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#1
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power brake booster vacuum
I installed a vacuum pump for my power brake booster because the cam I have in the new combo kills manifold vacuum. I tried driving with the manifold vacuum but it is just to marginal. However, I am leery of depending on the vacuum pump which could fail or the relay go out or some other electrical problem which would result in no brakes! My question is what would happen if I ran a t-fitting off the vacuum hose so I could also connect to the manifold vacuum? Will the two vacuum sources work against each other or cause some other problem?
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69 Bird w/1970 400 block(409 cubes), #64 heads, hyd. roller, Q-jet by Jeff E., original interior, ps, pdb, th350, and 3.73 gears. Pump gas, street driven muscle. 3800 lbs. race weight. Best, 11.39 @118, my son's car. 79 T/A w/463, Scat crank, Eagle rods, Icon pistons, Lunati solid roller, 262/270, KRE 325 heads,Northwind intake, QF950 carb, full interior, ps, pdb, th350, and 3.73 gears. Pump gas, 3650 lbs. race weight. 10.72 @ 126 so far... no tuning yet. |
#2
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I asked Stainless brake company that question and they said NO, do not do this. I ran for aprox 4 years on my vacuum pump system and only ever had 2 failures
that fixed themselves. Relay would stick occasionally and pump did not turn on. after a couple of pedal application it finally came back on. I change the switch first and did the same thing a month later so changed the relay and fixed it. I eventually swapped the system out for a Hydraboost. It's been flawless. Takes a little getting used to but you will like it.
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64 Lemans hardtop 4spd, buckets |
#3
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If you're worried about the vacuum pump or it's electrical components failing you have two other options. Setup the braking system for manual brakes or hydroboost. Hydroboost is not a great option if the car is used in open road race or auto-x conditions because it lacks the ability to finely modulate pressure. However from your signature it sounds like these are street/drag cars in which hydroboost would be perfectly acceptable.
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-Jason 1969 Pontiac Firebird |
#4
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Another thing to take into consideration about the electric vacuum pump is where you can mount it.
I had mie in the right front fender / rad support area and when driving down the road you could feel the pump turn on, felt like a U joint going out, but would only last for 20 seconds, took me a while to figure out what it was, soon swapped out to hydra boost.
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64 Lemans hardtop 4spd, buckets |
#5
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Ditto to the above. I ran a vacuum pump to address low vacuum. Helped a bit, not a lot. When I converted to Wildwoods all round, the Wilwood tach advised against keeping the pump and steered me to a hyrdoboost system. Best brakes I have ever had on my 76 TA. One ride and I was used to them.
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#6
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Try adding a vacuum tank , how much vacuum @ idle ?
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#7
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I used a cannister before the pump and the hydroboost. It saved more volume of the same low vacuum.
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#8
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Correct & depending on the amount of low vacuum it may be enough / works in some cases & not so in others.
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