PM vs. VAC

[jcawley3]

almost bought this kit to change over but after getting a few opinions I decided to think about it a little longer.....

Would like to get a few others opinions on this...please share a few conversion stories....ie. like/dislikes...advantages/ disadvantages...thanks
John
__________________

 

[Chrisk]

subscribed. Id like to hear this too.

 

[T-CHRGD]

If you ever lose your PM while driving (As happened to me) you Will swap over because it is an experience you never want to repeat ! IMO the only reason (but a good one) to keep the PM is if you are keeping your low mileage GN completely stock. If you drive it regularly, I would switch over. It isn't too expensive if you go used booster and pedal, with a new MC, which is what I did. If your MC does go bad, no matter where you are, you can find a new one. Also, you can always switch back if you decide to go "Show"

 

[PaCemkr86]

vaccum = reliability

 

[Dreamcar86]

Seems like I have been here before. You will have to sort through some of the strong opinions in this thread but maybe it will shed some light to your question.

http://www.turbobuick.com/forums/br...wheels/220516-vacuum-conversion-question.html

 

[notacarlo]

I have had the vac set up for 5 years or so and would not change back unless I decided to return the car to stock and show it.....and that aint gonna happen. I like the way it stops. I actually think it's better than PM.

 

[INEEDAGN]

I love my vac brakes. My car with 235/60 street tires can hold 15 psi at 2800 (restalled d5) without spinning the back tires on regular asphalt. I am assuming stock rear brakes because I've never had the drums off. No way in hell am I ever putting the powermaster back on. I should note that I used all NEW acdelco parts except the pedal, and I bought the good TTA check valve to replace the one that came with the new booster.

Some of us love them and have no problems, others can't stand them and switch back. These cars can't be THAT inconsistent. The guys having problems have to have something out of order, maybe mismatched parts or the wrong check valve or simply bad used parts. I don't want to start a pissing contest but I do know that I am lovin' mine.

 

[87GN]

Is it necessary to use the TTA check valve??

Nic

 

[86brick]

vaccum = reliability

That's it in a nutshell. My PM failed on me while I was driving in traffic and I was lucky enough to get off the road and into a parking lot before I had no brakes at all. After that I decided keeping the PM wasn't worth the risk of getting into an accident and I really don't care if the Vacuum setup is not original because neither is the 3" DP, PTE stock location IC, etc., etc., etc. that I have on my car. At least now I know that I have a reliable system that doesn't have several stupid things that can fail and cause me to be brakeless while driving in traffic. Another reason to do the Vacuum setup is the fact that it is a whole lot cheaper and easier to get parts compared to the PM.

http://www.turbobuick.com/forums/gnx-fortunate-547/224622-gnx-258-passed-away-bpg-ohio.html

^
Oh yeah, check out the GNX in this thread that was destroyed as the result of a failing PM and ask yourself if it is worth keeping it because it's original!

 

[back in black]

what parts are you guys useing to convert to vaccum
which booster?
which m/c?
brake pedal?
thanx lookin at doing this to my g.n.

 

[turbofish38]

what parts are you guys useing to convert to vaccum
which booster?
which m/c?
brake pedal?
thanx lookin at doing this to my g.n.

Everything is off a 78-88 vintage G-body. Thats Regal,Cutlass,MC,GP.......

Some tap into the PCV line for a vacuum source and others use the vacuum manifold from the TTA.

 

[INEEDAGN]

The TTA check valve is designed for boosted applications and is a lot more reliable.

 

[psycho6cyl]

Vac brakes are good but if your comming off high boost and need a quick stop pedal maybe hard for 1 or 2 sec.. For me i used an 86 chevy caprice mc (susposedly bigger bore), 86mote ss booster and i believe rear wheel cyl from an 85 manual trans s-10... I went to the scrap yard to get the pedal. I love the reliability of these brakes. Is well worth it especially since mine is a Daily Driver.....

 

[Bweavy]

Vac brakes are good but if your comming off high boost and need a quick stop pedal maybe hard for 1 or 2 sec.. For me i used an 86 chevy caprice mc (susposedly bigger bore), 86mote ss booster and i believe rear wheel cyl from an 85 manual trans s-10... I went to the scrap yard to get the pedal. I love the reliability of these brakes. Is well worth it especially since mine is a Daily Driver.....

Power master was designed for a non vacuum situation. Hit your brakes on a 23 lb + boost run & see what happens on a vacuum brake there is none. I talk people out of 100 Vacuum brake sales a year but we still sell 100 vacuum brake set ups because of what they read on a website.

My car & my family run on power master set ups.Properly maintained & serviced.

 

[86brick]

Power master was designed for a non vacuum situation. Hit your brakes on a 23 lb + boost run & see what happens on a vacuum brake there is none. I talk people out of 100 Vacuum brake sales a year but we still sell 100 vacuum brake set ups because of what they read on a website.

My car & my family run on power master set ups.Properly maintained & serviced.

You're right the PM was designed for a non vacuum situation, however, it was not designed to work if/when the stupid 30amp fuse blows Design flaw?:wink:

 

[J-B Racing]

Power Master all the way....:smile:

 

[back in black]

So point taken doesnt sound like something i want in my car.Reliable brakes is paramount.My p.m system is toast,so i need to replace all components,or convert.What about the hydroboost setup?
What doner set up would i be looking for?
Same ?
booster out of what?
m/c out of what?
what pedal assembly?
sorry for my ignorance just trying to learn something so i can get it right the first time.Thanx guys appreciate youre knowledge and help. mike.

 

[psycho6cyl]

So Brian, whats the proper way to service the PM setup? Are these parts readily available? How much? Im sure its easy to service and maintain when GNs are your business... I called a vendor once that could have gotten the motor for some real $$$ but told me to go vac instead bc the remanned ones were hit or miss. That vendor couldve made an easy buck or 2 but advised me to go w vac...Good luck to anyone that needs to stop that quick w 23lbs of boost... i guess vac brakes are a lil more predictable.. Psycho 6.....

 

[Dreamcar86]

You're right the PM was designed for a non vacuum situation, however, it was not designed to work if/when the stupid 30amp fuse blows Design flaw?:wink:

Go with a hydroboost setup and eliminate fuses, electric pumps, etc. Oh yeah, they too will hold 12 plus pounds of boost on the line. I have never taken my car over 12 but I might give it a try just to see.

 

[INEEDAGN]

If you have a good, properly functioning check valve there should be no problems with the vac. setup. The booster should hold enough vac for 1 or 2 applications. I will admit i've never tried to hit them immediately after boost but next time i drive the car i will try it just to see.

Detroit has made far more turbocharged vehicles with vacuum brakes than any other system. They're popular for a reason. I've already stirred the pot too much.

bob