Brake pedal return spring

[myblue67]

So I've been trying to track down some front brake lock up issues. Thought I'd fixed after replacing the master cylinder couple months ago....but problem returned. Anyway pulled front seat to get a good look at the brake pedal assembly to insure no preload issues starting with the pedal assembly (note this was front disc brake conversion) and noted a spring hanging down from the pedal assembly. UPC 5 A3 page 77 shows this spring. So 2 questions. First is the spring required with power discs.? ..pedal seems to return just fine, and Second is the extension I see in the drawing a different part or part of the pedal arm? I don't have anything to attached the spring to if I wanted to.

Thanks in advance,

[bertfam]

Manual brakes required the spring to pull the pedal back to its "parked" position because the return spring in the master cylinder wasn't strong enough to do it. If a manual brake car is missing the spring, the weight of the pedal is actually enough to engage the brakes causing a drag. Not a lot of drag, but enough the engineers felt it could be an issue.

Power brakes don't need the spring because the power piston return spring inside the booster is strong enough to return the pedal to it's "parked" position. For power brakes, you don't need the extension either.

However, manual brake cars and power brake cars have the clevis in different locations. Take a look at the AIM under J50 and you'll see where the clevis attaches for power brakes (UPC J50, sheet A2 - Bottom hole) vs. manual brakes (UPC 5, sheet A2 - top hole). You'll also need the striker (UPC J50, sheet A2, number 5) for the brake light switch.

Ed