88 Xj: Brake Upgrade Questions due to Axle Upgrade

use the prop. valve from the same year xj the donor axles are from. are you going to upgrade to discs in the rear also or no? if so then you can use a zj (4 wheel disc) prop valve in that case. hope that helps alittle.

wilwood has several adjustable proportioning valves.
look on summit and find the one you need with the appropriate port sizes.

May be too late, but..
Check Rockauto.com and look at the wheel cylinder bore diameters for the wheel cylinders used in each different axle - 8.25 & D35. You can click on "info" when looking at a part and most of the time they will give some specifications for it. I suspect they are the same diameter and thus will react identically to the proportioning valve / MC setup.

yossarian19 - No it is not to late. I think you have a good idea for evaluating detail.

Bear in mind it is the added mass of the 31" tires (...fortunately, they are not larger...yet.) I am most concerned with and not purely the D35-C8.25/drum brake system differences. The as yet undisclosed factors involved in this lift transfer is that my brake line fittings are not in good shape and I must severe the line to replace the threaded ends at a minimum. In turn, integrating changing/enhancing these small hydraulic components does little to contaminate that nasty hydraulic mess I must deal with.

Lastly, I also decided to protect my interests (i.e., getting my car back on the road soon.) and I intend to order the proportioning valve from www.teamcherokee.com if they have it in stock (I'm waiting for their return call.) because, I know this solution already.

Rick

Aren't there only two drum systems for an XJ regardless of axle model, 9" and 10"? Sadly, I have the 9" drums on mine... but at least they work now (just cleaned/greased the adjusters and derusted and painted the drums a couple weeks ago... will save hardware replacement and backing plate painting until I need new shoes)

If you're trying to get this back on the road quickly, you can rebuild drum wheel cylinders in situ; just disassemble the entire brakes down to the backing plate, then disassemble the wheel cylinders, hone, flush, reassemble with new cups and end seals ("wheel cylinder rebuild kit" from your FLAPS) as long as the bores aren't pitted and your bleeders are free that will keep you from having to replace the hard lines... although if they look really sketchy you may want to replace them anyway. I'd just replace the hose and that should work; cut the old hose in half before trying to remove it, then unscrew the hose from the fitting on the line from the body. That'll make it easier to free that flare nut up. I can't visualize what the axle end of the hose looks like, but if the block that the axle lines thread into is integral to the hose, well, might be time for the flame wrench and/or flaring and bending tools.