Slow pedal return after rear disc.

[BR3W CITY]

Hey yall, I just finished doing a rear disc swap on my truck, but have noticed a fairly slow pedal return after a stop.

Some info;

LS swapped '66, running hydroboost from a circa 97 Astrovan, including the master. Front brakes are Wilwood D52's, and WAS running stock 70's rear drums. On this setup, truck stopped well and pedal was responsive.

Now,
Exact same setup, except swapped the rears for stock-type D52s (aka my old front brakes) using the CaptainFab brackets. Bled the brakes down, bled the hydroboost also, got a rock hard pedal with truck off.

Drove truck a bit to test my prop valve settings, and noticed a very slow pedal return. Brakes don't appear to be hanging up badly (no smoke, noise, or discoloration, and I can watch them work with removeable bed floor). I put ~40-50 miles on to see if it sorted itself out at all, and the slow return is the same across all conditions.

So; are we thinking I need a disc/disc master off of something like a 'vette? Truck stops ok but the slow return ain't great for safety and repeated stops.

[Mpiersd]

Not sure if this is a thing with square bodies, however.
You probably need to change the rear line residual pressure valve. In some vehicles it keeps line pressure for the rear brakes for quicker braking.
Usually changing tro an adjustable pressure regulator will do the job.

[BR3W CITY]

No residual valves. All lines are brand new NiCo front to back. Only valving is the manual prop.

[mongocanfly]

When you say prop valve setting ,I assume yours is adjustable?....I know a disc/disc setup uses a different master cyl and combination valve

[BR3W CITY]

Just a wilwood adjustable valve. Brakes were bled with it wide open.

[Mpiersd]

Originally Posted by BR3W CITY

Just a wilwood adjustable valve. Brakes were bled with it wide open.

Have you adjusted it down since bleeding?
To be properly bled, keep adjusting until you get lock up on the rear brakes just before the front brakes lock up. Then diwl back out so that the fronts lock up first.