for play; Have you checked the bearing pre-load?

When the brakes are cool, do the wheels spin freely (any drag)?

If you are generating heat in the front brakes and have replaced the calipers / know there is no drag, my guess is that the m/c is bad keeping in residual pressure inside the system when you remove your foot from the brake pedal.

To confirm, jack up the front wheels when you get back from driving it and see how freely the wheels spin. If they are dragging, crack the bleeder and see if the caliper is pressurized. After see if there is still drag.

Good luck.

 

One more thing i forgot to mention was the heat from the hubs is fairly hot enough to not touch for long.

So i replaced the wheel bearings tonight. Both sides the grease was in two parts...a thick gritty substance in the center of the hubs and a basicly oil substance in and around the bearings. Drivers side inner bearing was a little damaged on the side of the inner race which was odd.

Anyways i took it for a pretty long drive up a 5 mile long canyon stretch and no binding at all. Hubs are cool to touch. However it is a very cold and rainy night here in morrison so im hoping that isnt a factor. Either way im picking up a 93 t100 MC tomorrow to swap out that i know is in good condition.

Will update tomorrow if it happens again.

 

Btw angrybob...the checking the bleeder idea is awesome ...ill try that tomorrow if it binds.


Thanks for the help guys

 

little update. After replacing everything but the lspv it still had issues. Took it to a brakes plus..found the oldest/wisest looking tech i could find and told him my problem. Water soaked fluid he says. did a complete fluid power flush and wala!!

ok so now to steering box, shocks, ebrake cable, bumpers, rust treatment......lol foooooook!!

 

I'm happy that your problem seems to be fixed, but water/moisture content alone in brake fluid only results in lower brake fluid boiling temp...nothing else. It won't mess up seals causing expansion, for example, that would cause the brakes to keep pressure.

What kind of brake fluid are you using?

 

brakes did that as well went to bleed the brakes soon as i did i lost my pedal( went all the way to floor no stiffness at all) and brakes. ended up replacing master cylinder. no problem at all. after