Brake Residual Valves

fmlewis · 06-06-2012, 11:05 AM

So I did the disc brake upgrade on my CJ. I am using the 69 Corvette Disc/Disc M/C and Caddy calipers. I have bled and bled and bled the system, using gravity, traditional pumping, and also purchased a vacuum system. I even bench bled the M/C.

Last night I took the jeep out for a test drive and noticed I still need to double pump the brake pedal to get a good pedal without excessive pedal travel. The jeep will stop on one pump but there is just too much pedal travel, almost to the floor.

Any ideas? I can't imagine there is air in the system, but I know this is the typical symptom of air. Do you think a 2lb residual valve would be a good idea for the rear brakes?

Does anyone know a good place to have brake systems bled?

Let me know.

cincygman · 06-07-2012, 07:45 AM

You put disc where drums used to be? Your going to have to swap out the proportioning valve or add a bias valve to the rear line. You need to search "rear disc brake upgrade" Your having to double pump because the check valve in the existing proportioning valve is designed for drum brakes. At least if my memory serves me correctly, that's what you have going on....

fmlewis · 06-07-2012, 09:44 AM

I forgot to mention I did change the proportioning valve over to a GM disc/disc proportioning valve.

I did make a modification that I figured wasn't a big deal but maybe it was. On the proportioning valve I removed the rear line port and re-used the one off of my original proportioning valve, that way I didn't need to add an adapter to adapt my brakeline or re-flare the fitting. When I reviewed the part they looked the same just a different fitting size.

C.P. · 06-09-2012, 10:39 AM

Do those calipers have parking brake levers? I did a conversion on a car a few years ago, and I had to have the park brake hooked up and adjusted to make the pedal feel right.

06-06-2012, 11:05 AM	#1
fmlewis The best damn Engineer!!! Join Date: Aug 2008 Location: Fairfield Posts: 135	Brake Residual Valves So I did the disc brake upgrade on my CJ. I am using the 69 Corvette Disc/Disc M/C and Caddy calipers. I have bled and bled and bled the system, using gravity, traditional pumping, and also purchased a vacuum system. I even bench bled the M/C. Last night I took the jeep out for a test drive and noticed I still need to double pump the brake pedal to get a good pedal without excessive pedal travel. The jeep will stop on one pump but there is just too much pedal travel, almost to the floor. Any ideas? I can't imagine there is air in the system, but I know this is the typical symptom of air. Do you think a 2lb residual valve would be a good idea for the rear brakes? Does anyone know a good place to have brake systems bled? Let me know.

06-07-2012, 07:45 AM	#2
cincygman Join Date: Nov 2008 Location: Pleasant Run Farms (near Fairfield) Posts: 378	You put disc where drums used to be? Your going to have to swap out the proportioning valve or add a bias valve to the rear line. You need to search "rear disc brake upgrade" Your having to double pump because the check valve in the existing proportioning valve is designed for drum brakes. At least if my memory serves me correctly, that's what you have going on.... __________________ Romans 7-8

06-07-2012, 09:44 AM	#3
fmlewis The best damn Engineer!!! Join Date: Aug 2008 Location: Fairfield Posts: 135	I forgot to mention I did change the proportioning valve over to a GM disc/disc proportioning valve. I did make a modification that I figured wasn't a big deal but maybe it was. On the proportioning valve I removed the rear line port and re-used the one off of my original proportioning valve, that way I didn't need to add an adapter to adapt my brakeline or re-flare the fitting. When I reviewed the part they looked the same just a different fitting size.

06-09-2012, 10:39 AM	#4
C.P. Join Date: Dec 2011 Location: HAMILTON Posts: 17	Do those calipers have parking brake levers? I did a conversion on a car a few years ago, and I had to have the park brake hooked up and adjusted to make the pedal feel right.