I have a 85 4-runner which I am in the process of upgrading the front brakes. I am using vented rotors for a 81 FJ-40, calipers from a 94 truck (2 large pistons per caliper), and a master cylinder with a 1" bore. From all the other post, I should have all the right parts.

I've installed all the parts with very few problems. I've bench bled the master cylinder then each wheel in the proper order, dr. rear, pass rear, pass front, dr. front,and then the LVPS. The problem is the brakes still go to the floor. I bled the whole system twice and used over 2 quarts so far.

Need advice, Would presure bleeding or gravity bleeding the system work better?

Thanks
Wilson

you didn't say if you did the lines or just replaced calipers if you did the lines check the flares if you made them if they are not seated they will leak so double check all connection you made if lines are rusty check for leaks

also may want to check if you bleed the proportion valve there is a bleeder on it as well up behind the pass rear where the brake line comes in just above that

I usually always try to gravity bleed them leaving the longest line to bleed the longest

also did you have the problem with the pedal going to the floor prior to the upgrade I recently had a power booster go bad and would have a pedal when not running as soon as it started pedal went to the floor

hope this helps you out brakes always seem simple but are a pain when things don't work out the way you would think they should good luck

Jim Ed

Thanks for the help Jim

Prior to the upgrade, my brakes were operating normally. I did have to replace one of the line cause I broke one while removing the caliper. I also stripped threads on the bolts that hold the caliper on which I repaired with a heilcoil.

I've checked for leak and found none. The pedal goes to the floor regardless of the engine running or not. The brakes do build up pressure if I double or triple pump the brakes with and without the engine running.

I'll try gravity bleeding next. When garvity bleeding, is the order the same as regular brake bleeding?

Thanks

Wilson

Yes!!!

Sounds like you may have a bad MC. Where did you get it? If it isfrom one of those "Lifetime" auto parts places, it took a friend of mine three trys before he got one that worked right, only to go out in three months!!! OEM <img src="/forums/images/graemlins/smile.gif" alt="" />

Yikes!! I bought the mc used from somebody on the board. I'll try another mc and see what happens.

thanks
Wilson

When you put that Master back on measure and make sure the rod from the Booster has the right gap. It could be too far away and the pedal travel is longer. New brake line and calipers were dry inside and could be holding air on the inside surface. You could pressure bleed and also use a rubber mallet and smack the caliper around to free the air bubbles.