i have an 86 4runner, i just replaced the brake booster on it, rebuilt the calipers and the master cylinder is about 2years old

ok now i just replaced the bad booster because my brakes were locking up while drivin, since i did that that problem has vanished but now a new problem has come up
when i brake it pulls hard ot the left....and only when i brake it does this, it seems to be the left front caliper that is doing this
the pedal is mysteriosly fine then spongy
now i discovered today that my resivour cap is loose and there seemed to be oily like bubbles and specks of dirt in the resivour......so should i bleed the system and hope that stops it...and possibly get a master cylinder rebuild kit.....or????

 

Yeah, start with bleeding- but didn't you do that when replacing the booster and calipers? It could be air in the lines of the right side. Could also be a bad caliper??

 

well the only time i diconected the lines recently is when we rebuilt the caliper...but we bled the crap out of the brakes after that....
my rubber cap on the resivour is really loose (like it wont latch on the little lip on the resivour) and it looks like a small amount of dirt and stuff got into it but would that cause the pedal to be spongy and have it pull to the left only when i brake?

 

I'm sure enough dirt could clog one of the lines, but I don't know for sure. Are you sure that the pass. caliper is engaging? If you attempt to bleed that side again and fluid doesn't come out or comes out slowly you might have a clogged line/faulty master. If it does come out strong, it may be your caliper.

The bubbles suggest to me that you still have air in the lines somewhere. I don't think that the little bit of dirt would cause the spongy feel.

 

sounds like they need to be bled. also check your brake lines real well. make sure you bleed your brakes in the right order. start with the right rear then left rear then right front and finally left front. basically what your doing is bleeding the one furthest away from the master cylinder first and working your way to the closest.

 

yea when i bled them today both sides were coming out normal from what i could see, ill double check the calipers tommarow, should the caliper pistons be fairly tight in the caliper? and it looks like the pass. side is engaging
and thanks for your advice!

 

also try pressing the brake pedal down hard with the engine not running have someone watch the reservoir and see if any bubbles appear. that would be a sign that the seals on the master are failing.

 

well i bled the brakes and it doesnt pull as hard to the left. im going to do a complete bleeding tuesday and hopefully that does it. and ill also check for bubbles in the resivour