XJ rear disc brake conversion ??

[autotech98]

i have heard you can switch the rear drums to discs on your xj by using parts off a zj.anyone done this?? i have a 98 sport.any help would be great.

[XJ Wheeler]

I just got through doing this. Its a great swap. What would you like to know?

[autotech98]

what exactly do you need from donor vehicle,how hard is it,and is it worth the effort.mine is my daily driver and i commute 27 miles each way to work and while i love my xj the braking could be better

[autotech98]

i just read on here that rear discs from a liberty will work.anyone done a write p on this ?

[XJ Wheeler]

On your first question you will need from a Zj...
-Backing plates/caliper mounts with the parking brake hardware and shoes
-Rotors
-Calipers with pads
-Lug studs
-Brake hoses to caliper
For the parking brake you can use Liberty cables. They are a bit long but just coil it and tie the excess up. I haven't done this yet and am also looking into explorer cables as they are suppose to work but not be so long.
Also you will need (8) 3/8"-16x1.5" grade 8 bolts with nuts for the backing plate assemblies.
For the parts from the donor vehicle, condition will negate what will need replacement on parts like pads and shoes.

Second question... I would say moderate. You will have to grind open the center hole if you have the 8.25 rear axle, not on the dana 35. The brake hose has to be bolted down. You can screw it to the shock mount but I don't like how it hangs down. I made and welded a bracket on to the housing. You also will need to either bend the brake line to meet the hose or cut, reflare, and bend the line to do the same. I personally don't like the first option cause the line is old (if original) and won't like being messed around with too much. And of course you have to remove the axles. Its not hard at all, easy actually. And a good time to change out the wheel bearings and seals.

Third question... Yes, I do believe so. Of course everyone is different but I was having quite a few problems with the stock drum brakes and really don't like drum brakes in general. If you think about it drums have about 12 moving parts to come together to apply braking pressure, whereas these discs only have one. I could instantly feel the difference. No more adjusting, one wheel locking up, or leaking wheel cylinders. My pedal feels great too. Some also swap out the proportioning valve for the zj version. I will probably try it but I don't see it being a necessity. I am coming out of my break in period for the pads so soon I will be "testing" to see just how it does with hard braking.

5956

Any more questions, feel free to ask.

[XJ Wheeler]

i just read on here that rear discs from a liberty will work.anyone done a write p on this ?

Yes, you can do that instead. Its done very similarly to the Zj swap. I actually wanted to do this but there were no Kjs in our junkyards, whereas I had my pick of Zjs to pull from.

[autotech98]

great pic,and thank you for all the info,i think the last time i was at my local jy they had one liberty and about 10 zjs.i have a limited budget( i have two teenaged daughters) and like to build things myself instead of just buying stuff.pretty sure mines the 8.25 so the liberty seems the way to go.wonder if the porportioning valve off the liberty would work too. my xj is mostly stock.

[XJ Wheeler]

great pic,and thank you for all the info,i think the last time i was at my local jy they had one liberty and about 10 zjs.i have a limited budget( i have two teenaged daughters) and like to build things myself instead of just buying stuff.pretty sure mines the 8.25 so the liberty seems the way to go.wonder if the porportioning valve off the liberty would work too. my xj is mostly stock.

Not sure on the Liberty prop valve or not. Also, with the Zj valve its actually more common and easier to just swap out the internals. That way you're not messing with the lines. But either way I think you'll be happy with it.

I can understand the budget thing. ;) And glad to help!

[XJ Rat]

My 98 has rear discs from a 2004 LJ. They bolted right on. Might be hard to find, though.

Trying to remember about the proportioning valve. I do know on my TJ, removed the spring. I believe I did the same on the XJ. Sorry, do not remember.

[autotech98]

awesome xjrat just what i was hoping to hear,my old job i had welders and a machine shop i could use.this new one frowns upon home projects..lol. A guy i work with says hes done a couple swaps and never changed the prop valve,told me the only time you notice is when the road is wet,makes it feel like rear is coming around on you. dont know if i like that idea.here in PA we dont have the best roads.

[RocknXJ]

I did the G2 Axle and Gear rear disk brake conversion and added an adjustable brake valve and cables from the KJ and WJ Jeeps. Much more pricey than a junkyard swap, but very good. Love the added brake power.

[rabies]

from research. the liberty had longer wheel studs in the back.
the liberty backing plate was thicker.

some junkyards iv seen zj backing plates rusted out and pretty gone and useless(hence no swap for me yet)
when it comes to longer studs. iv always got extended studs like teh 3-4" ones. then iv need be cut them down to size.

as for the prop valve. iv done this on alot of other cars.
you can go without changing it out. but you will feel a difference if you swap it out.
rear discs help. but a propl valve upgrade is even better. i hate front brake bias

[XJ Wheeler]

from research. the liberty had longer wheel studs in the back.
the liberty backing plate was thicker.

some junkyards iv seen zj backing plates rusted out and pretty gone and useless(hence no swap for me yet)
when it comes to longer studs. iv always got extended studs like teh 3-4" ones. then iv need be cut them down to size.

as for the prop valve. iv done this on alot of other cars.
you can go without changing it out. but you will feel a difference if you swap it out.
rear discs help. but a propl valve upgrade is even better. i hate front brake bias

On any of the swaps you need longer lug studs. There are three choices. Either ZJ rears, XJ fronts, or Liberty rears. Now the Liberty studs are suppose to thicker and harder to get pressed into the shaft. I went with the ZJ rears and it worked great. If I was buying new I would go with XJ fronts so they matched the front and you only need one kind should replacement become necessary later on.

[rabies]

what would the front xj calipers bolt to?
what if we didn't care about an ebrake i.e. doesn't work anyways

[XJ Wheeler]

what would the front xj calipers bolt to?
what if we didn't care about an ebrake i.e. doesn't work anyways

I was speaking of the lug studs, not calipers.

With the ebrake you just take your cables off and even remove, or don't add back the ebrake hardware to the backing plates. I don't recommend this though because you need the ebrake to pass inspection, as well as it being a good back up should something go wrong. Always good to have a backup. ;)

Sent via messenger pigeon - i talk, he types.

[autotech98]

Amen to that! I don't know about your state but her in PA we have a pretty strict inspection process.