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View Full Version : Rear disc proportioning valve?


JonBoy81
July 21st, 2017, 17:16
Just helped a friend install a G2 rear disc conversion kit on his 98 XJ. He is only getting rear braking if he double pumps the brakes. Is a different proportioning valve needed? If so, does anyone have a part number of a non-mopar part? Local parts stores dont seem to sell the Grand Cherokee valve.

jeeptec
July 22nd, 2017, 00:59
Go the wrecking yard. Find a ZJ with rear disc brakes. Yes early ZJ's had rear drum. Get the cap, spring and inner valve from the proportioning valve and install them in the XJ proportioning valve. Make sure you bleed the brakes again. Make sure the calipers are on right. The bleeder screws should on top.


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RCP Phx
July 22nd, 2017, 03:19
Something is wrong with the installation! A 98 doesn't require a new PV, what type of axle is it installed on?

ehall
July 22nd, 2017, 05:38
Do the G2 instructions say anything about it? Larger piston might need it but I didn't need it on my TJ Rubicon swap. Bleeding the distribution block after you swap the valve does more than anything.

cruiser54
July 22nd, 2017, 06:31
I've done my share of these conversions.

Stock prop valve is okay. Stock prop valve with ZJ guts in it is better.

My money is on the chance the calipers are on the wrong sides and the bleeders are on the bottom.

RCP Phx
July 22nd, 2017, 12:52
Other common problems would be........

Master Cylinder ran dry during the install
Rubber flex line(axle to body)
Run-out in the rotor(dirt, warped flange/rotor, worn axle bearings)
Excessive axle end play

JonBoy81
July 25th, 2017, 19:57
Thank you for all the responses. We re-bled everything. The main culprit ended up being the drivers side caliper. The front clipers had been replaced on the same day as the installation of the rear disc conversion. The drivers side front caliper had the bleeder on the bottom. We ended up pulling the wheel, pulling the caliper, inverting it, bleeding it, re-assembling, and all was good. Thanks again.

cruiser54
July 26th, 2017, 06:59
Thank you for all the responses. We re-bled everything. The main culprit ended up being the drivers side caliper. The front clipers had been replaced on the same day as the installation of the rear disc conversion. The drivers side front caliper had the bleeder on the bottom. We ended up pulling the wheel, pulling the caliper, inverting it, bleeding it, re-assembling, and all was good. Thanks again.

That will do it....Simple fix.

comanche91
July 26th, 2017, 08:38
Thank you for all the responses. We re-bled everything. The main culprit ended up being the drivers side caliper. The front clipers had been replaced on the same day as the installation of the rear disc conversion. The drivers side front caliper had the bleeder on the bottom. We ended up pulling the wheel, pulling the caliper, inverting it, bleeding it, re-assembling, and all was good. Thanks again.

The right and left side front calipers are different. Didn't think you could install them upside down.

comanche91
July 26th, 2017, 11:23
Are the calipers on the G2 kit proprietary? Installed a Teraflex rear disk kit many years ago on my D44, and the rotors, calipers, and pads are all replaceable using late 90's Ford Explorer components.

http://i.imgur.com/aTaFj5D.jpg

JonBoy81
August 2nd, 2017, 21:17
Are the calipers on the G2 kit proprietary? Installed a Teraflex rear disk kit many years ago on my D44, and the rotors, calipers, and pads are all replaceable using late 90's Ford Explorer components.

http://i.imgur.com/aTaFj5D.jpg

I have yet to look into it, as he has the 8.25 and I have the d44. I recall at least the rotors being a centric part

Einulfr
August 9th, 2017, 08:40
The rotors and calipers in my 8.25 G2 kit are both Centric, but I forgot to keep the boxes so I have no idea what part number they are. Anyone happen to know, so I can get the right pads when it's time to replace them? And is it possible to use a slightly larger pad? The included ones don't seem to fill out the rotor.

As far as the prop valve, I haven't noticed any major difference between the stock one and the ZJ one I grabbed from the junkyard, at least as far as normal braking goes. But the difference between the discs and drums is like night and day, and I had fairly new drums and hardware at the time when I did the conversion.

comanche91
August 9th, 2017, 08:52
Found this online:

What year and model would the replacement pads and rotors be?

Asked by bill from on 05/16/2016

Hi Bill, This G2 Axle and Gear Disc Brake Conversion Kit uses brake rotors used on the Ford Ranger's from 2000 to 2006, the pads are Posiquiet semi metallic, these items are parts that we sell however they are not listed on our site. Thank you for your inquiry.

Answered by Jim G Ext 4806 from on 05/16/2016

Einulfr
August 9th, 2017, 11:21
Thanks, I thought I remember seeing something about Explorer/Ranger hardware before but wasn't certain if I was recalling correctly.