I'm running for 4 wheel disc's on my 97 TJ, and I'm looking for a bolt in mastercylinder to work with the disc's.

P.S No ABS model here.

One from a ZJ will bolt right up and generate around 1300 psi line pressure with the stock booster.

I had the stock master on my YJ with D44 front and 9" rear with drums. Didnt stop like i wanted it too. Swapped to a 79 Bronco master for more volume and that didnt help either. Pulled the oring out of the proportioning valve and it stopped great. I just swapped to a GM60 front with stock calipers and did my own rear disk conversion on the rear 70 with 1/2 ton calipers. It stops on a dime and i can lock up the wheels if needed.

If i had to do it agian I would have stayed with the stock master.

Mrblaine,

Do I under stand you right, that you can use the stock booster that my TJ has, just buy the master off the ZJ?

Originally posted by M/C MAN
Mrblaine,

Do I under stand you right, that you can use the stock booster that my TJ has, just buy the master off the ZJ?

Yes, that is how I set up my wife's TJ with 4 piston Wilwoods up front on the 30 knuckles and adapted Explorer discs in the rear.

My reasoning was based on the fact that the Explorer discs are the same as the ZJ's and I wanted a bit more volume up front.

It was purely a test until it worked. It does work very fine. I did disable the front to rear proportioning by removing the 0-ring seal from the combination valve under the master.

Be aware that the ZJ uses a step bore master and they are a bit more difficult to bench bleed. Pay attention to the install directions.

If you do the swap, it is a good time to swap over to Valvoline brake fluid. Higher wet boiling point, and solved a few problems I had with vapor locking in my TJ.

When you bleed the brakes, do not pump them with a step bore master. All you wind up doing is aerating the fluid with millions of tiny bubbles if you do more than one pedal stroke per bleed cycle.

Try the stock setup minus the prop. valve. Mine works great, will lock all 4's at will.
Dave (Running D60's W/1ton calipers on front and 3/4 ton calipers on rear)

Originally posted by TJTRUBL
Try the stock setup minus the prop. valve. Mine works great, will lock all 4's at will.
Dave (Running D60's W/1ton calipers on front and 3/4 ton calipers on rear)

That's what I got going on too. I got the front brake lines coming straight off the MC and the back I have a Wilwood adjustable Prop. valve. Works great... Get rid of that stock comb/prop. valve.

Phil a.ka. 1TONJEEP modifed his stock one. IM him.

I agree with everyone else who said to remove the stock valve all together, the results are incredible.

CJ

Thanks guys, I have already taken the o-ring out when
I installed the rear axle. On my way home from work I bought a master cylinder from the 97 ZJ. I will give that a try and if that is not working I will try removing the prop. valve.

Has anyone ever found a master cyl. table that lists make/model bore diam and stroke length?

Originally posted by hybrid
Has anyone ever found a master cyl. table that lists make/model bore diam and stroke length?

Just about any parts store will have a book that lists the bore and stroke of master cylinders.