New Wilwood Disc Brakes Won't Release

shaundoyle09_193966
Sun, 22 Jun 2025 14:49:01 +0000
Maintenance/Repairs

Installed new 4 piston calipers on rear, 6 piston calipers on front, with complete new brake line to a new master cylinder and SS flex lines to the calipers. I did this about 8 years ago, but it has not been driven much since installation. When I went out for a test drive today, the brake pedal kept getting harder and harder to push and the vehicle struggled to move forward. By the time I got back to the house, they were completely jammed up. If I give it a day, they are released and the wheels spin freely. This is happening on all four corners, not one or two. This tells me the common denominator is the MC.

I took out the master cylinder and checked for trap valves and there were none. I exercised the main piston and it moved freely in and out of the chamber. Some of the SS flex hoses have a sharp bend, but not what I would consider a kink in the line.

Because of the size of calipers I put on the vehicle, should I run larger than 3/16 line?

Because of minimal usage, could the pistons in the calipers be seized?

No visible kinks in the 3/16 hard line either.

Thoughts, questions, suggestions?

Thanks,

WP

41 posts - 11 participants