Disc brake drag

I just converted to disc brakes. I added a 2psi residual pressure valve to the system. All works well, but the brake drag is noticable. Any way to lessen this effect?

 

does the M/C you are using already have a residual valve built in? If so you might have too much with the additional valve.

 

If the MC has a built in residual valve, it must be removed. They are located behing the fittings that the brake lines screw into on the MC.

 

I thought you only needed a residual valve on drum brakes, to keep pressure on the shoes. That is why you remove the one built into the M/C when you do a disk conversion. Am I wrong?
Keith

 

No first hand experience here, but I've read multiple times that you need more residual pressure on drum brakes than disc. That's why you remove the stock (10lb I think) residual valve in the MC and replace it with a 2lb for the disc.

 

The only reason you need the 2 lb valves is because the master cyl. is below the calipers. The fluid can drain from the calipers back into the M/C causing a pedal you have to pump to work. If the M/C were on the firewall, no valves would be needed. I would check for the original 10 lb. valves in the M/C itself and remove them if they are still present.

 

Thanks guys! I'm using the stock MC, I will find out if a RPV is built in. I'm thinking I need to loosen the wheel bearings enough to give a little play, thereby opening the calipers slightly. It stops like a dream!!