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Vac Pump Assisted Brakes


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Is it just me or is it normal to have to put some decent effort into stopping these SSS? Ive got a 03 and Im wondering if my vac pump is working. Ive been in like 05s and if you smack the brake you will chew the steering wheel. Is there a way to test these thing? Will it throw a code? Does anyone know WHEN they are supposed to work? For example, if the ignition is on engine off, and hit the brake.... should it turn on?


I donno, maybe its normal but geez. its got a pump it should be easier to stop this thing..



Help, thoughts, opinions welcome!




Fellow SS Driver.

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I have noticed the same thing with my truck it seems over the last year or so I have to push the pedal much harder and further to stop the truck almost like the brakes are not bled properly but i have bled them 3 times this summer to try and improve the feel in the pedal. I am getting ready to flush my brake system to see if that helps if it is not the brake assist. So I am also interested!!



But on a side not this section is ment for post that explain how to do something not asking on how to do something.

Edited by rojo_143 (see edit history)
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fyi , nbs trucks with drums/discs stop a ton better. the nbs trucks with disc are far from great. but add some baers and a hydroboost setup and your golden. imo just the hydroboost makes a difference but i did it after the baers.

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Alright. Interesting to know that Im not the only one out there applying more pressure then I thought would be normal for a newer truck. Anyone ever had the vac pump go down? I should pull it off and bench test it. Youd think a 6.0 would have lots of vac and not even need a pump...

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How much does a hydroboost conversion run??? i have never looked into it??

There's a couple threads on the forum here discussing the swap in detail; short answer is, it doesn't take much, just find a hydraboost master cylinder w/ lines from a donor truck ($75-150 at a wrecking yard) and install it. You will have to plumb the lines into the power steering circuit (not as big an issue as it sounds). The biggest area to research is the firewall bolt pattern for the master cylinder, GM used a few different 'spacings' in their 4-bolt mounting pattern which varied between the Suburbans, 3/4-tons, Hummers, and heavy-duty trucks; also make sure that the pedal rod from your brake pedal to the master cylinder is the correct length/alignment for the replacement cylinder. I have heard a couple reliable accounts that hydraboost was optional on heavy Tahoes, Suburbans, and Escalades and that those master cylinders interchange without modification; I have also read that the hydraboost cylinders from 3/4-ton Silverados needed minor modification to bolt into place and a pedal swap. :dunno:


Mr. P. :)


We need to hear from SS Wrecker, he did the swap in his tow truck and said it was a dramatic difference and I'm pretty sure he said that in the end cost him less than $75.

Edited by Mr. P. (see edit history)
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