The Stovebolt Site Forums The Shop Area The HiPo Shop Residual pressure valve

I know it's recommended that those with the MC mounted on the frame rail should use a residual pressure valve to help eliminate pedal travel, but I have the same issue & mine is mounted on the firewall. Shouldn't that work in my case as well? Looking at getting the 2lb valve since I have disc's on the back.

Robert the residual pressure valve is primarily to stop the fluid backtracking when the master cylinder is below the level of the brakes.
Their purpose is not to compensate for excessive pedal travel.
A firewall mounted M/C shouldn't need it as it has gravity on its side.

Too much travel at the pedal is usually caused by incorrect pushrod adjustment,wrong pedal arm ratio,too much clearance at the brakes or air in the system.
I think i'm correct in saying you're running discs on the back?
I had a similar problem until I found out you can adjust the 'venting clearance' on the rear calipers as part of the parking brake mechanism.
Simply adjusting them considerably reduced pedal travel as the rear pads had much less travel before contacting the disc.

Thanks Jock, I'll checkout the pushrod. I've bled them to death!

Just be careful Robert,it's easy to overtighten the pushrod which will then retain too much pressure on the system leading to overheated/binding brakes.
There should be a small amount of freeplay in the pedal before it actuates the M/C,I usually aim for 1/4 to 1/2" or there abouts.
If you temporarily remove the pedal return spring it'll give you a better feel for the freeplay adjustment.

It was mentioned about the parking brake for the rear calipers. You need to adjust it. If you have to much of a gap between the brake pads and the rotor your master cylinder won't have enough capacity with one push of the pedal.