[73LeMans]

Both front brake calipers are locked up - hoping to figure out why before I start swapping parts.

All parts have about 300 miles on them, except the line lock and the flex hose. Both of those are many years old. (13 years?)

- Right Stuff Booster
- Wilwood Master Cylinder
- Wilwood prop valve
- Biondo line lock
- All new hard lines
- Steel braided flex hoses
- Wilwood D52 Calipers



In the 7 hours of drive time since being assembled, brakes have been excellent with no deviation.

Last Sunday however, I went to an event and as I drove up to the stop light, I could feel the brakes harden up and it took a lot of pedal effort to stop. Didn't think anything of it - it seemed to brake fine for the mile to the event and the mile back to the trailer after that. I could see at the show (no hood or fenderwells) the brake rotors were discolored.



At the time I thought it might just be normal use.

When I got the car home, I used the line lock for the 4th time since being back on the road and did a small burnout after rolling off the trailer. (because I'm a child)



Drove the car into the garage and two days later, when I went to swap front wheels, I noticed both wheels were extremely hard to rotate.

To troubleshoot, I've done the following:

- Pulled the brake pedal up - no difference (it didn't move)
- Removed a caliper to verify the wheel spins freely - it does
- Reset caliper pistons, put it back on and verified wheel still spun freely.
- Applied the brake (car not running) and from that point forward, that rotor was again, very tough to turn by hand - almost locked.
- Disconnected the brake pedal from the pedal rod - no difference
- Pulled back on rod from inside car in case it was applying pressure - no difference
- Separated the M/C from the booster in case the rod was stuck and still applying pressure - no difference
- Still while separated, I reconnected the pedal and verified rod movement was free and smooth
- Cracked open the bleeder on a caliper and spun rotor - no difference. Still locked

Both rotors look to be the same off-color. It doesn't appear its more one side or the other and both are equally tough to rotate. There are no bent lines or crushed flex lines. The rear wheels spin just fine. When I removed the master cylinder from the booster, it appeared the cylinder was in its proper position of rest again the retaining clip in the back of the unit.

Operation of the line lock (Biondo unit) appears to be in order. The solenoid makes all the right sounds and worked fine when I rolled the car off the trailer.

I banged on the case with a ratchet just in case something was stuck, but it made no difference. I can rule out electricity holding the valve closed because my troubleshooting (except the checking of the solenoid) is all done with the master cutoff switch in the off position.

I've read these D52 Wilwood calipers get sticky - but both at the same time?



I saw no solution on how to keep them from getting sticky.

Im kinda stuck - see what I did there? - on next steps. Ideas?


I'm inclined to believe the biondo linelock is the culprit, given its age and the fact that it sat the last 6 years (2 without fluid) but I'm not 100% convinced. If I crack open the bleeders, thus eliminating and pressure exerted by the linelock, I would expect the rotor to then be easy to turn. They were still locked


Thoughts?