here is a helpful swap for YJ owners
yankee19934
Jeeper
this is a booster swap that will help you with that low rpm braking. like when you backup.
here is what you need
first find a double difram booster from a TJ, 95- up XJ, ZJ. i paid 20.00 for a complete booster out of a 2000 Tj
Then remove your old booster and bolt into place and run new lines. Too easy huh, well if you have a manual yj or an older yj, older than 90 you will have a spacer bracket. (as seen in pic) this is a simple fix. You measure the old yj shaft and compare to the tj shaft. Add what you need.. its a little over an inch. i had scap pipe laying around that had the same I.D. as the tj rod, drilled two holes and had a buddy do a little welding. bolt the new booster into place and bend up some new lines. bleed the brakes and adjust your bralke light switch and now you have great braking power to stop those big tires, even at low rpm's.

Extened shaft, and right above is the brake light switch, dont forget to put the locking pin back on.
The tj booster in place, still needs new brake lines

booster difference, little yj booster compared to the huge tj booster

the YJ spacer that brings the booster off the wall to make clearence for the clutch master cylinder
good luck
here is what you need
first find a double difram booster from a TJ, 95- up XJ, ZJ. i paid 20.00 for a complete booster out of a 2000 Tj
Then remove your old booster and bolt into place and run new lines. Too easy huh, well if you have a manual yj or an older yj, older than 90 you will have a spacer bracket. (as seen in pic) this is a simple fix. You measure the old yj shaft and compare to the tj shaft. Add what you need.. its a little over an inch. i had scap pipe laying around that had the same I.D. as the tj rod, drilled two holes and had a buddy do a little welding. bolt the new booster into place and bend up some new lines. bleed the brakes and adjust your bralke light switch and now you have great braking power to stop those big tires, even at low rpm's.

Extened shaft, and right above is the brake light switch, dont forget to put the locking pin back on.

The tj booster in place, still needs new brake lines

booster difference, little yj booster compared to the huge tj booster

the YJ spacer that brings the booster off the wall to make clearence for the clutch master cylinder
good luck