Hot Rods Front disk brake drag?

Hi everybody. My 28 Tudor has drums in the rear and disks up front with the master cylinder under the floorboard. I have the 2psi residual valve installed for the front brakes. The other day I noticed the front brakes dragging pretty good, yes I know the 2psi is pushing on them, but is this too much drag? Seems like a lot to me. Seems like the brakes would wear and heat up pretty fast this way.
Let me know what you think

Aaron

 

I have the same drag on my 57 Chev. I talked to a guy at a brake booth at the Syracuse Nationals about it and he had some mockups of different setups and the one like mine has drag on it. He said once the car is rolling and the caliper moves about the drag is less. Multi piston calipers had less drag then the single setup.

 

Isn't the residual pressure for drums only ? I thought disks didn't want residual pressure dragging the pads, drums need it, but disks will heat up and not release. Or so I thought...

 

The statement about drag lessening when the car moves might be correct but I would check for free play at pushrod to master cylinder just to be sure. The 2 pound residual valve is needed when the calipers are higher than the master cylinder.

 

I experienced the same drag issue on ford calipers. Turned out the calipers needed cleaned and a bit of lube put on the brackets that allowed the caliper to 'release'. I had the 2# residual valve on the front, 10# in the back, and the under floor MC. Once the calipers were freed up the system works great. My brake shop guy says this is common with cars that sit and have slide systems that tend to gum up. He also said GM type pin calipers need regular greasing, as the heat developed by the brake system has the tendency to gum it up, even high temp stuff.

 

Do you have a e-brake/park brake ? If yes, here's how you can test and see if the caliper is backing off as you drive as described above. You'll need a stretch of road where it's safe to bring your vehicle to a stop using your e-brake once you've driven a short amount of distance. Once stopped (oh ya, bring a floor jack along) jack the front up and see.

 

"Seems like the brakes would wear and heat up pretty fast this way."

Well, are they?

 

Had the same problem on my thirty sedan it was the cheap residual valve I removed the internal parts and put it back on no more problems .Great pedal..

 

Sounds like you still have the 10 lbs residual valve in the mastercylinder that would not bother the rear drums but would hold the front brakes on.