Dana 60 Rear Axle Disc Brake Problems

[bowsher]

I am new to all this forum stuff but i hope i am doing this right.  I am currently running a dana 60 rear end and a dana 44 front on my 89 comanche.  I reciently did a rear disc conversion on the jeep.  I am now experiencing a spongy pedal that goes to the floor.  I blead and blead the brakes and even ran all new lines.  I reciently took the prop. valve out to see if that might help but nothing.  This is probably something really easy that i am just not catching on to.  I am also running 38" tires if that means anything.  If anyone has any input it would greatly be appriciated!  thank you

[Thomas]

First off we need pics!

Do you have the stock master cylinder? If you do it may not be up to the new calipers volume of fluid they need. I would try a 95+ master cylinder and brake booster.the booster is dual diaphragm which helps a ton! It did on mine!

Good luck!

[bowsher]

Thank you!  Sorry for the lack of pics.  It will not let me load any for some reason.  I am running the stock master and booster.  What model should i get the booster and master from?

[Thomas]

I got mine from a 95+ xj. I've heard wj master cylinder work too but I don't have any experience with them...you will have to make new front brake lines possibly...get the prop valve while your at it!

[mvusse]

With rear disc brakes, take the load sensing valve out of the system and get a prop valve for something that has rear discs, like an Exploder or a ZJ. And yes, the dual diaphragm booster is a great upgrade, but the windshield washer reservoir will need to be moved forward a bit to clear it, and you will need to modify it to hook up to your brake pedal, unless you also swap the matching brake pedal in.

[Bounty Hunter]

Are the rear calipers in the correct side? Make sure the bleeder valve is higher than the brake line attachment or you'll never get all the air out of the system.

[87Warrior]

You probably need more volume for the larger brakes. Search Pirate4x4 for 'Ram 2500 Master Cylinder' in the Cherokee section. Or just review the brakes section of the Jeep Bible over there.

[HOrnbrod]

Are the rear calipers in the correct side? Make sure the blessed valve is higher than the brake line attachment or you'll never get all the air out of the system.

 

Yeah, that^^. And what calipers/rotors did you use for the conversion?

[87Warrior]

 

Yeah, that^^. And what calipers/rotors did you use for the conversion?

I'm assuming the '75 Chevy K20.

[bowsher]

yes i am using the chevy calipers.  I do have the bleaders above the brakes.  I think I will try out the master cyl and booster from a 95+  Thank you for all the help and input!

[Bounty Hunter]

I used a master cylinder from a '79 Grand Marquis with 4whl discs, and a Grand Cherokee 4whl disc proportioning valve.

[Dirteatr717]

Most people upgrade to a dual diaphragm booster and a ram 2500 master or a E350 master cylinder when running full width axles. Post pics!

[bowsher]

Well just for an update, I went with a master and booster from a 98 grand Cherokee that had 4 wheel disk brakes. It was a dual diaphragm. Didn't have to do any install mods except the pushrod had to be drilled in order to get the lock pin and bushing in. Just took it to the local off road park and it worked excellent! Thank you everyone for all of the help!