Drums to Rotors C 8.25
05-26-2016, 09:13 PM
#16
05-26-2016, 09:32 PM
#17
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Year: 1999
Model: Cherokee
Engine: 4.0 Inline 6
Thanks, I have an XJ with a drum to disc conversion, not really sure how this applies to my conversion or why I need this part - help me out to clarify.
Thanks!
Thanks!
05-27-2016, 06:22 AM
#18
You have that part on your XJ.
If you don't understand what this part is or what I was referring to........you dont understand the brake system and you are not prepared for a disc swap.
You need to study the system and how it works.
If you don't understand what this part is or what I was referring to........you dont understand the brake system and you are not prepared for a disc swap.
You need to study the system and how it works.
05-27-2016, 06:35 AM
#19
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Year: 1999
Model: Cherokee
Engine: 4.0 Inline 6
I have help with the conversion so I think I'll be ok, thanks.
05-27-2016, 09:31 AM
#20
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Year: 1996
Model: Cherokee
Engine: 4.0
I think alot of folks have done this conversion without worrying about metering devices. Most folks that I have read about did the swap and didn't even do anything with the proportioning valve.
05-27-2016, 09:35 AM
#21
::CF Administrator::
Blueridge, it is a proportioning valve. It's what controls the amount of force to the front vs rear brakes when pressure is applied to the pedal. Drum brakes operate differently than disc. Here's a link that explains it.
http://www.classicperform.com/How/Ho...-Prop-Work.htm
Never hurts to be armed with information, however, LOL
Good luck
05-27-2016, 10:15 AM
#22
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Year: 1999
Model: Cherokee (XJ)
Engine: 4.0L
It's certainly one of the most noticeable upgrades I've done, and I love knowing that I never have to mess with changing drums, shoes, cylinders, or any damn springs ever again. Just two bolts, pop new pads in. Done.
05-27-2016, 10:36 AM
#23
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Year: 1999
Model: Cherokee
Engine: 4.0
Big David supplies the valve with his kits and it does make a difference also when you change it, better braking. His kits are the best way to go for a swap cheapest and you do get it all.
05-27-2016, 11:03 AM
#24
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FINALLY got to install my kit 2 weeks ago(got it last Sept). All went well considering I lost internet connection right after I started thus all my saved info for the swap. Just got internet back at noon today. Only glitch I ran into was with the ZJ PV guts. When it came time to bleed the brakes fluid kept wanting to come out of the bleeder on the PV. I replaced the ZJ parts with the XJ parts and all is fine. Brakes are GREAT but I'm just wanting to know if anyone else had this issue or may know the cause.
05-27-2016, 12:14 PM
#25
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A Proportioning valve is required on vehicles that have disc brakes on the front wheels and drum brakes on the rear wheels. Disc brake pads are normally in contact with the disc, while the drum brake shoes are normally not in contact with the drum. If the pressure was not proportioned the disc brakes would engage before the drum brakes when you depress the brake pedal.
The Proportioning valve compensates for this, allowing the drum brakes to engage first before the disc brakes. The Proportioning valve does not allow any pressure to the disc brakes until a pre-determined pressure has been reached. The pre-determined pressure is low when compared to the maximum pressure in the braking system, this allows the drum brakes to engage before the disc brakes engage. Having the rear brakes engage first provides the control and stability needed to stop your vehicle safety.
The proportioning valve reduces the pressure to the rear brakes. Whichever type of brakes your vehicle has, the rear brakes require less pressure than the front brakes.
If equal braking force were applied to all four wheels during a stop, the rear wheels would lock-up before the front wheels. The proportioning valve only lets a portion of the amount of pressure to the rear wheels thus preventing rear wheel lock-up.
The Proportioning valve compensates for this, allowing the drum brakes to engage first before the disc brakes. The Proportioning valve does not allow any pressure to the disc brakes until a pre-determined pressure has been reached. The pre-determined pressure is low when compared to the maximum pressure in the braking system, this allows the drum brakes to engage before the disc brakes engage. Having the rear brakes engage first provides the control and stability needed to stop your vehicle safety.
The proportioning valve reduces the pressure to the rear brakes. Whichever type of brakes your vehicle has, the rear brakes require less pressure than the front brakes.
If equal braking force were applied to all four wheels during a stop, the rear wheels would lock-up before the front wheels. The proportioning valve only lets a portion of the amount of pressure to the rear wheels thus preventing rear wheel lock-up.
05-27-2016, 01:33 PM
#26
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on some veh their is a switch on the proportioning valve that will set a light on the dash if the guts are removed ,or the valve is stuck to one side IE a leak. Not sure if that is true for a xj .
And on a side note, once you have front and rear disk brakes you may want to change the master cylinder to one with a larger piston this will give you a higher harder brake pedal .
And on a side note, once you have front and rear disk brakes you may want to change the master cylinder to one with a larger piston this will give you a higher harder brake pedal .
05-27-2016, 01:59 PM
#27
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Year: 1999
Model: Cherokee(XJ)
Engine: 4.0
on some veh their is a switch on the proportioning valve that will set a light on the dash if the guts are removed ,or the valve is stuck to one side IE a leak. Not sure if that is true for a xj . And on a side note, once you have front and rear disk brakes you may want to change the master cylinder to one with a larger piston this will give you a higher harder brake pedal .
05-27-2016, 02:21 PM
#28
::CF Administrator::
A Proportioning valve is required on vehicles that have disc brakes on the front wheels and drum brakes on the rear wheels. Disc brake pads are normally in contact with the disc, while the drum brake shoes are normally not in contact with the drum. If the pressure was not proportioned the disc brakes would engage before the drum brakes when you depress the brake pedal.
The Proportioning valve compensates for this, allowing the drum brakes to engage first before the disc brakes. The Proportioning valve does not allow any pressure to the disc brakes until a pre-determined pressure has been reached. The pre-determined pressure is low when compared to the maximum pressure in the braking system, this allows the drum brakes to engage before the disc brakes engage. Having the rear brakes engage first provides the control and stability needed to stop your vehicle safety.
The proportioning valve reduces the pressure to the rear brakes. Whichever type of brakes your vehicle has, the rear brakes require less pressure than the front brakes.
If equal braking force were applied to all four wheels during a stop, the rear wheels would lock-up before the front wheels. The proportioning valve only lets a portion of the amount of pressure to the rear wheels thus preventing rear wheel lock-up.
The Proportioning valve compensates for this, allowing the drum brakes to engage first before the disc brakes. The Proportioning valve does not allow any pressure to the disc brakes until a pre-determined pressure has been reached. The pre-determined pressure is low when compared to the maximum pressure in the braking system, this allows the drum brakes to engage before the disc brakes engage. Having the rear brakes engage first provides the control and stability needed to stop your vehicle safety.
The proportioning valve reduces the pressure to the rear brakes. Whichever type of brakes your vehicle has, the rear brakes require less pressure than the front brakes.
If equal braking force were applied to all four wheels during a stop, the rear wheels would lock-up before the front wheels. The proportioning valve only lets a portion of the amount of pressure to the rear wheels thus preventing rear wheel lock-up.
05-27-2016, 03:47 PM
#29
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Either the pressure differential valve not centered or having the parking brake engaged with the ignition "ON" will activate the indicator light.
05-27-2016, 05:15 PM
#30
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I didn't do anything with the proportioning valve. it's fine. I put over 40k miles on it in its current state.
to the op: it appears you've already got parts, if not - get them from a junkyard. zj rear brakes are fine. I had roughly $65 in my swap. it would have been less but I did not have cores to turn in. take some old rotors with you if you have some laying around. I did not reconnect my parking brake but did install zj wheel studs.
to the op: it appears you've already got parts, if not - get them from a junkyard. zj rear brakes are fine. I had roughly $65 in my swap. it would have been less but I did not have cores to turn in. take some old rotors with you if you have some laying around. I did not reconnect my parking brake but did install zj wheel studs.