I recently purchased a 1995 SR5 4Runner, and noticed intermittint brake pedal travel, some times they worked perfectly and others, the pedal traveled near to the floor before I feel any resistance. I inspected the system and found that the rear shoes were worn, so I replaced them and bled the system. It worked well for the first day and then It started again. I thought pin hole in the master cylinder piston seal. Toyota rebuild kit $41.00 I put it in, and bled the system. Once again fine for a day and then So I then bought a new master cylinder $200 I put it on, bled the system. Fine for a day, and then I tried adjusting the LPSV to show more load in the rear, hoping this may be the problem Any thoughts or ideas on this would be greatly appreciated, I refuse to take it to the local stealership..... Thanks.

 

You said you replaced the shoes and bled the system, that right there typically repairs the problem you describe.

Perhaps your brake pedal has too much freeplay? There should be a locknut just underneath the dash. You may have to adjust for a little bit lower freeplay. Other than that, did you notice any fluid lose? Maybe you have a fluid leak somewhere. usually when a pedal falls to the floor, it can be a fluid leak or air in the system. Try looking at your wheel cylinders, use a small flat head screwdriver to lift the dust boot off to see if it is moist back behind the boot, maybe your wheel cylinders are shot?

Good luck man.

 

Did you also bleed the brake proportioning valve?

 

Oh one more thing...not to insult your intelligence, but are your shoes properly adjusted? Sometimes too loose it will not provide effective braking, especially true in Toyota's. Make sure the drum drags a bit (not a lot) when you feel for adjusting shoe clearance as you turn them.

 

Tanks for the insight, but I bled the lsp valve every time I bled the system. When I adjusted the back drums, I adjusted with some resistance on the wheels, I don't believe that's the problem either. I will re-check though. However I have not checked behind the drum brake wheel cylinder dust caps. This weekend, I'm gonna try soaping every connection within the system and have a friend pump the brake, Maby there is a small leak that flows air, but not fluid. The system is completely dry, with no visible leaks.
Any other thoughts or suggestions.

I'm debating on torching the vehicle, it's driving me

 

Have you thought about just letting the dealership take a look at it? I hate spending money too, but is all this headache worth $70?

You can let them find your problem and then you fix it. Or you can apply that $70 toward fixing the problem.

Just a thought

 

hey come on now, the joy comes from working on your own car and not paying a stealer money that might otherwise go towards a new lift

one more suggestion, if you car has ABS, try bleeding the modulator/pump whatever the heck it is called. I don't know why, but when I did have my Runner, I had the dealer look at my brakes and at the end he ask me if I had replaced my Power Steering pump? I of course replied yes, and he told me that once you do that, you also need to bleed the ABS. I never did get a chance to look on the pump and see if there is a bleed screw or not before I sold it, but hey's it's another idea. My class textbook manual says that some systems require their modulator to be bled and they do have bleeder screws on them.

 

My problem was on steep grades the pedal would be really sticky and go further down. I took it to Toyota (knew someone there) and they diagnosed it as a bad proportioning valve. Paid $135 (includes a slight discount), replaced it myself and no more problems. BTW, I did replace my master cylinder because I thought that was the problem. Hope this helps.