Interesting brake issue

[jlwdvm]

I figured I had to do the toe thing to get the brake lights to turn off because of a combination of the brake light switch not properly adjust and the brake pedal rod not properly adjust for length. Today's problem didn't show up until I lengthened the master cylinder push rod end...to preload the master.

[blitzer454]

Preloading the master cylinder sounds like a bad idea to me. The piston in the master cylinder needs to be fully uncompressed when your foot is off the brake otherwise the port to the reservoir will be blocked off, and believe me it doesn't take much movement of the piston to block off that port. You also won't be able to bleed the brakes when that port is blocked by the piston. The booster to master cylinder rod needs to be adjusted such that there is a small gap between the rod and the piston of the master cylinder. Then adjust the rod length of the other side of the booster to fix the brake light problem.

Also make sure your parking brake is working. It could be that the pistons in the rear caliper is having to travel too far because the parking brake has not been adjusted.

[Musclerodz]

Originally Posted by jlwdvm

I figured I had to do the toe thing to get the brake lights to turn off because of a combination of the brake light switch not properly adjust and the brake pedal rod not properly adjust for length. Today's problem didn't show up until I lengthened the master cylinder push rod end...to preload the master.

you don't preload the master. it has to have play so there is no pressure on the brake system when your not using it or the end result is your brakes trying to lock up.

[jlwdvm]

Manual system....no booster.

[dhutton]

If you want a little preload on the brakes use residual pressure valves.

Don

[GregWeld]

Originally Posted by dhutton

If you want a little preload on the brakes use residual pressure valves.

Don

Fact!