i am debating on changing my 87 gn over to vacuum brakes because i dont know what is wrong with my brakes now . the brake light comes on everytime i step on the brakes and if i keep my foot on the brake the light goes out the the pedal goes down some.i took the master cylinder cap off and the fluid was brown and when i pumped the brakes to take the master cylinder cap off the fluid had bubbles on one side off the master cylinder the side facing the pass side of the car if u are standing in front of it.what should i do change over to vacuum brakes or what then i heard u cant hold that much boost with vacuum. please help
how many people are using vacuum brakes?
- Thread starter the wrath
- Start date
I went through 2 rebuilt powermasters (Cardone is the only rebuilder of these things). The first one leaked fluid all over the place. I discovered this after a test ride around the block. I would have lost the brakes if I had driven further. The second one worked for a few days and then I had no brakes at all. This was enough - went to vacuum and have been happy knowing that the car will actually stop when I hit the brakes.
IMHO if you value your car and your life, make the switch!
IMHO if you value your car and your life, make the switch!
Red Regal T
Senior Member
- Joined
- May 24, 2001
THOUSANDS! 
Everytime there is a post about someone not being able to hold boost, TEN guys say they have no trouble holding boost. So, while some may have a problem, holding boost for drag racing is easily attainable.
Even if you buy a brand new PowerMaster, there is no guarantee the brakes won't go out 6 months down the road. Vacuum brakes have been around forever and they still are even on new cars. They are reliable and work well.
Everytime there is a post about someone not being able to hold boost, TEN guys say they have no trouble holding boost. So, while some may have a problem, holding boost for drag racing is easily attainable.
Even if you buy a brand new PowerMaster, there is no guarantee the brakes won't go out 6 months down the road. Vacuum brakes have been around forever and they still are even on new cars. They are reliable and work well.
Re: Re: how many people are using vacuum brakes?
Personally, I'm not a fan of vacuum brakes on turbo charged applications, (even my Powerstroke truck uses the hydroboost system) BUT, with that said, maybe you can advise me on something.
I was working on a friends car, and noticed it had vacuum brakes (not the problem we were troubleshooting).
Anyway, when we got the problems we were working on fixed, I backed it out of the garage and tried doing a "power brake" to build some boost.
As soon as the gauge went from vacuum to boost, the boost started pushing the brake pedal back up against my foot.
Is it supposed to do that? and if not, what's the problem?
Originally posted by Red Regal T
THOUSANDS!
Everytime there is a post about someone not being able to hold boost, TEN guys say they have no trouble holding boost. So, while some may have a problem, holding boost for drag racing is easily attainable.
Even if you buy a brand new PowerMaster, there is no guarantee the brakes won't go out 6 months down the road. Vacuum brakes have been around forever and they still are even on new cars. They are reliable and work well.
Personally, I'm not a fan of vacuum brakes on turbo charged applications, (even my Powerstroke truck uses the hydroboost system) BUT, with that said, maybe you can advise me on something.
I was working on a friends car, and noticed it had vacuum brakes (not the problem we were troubleshooting).
Anyway, when we got the problems we were working on fixed, I backed it out of the garage and tried doing a "power brake" to build some boost.
As soon as the gauge went from vacuum to boost, the boost started pushing the brake pedal back up against my foot.
Is it supposed to do that? and if not, what's the problem?
TR Custom Parts
Mark Hueffman - Owner
- Joined
- May 25, 2001
Re: Re: Re: how many people are using vacuum brakes?
Bad check valve??
Originally posted by TurboDave
Personally, I'm not a fan of vacuum brakes on turbo charged applications, (even my Powerstroke truck uses the hydroboost system) BUT, with that said, maybe you can advise me on something.
I was working on a friends car, and noticed it had vacuum brakes (not the problem we were troubleshooting).
Anyway, when we got the problems we were working on fixed, I backed it out of the garage and tried doing a "power brake" to build some boost.
As soon as the gauge went from vacuum to boost, the boost started pushing the brake pedal back up against my foot.
Is it supposed to do that? and if not, what's the problem?
Bad check valve??
xrunner123
Member
- Joined
- Oct 2, 2002
Sorry to jump in here, but if the powermaster fails do you totally lose all braking capabilities. And if the vacuum brakes fail do you also loose them? Do I do the 'if it's not broken don't fix it'?
Red Regal T
Senior Member
- Joined
- May 24, 2001
If holding boost is attainable, as just posted by FlyinGN, and as I have said, what's the problem? Also search the many posts on this subject and you'll find all you need to know. Brakes are for reliable stopping and for me, holding boost, is way down on the list after that. Eventually, you are going to have to change over anyway, unless you hit the lottery to afford fixing PMs. I'm certain there's probably more guys out there with vacuum brakes than with the PM. Join the club!
Red Regal T
Senior Member
- Joined
- May 24, 2001
Re: Re: Re: Re: how many people are using vacuum brakes?
Sounds like a plan!
Sounds like a plan!
If you want the absolute best in reliability, then you want manual brakes. The downside is pedal effort, and it's not *that bad*, when done correctly.
As far as master cylinders.
http://www.t6p.com/forums/showthread.php?t=5863
There's also a few other brake threads there.
When in boost you don't have any vac., so if you start to stage, without having enough pedal pressure, then you may not be able to hold much boost. So you need to push firmly on the pedal, and then stage.
Not to mention a large portion of the problem, is that the oem brakes are just crappe for any modified GN. With the advent of adapters for the LS1 Camaro front brakes, there's just no excuse, IMO, for running dangerously.
I've run my car with manuals, or vac for the last 50K miles without any problems.
Any brake system can fail. The trick, IMO, is which one when it fails still leaves you with USEABLE Brakes!. With the Vac brakes, you still can still relatively easy stop the car. A panic stop at 75 MPH with a failed PM, or Hydravac, system will leave your front bumper the color of the car in front of you.....
As far as master cylinders.
http://www.t6p.com/forums/showthread.php?t=5863
There's also a few other brake threads there.
When in boost you don't have any vac., so if you start to stage, without having enough pedal pressure, then you may not be able to hold much boost. So you need to push firmly on the pedal, and then stage.
Not to mention a large portion of the problem, is that the oem brakes are just crappe for any modified GN. With the advent of adapters for the LS1 Camaro front brakes, there's just no excuse, IMO, for running dangerously.
I've run my car with manuals, or vac for the last 50K miles without any problems.
Any brake system can fail. The trick, IMO, is which one when it fails still leaves you with USEABLE Brakes!. With the Vac brakes, you still can still relatively easy stop the car. A panic stop at 75 MPH with a failed PM, or Hydravac, system will leave your front bumper the color of the car in front of you.....
bruce I agree.
I had the powermaster on a "T" I bought that is a track only car.
It held boost fine. Then the light came on and I decided that I didn't want the brakes to fail while trying to stop at the track. After hearing about the great vacuum brakes I bought Red's kit. I haven't held boost since. I thought a vacuum canister from comp cams would help,nope. I then tried the s-10 wheel cylinders,nope. I put on new pads, rotors and drums front and back! I even went as far as removing all the old fluid! I got a friend to help bleed them(pump and hold pedal)so I knew it was right,nope.
DONT' GET ME WRONG THE CAR STOP'S GREAT IN ANY DRIVEING SITUATION!
I think my problem is my stall speed. I have a converter that stalls at 4000rpm @ zero boost! I dont think it's the brakes I think the stall is just too much!
Since my car is a track only car I am going to go manual.
Hopefully this will be the last brake conversion I will have to do!
I had the powermaster on a "T" I bought that is a track only car.
It held boost fine. Then the light came on and I decided that I didn't want the brakes to fail while trying to stop at the track. After hearing about the great vacuum brakes I bought Red's kit. I haven't held boost since. I thought a vacuum canister from comp cams would help,nope. I then tried the s-10 wheel cylinders,nope. I put on new pads, rotors and drums front and back! I even went as far as removing all the old fluid! I got a friend to help bleed them(pump and hold pedal)so I knew it was right,nope.
DONT' GET ME WRONG THE CAR STOP'S GREAT IN ANY DRIVEING SITUATION!
I think my problem is my stall speed. I have a converter that stalls at 4000rpm @ zero boost! I dont think it's the brakes I think the stall is just too much!
Since my car is a track only car I am going to go manual.
Hopefully this will be the last brake conversion I will have to do!
Originally posted by IDISAPR
bruce I agree.
I had the powermaster on a "T" I bought that is a track only car.
It held boost fine. Then the light came on and I decided that I didn't want the brakes to fail while trying to stop at the track. After hearing about the great vacuum brakes I bought Red's kit. I haven't held boost since. I thought a vacuum canister from comp cams would help,nope. I then tried the s-10 wheel cylinders,nope. I put on new pads, rotors and drums front and back! I even went as far as removing all the old fluid! I got a friend to help bleed them(pump and hold pedal)so I knew it was right,nope.
DONT' GET ME WRONG THE CAR STOP'S GREAT IN ANY DRIVEING SITUATION!
I think my problem is my stall speed. I have a converter that stalls at 4000rpm @ zero boost! I dont think it's the brakes I think the stall is just too much!
Since my car is a track only car I am going to go manual.
Hopefully this will be the last brake conversion I will have to do!
Do you have the right Master Cylinder?.
Are you SURE the combination valve is working?.
For a Track Only car with an experienced driver, you might consider blocking off the combo valve, so that it's just a distribution block.
If you go to manuals, be sure to look at the pedal/ rod/ master cylinder geometry. Some combos actually can get scarey looking.
After you set the prestage, and stage lights, *firmly* press on the pedal, ie a fair bit more then like when your at a stop sign, THEN push on the throttle to bring the rev's up. If you don't have enough line pressure on the brakes, before going into boost, you'll always push thur the brakes.
If you look inside some of the Faster Classes of cars, they run a brake pressure guage in the car, so the driver KNOWS when he stages how much holding power is available, and it makes for a more consistant launch.
Originally posted by Red Regal T
If holding boost is attainable, as just posted by FlyinGN, and as I have said, what's the problem? Also search the many posts on this subject and you'll find all you need to know. Brakes are for reliable stopping and for me, holding boost, is way down on the list after that. Eventually, you are going to have to change over anyway, unless you hit the lottery to afford fixing PMs. I'm certain there's probably more guys out there with vacuum brakes than with the PM. Join the club!
Excuse me for saying so, but what FlyinGN said about holding "plenty" of boost really doesn't mean much. After all, he didn't specify any amount at all. Maybe 5-10# is a "lot" or "plenty" for some.
Holding boost on the line is near the top of my priority list, as it is with many other that really want to optimize ET and MPH, and need a good launch to do it.
Personally, if I can't hold 15-20# on the line then I would never give up my PM.
BTW, for those that mention it, Just because Pontiac didn't use the PM, doesn't mean a thing. There were reasons why they didn't, and unless anybody knows for sure why they didn't, speculating on why is pretty useless, after all.
Vacuum brakes just aren't "the hot ticket" on boosted (epsecially turbo'd) applications.
On most mild mannered street apps. it's fine, but when there's going to be a lot of boost used, or boost over a consistently long period of time, vacuum brakes would be a dangerous detriment.
Probably why Ford still uses the HydroBoost system on their Powerstroke diesels. Lots of boost and under boost virtually all the time.
If I didn't ever take my GN to the track, vacuums would probably be fine also.
brakes
My first turbo regal had a power master. Were I lived at the time I was going down a hill when the fuse blew or something in the power unit failed. After numerous parts replacements after another I junked the unit. To make things worse I have a disability & drive with handcontrols. I cant be fooling around with that. Now on my latest regal T I did a vac conversion which I have absolutely no problems with. I also have an extra vac canister in line as well for that time I may need extra vac.
My first turbo regal had a power master. Were I lived at the time I was going down a hill when the fuse blew or something in the power unit failed. After numerous parts replacements after another I junked the unit. To make things worse I have a disability & drive with handcontrols. I cant be fooling around with that. Now on my latest regal T I did a vac conversion which I have absolutely no problems with. I also have an extra vac canister in line as well for that time I may need extra vac.
salvageV6
Daily Driver
- Joined
- May 25, 2001
18 years on the Powermasters.
One would think a reservoir tank for the vacuum brake conversions would be a hot item and easy to install?
Available at Jegs and Summitt cheap enough.
I would convert over if I didn't understand the system or parts weren't available to fix it.
Not really the case yet however.
One would think a reservoir tank for the vacuum brake conversions would be a hot item and easy to install?
Available at Jegs and Summitt cheap enough.
I would convert over if I didn't understand the system or parts weren't available to fix it.
Not really the case yet however.
