So I recently purchased and installed a rebuilt brake booster for my 1970 mustang. At first, the pedal went down really far but got the job done, so I didn‘t mind. Now, the brakes don‘t work as well and the booster is not generating enough pressure for the stop light switch (which is brand new) to make my brake lights go on until I am slamming the pedal down. First, how can I adjust the push-rod length and what is the deal. It is very possible that the braking issue is due to air in the system cause I just checked that and the back reserve is really low. I want to adjust the pedal travel distance though regardless.
try bleeding the system. also check the rear brake adjustment.
why is the rear chamber in the master cylinder low?, you better start checking for a fluid leak in your back brakes someplace, wheel cylinders or brake line, also sounds like there is air in the system, fix the leak if there is one and bleed all the brakes again.
Sounds like you need to bleed the system and then re-adjust your brake light switch. The switch has to be positioned and adjusted properly in order for it to come on at the correct time of brake pedal travel. The push rod cannot be adjusted, the brake switch is the problem, adjust it. ASE technician 25 years
