XJ Rear disc swap with Pics!

[96XJ_4.0]

Please please make a list in the OP of the ALL the parts you took of the GC.

Thank you!

 

[Crusher16]

I got studs for a ZJ rear axle. Thread engagement seemed fine to me with the stock studs when I put disk brakes on my D35. When I swapped out the D35 and put in an 8.25 and kept the disk brakes is when I put in the ZJ studs. I also used the stock parking brake cables.

 

[M4Madness]

Please please make a list in the OP of the ALL the parts you took of the GC.

Thank you!

You'll need the following:

Caliper mounts/backing plates (with parking brake hardware)
Calipers (with bolts)
Rotors
Brake hoses (the rubber section)
Studs/nuts that attach mounts to axle
Wheel lugs (studs) if you can remove them

 

[XJensen]

Hey thanks all for the comments! Yes its a 8.25. I should have gotten longer studs but I feel like there is enought thread engagement to be more then fine. As for the parking brake...You can modify the stock one, which i was going to do but the pass. side got messed up from wheeling and didn't work. So I am either going to buy new stock ones or by liberty one. Most likely I will go with the Kjs.

Are KJ cables long enough. I though I read Explorer or was it sport trac cables will work for length and have the proper ends.

Josh

 

[danny Benavidez]

what about the drum brake pads that work only with the parking brake ?
And do you also get them from the grand cherokee or do the XJ work ?

 

[M4Madness]

what about the drum brake pads that work only with the parking brake ?
And do you also get them from the grand cherokee or do the XJ work ?

The parking brake shoes on an ZJ are way smaller than the drum brake shoes on an XJ. You can use the parking brake shoes from the salvage yard ZJ if they aren't in too bad of shape. I think they can be bought new from Autozone for something like $20.

 

[kastein]

its been a while since i payed attention to the inside of a 35, but that looks more like an 8.25 to me. (plus the plates from a zj 35 will bolt on to an xj 35 without needing to open up the center hole).

also, for the benefit for those searching, pull the studs and nuts that go from the axle housing to backing plate. they are longer than the stock xj studs and fit better with full thread engagement. a punch and bfh make sort work of removing them).

Already answered, but look for the 35c stamp in the upper right case/tube gusset (right above the right tube) and you can see the corners of the flat lower lip on the 8.25 if you look closely.

Wow its about time someone did a proper job on the write up with EXCELLANT PICS that were NOT taken from a cellphone and were in Focus!!!!!!

THANK YOU THANK YOU!

Wow the Junk Yard sold you all those parts for 20.00 Damn! Lucky!

Fully agreed! Great writeup. I'd probably pay ~40 around here for those parts. You can get rebuilt/remanufactured calipers for ~25 each on rockauto usually.

 

[M4Madness]

I'd probably pay ~40 around here for those parts. You can get rebuilt/remanufactured calipers for ~25 each on rockauto usually.

The salvage yards in my area want to sell complete rear axle assemblies and won't let you pull the caliper mounting brackets off. I finally had to pay a gear shop $110 for the used hardware from a ZJ axle they'd junked.

If you could find a junked Jeep Liberty (KJ), the brakes are a direct bolt-on without the modifications that the ZJ brakes require.

 

[JNickel101]

Are KJ cables long enough. I though I read Explorer or was it sport trac cables will work for length and have the proper ends.

Josh

KJ cables are plenty long (too long, IMO) - and yes, cables from a 1996-ish Ford Exploder will work (better, again, IMO).

 

[Ogrebonz]

I finished my disc swap last weekend. If you think the swap to discs is an improvement, swap to a '98 Grand Cherokee proportioning valve. It makes an incredible difference. The valve cost me $12.00 at a salvage yard and I got a 12v power outlet thrown in too.

I found a core rear end from a '98 Grand in a salvage yard for $100.00. I got that back with the core charge for new calipers. Altogether I'm into the swap for les than $400.00 with new calipers, rotors, pads, p-brake shoes and a hardware kit. I also spent the money for ZJ wheel studs. I was able to cable clamp the ends of the XJ p-brake cables to the actuating arms. So far everything works perfectly.

 

[XJosh95]

I finished my disc swap last weekend. If you think the swap to discs is an improvement, swap to a '98 Grand Cherokee proportioning valve. It makes an incredible difference. The valve cost me $12.00 at a salvage yard and I got a 12v power outlet thrown in too.

I found a core rear end from a '98 Grand in a salvage yard for $100.00. I got that back with the core charge for new calipers. Altogether I'm into the swap for les than $400.00 with new calipers, rotors, pads, p-brake shoes and a hardware kit. I also spent the money for ZJ wheel studs. I was able to cable clamp the ends of the XJ p-brake cables to the actuating arms. So far everything works perfectly.

Ford Exploder 8.8 Axle w/discs: $125, RuffStuffspecialties.com 8.8 swap kit $120, a little bit of work: Free....~$250. Finally by my math 250>400. I know it's not the easiest and you'll need a pinion flange adapter for your driveshaft, but if you can do the work, way worth it. Not to mention the extra strength of the 8.8 you may or may not ever need.

 

[Gigantor]

Nice job.

 

[ericfx1984]

also, for the benefit for those searching, pull the studs and nuts that go from the axle housing to backing plate. they are longer than the stock xj studs and fit better with full thread engagement.

people running steel wheels should be good to go I would think

 

[yossarian19]

Ford Exploder 8.8 Axle w/discs: $125, RuffStuffspecialties.com 8.8 swap kit $120, a little bit of work: Free....~$250. Finally by my math 250>400. I know it's not the easiest and you'll need a pinion flange adapter for your driveshaft, but if you can do the work, way worth it. Not to mention the extra strength of the 8.8 you may or may not ever need.

Flange = $50 or so.
+ welder, supplies & skill to do it safely.
+ $50-$130 wheel spacers, if you like your current track width
and, FWIW, I've yet to see a $125 8.8 with discs, anywhere I've been

Then there is the gearing to consider - may or may not be an issue...
I know I'm beating a dead horse, but the "just go 8.8 swap, dood!" argument doesn't work for everyone.

 

[Ogrebonz]

Ford Exploder 8.8 Axle w/discs: $125, RuffStuffspecialties.com 8.8 swap kit $120, a little bit of work: Free....~$250. Finally by my math 250>400. I know it's not the easiest and you'll need a pinion flange adapter for your driveshaft, but if you can do the work, way worth it. Not to mention the extra strength of the 8.8 you may or may not ever need.

I respect your opinon, however:


If I had needed a stronger axle (I don't) and if I could be without the XJ (it's my DD) for a few weeks while I fabbed the mounts (I don't have the free time) I would have gone with the 8.8. All I wanted was disc brakes and a bit of a safety margin if I snap an axle. BTW, my costs included new rotors, calipers, pads, p-brake shoes, hardware kit, wheel studs and (I forgot to mention earlier) rubber lines. The proportioning valve is used, but was $12.00 and makes all the difference in the world.

As it is, I'm silly-happy with what I have. FWIW, over the last 23 years I've owned 16 four wheel drive vehicles, 9 of them Jeeps and this is by far my favorite. :gee:

 

[DeftwillP]

I finished my disc swap last weekend. If you think the swap to discs is an improvement, swap to a '98 Grand Cherokee proportioning valve. It makes an incredible difference. The valve cost me $12.00 at a salvage yard and I got a 12v power outlet thrown in too.

I found a core rear end from a '98 Grand in a salvage yard for $100.00. I got that back with the core charge for new calipers. Altogether I'm into the swap for les than $400.00 with new calipers, rotors, pads, p-brake shoes and a hardware kit. I also spent the money for ZJ wheel studs. I was able to cable clamp the ends of the XJ p-brake cables to the actuating arms. So far everything works perfectly.

What year is yours? I've heard that only the older ones need the grand valve.

but the "just go 8.8 swap, dood!" argument doesn't work for everyone.

thank you. It's amazing how often the 8.8 homers interject when not needed.

 

[Ogrebonz]

Mine's a 2000, and didn't come with anti-lock, though I did use a valve from a Grand with antilock. I wonder if there is a difference.

 

[XJosh95]

Flange = $50 or so.
+ welder, supplies & skill to do it safely. -This is a must!
+ $50-$130 wheel spacers, if you like your current track width -I have yet to install so I don't know how the track will be, I'm curious though.
and, FWIW, I've yet to see a $125 8.8 with discs, anywhere I've been -I actually paid $140, but the extra $15 was for them to cut it out.

Then there is the gearing to consider - may or may not be an issue...
I know I'm beating a dead horse, but the "just go 8.8 swap, dood!" argument doesn't work for everyone.

-I wasn't necessarily saying it's the best route. I've considered many times over to do a disc swap on my 8.25 and just found the 8.8 to be financially an easier option...until I ordered a big box that said Detroit on the side.

What year is yours? I've heard that only the older ones need the grand valve.



thank you. It's amazing how often the 8.8 homers interject when not needed.

-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?

 

[kastein]

The 8.25 I put in my MJ with a ZJ disc swap has been doing great. Better than the stock drums with no prop valve change... and yes, the MJ uses a different proportioning setup so I know this probably affects my results.

I will probably be going to an 8.8 soon but not due to durability or anything else, mostly because I am considering upgrading to 4.10 gears, I already have an 8.8 with 4.10s sitting in my storage unit stripped down waiting to install and most of the parts on hand. The 8.25 is a perfectly fine axle that will stand up to a LOT of abuse, even in 27 spline variety. I thrashed the hell out of my 27spline 8.25 on 33s (open, 3.55s) for quite a while and never managed to break it. In fact I stretched my U-bolts 1/8" and badly wrapped/sagged my leafs instead of damaging the axle at all.

 

[Ogrebonz]

Does the MJ use a load-adjusting valve? IIRC I had a Toyota that had one of those.