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  #1  
Old July 21st, 2017, 18:16
JonBoy81 JonBoy81 is offline
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Rear disc proportioning valve?

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.
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Old July 22nd, 2017, 01:59
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jeeptec jeeptec is offline
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Rear disc proportioning valve?

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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  #3  
Old July 22nd, 2017, 04:19
RCP Phx RCP Phx is offline
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Re: Rear disc proportioning valve?

Something is wrong with the installation! A 98 doesn't require a new PV, what type of axle is it installed on?
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Old July 22nd, 2017, 06:38
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ehall ehall is offline
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Re: Rear disc proportioning valve?

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.
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Last edited by ehall; July 22nd, 2017 at 06:42.
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  #5  
Old July 22nd, 2017, 07:31
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cruiser54 cruiser54 is offline
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Re: Rear disc proportioning valve?

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.
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Old July 22nd, 2017, 13:52
RCP Phx RCP Phx is offline
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Re: Rear disc proportioning valve?

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
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  #7  
Old July 25th, 2017, 20:57
JonBoy81 JonBoy81 is offline
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Re: Rear disc proportioning valve?

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.
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Old July 26th, 2017, 07:59
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Re: Rear disc proportioning valve?

Quote:
Originally Posted by JonBoy81 View Post
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.
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  #9  
Old July 26th, 2017, 09:38
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comanche91 comanche91 is offline
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Re: Rear disc proportioning valve?

Quote:
Originally Posted by JonBoy81 View Post
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.
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  #10  
Old July 26th, 2017, 12:23
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comanche91 comanche91 is offline
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Re: Rear disc proportioning valve?

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.


Last edited by comanche91; July 26th, 2017 at 12:27.
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  #11  
Old August 2nd, 2017, 22:17
JonBoy81 JonBoy81 is offline
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Re: Rear disc proportioning valve?

Quote:
Originally Posted by comanche91 View Post
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.

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
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Old August 9th, 2017, 09:40
Einulfr Einulfr is offline
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Re: Rear disc proportioning valve?

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.
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Old August 9th, 2017, 09:52
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comanche91 comanche91 is offline
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Re: Rear disc proportioning valve?

Found this online:

Quote:
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
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  #14  
Old August 9th, 2017, 12:21
Einulfr Einulfr is offline
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Re: Rear disc proportioning valve?

Thanks, I thought I remember seeing something about Explorer/Ranger hardware before but wasn't certain if I was recalling correctly.
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