Toyota 4Runner brake question

[fastpakr]

I've been helping a friend with his '90 4Runner. Trying to chase down a soft brake issue that existed when he purchased it. Rear brake components appear to be brand new, and we put on new front pads and resurfaced the rotors a couple of weeks ago. Also completely flushed the brake fluid and bled the system carefully. All said and done, we haven't managed to eliminate the spongy brakes. There is feedback to the pedal, but it is limited and you can push the pedal to the floor without that much effort.

I haven't found any sign of fluid leaks. At this point, is there anything else to check except ballooning rubber lines before replacing the master cylinder? I want to make sure that if we replace a part we get it right the first time.

 

[Dead_Moose]

If its an abs vehicle there might be a bit of air trapped in the pump, make a couple of abs stops (dirt road, alley ect) and re bleed. It might not be it but its cheep and easy to do. One way to check if its the master (or air in the lines somewhere) is with the truck off pump the brakes a couple times to deplete the booster and then press and hold the pedal, if it slowly goes to the floor the master is suspect. If it holds, but feels soft, pump it 3 or 4 times and hold it, if it feels firmer there's air somewhere. hope this helps a bit

 

[fastpakr]

No ABS. I'll double check the pedal with the truck off tonight when he stops by. Thanks for the suggestion.

 

[mhughes165]

yo man, its actually quiet simple, usually those rear brakes are a mother ****er to get right, its probably the proportioning valve on the rear end, its the valve on the passenger side of the frame rail. also, if the rear brakes arent adjusted properly and the e-brake doesnt work then u will experience a soft pedal in these trucks. thats where i would start

 

[fastpakr]

Thanks. While the truck eventually ended up at a shop because we had trouble coordinating time to work on it, misadjusted rear brakes did turn out to be one of the primary issues. Oddly, we were continuing to get air in one of the brake lines as we bled, but apparently once the brakes were adjusted that problem went away. I can't wrap my head around that, but as long as it works everybody walks away happy. The shop only charged $42 for diagnosis/repair, so he's very satisfied.

 

[Jay FX4]

The shop only charged $42 for diagnosis/repair, so he's very satisfied.

Can't beat that!