Front axle swap, brake questions

[Backroads]

I saw it brought up in a build thread on here about differences in the brakes from CAD and non CAD axles.

 

It seemed like someone was saying to keep the original style brakes off the original axle, when swapping in a newer non disco axle? Is that right?

 

I was planning on just leaving the brakes on the axle I have and plumbing them up that way. Just wanted to post up and make sure I'm not missing something here!

[JeffK]

I'm running a '99 D30 with '95 brakes/hubs, with aftermarket SS lines plumbed into the old hard-lines. I personally think the newer brakes are a little better, the rotors are inexpensive and there is a few more pad options.

 

[Backroads]

Pretty much what I had planned.

 

What year rotors are good/bad?

[one_bad_MJ]

When i did my 94 non vac assist axle swap on my 89 xj last spring, i had to buy new rotors and calipers/brake pads

 

 

the 94 axle has larger rotors and smaller hubs

 

as for the 89 has larger hubs and smaller rotors but huge calipers

[JeffK]

Pretty much what I had planned.

 

What year rotors are good/bad?

 

You have 3 choices.

 

1) 86-90(?) GM style brakes

 

2) 90(?)-early 96 Chrysler w/composite rotors

 

3) late 96-01 Chrysler w/solid rotors

 

Any of those will work on your axle. As mentioned there is good and band with all of them. I prefer the mid 90's stuff because I'm most familiar with it and the calipers use a hex head bolt.

[johnnyc]

Actually, mid-99 is when they switched from composite to cast rotors. Whatever rotors you decide on, be sure to use the corresponding unit bearing, or else you'll have big problems. You cannot just freely interchange rotors only.

[Eagle]

You have 3 choices.

 

1) 86-90(?) GM style brakes

 

2) 90(?)-early 96 Chrysler w/composite rotors

 

3) late 96-01 Chrysler w/solid rotors

 

Any of those will work on your axle. As mentioned there is good and band with all of them. I prefer the mid 90's stuff because I'm most familiar with it and the calipers use a hex head bolt.

As noted, Chrysler went back to one-piece rotors in mid-1999, not 1996. I've posted the run-down before, but here it is again. As before, this is from a book I am writing and it is copyrighted. By posting it here I do NOT grant anyone permission to copy it elsewhere, post it elsewhere, or in any way give or send it to anyone else.

 

In general, the parts to be concerned with in keeping the front brakes compatible are the steering knuckles, the hub/bearing assemblies, the rotors, and the calipers. (There is a more complete enumeration of the interrelationship of these parts in Chapter 6, Axles.)

 

• Only two steering knuckle designs were used: 1984 through 1989, and 1990 through 2001. Left and right side knuckles are different part numbers within each group.

 

• Three different hub/bearing units were used. The hub/bearing units are the same for both sides of the vehicle. The different years for hub/bearing assemblies were: 1984 through 1989; 1990 through mid-1999 (composite rotors); and late-1999 through 2001 (cast rotors).

 

• Three rotor types were used: 1984 through 1989; 1990 through mid-1999 (composite); and late-1999 through 2001 (cast).

 

• Only two caliper types were used: 1984 through 1989, and 1990 through 2001. Left and right side calipers are different part numbers within each group.

It is important to ensure that you have matching knuckles, hubs, rotors AND calipers. Mix and match, and the calipers may sit off-center on the rotors and cause all manner of problems.

[green_miner]

will i be alright running a 86 d30 with 98 rotors/calipers?

[JeffK]

You have 3 choices.

 

1) 86-90(?) GM style brakes

 

2) 90(?)-early 96 Chrysler w/composite rotors

 

3) late 96-01 Chrysler w/solid rotors

 

Any of those will work on your axle. As mentioned there is good and band with all of them. I prefer the mid 90's stuff because I'm most familiar with it and the calipers use a hex head bolt.

As noted, Chrysler went back to one-piece rotors in mid-1999, not 1996. I've posted the run-down before, but here it is again. As before, this is from a book I am writing and it is copyrighted. By posting it here I do NOT grant anyone permission to copy it elsewhere, post it elsewhere, or in any way give or send it to anyone else.

 

In general, the parts to be concerned with in keeping the front brakes compatible are the steering knuckles, the hub/bearing assemblies, the rotors, and the calipers. (There is a more complete enumeration of the interrelationship of these parts in Chapter 6, Axles.)

 

• Only two steering knuckle designs were used: 1984 through 1989, and 1990 through 2001. Left and right side knuckles are different part numbers within each group.

 

• Three different hub/bearing units were used. The hub/bearing units are the same for both sides of the vehicle. The different years for hub/bearing assemblies were: 1984 through 1989; 1990 through mid-1999 (composite rotors); and late-1999 through 2001 (cast rotors).

 

• Three rotor types were used: 1984 through 1989; 1990 through mid-1999 (composite); and late-1999 through 2001 (cast).

 

• Only two caliper types were used: 1984 through 1989, and 1990 through 2001. Left and right side calipers are different part numbers within each group.

It is important to ensure that you have matching knuckles, hubs, rotors AND calipers. Mix and match, and the calipers may sit off-center on the rotors and cause all manner of problems.

 

I bow to the experts.

 

It is important to ensure that you have matching knuckles, hubs, rotors AND calipers. Mix and match, and the calipers may sit off-center on the rotors and cause all manner of problems.

 

Best advise so far.

[Eagle]

will i be alright running a 86 d30 with 98 rotors/calipers?

Not unless you also change knuckles and hubs.

 

Read my post immediately above yours.

[green_miner]

what exactly is it that makes them so different? they look the same to me

[Backroads]

Thanks Eagle. Solid information, and just for the record I'd buy a book that has info like that in it! :bowdown:

 

So basically as long as I keep the brakes rotors etc the same for that year axle, and not the original year of the vehicle, its all good? Thats pretty much what I was assuming anyways.

 

I wasn't really planning to swap my brakes over or anything. The axle I have to swap in in complete with newer hubs rotors and pads on it already. So I guess the major thing is just to note the year of the axle and go by that for buying axle components in the future i.e. My MJ is an 86, if it has a 94 axle under it, just get parts for a 94 cherokee.

[Eagle]

what exactly is it that makes them so different? they look the same to me

They aren't the same. If you could set a "first generation" hub next to a "second generation" hub, off the vehicle, you'd see the difference instantly. Ditto the early rotors next to the composite rotors.