vacuum

[skilletky]

how much vacuum is the vacuum pump supposed to pull? i am having a problem with my power brakes and the lack there of. the booster had two holes in it and was leaking vacuum bad, i just put a new booster and master cyl on and there was no change, vacuum pump feels like it has good vacuum( stuck my thumb on the end of the main vacuum line), and i can not find a vacuum leak any where. did i get a bad booster? is the pump going bad?

[dpuckett]

My last 2 pumps have pulled at least 20hg-M of vacuum.

Dan

[skilletky]

well i put the gauge on it and it is pulling 30in. can't find a vacuum leak any where. the cruise still works along with the a/c controls. i am guessing my new booster is bad. could the fitting where the main vacuum line connects to be a cause?

[Cumminsdriver]

I have had similar problems on two different truck. Each time it was something besides what I was aiming at. Having changed your booster and MC I would look elsewhere. Have you done an ABS delete?
I once went down he road your on now only to find that my ABS was the problem. And on another occasion it was a bad booster after fighting with the ABS.
What is your brake pedal feedback? That can give an indication of the real issue.

[skilletky]

when you go to stop, it is like driving something with all drum none power brakes. i have not done the abs delete. don't even know if the truck has abs.

[Cumminsdriver]

"don't even know if the truck has abs"

If you had good brakes once and now do not,despite your new parts, most likely its still there.
Look for a valve block @ the rear left frame rail behind and above the rear axle. The rear brake line runs to it then back out to the flex line to the axle Tee. If its there, this "could" be part of the problem.
Search ABS delete for details. I know there is allot on the TDR about this but I'm no longer a member so I can't search. Its a good read anyway.

[PJ 3]

"don't even know if the truck has abs"

If you had good brakes once and now do not,despite your new parts, most likely its still there.
Look for a valve block @ the rear left frame rail behind and above the rear axle. The rear brake line runs to it then back out to the flex line to the axle Tee. If its there, this "could" be part of the problem.
Search ABS delete for details. I know there is allot on the TDR about this but I'm no longer a member so I can't search. Its a good read anyway.

I just recently disconnected my abs system on my truck and it's one of the best mods I could have ever done. I have brakes now !

[skilletky]

then yes the truck does have abs. i will have to do the delete. thanks all for the info.

[PToombs]

If the pedal is hard, the ABS isn't the problem. Most likely the booster is bad. The rebuilders don't give a hoot about guys with 15 year old trucks stopping. We aren't driving in China, so too bad for us!
If the ABS was bad, the pedal would be soft and spongy. Before you play with the ABS, double check the booster.

I did the delete on my truck too, as the pedal was spongy and I couldn't stop for crap. Made a biiiiig difference.

[skilletky]

i am pretty sure its the booster. after i replace it again i am definatly going to do away with the abs valve.