Wow, what a title! :D

Anyways, I was wondering if anyone has any experience with these master cylinders? They seem to come on GM station wagons from '85-'86 and Grand Nationals (though GN's are a little different).

Pic #1 (http://www.chevelles.com/showroom/PowerMasterUnit.JPG)

Exploded view (http://www.chevelles.com/showroom/powermasterExplodedView.JPG)

I've tried to get information on "other" message boards (I should have known better :rolleyes: ), but no one really knows. The Grand National guys have some info but I would like to hear from guys that have hands on experience with these units.

The seem to be plagued and tagged early on as crappy units as they had a recall on the pressure switch that would allow air into the system and/or leak brake fluid. Also the accumulator diaphram is known to break as well. But that's really all I've been able to come up with.

Thanks for any help (and yes, I have something up my sleeve ;) )!

Joe

Check out the forums at www.pro-touring.com (http://www.pro-touring.com) There are some excellent discussions about these units produced by HydraBoost.

Originally posted by Clint44:
Check out the forums at www.pro-touring.com (http://www.pro-touring.com) There are some excellent discussions about these units produced by HydraBoost. Clint,
Yep, I've been over there and asked. Not much help, actually I think I informed some guys over there about the setup ;)

As for the hydraboost system that hydratech sells, its trick, but I'm a junkyard dog by nature (I think its 'cause my mom dropped me on my head once too many times when I was younger :D ) and cheap (e.g., I'm not employed at the moment and just graduated) thus I have a feeling I can figure out this bad boy one way or another graemlins/thumbsup.gif

Joe

The powermasters are pretty good units that will develop lots of assist, but the cycling on and off may bug some people, and the accumulators are known for going out.

Some of the guys over at turbobuick.com say you can get them rebuilt with a lifetime warranty from AutoZone for $150 or thereabouts.

The hydroboost is a more reliable and more powerful unit than the Powermasters. GM still uses them to this day, as does Ford. The new ones don't have the leakage problems the old ones did.

Myself, I have a Level III blueprinted Hydroboost from Hydratech sitting down in the garage. If I ever get my tranny in, I can let you know how it works. smile.gif

Troy

http://cgi.ebay.com/ebaymotors/ws/eBayISAPI.dll?ViewItem&item=2417471549&category=33566

Thanks Whittaker!

I think I'll have to pass on that auction though as I've seen these at junkyards and can grab them for about $10.

I think I'll have to modify it by drilling out the rivits on my stock vacuum booster to mount the unit (just like guys do to use the dual diaphram boosters on our A-bodies).

I won't do this probably until the car becomes closer to being on the road. Its more of an idea floating in the noggin'.

Joe

Wh ynot just put a GM vacuum Pump from a J or X-body car on it. I got 2 for $10 each the last time we went to the yard. They work great, just be sure to get the rubber isolated mounting bracket with it.

check out : http://www.gmcmotorhome.com/tech/vacuum_pump/index.html

I am interested in using a hydrobooster or the other one for my chevelle, but I am still confused on what it is/does. I dont have enough vaccuum to run power brakes so this sounds like the thing to do. Will it be a direct swap into the chevelle. How does it operate? Where can I find a used one (i.e. what cars had them)?
Thanks,
Jon

well, i have a GN and never had a problem with the powermaster system. i have replaced the accumulator 2 times @ $60 a pop, and also had the dealer replaced the switch. the switch was back in 1988 or 89 and was a recall. last yr or a few yrs ago there was a 67 gto (silver) on the cover of hot rod mag that used a powermaster system.
i think the hydro brackes run 2 lines to your power steering pump. correct?
Rob

"well, i have a GN and never had a problem with the powermaster system. i have replaced the accumulator 2 times @ $60 a pop, and also had the dealer replaced the switch."
I would call that having problems with the powermaster unit.

i guess it does sound kinda funny huh. i did have the car since 87 and the accumulator balls are pressurized like a CO2 cartridge when they run out of pressure you replace them. as for the switch it was a recall back in 88 or 89. so the switch wouldnt be an issue to anyone but the accumulator ball would have to be replaced every 23k miles or 8 yrs. since its 16 yrs old and i have 46k miles on my GN. i stand corrected. Rob