J20 Rear Disk Brake Proportioning Valve

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threepiece
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J20 Rear Disk Brake Proportioning Valve

Post by threepiece »

I’m looking to convert my J20 to rear disc brakes and I am curious if the original proportioning valve is up to the task. I have read about others who have done this on several different threads but I did not see mention of the valve so I have assumed there is no issue with using the original one. Can anyone confirm my assumption?
I used to name my FSJ’s after their previous owners, I realized I had too many with five named Rick.

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Stuka
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Re: J20 Rear Disk Brake Proportioning Valve

Post by Stuka »

It depends which factory brake system you had. If you had factory power front disc brakes, you should be fine with your existing proportioning valve.

Its not perfect. And you can buy a correct valve for 4 wheel disc from Willwood or the like, or get fancy and get an adjustable one. But provided you have the above stock setup, you should be fine for most scenarios.
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sonoraed
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Re: J20 Rear Disk Brake Proportioning Valve

Post by sonoraed »

used the valve from BJ's on my truck works very well, some time you will find a check valve to the drum brakes, this hold some pressure to the wheel cylinder so the shoes don't have to travel so much when applied, when converted to disc this pressure keeps the pads applied which is not ideal.

itselliott
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Re: J20 Rear Disk Brake Proportioning Valve

Post by itselliott »

When I did the disc conversion on my J20,....I went hydro boost and used a corvette Prop. valve and master cylinder..

sonoraed
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Re: J20 Rear Disk Brake Proportioning Valve

Post by sonoraed »

itselliott wrote: Fri Jan 08, 2021 10:05 am When I did the disc conversion on my J20,....I went hydro boost and used a corvette Prop. valve and master cylinder..
With you there Hydro boost is one of the best mods I've ever done to my J10!

itselliott
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Re: J20 Rear Disk Brake Proportioning Valve

Post by itselliott »

sonoraed wrote: Sat Jan 09, 2021 7:13 am
itselliott wrote: Fri Jan 08, 2021 10:05 am When I did the disc conversion on my J20,....I went hydro boost and used a corvette Prop. valve and master cylinder..
With you there Hydro boost is one of the best mods I've ever done to my J10!

I went with the El Dorado calipers....

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Re: J20 Rear Disk Brake Proportioning Valve

Post by SJTD »

I bought a Cad axle to get the Calipers but they offended my sense of symmetry with one if front and one in back of the axle. Ended up using Lincoln.

This was back before every truck and its brother had rear discs.
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