Answering my own question - XJ Rear Discs

A month or two ago, I asked whether stock XJ wheels would still fit if
Liberty Rear Discs were mounted onto my '98 XJ.

On Saturday AM, I pulled the rear brake parts from a crashed '07
Liberty. They essentially were a direct bolt-on, and the stock wheels
are fine - no interference with the calipers.

The brakes are smooth and work great. My total cost would have been
about $175, except that I had the rotors turned, which added $36.

Jim
98 XJ

"98XJ" wrote in message ...
>A month or two ago, I asked whether stock XJ wheels would still fit if
> Liberty Rear Discs were mounted onto my '98 XJ.
>
> On Saturday AM, I pulled the rear brake parts from a crashed '07
> Liberty. They essentially were a direct bolt-on, and the stock wheels
> are fine - no interference with the calipers.
>
> The brakes are smooth and work great. My total cost would have been
> about $175, except that I had the rotors turned, which added $36.
>
> Jim
> 98 XJ

Howdy,
So, what you did was swap out a rear drum setup for a rear disc setup?
How is the pedal response and feel?

Spdloader

P.S. Got some things cookin' with the centers right now. More on that later.

Tell me your going to post a write up with photos, how hard was it, how
long, how many beers

Mark
98 XJ

<98XJ> wrote in message ...
>A month or two ago, I asked whether stock XJ wheels would still fit if
> Liberty Rear Discs were mounted onto my '98 XJ.
>
> On Saturday AM, I pulled the rear brake parts from a crashed '07
> Liberty. They essentially were a direct bolt-on, and the stock wheels
> are fine - no interference with the calipers.
>
> The brakes are smooth and work great. My total cost would have been
> about $175, except that I had the rotors turned, which added $36.
>
> Jim
> 98 XJ

How did you address the pressure differential between the old hydraulics
and the new? There is a combination valve in the system designed to
limit the pressure to the rear drum brakes so they cannot lock up during
a panic stop. If they do lock up, you will swap ends faster than you
can blink.

The brake master cylinder also sends different volumes of fluid for drum
wheel cylinders vs calipers. The, or some for sure, master also has
check valves for drum brake fluid flow that can jam disk calipers 'on'.

I know 100% for sure that a master cylinder for drum brakes will 'not'
work for disk brakes on a CJ7 or CJ5. It 'will' jam the calipers in an
'on' position, I have seen it happen several times with sloppy parts
counter persons giving out the wrong one or the wrong one in the right
box. So if your gas mileage starts to drop....

Just a heads up for you.

Mike
86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00
'New' frame in the works for '08. Some Canadian Bush Trip and Build
Photos: http://mikeromainjeeptrips.shutterfly.com

98XJ wrote:
> A month or two ago, I asked whether stock XJ wheels would still fit if
> Liberty Rear Discs were mounted onto my '98 XJ.
>
> On Saturday AM, I pulled the rear brake parts from a crashed '07
> Liberty. They essentially were a direct bolt-on, and the stock wheels
> are fine - no interference with the calipers.
>
> The brakes are smooth and work great. My total cost would have been
> about $175, except that I had the rotors turned, which added $36.
>
> Jim
> 98 XJ

I was wondering the same thing Mike,

Mark 98 XJ
"Mike Romain" > wrote in message
ng.com...
> How did you address the pressure differential between the old hydraulics
> and the new? There is a combination valve in the system designed to limit
> the pressure to the rear drum brakes so they cannot lock up during a panic
> stop. If they do lock up, you will swap ends faster than you can blink.
>
> The brake master cylinder also sends different volumes of fluid for drum
> wheel cylinders vs calipers. The, or some for sure, master also has check
> valves for drum brake fluid flow that can jam disk calipers 'on'.
>
> I know 100% for sure that a master cylinder for drum brakes will 'not'
> work for disk brakes on a CJ7 or CJ5. It 'will' jam the calipers in an
> 'on' position, I have seen it happen several times with sloppy parts
> counter persons giving out the wrong one or the wrong one in the right
> box. So if your gas mileage starts to drop....
>
> Just a heads up for you.
>
> Mike
> 86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00
> 'New' frame in the works for '08. Some Canadian Bush Trip and Build
> Photos: http://mikeromainjeeptrips.shutterfly.com
>
> 98XJ wrote:
>> A month or two ago, I asked whether stock XJ wheels would still fit if
>> Liberty Rear Discs were mounted onto my '98 XJ. On Saturday AM, I pulled
>> the rear brake parts from a crashed '07
>> Liberty. They essentially were a direct bolt-on, and the stock wheels
>> are fine - no interference with the calipers.
>>
>> The brakes are smooth and work great. My total cost would have been
>> about $175, except that I had the rotors turned, which added $36.
>>
>> Jim
>> 98 XJ

I would really like to see a write up with photos.

Please give us a follow-up in a month or two after you have driven in
rain and on gravel and after a couple of panic stops.

I'm surprised you didn't try to use the master cylinder as well, but
i'm glad it worked out well for you.

Merrill

On Mar 11, 7:54*pm, 98XJ <> wrote:
> A month or two ago, I asked whether stock XJ wheels would still fit if
> Liberty Rear Discs were mounted onto my '98 XJ.
>
> On Saturday AM, I pulled the rear brake parts from a crashed '07
> Liberty. *They essentially were a direct bolt-on, and the stock wheels
> are fine - no interference with the calipers.
>
> The brakes are smooth and work great. *My total cost would have been
> about $175, except that I had the rotors turned, which added $36.
>
> Jim
> 98 XJ

On Wed, 12 Mar 2008 16:04:04 -0700 (PDT), merrill
> wrote:

>I would really like to see a write up with photos.
>
>Please give us a follow-up in a month or two after you have driven in
>rain and on gravel and after a couple of panic stops.
>
>I'm surprised you didn't try to use the master cylinder as well, but
>i'm glad it worked out well for you.
=======

I did consider taking photos as I worked, but I considered others
already have done a better job than I would have. Without a doubt,
the best source that I studied is Eric Zappe's book, High-Performance
Jeep Cherokee XJ Builder's Guids 1984-2001". The descriptions are
concise and the photos well-framed and crystal clear (ericsxj.com).

This subject is also covered extensively on the NAXJA site, including
a photo essay he http://www.geocities.com/dcpaschal/mitch02.html
I guess I should pay NAXJA dues, now...

It was in Zappe's book that I realized that my stock wheels would
interfere with the calipers if I used ZJ parts. Zappe's used a
TeraFlex kit (with Ford Explorer rotors and TF's own backing plate
assemblies). But the process is identical, save for the brake lines.
I kept the Liberty's hard lines (mine are 10 years old, after all).
The biggest waste of time, in a fatigued state, was not realizing that
the Liberty's fittings were metric; the XJ's English. Once I
flared-on new fittings, no more problem.

I also wondered about the proportioning valve. I talked with someone
who did the Liberty/XJ swap about 3 years ago & he's had no problem
(running 31s or 32s). The Zappe book said, "I didn't need to install
a different proportioning valve or modify the master cylinder per the
TeraFlex instructions". My comment: Your (or my) results may vary.

I still haven't connected the E-brake cables, but I don't expect too
much of a problem.

I have been working solo (Getting grease all over the garage while my
wife's been out of town - but now it's all clean for when she gets off
the plane in a couple of hours.), so I've only bled the rear lines, so
far. Consequently, the pedal is a little spongy - but travel is less
than before the change.

There still is some snow around, so I guess I could try some panic
stops, to see how it tracks. I'll let everyone know after I've driven
for a longer time and in varying conditions. I may go back to the
yard to pull that master cyl, just for insurance.

Jim

P.S. - Spdloader - keep me posted on your project. js

How did you address the pressure differential between the old
hydraulics
and the new? There is a combination valve in the system designed to
limit the pressure to the rear drum brakes so they cannot lock up
during
a panic stop. If they do lock up, you will swap ends faster than you
can blink.

The brake master cylinder also sends different volumes of fluid for
drum
wheel cylinders vs calipers. The, or some for sure, master also has
check valves for drum brake fluid flow that can jam disk calipers
'on'.

I know 100% for sure that a master cylinder for drum brakes will 'not'
work for disk brakes on a CJ7 or CJ5. It 'will' jam the calipers in an
'on' position, I have seen it happen several times with sloppy parts
counter persons giving out the wrong one or the wrong one in the right
box. So if your gas mileage starts to drop....

Just a heads up for you.

Mike
86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00
'New' frame in the works for '08. Some Canadian Bush Trip and Build
Photos: http://mikeromainjeeptrips.shutterfly.com
================================================== ===================

Final note:

Over the weekend, I drove up to visit my dad. Up there on the 45th
parallel, the secondary roads are still completely snow packed or
iced-over, which gave me several opportunities to mash on the brakes
to see how the Jeep tracked. It glided completely straight on both
snow and ice.

So, I do not think there's an issue with using the stock XJ master
cylinder and proportioning valve with the Liberty rear discs.

If I experience anything different on dirt, sand, or dry pavement, I
will post it here.

Jim

On Sun, 16 Mar 2008 22:35:55 -0400, 98XJ <> wrote:

>How did you address the pressure differential between the old
>hydraulics
>and the new? There is a combination valve in the system designed to
>limit the pressure to the rear drum brakes so they cannot lock up
>during
>a panic stop. If they do lock up, you will swap ends faster than you
>can blink.
>
>The brake master cylinder also sends different volumes of fluid for
>drum
>wheel cylinders vs calipers. The, or some for sure, master also has
>check valves for drum brake fluid flow that can jam disk calipers
>'on'.
>
>I know 100% for sure that a master cylinder for drum brakes will 'not'
>work for disk brakes on a CJ7 or CJ5. It 'will' jam the calipers in an
>'on' position, I have seen it happen several times with sloppy parts
>counter persons giving out the wrong one or the wrong one in the right
>box. So if your gas mileage starts to drop....
>
>Just a heads up for you.
>
>Mike
>86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00
>'New' frame in the works for '08. Some Canadian Bush Trip and Build
>Photos: http://mikeromainjeeptrips.shutterfly.com
>================================================= ====================
>
>Final note:
>
>Over the weekend, I drove up to visit my dad. Up there on the 45th
>parallel, the secondary roads are still completely snow packed or
>iced-over, which gave me several opportunities to mash on the brakes
>to see how the Jeep tracked. It glided completely straight on both
>snow and ice.
>
>So, I do not think there's an issue with using the stock XJ master
>cylinder and proportioning valve with the Liberty rear discs.
>
>If I experience anything different on dirt, sand, or dry pavement, I
>will post it here.
>
>Jim


Final Post +1 to address other questions:

The pedal feel is great and the braking is much improved.
My mileage was slightly over 20 mpg for the trip. This included some
4wd driving, too. js

We put an explorer 8.8 rear end, with disks in a freinds 88 YJ last year,
no problem with brakes, just re-hooked and away he went.

<98XJ> wrote in message ...
> How did you address the pressure differential between the old
> hydraulics
> and the new? There is a combination valve in the system designed to
> limit the pressure to the rear drum brakes so they cannot lock up
> during
> a panic stop. If they do lock up, you will swap ends faster than you
> can blink.
>
> The brake master cylinder also sends different volumes of fluid for
> drum
> wheel cylinders vs calipers. The, or some for sure, master also has
> check valves for drum brake fluid flow that can jam disk calipers
> 'on'.
>
> I know 100% for sure that a master cylinder for drum brakes will 'not'
> work for disk brakes on a CJ7 or CJ5. It 'will' jam the calipers in an
> 'on' position, I have seen it happen several times with sloppy parts
> counter persons giving out the wrong one or the wrong one in the right
> box. So if your gas mileage starts to drop....
>
> Just a heads up for you.
>
> Mike
> 86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00
> 'New' frame in the works for '08. Some Canadian Bush Trip and Build
> Photos: http://mikeromainjeeptrips.shutterfly.com
> ================================================== ===================
>
> Final note:
>
> Over the weekend, I drove up to visit my dad. Up there on the 45th
> parallel, the secondary roads are still completely snow packed or
> iced-over, which gave me several opportunities to mash on the brakes
> to see how the Jeep tracked. It glided completely straight on both
> snow and ice.
>
> So, I do not think there's an issue with using the stock XJ master
> cylinder and proportioning valve with the Liberty rear discs.
>
> If I experience anything different on dirt, sand, or dry pavement, I
> will post it here.
>
> Jim