I have searched the threads and have been unable to find info to my problem.

1989 F 250 4X4

Everything is new. MC, lines, flex hoses, calipers, wheel cylinders, ABS unit.

MC has been bench bled. If I cap off both ports I have a rock hard peddle. If I have just the rear hooked up and the front caped off I have a great peddle. If I hook up the front brakes alone ( rear caped off ) or with the rears hooked up I have a crappy peddle. It acts as if there is still air trapped. Peddle will stop about 2 inch off the floor. With the rear only It only goes down about a inch and stops. I have replaced all the hard lines once more, replaced the drivers side flex hose, tried another set of calipers all to no change. Only problem I can find is :

If bleeding with vacuum pump on bleeders on the drivers side if I get up to about 20" of vacuum it will start pulling Air. I can NOT find it! I have changed the flex hose, gone through about 8 sets of copper washers, I cant find a leak of fluid and there is no puddle under the truck. Also I have a good to fair peddle when the truck is not running. Once I start it and have the front brake hooked up I have a poor peddle.

When Vacuum bleeding I have a bleeder that is drilled all the way through so I can seat the bleeder and still pull fluid and air. I also have a power bleeder that you fill with fluid and hook to the master cylinder to use low pressure to help push fluid and it fills the M C as you go. No matter what I use to bleed its no good. I have even done the peddle pushing person to no avail.

I know I'm over looking something! If someone has a good idea whats happening please chime in. I think it's on the drivers side caliper but what is it? its all new.

Thanks

 

How are the rear brake shoes adjusted. To little and you will get crap for brakes. They should have a drag to them if you spin the tires up in the air when trucks in neutral.

 

Front calipers on the wrong sides, maybe? The bleeder screws should be on the top.

 

There not even hooked up so that does not help. When I just hook up the rear breaks I have a great peddle so the rear is fine.

There on the correct side. Not sure the flex hose would reach if the calipers were on upside down.


I have done 100 of brakes and only had a hand full of odd problems. There is some odd strange little bugger giving me troubles. As I said right now the rear is fine and there not even hooked up. the rear port is plugged off problem is in the front end.

 

You didn't get the wrong year master cylinder did you?
Thats all I got!
Jim

 

I dont know if this will help but i had a similar issue with a truck and it turn out the line connecting the hard line from the frame to the hard line on the rear axle (a flex line) was half plugged and it would kind of bleed right but never let all the fluid to the drums. Kinda sounds like your issue because your not leaking fluid at all. Replaced the line and rebleed from farthest to closest and worked.

Dont know if it helps, good luck.

 

What did you find?