Front wheel drag

[ChrisCairns]

I'm speaking of the drag that remains on the front wheels that is always present on our cars once the brakes are released. It's called residual pressure and they even made valves just for this purpose to be used on street rods since the master cylinder was usually lower than the wheel cylinder. This pressure is created by the master cylinder in our cars I believe...in other words it doesn't allow all the brake pressure to release thereby keeping a small amount of drag on the front pads/rotors.

Someone recently told me that Chrysler products didn't have this residual pressure in their master cylinders and I know that one of the vendors once sold something that would help release this pressure.

I once tried to put some springs on the long bolts that hold the calipers together...the spring was supposed to force the calipers back apart but it was just eaten up by the turning rotor.

Anyone here that has managed to release this pressure? Or forcing the pads apart so there isn't any drag?

Chris

 

[REDS HOT AIR]

not sure about pm brakes but gm went to quick take up master cylinders in early 80's which actually pull the calibers in off the brakes for no drag.

if you convert to vacum brakes make sure you get an alum master cylinder and your drag will be gone.

 

[TurboDave]

Originally posted by ChrisCairns
I'm speaking of the drag that remains on the front wheels that is always present on our cars once the brakes are released. It's called residual pressure and they even made valves just for this purpose to be used on street rods since the master cylinder was usually lower than the wheel cylinder. This pressure is created by the master cylinder in our cars I believe...in other words it doesn't allow all the brake pressure to release thereby keeping a small amount of drag on the front pads/rotors.

Someone recently told me that Chrysler products didn't have this residual pressure in their master cylinders and I know that one of the vendors once sold something that would help release this pressure.

I once tried to put some springs on the long bolts that hold the calipers together...the spring was supposed to force the calipers back apart but it was just eaten up by the turning rotor.

Anyone here that has managed to release this pressure? Or forcing the pads apart so there isn't any drag?

Chris

There should be NO drag after a second or so of releasing the brakes. If you have consistent drag, something is amiss.
Are your "piston side" pads "clipped" to the pistons?

 

[ChrisCairns]

Originally posted by REDS HOT AIR
not sure about pm brakes but gm went to quick take up master cylinders in early 80's which actually pull the calibers in off the brakes for no drag.

if you convert to vacum brakes make sure you get an alum master cylinder and your drag will be gone.

Interesting Red.

I remember once having my Toyota on a lift and the mechanic and I started to talk about domestic cars and their residual pressure. He showed me how the Toyota pads, once relaxed, would actually pull back just a hair from the rotors. You could actually see it.

My present race car is the one with the excessive drag...and my last race car (pm system) had it also, but not as much. So perhaps the power master system doesn't allow the pullback like you described.


I have a vac brake setup ready to go. I'll check and see if it's the aluminum mc. Thanks for the help.

Chris