Yeah, what ford said. The residual pressure check valves are on the order of 2psi for disc and 10psi for drum, and that's the aftermarket stuff. Probably very close to, if not exactly what was used from the factory.
But unless it's clogged, it's not going to lock up your brakes. They can drag a bit when driving, but not do this.
I drove around for a week or two as a test, with the check valve still in my stock master when I installed disc brakes. No perceived dragging.
But first of all, have you even cracked a bleeder open yet? If so, what happens.
And if not, before you do, can you eyeball down the caliper to see if the piston is already fully compressed or not?
If there is still room for the piston to compress, then crack a bleeder and get the pressure issue resolved.
If there is no more room, then it's likely that either your pads or the rotors are too thick. This is unfortunately way too common a problem these days. Almost no regard for original tolerances in modern wear parts.
I've had personal experience in the last five years with pads to thick to even fit into the calipers over the rotors, shoes to thick (or the wrong radius) to fit under a drum, drums machined incorrectly and not fitting over correct shoes, rotors too thick to fit under the calipers, and splined bearing hubs with splines too short for the locking mechanisms to fit.
So if one or more of your parts are not to spec, it's not without precedent.
But only you can check. How hard was it to slide the loaded calipers over the rotors?
If they went on easy enough, then thickness is not a problem and it's either pressure or offset. (seemingly that is!)
Paul
