Outer Limits 4x4 Board

I have a 60 series with a 2h in it.Sometimes when travelling and using the brakes the pedal goes very hard and the brakes don't work well.It is not that the brakes have over heated because it can sometimes happen when i need to use the brakes often in a short period of time,althought the brakes have not needed to stop the car at speed ie doing a 3 point turn on a track.Seems to be vacuum related..i guess.Any feedback would be appreciated.

Test to see if your Booster is working.

Press the brake pedal a few times with the engine off, make sure there is no change in the distance the pedal travels.

Now press down the brake pedal and start the engine. If the pedal goes down a bit, it's working fine.

Booster fault or vac pump/system fault... Check the tension on the alternator belt if it's badly adjusted you may not be developing enough vacum to operate the booster system .... could also be a vacum hose leak..