WJ booster master cylinder swap, zj rear discs on xj 44, zj prop spring, and

[blondejoncherokee]

so ive been reading all the threads for the WJ swap
i have an 89 with single diaphragm booster,
brakes havent been amazing,
swapped in rear discs on the discs44 a while back,
and last few nights after work i swapped in the wj booster and the zj proportioning valve spring.
havent bled the brakes yet,
whats the process for bleeding the proportioning valve?
im pretty sure i did a good job bleeding the Master cylinder
ive never bled the proportioning valve before, but bled the brakes alot,

 

[blondejoncherokee]

basically i dont know how to bleed the proportioning valve

 

[jeeptec]

perform a normal bleed sequence. r.r. l.r. r.f. then l.f. the fluid will flow from the master thru the prop valve down thru the lines to the calipers. let me know how the brakes turn out. i have and 87 that i have done the read disc swap and cut one coil out of the prob valve.still have the single booster. stops better than stock but not good enough for me

 

[fabjunkie]

I put the booster and mc from an 99 grand cherokee in my 91, (which has vette calipers on the rear) and I bled the brakes in the normal fashion. After all 4 wheels were bled, I bled the prop valve by having my kids stomp the pedal, and cracked the front fitting.

Weird thing is, they weren't great right away, but after a few times around the block, they are awesome now.

I did do the mod to the prop valve as outlined in Lunds site, but it didn't work well on mine. Also installed an adj prop valve in the rear line so I could balance everything. I recommend the swap to anyone over the stock single diaphragm setup any day.

total investment was about $140 for the booster swap

 

[blondejoncherokee]

cool
i read hoe to bleed the prop valve
super easy
undo the front nipple thing on the prop valve(19mm socket 6 point)
just enough for fluid to come out
and i ran alot of fluid through and alot of air came out
i already bled the mc earlier today
next i bled the brakes
pedal feels a little soft and seems to go down a little further than i thought
but so far the thing stops so much better already
( that is after finally adding the zj spring(its way harder/firmer and shorter) and the wj mc/booster)
just drove it around the block, and before i would kinda stop at a stop sign if i gave it a little distance, now it stops dead on
i need to drive it around a bit and maybe re-bleed the system again, then ill feel more confident, but as of now its a huge improvement.
noticed it immediatly after pulling out of the garage

 

[blondejoncherokee]

i paid 100$ for the 2004 wj booster/mc combo
prop valve spring was free(have 3 of them from pnp)
20$ worth of brake fluid
very very happy addition to the rear brake swap
and all my brake fluid in the two front lines was very dirty and wasnt that old
i might rebuild the front calipers,
rears were clean

 

[blondejoncherokee]

just to follow up
bled the brakes again
everything seems great now
ill probably bleed them again in a week or so
why the prop valve in the rear line?