Brake Problems

[8t7jimmy]

I need some help with my brake problems. The brakes suck. I use to be able to almost lock up the brakes (rear won't lock because of ABS), but now i don't think they would lock up on ice! Also, if you sit stopped for a while the brake pedal will slowly sink to the floor. The truck is a 89 K1500, short bed reg cab. I do have 285/75/16 (33's), BFG ATs but i still have the problem with 265/75/16 (Factory Size 31's),tires.

Here is what i have done
New pads all the way around.
Blead the system twice.
New master cylinder.
New brake hoses all the around.

I think that it is either the problem with the proportioning valve or ABS system. Does anybody have any ideas.

Thanks

 

[88sub4x4]

Make sure the rear brakes are adjusted properly, then check the proportioning valve, although it may be electronic and be inside the abs unit.