86 bronco II rear disc brake problems

[peatypaul@yahoo.com]

I currently have a 86 broncoII with a 302 v8. Im having issues with the braking performance. The brake pedal seems spongy for the majority of the travel then gets stiff with out any extra response to the braking. It does stop but not as fast as i would like. I am not able to make any sudden stops because the the pedal gets hard with no added braking powere no matter how hard i press. I recently installed a 95 explorer 8.8 with disc brakes. I replaced the front and rear calipers and installed a master cylinder from the explorer and an adjustable proportioning valve. I have recently installed a vacuum storage tank to help but not knowing if vacuum is the problem. Im not sure if there is any residual valves affecting the pressure. The only issue with the master cylinder is the resivour makes contact with the booster so i shimmed it out to clear and adjusted the booster pushrod out. planning installing a master cylinder with the dual resivour to fix the clearance issue any suggestions??

 

[trail B2]

The Explorer has a more powerful booster as I understand it it has 2 diaphragms in it instead of one.In my 86 B2 I put a explorer booster in and it made it stop with easy pedal pressure when I put on 33s.Also the explorer master cylinder has a slightly larger piston than the B2 7/8 to 1" so your loosing leverage.Going over your mods it sounds like you need to change the booster too.

 

[peatypaul@yahoo.com]

did the explorer booster bolt up with out any mods? I looked at one from the junkyard and it appeared the bolt pattern has a bigger spread. It does have a new booster but a stock one for the b2

 

[peatypaul@yahoo.com]

I put in the explorer brake booster and the brakes are alot better now. Thanks for the tip