75gmck25
Full Access Member
- Joined
- Oct 13, 2016
- Posts
- 2,375
- Reaction score
- 2,386
- Location
- Northern Virginia
- First Name
- Bruce
- Truck Year
- 1975
- Truck Model
- K25 Camper Special TH350 NP203
- Engine Size
- 5.7
If the linkage is all intact, my best (somewhat educated) guess is that the piston seal inside the master cylinder has torn or otherwise failed. However, the pedal will usually still return up, so check the external mechanical linkage and the rod first.