A couple Brake modification questions
03-06-2012, 05:18 PM
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Year: 1992
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A couple Brake modification questions
Firsts things first. stock xj brakes suck. I took out the ABS system and replaced it with a 01 grand cherokee brake booster/master cylinder and did a proportioning valve from a 95 cherokee w/out abs.
That helped with braking alot. but now i face some more questions. i have an 8.25 going in very soon, and it has zj rear discs...and ive read that you have to swap out the xj prop valve for a zj's valve. i assume its to reduce the flow to the rear brakes? what exactly would happen if i didnt change the proportioning valve?
and ive also read about upgrading the front brakes to the zjs twin piston setup with larger rotors. i know to do this you have to get the wheel bearing spacers that go between the wheel bearings and hubs, however that pulls the front axle out further from the carrier, and my thinking is that this would essentially weaken the 27 spline D30 because there would be less contact between the carrier splines and axle splines. and i will be running 33s so bigger brakes would be nice, but so would a stronger axle...
That helped with braking alot. but now i face some more questions. i have an 8.25 going in very soon, and it has zj rear discs...and ive read that you have to swap out the xj prop valve for a zj's valve. i assume its to reduce the flow to the rear brakes? what exactly would happen if i didnt change the proportioning valve?
and ive also read about upgrading the front brakes to the zjs twin piston setup with larger rotors. i know to do this you have to get the wheel bearing spacers that go between the wheel bearings and hubs, however that pulls the front axle out further from the carrier, and my thinking is that this would essentially weaken the 27 spline D30 because there would be less contact between the carrier splines and axle splines. and i will be running 33s so bigger brakes would be nice, but so would a stronger axle...
Last edited by XJ4life92; 03-06-2012 at 08:36 PM.
03-06-2012, 06:17 PM
#2
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Year: 1990
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Here's what you need. Be sure to get the lug studs and caliper bracket mounting studs from the donor Grand Cherokee. Get teh guts of the prop valve while you're at it and swap them into your valve.
http://www.jeepforum.com/forum/f11/z...-brake-920103/
http://www.jeepforum.com/forum/f11/z...-brake-920103/
03-06-2012, 08:26 PM
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very thorough write up, but i already have an 8.25 w/ locker and discs, i was just asking what was different about the prop valve and about the front swap if anybody has had problems with it or has done the front zj swap.
im still going to read that write up just for good info. thanks!
im still going to read that write up just for good info. thanks!
03-06-2012, 08:50 PM
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very thorough write up, but i already have an 8.25 w/ locker and discs, i was just asking what was different about the prop valve and about the front swap if anybody has had problems with it or has done the front zj swap.
im still going to read that write up just for good info. thanks!
im still going to read that write up just for good info. thanks!
03-27-2012, 04:35 PM
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Firsts things first. stock xj brakes suck. I took out the ABS system and replaced it with a 01 grand cherokee brake booster/master cylinder and did a proportioning valve from a 95 cherokee w/out abs.
That helped with braking alot. but now i face some more questions. i have an 8.25 going in very soon, and it has zj rear discs...and ive read that you have to swap out the xj prop valve for a zj's valve. i assume its to reduce the flow to the rear brakes? what exactly would happen if i didnt change the proportioning valve?
and ive also read about upgrading the front brakes to the zjs twin piston setup with larger rotors. i know to do this you have to get the wheel bearing spacers that go between the wheel bearings and hubs, however that pulls the front axle out further from the carrier, and my thinking is that this would essentially weaken the 27 spline D30 because there would be less contact between the carrier splines and axle splines. and i will be running 33s so bigger brakes would be nice, but so would a stronger axle...
That helped with braking alot. but now i face some more questions. i have an 8.25 going in very soon, and it has zj rear discs...and ive read that you have to swap out the xj prop valve for a zj's valve. i assume its to reduce the flow to the rear brakes? what exactly would happen if i didnt change the proportioning valve?
and ive also read about upgrading the front brakes to the zjs twin piston setup with larger rotors. i know to do this you have to get the wheel bearing spacers that go between the wheel bearings and hubs, however that pulls the front axle out further from the carrier, and my thinking is that this would essentially weaken the 27 spline D30 because there would be less contact between the carrier splines and axle splines. and i will be running 33s so bigger brakes would be nice, but so would a stronger axle...
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