I have a 96 2500 auto 4x4. When I use a hand vacuum pump gauge to apply vacuum to the brake booster only, (all other lines are disconnected) the vacuum gauge will read 10 inHg not more. If I try and apply more It will stay at 10 inHg. has anyone else ever done this. Shouldnt the vacuum keep going up and hold. I tested all the other lines also, the more I pump those the more vacuum i get and it holds. Is there any other test I can do to see if brake booster is bad?
Thanks for any help John McHorney

 

It should pump up as high as your gauge will go and stay.

 

Thanks thats what i thought. I guess i need to order a new brake booster. I will let everyone know what I find.

 

Do I have to remove lines from master cylinder to change brake booster?

 

No. Two nuts hold the master to the booster and even though it doesn't look like it the master will swing out of the way enough.

Moving the master this way is also the only sane way to change the fuel filter.