rear disc from grand cherokee on a 8 3/4

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stansblue72

stansblue72

one of one 1953 ME!
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After seeing daniel depetro's post in the rear disc conversion thread about being able to use jeep grand Cherokee rear disc brakes I decided to try it.

I found a fellow that was parting out a 94 and bought the rear disc's off him for $50.

So we pulled the 83/4 out from under my 72 dart and stripped it down.

disc%20brake%20conversion.jpg


The first thing we had to do was drill the fifth hole through the dust shield and caliber housing as they only had four.

disc%20brake%20conversion%20001.jpg


Here they are drilled out and installed on the rear end.

disc%20brake%20conversion%20005.jpg


This is with the rotor mocked up with no axle in.

disc%20brake%20conversion%20003.jpg


These pictures are a little fuzzy but what I found out was that the hole through the middle of the caliper housing was not big enough for the axle baring to go through.

disc%20brake%20conversion%20006.jpg

disc%20brake%20conversion%20007.jpg


So out came the die grinder and in about 30 minuets I had the holes big enough.

disc%20brake%20conversion%20010.jpg


Here's a pic of the brakes on minus the dust shield ( I haven't made the hole big enough for the axle barring to go through it yet).

disc%20brake%20conversion%20008.jpg



Just for sh*ts and giggles After installing the axles I tried putting one of my stock 14" rally wheels on to see if they would clear the calipers.
No dice they won't work.
So that's where I'm at on the conversion my next step is to find me some bbp axles for my 8 3/4. Guess I'll be talking to Dr. Diff in a few days.

Then try to figure out if I can come up with some kind of parking brake.

Thanks to member daniel depetro for the idea.

More to come!!!

We're going to try this conversion on my son-in-laws 8 1/4 too.
 
Hi. My brother is doing the same conversion on his Duster right now, 1973 8-1/4 rear. He didn't have to drill any holes just grind the hole in the bracket a little larger as you did. It's almost a direct bolt on. He is also trying to figure out parking brake cables, nothing yet. I'll let you know if he comes up with something. Bobby
 
I'd like to see how this turns out, nothing beats DIY home brewed swaps. I think it was a Staple of Mopar life until the great mopar craze of 2005 brought all the plug and play parts like the GM tards get.
 
Doesn't the later model JGC have a drum style e-brakes, 97-99? Why not just use the whole assembly, or is there some sort of interference? This would give you e-brakes and rear disc's, best of both worlds. Now are the calipers from the earlier models using a cable to clamp the disc for an e-brake?, if so why not have one made to fit the caliper and the factory stuff from your cars? I'm asking all these questions cause I'm gonna do the same thing, just looking for the best options.
 
You might be able to but I think you would have to eliminate the fifth bolt, the jeep only has 4 because that is where the wheel cylinder is for the e brake. Not sure what that would do to the strength of the axle flange as far as holding it in on the 8 3/4.
We ran in to another problem the axle dosn't stick out far enough to allow propper alighnment for the rotor to the caliper.
We would had to have added a backing plate to the rotor. Looks to be around 3/4 of an inch.

We have a 8 1/4 sitting in the shop so we dismantled it and tried the jeep disc's on it. They seem to be a direct bolt on and everything lines up good.

So for now we're going to forget about putting them on the 8 3/4 and put them on my son-in-laws 8 1/4 under is dart.
We'll be doing that this friday so i'll take pictures and post here.
 
I tried the same thing on my 8-3/4 and found the caliper bracket was so thick it moves the axle bearing almost half way out of the axle tube, not to mention the splines are out of the diff by the same amount. If you order custom axles to fit I think it would be fine. I already have the yukon axles so oh well.

PS the emergency brakes cleared everything also, and I was going to reuse the jeep cables.

I gave up for this year also.
 
I have an 8.75 in my Volare and was all excited about this till you guys ran into spacing problems. I had an idea and maybe you guys can look at your setups and see if it is possible.

What if you chopped the bottom part of the bracket off? Where the 5th bolt would go on the bracket to mount it without having to remove the axle. It would just slide over the part of the axle that sticks out. Failing that could someone measure the width of the mounting bracket for me?


Thanks,
Dan...
 
We put the jeep rear disc's on my son-in-laws dart today. Every thing bolted right on, brakes seem to work good. We did buy new rotors and pads so total for the conversion was around $150. not to bad I think!

They work good on the 8.25 but look like some modifications would need to be made to get them to work on a 8.75.

The End!!!! :toothy4:

Rear disc's.jpg
 
I installed an 8 1/4 in my 1967 barracuda fastback and im planning on doing this swap also. Do the emergency brake hardware from the jeep work with the 8 1/4 a body rear? Did you have to weld a mount on the housing for the caliper hoses? Thanks man!
 
what about a 95 jeep grand cherokee Laredo..I just got one super cheap that is dead no run.....
 
RPMmachine said:
I installed an 8 1/4 in my 1967 barracuda fastback and im planning on doing this swap also. Do the emergency brake hardware from the jeep work with the 8 1/4 a body rear? Did you have to weld a mount on the housing for the caliper hoses? Thanks man!
Click to expand...

We didn't use the e brake hardware on our swap but I can't see why it wouldn't work if you could figure out how to hook the e brake cable up to them.
We didn't have to weld anything on the housing the caliper hoses hooked right into the existing brake lines. We did have to bend the lines some to make it work though.
 
So am I understanding this correctly that there are no clearance issues with the parking brake assemblies when the Jeep kit is installed on the 8 1/4?

I have the brake gear in the garage, but I thought there were issues with the axle standoff that kept the park brake assembly from fitting properly?

If not, cool beans. I am getting custom axles from Dr. Diff due to the late model 29 spline Dakota carrier I am using. He is going to set them up with a Jeep center register so I won't need to grind the rotor out. I have not ordered them yet, but will be soon.
 
i cant see the jeep bracketry,,maybe a spacer can be made to space the bracket inwards,,,,spacing it out wards would make tire clearance an issue on some models,,,finally the 8 1/4 gets it due
 
Damn it Stan, you just gave me a new project for the 8 1/4 sitting on my workbench! So doing some checking the interchange is something like this...

Rotors = 94-98 Grand Cherokee
Pads = 94 Grand Cherokee
Calipers= 94-96 Grand Cherokee


You said that the lines work but what about the proportioning valve?
There is no clearance issues with the 8 1/4 and stock 14" wheels?
Can we get some more pics from all angles?
 
i believe he said 14" rims will not clear, but the first poster says 15" fit fine,,,
 
We put a stock 15" ralley wheel on it and it cleared fine, the 14 did not it hit the caliper. His car has front disc's so we used the existing proportioning valve and it seems to work okay.
We didn't have the e brake assembly to try it on so really don't know if it is a perfect fit or not. But it looks like it would fit.

Look at it this way J.R, now you have something to do besides watching Oprah !!!
 
Oh darn...and I was looking forward to her next show.....god I hate that woman!:angry7:

I still need to measure the driveshaft in my car and come up to your place.
 
Green,
let me ask this.What if I shortened my 8 3/4 axle tubes 3/4" on each side, to make up for the difference? would that make it work?
Andrew
 
We just eye bald it on the 3/4". The stud end of the axle would need to stick out past the housing some where around 3/4 to an inch father to be able to get the rotor to line up with the caliper.
The e brake hub on the rotor is what causes the difference.
So I don't know if it would work, we gave up on it at that point and installed the set up on Larrys dart with a 8.25 under it.
 
Damn, I knew I was looking for an 8 1/4 for a reason. Now if I find one I will know more to do with it.
 
does it make a difference if you remove the brake assembly off of a jeep with a dana 35 rear axle or does the jeep have to have an 8 1/4? there were two rear axles optional in the 1994 through 1998 jeep cherokees, dana 35 and 8 1/4
 
Just so I completely understand, no one has done the 8 3/4 swap---cause I dont see any pics. Seems the 8 1/4 is simple bolt on, but the 8 3/4 is more of a hassle? Does this sound correct?
 
The guy we bought the jeep parts from said it was a dana rear end under the jeep.

The swap to the 8.75 might be possible, but it was over my head on what needed to be done so we just put the disc set up on the dart with the 8.25 under it.
 
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