WJ Booster and disc swap

I'm doing a WJ outer swap along with a 8.8 disc in the rear of my 98. Would it benifit me any to swap to a WJ booster, master , and prop valve? Or should my 98's dual diaphragm booster be fine?

It would not be a bad idea, but not a must. The WJ prop valve is made for disc brakes as or XJ one is set up for drums. If you can get the parts for cheap I would do, but that is just me.

You can always add it later iff you feel the need. On my 1990, with just the upgraded rotors and calipers, I can lock up the fronts on a gravel road.

Well I picked one up for $40 can't beat that just need to get a prop valve.

Your 98 will not really benefit from a WJ booster swap, as you already have a dual diaphram booster.

You would benefit from a ZJ prop valve after your rear disc conversion, however.

cal said:

Your 98 will not really benefit from a WJ booster swap, as you already have a dual diaphram booster.

You would benefit from a ZJ prop valve after your rear disc conversion, however.

Click to expand...

So it wouldn't be worth it. Even though it was designed to stop a larger vechile?

It was awsome for me.

Like I said before: Just do the rotors/calipers first, then if that isn't enough for you, you can always put it on later.

Just swap the WJ proposioning valve and you will be all set.

Hi, guys! I need your advice.

I have 1992 XJ 4.0 and I'm doing ZJ rear disc brakes conversion for DANA35.
I wanted to replace my stock brake booster, MC and proportioning valve from ZJ. But found out WJ front brakes conversion. I'm planning to make it later.
Because of this I'm stuck. Which booster, MC to use? From WJ or ZJ? Does it matter?

I would also like to keep ABS. What do I need for this?

Keeping ABS with the WJ swap should be fine, but there are a few things you'll need to eyeball.
Basically, you need to see whether the XJ abs sensor reaches, fits, has a reasonable air gap to your axle shaft's tone ring, etc.
Nobody really uses the ZJ booster that I've heard of. I think it's the same as the XJ, year for year. MC, too. The difference between ZJ and XJ brakes is the rear disc that ZJs had & the prop valve to match the rear disc.
WJ's had front and rear disc, a bigger booster than XJs had, and a different MC / prop valve to match all of that. The booster (but not MC or prop) gets swapped onto older XJ / MJ stuff because it is easier to swap than the newer XJ / MJ stuff, for whatever reason. WJ prop valve has lines in the wrong place and as far as I know, you can't just gut them and put the internals into your XJ valve - so nobody uses it. the ZJ valve also has the lines in the wrong place, but the guts swap over - so it gets done.
The rear disc swap is a no-brainer. Benefits include that they aren't drum brakes & that they perform better.
Front WJ swap will perform Hella better.
Dual diaphragm booster, whatever you get it from, will increase pressure to your brakes & make *whatever* you run perform better (assuming you started witha single diaphragm booster). On the other hand, your stock brakes will still heat up, make noise, etc - and maybe get worse due to the increased pressure?
After your ZJ swap, I'd go WJ booster. Then start saving money for the WJ front brake swap (unless your rich, then just do it)
Note that a lot of guys spend additional money with their WJ swaps to update the steering, too. This is totally valid on a lifted rig (any rig, really) and is indeed part of the benefit of the swap - but it isn't necessary if you just want the brake upgrade. You can run your stock type track bar & steering just fine.

Thank you, yossarian19 for your share.

On http://www.4x4wire.com/jeep/tech/brakes/xj_wjbrakes03/valve/index.htm described WJ proportioning valve swap.

So, I think I'll make my ZJ rear disc swap as first step, then add WJ booster/MC/Proportioning Valve (as described on 4x4wire.com).

After that I plan WJ steering and brake components swap as a third step.

I laughed when someone called it a proposition valve... :looney:

AFAIK WJs don't even have a proportioning valve. It's built into their ABS module. However, I have a WJ booster/master and ZJ discs and like the setup. No WJ swap on the front, I collected the parts to do it and then decided not to, changed my plans to a front 44. Then bought a front 60. Still haven't put any of it on the jeep :dunce: the WJ master/booster and ZJ discs are quite nice though.

For a pre 95- which has a single dia. booster, 95+ XJ/ZJ/WJ etc booster is an upgrade. for XJ's with dual dia. boosters already, if it needs replaced, do it. If not, do not worry about it. ZJ prop valve should help if you do not like how the brakes feel after the swap.