MG Car Repair: Breaklight, brake light switch, brake master cylinder

Question
Hallo Howard.
I am the lucky owner of a 1965 mgb.
Last week I pulled the engine and changed the clutch and release bearing. after installing the engine again, the breaklights are constantly on. The breaks work fine and there are no other electrical issues. Do you have any suggestions as to what the problem is?

Best regards
Miller

Answer
Hi Miller,

First thing to do is to step on the brakes and get the brake lights to come on and then check to see that you have about an inch of free play in the pedal when you release the pedal.

Then open a bleeder valve on the brake caliper and watch to see if the brake light goes off. If the lights go out then you have either a lack of free play in the pedal, the pedal is sticking and not returning (look at the pedal return spring under the dash) or you have a brake master cylinder problem.

If the brake lights didn't go off when you opened a bleeder valve then go to the brake light switch (it is a hydraulic switch on a 65 B) and remove the two wires off the switch to see if the lights go ont. If they do go out the switch is bad and if they stay on, you have a wiring problem and need to trace the wires to the brake lights and check to see if all the wires are plugged into the correct sockets at the tail light assembly.

Howard