Chuck82

So my question here is if I convert my 8.25 to disc and then do the WJ swap will I need an adjustable prop valve or how does this all work? Dual piston and disc on the back seems like I would need a lot of fluid. Just want opinions on if I should go with that set up. Oh almost forgot I have a 99 XJ

roadraje

I just did the conversion on my 99's 8.25 last week. I purchased the parts from member Big_Dave and although he sent me the prop valve I didn't install it yet. The "kit" came with everything but rotors and pass. side e-brake cable. I was informed by a few senior members that installing the prop valve will net greater results so I may take their advice and throw it in over the weekend. I did have to weld a couple of tabs to the diff. to properly mount the rubber lines from the calipers. You will also have to bend the hard lines to the block to connect to the rubber caliper lines, I opted to custom-bend new lines. There are numerous write-ups on the conversion and unless you're changing your bearings and seals like I did there are no special tools required. Good Luck.

Chuck82

Thanks for that, but I was wondering since I'll be getting parts for the WJ swap when I have Dual Piston calipers on the front and disc brakes on the back is there anything special I need to do with the brake system?

roadraje

I'm sure you'll receive several different suggestions/opinions but I think since yours is a '99 you already have the right master cylinder and booster. You could try different prop. valves to find the right balance between your front and rears. Upgrading your brake lines couldn't hurt either.

cruiser54

Since it's a 99, and as stated above already has a dual diaphragm booster, you're good there.

When I did the zJ rear discs on my 88, I just swapped the "guts" of a 94 to 98 prop valve into my prop valve.

It DOES make a difference.

Chuck82

Yeah I was going to swap the guts no question about it I'm not taking a chance with brakes, I was also watching a video on YouTube and the guy mentioned the right prop valve had to be from a Grand with ABS, is that true?

cruiser54

Do you have ABS?

Probably not. You have a prop valve right? Guts from a 94 to 98 Grand.

Chuck82

Correct, thanks man!

cruiser54

Enjoy.

The suggestion about upgrading the brake hoses to "braided" is a good one. I got a few sets from Frank at Serious Off Road.

I've put them on almost every vehicle I've owned for years.

Chuck82

Good idea!