XJ Rear disc swap with Pics!

[kastein]

It does.

 

[DeftwillP]

--Not needed is a bit of an exaggeration. It's an open forum. C'mon, gimme a break. I'm not here to whiz in anyone's Cheerios.

Btw, how'd that Aussie work out for ya?

Its all good. I just meant that this is a thread specifically about adding discs to a 8.25, not a "which rear axle should I run". Since I've already got 4.56's, an aussie, and relocated shock mounts, should I swap axles to gain discs?

And since you asked, I actually just installed the locker a few weeks ago. Haven't had a chance to wheel it yet

 

[JOSEJALAPENO]

I put in the longer Liberty backing plate studs, glad i did, but wish i put in longer KJ wheel stud too. I read I did not need to with steelies but while it is OK as is I would feel much better with my thread depth closer to stock.

Josh

I also did the longer Liberty studs in the my 44. I am so glad i did, I just nice to just a bit more stud to grab on to..

 

[montanaman]

The only thing else to do is hook up the parking brake cable which I will do tomorrow.

Are you able to hook up the stock XJ parking brake cable to your new ZJ brakes? Or did you have to mod it?

 

[Veeb0rg]

You have to nip like 1/2 the spring and then loop the end around to make a hoop. Alternatively you can get the parking brake cables from Napa. Part numbers: 95969 and 95963. These work according to a guide I read, and they look right. No idea what vehicle they're off though.

 

[montanaman]

These work according to a guide I read,

Can you link to the guide that you mentioned?

I really want to do this mod now. I'm thinking ZJ rear disc system like 98xJeep's and the '98 ZJ proportioning valve, and a WJ MC/Vacuum boost.

I only wish I did this when I did the complete front & rear brake rebuild 2 years ago ... LOL.

 

[Veeb0rg]

http://www.cherokeeforum.com/f51/rear-zj-disc-brakes-cherokee-xj-chrysler-8-25-a-57807/

 

[kastein]

Also - I just noted something I missed on my first read through this thread.

OP - you used the backing plate studs that came with your 8.25 right? They look a little short, the nuts aren't completely on the studs in your pic because the disc backing plates are thicker. Ideally you should knock the studs off the axle tube flanges on the ZJ you pull the disc backing plates from and use those on your axle when you do the swap, they are long enough to get full thread engagement. It isn't the biggest deal in the world but I don't like to play games with my brakes. Next time you are in there to fix something else I would definitely put loctite on those nuts, the nuts in this case are staked all-metal locknuts and when you don't have full thread engagement, you risk them not actually locking onto the studs and possibly loosening.

 

[cruiser54]

Also - I just noted something I missed on my first read through this thread.

OP - you used the backing plate studs that came with your 8.25 right? They look a little short, the nuts aren't completely on the studs in your pic because the disc backing plates are thicker. Ideally you should knock the studs off the axle tube flanges on the ZJ you pull the disc backing plates from and use those on your axle when you do the swap, they are long enough to get full thread engagement. It isn't the biggest deal in the world but I don't like to play games with my brakes. Next time you are in there to fix something else I would definitely put loctite on those nuts, the nuts in this case are staked all-metal locknuts and when you don't have full thread engagement, you risk them not actually locking onto the studs and possibly loosening.

I just did this a week ago, Ken. I took the backing plate studs and wheel studs from the donor GC axle as the ones on the 8.25 were indeed too short.

 

[customcreationsllc]

another way to convert to disk brakes is to just use the weld on caliper brackets for the GM metric or standard brakes you can get the brackets from places like speedway motors and summit racing. The brackets are around $10 each and calipers are around $20
the metric is smaller the standard are larger.

The normal rear caliper disk brake conversion us very small calipers if you want to be able to use cutting brakes to do 3 wheel digs you really need larger calipers event the metric calipers are hard to keep the tire from spinning
The metric however also offer a built in e-brake version on one of the cadilac versions.
If not you will loose the e-brake I just install hydraulic parking locks not an e-brake but you can use it as a parking brake.

Just cut off the backing plate so you have the correct clamp on the bearings.
Buy an extra set of front calipers, align and weld on brackets you may need to grind the caliper brackets out to fit.

Also when converting to disc remove the o-ring on the check valve in the combination valve.

If your rear calipers get to large you may need a larger master or a proportioning vavle.
The metric calipers conversion I've done so far didn't need either.

Hope this helps

 

[Thunderhead7]

another way to convert to disk brakes is to just use the weld on caliper brackets for the GM metric or standard brakes you can get the brackets from places like speedway motors and summit racing. The brackets are around $10 each and calipers are around $20
the metric is smaller the standard are larger.

Very nice! Thanks

 

[Cody90XJ]

I've seen the weld on brackets for years but, never knew anyone that had used them.

Thanks for the info!:cheers:

 

[montanaman]

another way to convert to disk brakes is to just use the weld on caliper brackets for the GM metric or standard brakes you can get the brackets from places like speedway motors and summit racing. The brackets are around $10 each and calipers are around $20 the metric is smaller the standard are larger.

The normal rear caliper disk brake conversion us very small calipers if you want to be able to use cutting brakes to do 3 wheel digs you really need larger calipers event the metric calipers are hard to keep the tire from spinning. The metric however also offer a built in e-brake version on one of the cadilac versions. If not you will loose the e-brake I just install hydraulic parking locks not an e-brake but you can use it as a parking brake.

Just cut off the backing plate so you have the correct clamp on the bearings.
Buy an extra set of front calipers, align and weld on brackets you may need to grind the caliper brackets out to fit.

Also when converting to disc remove the o-ring on the check valve in the combination valve.

If your rear calipers get to large you may need a larger master or a proportioning vavle. The metric calipers conversion I've done so far didn't need either.

Hope this helps

Very cool. Will these work on a D35? What year of Cadillac calipers will fit on these brackets and have the built-in ebrakes? You also mentioned buying an "extra set of front calipers." What exactly did you mean by that? Were You just talking about the calipers to mount on the rear?

 

[kastein]

Very cool. Will these work on a D35? What year of Cadillac calipers will fit on these brackets and have the built-in ebrakes? You also mentioned buying an "extra set of front calipers." What exactly did you mean by that? Were You just talking about the calipers to mount on the rear?

I am sure you can find a way to do it, but you are wasting your money if you do. Buy an 8.25 for a hundred bucks and build it up till it's ready to install to minimize downtime.

 

[customcreationsllc]

Doing anything to a D35 would a waste of time and money but why wouldn't it work. As long as you can find rotors then you can just weld on the brackets. 5 on 5.5 rotors are hard to fine dodge 1500 around 2000 use them but not to many 5 on 5.5 knock off rotors. also have to consider rotor thickness

As for the version with the ebrake
go on speedwaymotors.com and search the GM brackets they list the years and stuff you need the ebrake version uses smaller pistons and are around $90 each.
a hydraulic parking lock is $30 from speedway.

The standard calipers you can get in a wider rotor version and the piston is larger these are what they use on the 14bolt and stuff disk brake conversions.

Good luck

 

[cruiser54]

Aren't we 5 0n 4.5?

 

[customcreationsllc]

yes OEM XJs are 5 on 4.5 but to get anything stronger than a D30/D44 with unit bearings you need to go to 5 on 5.5

For the 5 on 4.5 I just use the front rotors from an XJ I don't think rear rotors will work the GM calipers are front brakes so larger pads.

 

[Blk96XJ]

Im going to look for these parts here soon, after i find out if mines a 29-spline. Got any more info on the parking brake cable. I need longer ones, and if I end up doing this Ill just buy new ones.

 

[XJensen]

Doing anything to a D35 would a waste of time and money but why wouldn't it work. As long as you can find rotors then you can just weld on the brackets. 5 on 5.5 rotors are hard to fine dodge 1500 around 2000 use them but not to many 5 on 5.5 knock off rotors. also have to consider rotor thickness

As for the version with the ebrake
go on speedwaymotors.com and search the GM brackets they list the years and stuff you need the ebrake version uses smaller pistons and are around $90 each.
a hydraulic parking lock is $30 from speedway.

The standard calipers you can get in a wider rotor version and the piston is larger these are what they use on the 14bolt and stuff disk brake conversions.

Good luck

I have been struggling with the direction of my new rear disc set up all morning. I wanted to go with a weld on bracket and GM calipers, the Ruffstuff approach. But I did not want to loose my e-brake in the end.

Looked into drive line brakes, $320 yikes, and the speedway motors calipers with e-brake built in. How do you like the sppedway calipers.

I was leaning this way until you mentioned the PARK-LOK HYDRAULIC BRAKE for $30. This would be a great cheap way to go.

 

[Begster]

I have been struggling with the direction of my new rear disc set up all morning. I wanted to go with a weld on bracket and GM calipers, the Ruffstuff approach. But I did not want to loose my e-brake in the end.

Looked into drive line brakes, $320 yikes, and the speedway motors calipers with e-brake built in. How do you like the sppedway calipers.

I was leaning this way until you mentioned the PARK-LOK HYDRAULIC BRAKE for $30. This would be a great cheap way to go.

To be honest with you, I wouldn't go this way for an e-brake. As you know the "e" stands for emergency, which means that it is there for you to use in an emergency situation. The main emergency situation you would use the e-brake in would be in the event of a hydraulic failure, such as a burst line, etc. With that park-lok, if you lose hydraulics, you lose both the brakes and your sole back up for events like this, leaving you SOL.

Having personally been experienced hydraulic failures that required me to use the e-brake (both on and off road), I would never use that type of system for an e-brake.

My rear disk set up on my D44 is:
Explorer rear brakets/caplipers/pads/e-brake set up and ZJ rotors drilled to 5x5.5

Works good.