Mind Boggling Brake Problem

Ok to start out here is some info:
88 cherokee w/
8.8 in rear w/discs
'92 D30 in front

I had to replace the frontend in the jeep and the junkyard told me the 92 d30 was the same and would swap in. Everything was the same untill I got to the brakes. The new frontend had different calipers, rotors, knuckles, hubs. So i just switched in the 92's and hooked everything up. But when I went to bleed the brakes I get no pedal at all; it goes right to the floor. But, when bleeding the brakes, I start from the rear furthest from MC and I get no air and fluid shoots at least 7 feet from the caliper. So I am getting plenty of fluid and no air but just have no pedal. So from here I figured it may have something to do with the MC or proportional valve. So I changed in the 92 prop valve and MC and it helped none. I still get plenty of fluid to the calipers but have no pedal. Any help is appreciated, because Im totally lost with why Im not getting any pedal.

If the calipers came from the junkyard, check to see if one (or both) of them are seized. Did you bleed the master cylinder when you swapped it in? Ideally you do it on the workbench before installing it (hence the name "bench-bleeding"), but you can do it if it's already mounted.....just be very careful not to overextend the piston by using the brake pedal to do it. Use very slow, short applications...no more than an inch of pedal travel.
Jeff

Those 92 calipers have a larger bore piston in them when compared to your older calipers.

I'm told the 8.8 disc brakes require more fluid than the stock drums as well.

Perhaps the combination of both front and rear brake requiring more fluid means you don't have enough capacity in your M/C bore.

How were your brakes before you put the 92 front axle in?

Just an FYI...you can put all your old stuff on the 92 axle from the ball joints out. I.e. outer knuckles, hubs, rotors, calipers etc and it will work fine. You can do this if you want to go back to your old setup.

Jeff:
I did check the calipers to make sure they weren't seized up and bled the MC according to the directions it gives.

Bender:
I realized after I changed all the brakes out that I could of just changed the old knuckles/out from the 88, but the problem was that I exchanged all my old stuff for the 92's at the junkyard to cut costs of crap. But I guess if I can't figure out the problem I will just have to buy the 88 stuff from the parts store and bite the bullet.

I thought that maybe that the bore of the MC may be too small too, but I got to thinking and there are people that swap in 8.8's into 92 and up cherokees and dont have a problem, because as of now I have everything from the 92 installed, except the power booster (would that make a difference?). As far as how my braking was before the swap, everything was perfect. I did the ole O-ring trick with the pvalve and had much more braking power than with the old d35 drums.

btt

I don't know if this will help, but check the part numbers for the combination valve between what you had and what you swapped. Also, most combination valves have a reset button on them. Check to see if you have that.
Ed
web/gadget guru