rf brake locking up

[ncracer1st]

how do you keep rf brake from building pressure when using 3 wheel brakes? One guy told me to turn the rf brake on and back off every couple laps.

[Egoracing]

how do you keep rf brake from building pressure when using 3 wheel brakes? One guy told me to turn the rf brake on and back off every couple laps.

What type of shut off are you running? We ran electric and when installed correctly we never had any issues with it trying to lock up. If you are running a shut off valve GRT made on with a pressure bypass on it that would allow pressure to come back past the valve and not allow brake pressure to go to the caliper.

[ncracer1st]

I have an electric but havent used it yet. My old car had a ball valve type and never had a problem but i dont know if it had a relief valve. Some one told me you can use a residual valve installed backwards.

[Egoracing]

I have an electric but havent used it yet. My old car had a ball valve type and never had a problem but i dont know if it had a relief valve. Some one told me you can use a residual valve installed backwards.

The electric are designed for a drag car to lock the brakes on. For a dirt late model you put it in backwards to the direction that is was made for. In it's original use is allows fluid to pass if it is turned on before the brakes are pressed to lock the fronts. When we put it in a late model it locks the pressure from the RF but should allow any pressure to come back thru it if it builds up.

[joedoozer]

I read this thread when it was first posted and thought something sounded strange. I ran an entire season with the RF shut off and never had a lock up problem. I just use a simple ball valve. I raced last weekend and guess what happened, the RF locked up haha. During practice earlier in the week I had broken a fitting on the LR caliper. So I removed the fitting from the RF to fix the LR. I then removed the RF caliper because I couldn't tape the hole up and I didn't want the fluid getting shook all over the car. When I made the repairs in the garage I did a quick bleed. When the RF locked up in warm ups I figured it was 2 possibilities. #1 there was air in the line and with the brake shut off, the little bit of air in the line had heated up from the header causing the caliper pistons to move. #2 I bumped the shut off when my foot was on the brake. I bled the brakes just to be safe, although I didn't believe it was air in the line. I figured my dumb a$$ bumped the valve. I didn't have a problem next time out.

[drtrkr244]

Its hard to beat the $10 ball valve. They hardly ever fail.

The biggest mistake racers make is turning the RF off, while they are applying the brakes. Remember to ONLY adjust valve while not applying the brakes.

[joedoozer]

I think the little bit of air in the line may have played a roll in it. A system without a shut off will allow pressure to escape into the master cylinder. But if you have the valve closed there is no place for that pressure to go. Could heated air in a brake line cause enough pressure? I don't know. It was a theory, so I bled the brakes.

[QuesinberryRacing]

One more little tip, or habit of mine, I used to have the lockup problems with the ball valves, everything I have now has the electric setup, but I always pull up on the pedal before I flip the switch.

[Dirtrunner35]

I have ran my car with no right front brake with a ball shutoff valve with no problems for 3 years.

[jedclampit]

air is compressible, fluid is not
brakes make no heat unless they are applied or dragging
usually there is drag, and the fluid will expand on long green runs w 3 wheel ball valve style
air is not the problem drag usually is or residua lpresure when the valve was shut, brake guages in a car will tell your driver whats up and when bias is correct/repeatable
the electric ones make a nice park brake when you need to hold the car on a hill!

[Egoracing]

the electric ones make a nice park brake when you need to hold the car on a hill!

Love that part! Another thing many people do not think about, brake fluid will absorbe water and if there is a pad draging and causing heat the water will release and create steam and it will lock up a shut off caliper quickly. The best thing you can do for your car is replace the brake fluid once a season. I seen an old farm truck that had so much water in the brake fluid that when winter came the master cylinder had ice crystals in the lid and the brakes would not work.

[QuesinberryRacing]

I am guilty on the parking brake! Had to get out of the car one night for driver intros and used it to hold the car rather than putting it in gear! It did work!

[PushinTheLimit]

Just to bring this up and not start a new thread, I checked my brakes this past weekend and noticed that even with my RF shutoff with my electric switch, my RF was still locking up. Not as much as the others so there must be some bleeding through on that corner. Will bleeding the brakes possibly fix this?

[7uptruckracer]

Might be time to refresh the calipers, and MC, which is a good idea in the offseason

[DaveBauerSS6]

Get a new solenoid.

[powerslide]

Just to bring this up and not start a new thread, I checked my brakes this past weekend and noticed that even with my RF shutoff with my electric switch, my RF was still locking up. Not as much as the others so there must be some bleeding through on that corner. Will bleeding the brakes possibly fix this?

Sounds like its time for a new Shutoff, its allowing pressure by.

[PushinTheLimit]

We bled the brakes over the weekend and everything seems like it working fine now.