I replaced the pads on my EF XR6 over the weekend and had the Mrs pump the pedal while I bled the lines. I think she has pushed it to the floor and damaged something as now it feels like there is no vacuum assistance.

I have tested this by pumping the brake with the engine off, and then starting the car with my foot on the brake, only to feel no difference in pedal travel.

The car is now idling high, so I removed the vacuum line to the booster and plugged it, only for the idle to return to normal. This has me thinking that I have a leak in the brake booster (big black thing?). I read somewhere that this can happen because pushing the pedal to the floor can cause an issue with the Master Cylinder seals. I'm trying to work out if I need to replace the master cylinder or the brake booster, or both?

This car is due to go over the pits on Wednesday to be re-registered so I really need to get this sorted today.

Any assistance is much appreciated.

Cracked brake booster.
Happens that often its nearly factory fitment.

Beauty, thanks for the reply EVL098.

Do I need to drain the master cylinder to replace the booster?

Should get one from the Wreckers or purchase new?

Look for a crack from centre of booster down, usually its a very fine crack. If no crack evident internal seals. Its an easy remove replace job. Dont drive the car until the booster is replaced as you will have very little braking power!