Boost and Vacuum Brakes???

[RI-Matt]

Well my Powermaster finally died on me at about 70mph I was only about a mile from home, it took me half an hour to get back home.

Anyway, I had purchased a vacuum brake conversion kit a while back so I would have it when the slugmaster died. So I installed it this weekend. What a difference! But this got me thinking, what happens under boost as far as pressure on the booster? I know the booster has a check valve on it that is supposed to be a one way valve but was it designed for boost? I have one of those PCV in-line check valves that I don't use and was wondering if it could be used in-line on the booster line.

Also, to the people that use vacuum brakes do you use the that black vapor trap? I noticed that the TTA doesn't use one. I would rather just run the hose line without it if I don't need it.

TIA
Matt

 

[Steve Wood]

I have never had any problem with boost and the normal checkvalve that goes in the booster. What do the TTA's have?

I have one car with the vapor trap and two that don't. I have not had any problems.

 

[Dwayne]

I do not use the vapor trap either...as long as your check valve is working properly you shouldn't have any problems........remember that all 84-85 cars had vacum brakes and they work fine.....it's another one of those GM designs that they should have left alone instead of switching to the powermaster setup

 

[Chris Taylor]

I have vacuum brakes on my T. I have asked this question about the vaper trap also. My 87 T V8 came with the vaper trap. (It also had the V8 but not now)

The TTA does not have a vapor trap. I looked at Ron's TTA at the Metco trailer in BG, it has a black check valve in the booster.

I took the vacuum system off of my V8 T and installed it on my Turbo T without the vapro trap. It works great. I guess you could purchase a check valve for the TTA and use it in the booster.

 

[RI-Matt]

Thanks guys

Thanks for the replies guys. I am gonna take the vapor trap off because I don't like the way it looks. I took my check valve off and tested it and it holds against boost just fine. If it's good enough for the TTA's then it should work for the GN. You never see those guys having brake problems.

BigDaddy, I agree that GM should have just made the cars with vacuum brakes to begin with, the car stops so much better now.

Thanks again,
Matt

 

[Ormand]

Vacuum on 84/85?

I thought the 84 and 85 Turbo's had the Hydroboost brakes, not vacuum? Or was that just on the hot-air cars?

 

[b4black]

1978 / 82 = Vacuum
1983 / mid-85 = Hydroboost II
mid-1985 / 87 = Powermaster