Aftermarket Vacuum Pumps
- Thread starter CHRIS W
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If you need a vac pump for the brake booster, something is wrong somewhere?
Remember, the 1989 TTA has a vac booster from the factory!:biggrin:
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Something is wrong there too with only 10" of vac?
My 9 sec. car has much more than that.
Im running a 208 /208 cam w/ a 62 turbo. my powermaster took a dump. converted to standard hyd brakes 35.00 bucks. vac pump 200.00 bucks on ebay. works great and now i can launch the car with no problem stops fine and pulls like a bullit train!
If you need a vac pump for the brake booster, something is wrong somewhere?
Remember, the 1989 TTA has a vac booster from the factory!:biggrin:
Thanks Nick, I just can't seem to build any boost at the line without pushing through the brakes. Figured pump might help hold a little boost.I can only hold about 1-2#. This car feels faster than its time slips 12.2 @113 but 60 is horrible 2.11. I just don't want to go back to the powermaster.
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With either vac or the PM assist, the brakes should act the same. If you have not checked the rear shoes for good contact, that could be a problem?
Linings can be worn or drums out of round, as well as the self-adjusters not doing their job.
Oh, about my cam in the prior post, it is in the 230's. Sounds like a vac leak in your system?
POWERBRAKEBOB
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Vacuum pumps
Oddly enough, Buick never installed vacuum boosters on their turbocharged cars. Vacuum boosters need vacuum. 20" at all times. Electric pumps have only a 1/8" id hole in the port to pull a high volume of air from the vac booster every time you release or apply the brake. Those pumps can not pull the huge volume of air out of the booster in time for a second quick application. They are also irritating to listen to. We tried all of that for the last 30 years. 12v pumps have a very short life, and when they quit, there you are all over again. Buick used both Hydroboost and Powermaster to avoid being sued when a vacuum booster failed because it was supercharged, or the hose blew off under boost. A 231 ci engine with an overdrive automatic has little chance of pulling high vacuum on deceleration anyway. The new Hydroboosts are completely reliable, can last 200,000 miles with just an oil change. They deliver up to 2000psi to the brakes even under a 6000RPM, 22lbs of boost, drag race start! No vacuum booster can do that. even the Powermaster on a good day can't do it.
Oddly enough, Buick never installed vacuum boosters on their turbocharged cars. Vacuum boosters need vacuum. 20" at all times. Electric pumps have only a 1/8" id hole in the port to pull a high volume of air from the vac booster every time you release or apply the brake. Those pumps can not pull the huge volume of air out of the booster in time for a second quick application. They are also irritating to listen to. We tried all of that for the last 30 years. 12v pumps have a very short life, and when they quit, there you are all over again. Buick used both Hydroboost and Powermaster to avoid being sued when a vacuum booster failed because it was supercharged, or the hose blew off under boost. A 231 ci engine with an overdrive automatic has little chance of pulling high vacuum on deceleration anyway. The new Hydroboosts are completely reliable, can last 200,000 miles with just an oil change. They deliver up to 2000psi to the brakes even under a 6000RPM, 22lbs of boost, drag race start! No vacuum booster can do that. even the Powermaster on a good day can't do it.
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The hydraboost is a good system as I have had them on many vehicles in the past. But your information for selling them here is flawed.
The turbo Trans Am in 1989 used a vac booster, as did the GM 4 cylinder cars from that era. Oh, I remember Chrysler doing many turbo cars as well w/o a hydroboost.
Also, the PM's were on some GM intermediate station wagons that were NOT turbo or supercharged.
Your info about GM avoiding a suit is MUCH different than mine? When discussing this with GM engineers in 1987, they had their own version.
Their reason was they wanted to field test the electro-hydraulic pump system before it went into full production to be used on ABS cars, like the 1989 Cadillac.
The booster does need vac at all times, and that is why they use a check valve to keep power assist for 2 or 3 pedal applies.
As far as a drag racing application, when the pedal is depressed, assist is available no matter if leg muscle, vac, PM or hydro. The ability to hold the car from moving then depends on the pads, shoes, drums, etc. If vac goes away, makes NO difference.
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