Rear disks/drums and pedal feel

Welp, the front axle is starting to come together pretty nicely. Ordered the WARN 5on5.5 hub kit and ARB today. 4.56s and HP housing are on the way already. Probably overkill for the metric equivalent of 32" tires but I'll never have to worry about breakage. :looney:

Time to start researching (obsessing?) about the rear axle.

What I have in mind is to use the Scout Dana 44 with ARB I already have and more or less just bolt that in once I get the perches/SYE set correctly.

I've been reading/searching up on using this combination and I'm starting to get a little nervy about the brakes. I had read that the larger drum wheel cylinders on the Scout axle will overwhelm the stock XJ master cyclinder. I've also read that using rear disks (ZJ donor? GM Caddy donor?) will also overwhelm the circuit. I have good drum brakes still in boxes so I was going to do the disk upgrade once the drums were used up.

I've read up on a few swaps. The E350 MC, ZJ/WJ MC, etc.

Who has done a similar upgrade on their XJ?

What did you end up with in the end?

Were you happy with the final braking power once you got the proportioning valve dialed in?

What would you do differently?

FWIW: 2001 XJ Sport w/o ABS, AW4/NV242, daily driver, weekend warrior, high mileage per year.

Any insights appreciated!

r@m

I you use the ZJ rear disks you will not have to change the M/C to a ZJ one as they are exactly the same part number and all. You can then fit a ZJ p/valve to get the full factory setup like I have done. If you use a different rear disk setup due to your change in stud pattern, you will most likely need to change the M/C to get the extra fluid capacity. The E350 and all disk Firebird ones are the most used ones out there. Others will tell you of any others.
I have a few comments about different P/valves etc on my site. http://go.jeep-xj.info

Thanks for that. I'll check out the link. I guess I need to sort out how I am going to get around the 5on5.5 thing on the rear. The WJ has rear disk and 5 on 5.5" I think?

May ebay my drum parts and do rear disk right away is what I'm thinking.

r@m

my friend can lock up his 40's with chevy large dual piston callipers on all four corners

I agree with the other posts - a 2001 XJ with discs will feel like it came that way from the factory with no other system mods. Pedal feel is excellent, stopping power is very nicely balanced front to rear...just do it. It's the early model XJ's that have the upgrade requirements.

Nay

Nay said:

I agree with the other posts - a 2001 XJ with discs will feel like it came that way from the factory with no other system mods. Pedal feel is excellent, stopping power is very nicely balanced front to rear...just do it. It's the early model XJ's that have the upgrade requirements.

Nay

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So do you suggest I do the ZJ caliper and see how that works?

I was looking at the Nissan/Suzuki rear disk thread at PBB. I'm fairly certain the TracKick rotor will fit over my axle shafts - may even have one kicking around to test with.

So just ZJ calipers and pvalve...

r@m

You shouldn't need to touch the proportioning valve. It is the same part as the quad-disc ZJ on your 2001 XJ.

Literally all I did was mount up the calipers (TSM) slap on the rotors, attach the lines, bleed it, and drive away on my '97. I also have D44 front brakes and the stock system handles them perfectly. Neither side locks up prematurely, pedal feel is as good as I've ever had on any vehicle.

The bid issue is making sure the bleeder screws are pointed up so you can gravity bleed the thing...most problems I've read about on late model XJ installs were cured by additional bleeding.

I don't have any experience with the ZJ conversion, but these conversions are ultimately all the same and the ZJ discs, as long as they install with proper clearances, should work perfectly.

Nay

Nay said:

You shouldn't need to touch the proportioning valve. It is the same part as the quad-disc ZJ on your 2001 XJ.
Nay

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Are you sure on that as my 95 p/valve was different to the zj one that I swapped in, part number and all??? Even the bracket had to be changed over just to get it to mount up!!

Gojeep said:

Are you sure on that as my 95 p/valve was different to the zj one that I swapped in, part number and all??? Even the bracket had to be changed over just to get it to mount up!!

Click to expand...

I wonder if this was a MY97+ or MY00+ thing? I know DC did a lot of little changes in these two ranges.

Nay said:

I don't have any experience with the ZJ conversion, but these conversions are ultimately all the same and the ZJ discs, as long as they install with proper clearances, should work perfectly.

Click to expand...

Have you heard anything RE: the "stopping power" of the ZJ parking brake?

I ask becuase I know first hand that the Caddy drum in disk setup is kinda lacking. "Where'd you park your Jeep? Just over there on that little rise....ack!"

Apparently the Nissan calipers on that PBB thread are "adequate". Whatever that means.

r@m

I haven't heard...and yes, the Caddy e-brake is a little bit lacking. I'd imagine the ZJ is better, but you'd have to ask somebody who's done it.

Nay

Gojeep said:

Are you sure on that as my 95 p/valve was different to the zj one that I swapped in, part number and all??? Even the bracket had to be changed over just to get it to mount up!!

Click to expand...

I'll call a possible SPOBI on my part - I've heard it is the same part number, but have never confirmed it personally. May have been a '97 thing. In any case, the 97+ p-valve works perfectly with rear discs, whatever the part number. Should require no adjustments at all.

Nay