Axle swap, now horrible brakes

THE guyrock

THE guyrock

Gentle Giant
Joined
Jun 26, 2012
Location
Greenville
I swapped a pair of 79 ford axles under my 95 grand cherokee with new calipers-pads-rotors on the 44 up front and good shoes-wheel cylinders out back on the 9".

Bled them RR_LR_RF then LF, from farthest to closest. And so much that the fluid is coming out clear, still super soft pedal. All stainless lines, and good brake parts far as I know. Could the ABS unit not functioning cause this? Though I dont see how since I've bled the brakes before with it still being in there and not working and they bled fine. Just stumped and really want to go wheel it.

just need to figure this out and the death wobble and she's good to go. Thanks for any help guys
 
Master cylinder may very well be too small to make the brakes work like they should. I'd bet the stock brakes are much smaller than the ones on the 44/9 combo.

I've got the same sort of deal, to a lesser degree, going on with my Silverado. It's got HUGE Ford Dana 60 dual piston calipers up front and duals on the rear now. I really need to swap on a 2500HD master cylinder. Stops fine as it, but could use a better pedal feel.
 
Yeah, MC is probably undersized for your calipers now.

And honestly, this is a separate issue, but those Ford D44 fronts had crappy calipers on them to begin with. You'll have to do a little research, but my memory is that there's a car caliper from the same era (LTD or something like that) that has bigger pistons and swaps right in. If your master cylinder is too small, that's only going to make that problem worse, though.
 
Soft or spongy brake pedal can be several things. Usually related to air in the lines, an old rubber line "ballooning" under pressure or drum brakes not adjusted properly. I'd start with the rear drums and make sure they are adjusted to a slight drag.
 
You probably need a bigger MC
 
I agree it could be the MC but it could be so many other things. You have a MC and proportioning valve designed for 4 wheel disc brakes. That's an issue with now having drums in the rear. MCs generally don't go bad, especially a 95. I have had several semi stock rigs with 1 ton axles swapped in that the stock MC performed adequately. Not saying you couldn't use a larger MC, just saying it could be other things in conjunction with the MC. FWIW, I did the E350 MC swap on a YJ ton'ed rig once and it didn't really help my braking. Just sayin ..... trouble shoot instead of throwing parts at it.
 
Hopefully its just a bubble i have somewhere. Going.to bleed them again today with a brake vaccum. I've replaced the front calipers with chevy K10 units and just put some speed bleeders in.

MC should be adaquate I would think, but I'll look.into another unit. Any larger ones that swap right in? I have a local friend that did the same swap and still uses his stock MC and his brakes would stop a train.haha.

I'll post up in a few if the re bleed/new bleeders help.
 
This swap has been done countless thousands of times. I'm sure if you look around on the net there is info on a good sized master that will bolt in. I also agree with JC though, rule out everything else.
 
One of calipers is holding air, I've had this happen three times and it took me hours to figure it out the first time. You cant bleed it normal. Pull the caliper hit the brakes a couple time to push the piston out, crack the bleeder and squeeze the piston in with a pair of channel locks or a c clamp.
 
Thanks guys. I took the calipers off and pumped them, then adjusted the drums and re bled the system with a vaczilla. I could stop a mac truck now. Haha

Thank you for the fast responses. I guess with all the work I did the last two weeks on it I over looked one or two tiny things. I am ditching the drums monday when I put the chromo shafts in and doing the 3/4 ton disc swap in the rear.
 
CarolinaTruggies said:
One of calipers is holding air.
Click to expand...

LOL... you just reminded me. A buddy of mine had a problem kinda like this one time. We went round and round over what could be wrong. Turns out, he had the calipers on the wrong sides. It put the bleeders at the bottom.

:beer:
 
Are the dual piston Ford 60 calipers known the hold some air too? I'd love to know that I don't need to swap in a 2500HD MC to make them work. However, the rear calipers on the AAM 11.5 are the same calipers that used to be on the front with IFS....so, they're pretty damn big.
 
shawn said:
LOL... you just reminded me. A buddy of mine had a problem kinda like this one time. We went round and round over what could be wrong. Turns out, he had the calipers on the wrong sides. It put the bleeders at the bottom.

:beer:
Click to expand...
My 79 GMC was like this when I got, it stopped fine. Did'nt realize it till I was changing to longer brake lines. So I swapped them, had a slight pull to right for a split second before left side caught up. Finally bought new calipers,problem solved. Still can't figure out how PO bled all the air out!
 
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