Two beautiful cars you have there!!!..........Some good pictures of the 2007 Kirban Reunion as well. :smile:
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- Thread starter Ross L
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Two beautiful cars you have there!!!..........Some good pictures of the 2007 Kirban Reunion as well. :smile:
There is one for sale here!
:biggrin:
eBay Motors: 85-87 Grand National/Ttype Power Master Brake assembly (item 260348078218 end time Jan-23-09 13:22:38 PST)
:biggrin:
eBay Motors: 85-87 Grand National/Ttype Power Master Brake assembly (item 260348078218 end time Jan-23-09 13:22:38 PST)
I agree that the PM system is great when it's working like it should. It's the complete failure when something goes wrong that I don't like. Car manufacturers went from single reservoirs to dual in the interest of safety in case of a braking failure. At least you had something if there was a problem. Then they come out with the PM. Obviously, the car maker didn't do any failure analysis? I'm sure now, GM wants the PM to fade away into the past as soon as possible.
I'm willing to bet that most of you that are praising the PM have not yet felt what it's like to completely lose all your braking. It is a very, very scary deal. I work on these things and thank GOD people stopped supplying replacement parts for them. The PM idea needs to be buried deep in the south 40. Be erased from the history books. Even if parts were still available, I now would not replace a PM with a PM, unless it was a collector grade car that would not be driven. I have much more respect for my clients life than that.
I'm sure that over time everyone will come around to feel the same way about the PM. I just pray that most of you will survive the lesson, and more importantly, don't kill anyone else in the process.
My opinion about any type of racing with a PM,... well, I think that can go without saying, right?
I'm willing to bet that most of you that are praising the PM have not yet felt what it's like to completely lose all your braking. It is a very, very scary deal. I work on these things and thank GOD people stopped supplying replacement parts for them. The PM idea needs to be buried deep in the south 40. Be erased from the history books. Even if parts were still available, I now would not replace a PM with a PM, unless it was a collector grade car that would not be driven. I have much more respect for my clients life than that.
I'm sure that over time everyone will come around to feel the same way about the PM. I just pray that most of you will survive the lesson, and more importantly, don't kill anyone else in the process.
My opinion about any type of racing with a PM,... well, I think that can go without saying, right?
I have not investigated much on the PM, but I know it has its share of issues. I wanted to keep it because of the boost you get off the line, I dont belive you get the same results from Vacuum. But when i step on my brakes the motor runs for a second or two....i changed the switch,problem solved...months later started again, I went to aluminum drums and all of a sudden the motor dosnt stay on amymore???? now its doing it again for aboout a second or two,,,the fluid level is good and clean/new....I have a vacuum setup in the garage...ready to go. I would like to go 4 wheel disk w/vac but how will i be able to build good boost at the line?? But I would give that up to know I will stop safely on the street...I know what it feels like to hit an object at 65mph without hitting the brakes, and it had no air bags or abs trust me, I DONT want to do that again.
its just what i heard...vac is not a boosting problem but cant hold as much on the line vs the PM ??? and drums hold better than disk..I know nothing about brakes on these cars, im trying to achieve the best of both worlds...and dont know how to do it..lol so i guess my statements would be more like questions if that makes sense...
I don't know about holding at the line, but stopping in the shutdown area is far better with all discs.
My PM went out on me on a highway offramp with no signs 
Luckily there was no one coming through the rotary when I came through. No brake light, no nothing (pump failed). Drove 2 years without the pump running after that. As Grumpy told me once, just leave an extra 10 feet of space when you want to stop
Put another pump in a year or so ago.
Immediately after, this current one started leaking. I'm done
I am now thinking of going manual with a Willwood MC. Simplicity!
Luckily there was no one coming through the rotary when I came through. No brake light, no nothing (pump failed). Drove 2 years without the pump running after that. As Grumpy told me once, just leave an extra 10 feet of space when you want to stop
Put another pump in a year or so ago.
Immediately after, this current one started leaking. I'm done
I am now thinking of going manual with a Willwood MC. Simplicity!
Just to keep beating the horse - the PM is good when it works and it looks like everyone in the know agrees that the biggest problem is failure without notice. All of my street cars still have their original PMs. I've experienced the "hard pedal" and brake light several years ago - fortunately I was coming up to a stop sign in a residential area and not at the end of a 1/4 mile run! Mine was simply a blown fuse due to a bad pressure switch allowing the PM motor to overheat. I have also replaced the accumulator ball. All is well now but I don't trust the thing.
It is imperative that it has CLEAN fluid as several have stated above. Another good idea is when you turn the car off to park for an extended period of time, pump the pedal about ten times to relieve the pressure off the pressure switch and accumulator. It's not a complex system but it does have it's design flaws.
What worries me the most is the fact that as you stage the car at the track, for all you know it's already dead and that was the last reserve pressure it had - end of the track at 120+ and a hard pedal would not be good! I've always thought a good idea would be to insert a pressure switch or gauge into the system to let you know it's not dead.
Since the HP on my street car is about to go up about 300-400hp with my new engine combo, I am seriously entertaining the idea of switching over to a manual Wilwood system when I convert over to 4wheel discs just so I don't have to look over my shoulder anymore wondering if and/or when the PMs going to take a dump. I can guarantee anyone that a properly setup manual system with 4wheel discs will build as much if not more boost without pushing than a PMaster. JMOFWIW.
It is imperative that it has CLEAN fluid as several have stated above. Another good idea is when you turn the car off to park for an extended period of time, pump the pedal about ten times to relieve the pressure off the pressure switch and accumulator. It's not a complex system but it does have it's design flaws.
What worries me the most is the fact that as you stage the car at the track, for all you know it's already dead and that was the last reserve pressure it had - end of the track at 120+ and a hard pedal would not be good! I've always thought a good idea would be to insert a pressure switch or gauge into the system to let you know it's not dead.
Since the HP on my street car is about to go up about 300-400hp with my new engine combo, I am seriously entertaining the idea of switching over to a manual Wilwood system when I convert over to 4wheel discs just so I don't have to look over my shoulder anymore wondering if and/or when the PMs going to take a dump. I can guarantee anyone that a properly setup manual system with 4wheel discs will build as much if not more boost without pushing than a PMaster. JMOFWIW.
Keep driving it like that and you'll join the ranks of the PM haters who can only gripe about it crapping out on them and being a piece of junk.
Replace the accumulator and drive on for many more years.
Dave, you're in for a big surprise when your master cylinder wears out.
I understand your point of view, but you must understand, the kind of car you drive at the track requires NO foot brake boost holding capabilities. You're way beyond that with your electronic tranny brakes, etc.
Unfortunatley, us regular "joes" that don't have a truck load of money to put in our cars, race with foot brake launches.
The vacuum brake system, while being dependable for street use, can not build the brake system pressures that the PM can. Simple physics
Manual brakes will hold even less,
and disks on the rear axle are even worse than that . While being the best braking system available, disc brake systems just don't have the clamping forces needed for foot brake launches against high boost launches.
The only dependable/reliable system that can even hold a candle to PM holding forces (and even surpasses it) would be the Hydroboost system, and would be the only system I would even consider replacing the PM with.
HB system is on litterally millions of vehicles today and has been for decades. A perfect, prooven system.
I hope not to have to replace my PM system anytime soon as the budget wouldn't withstand such a hit.
Finally, I have no doubt there are those rare occasions that the PM system can fail without warning, but they are very rare.
In talking to people and really holding their feet to the fire, it turns out about 99% of the time there were warning signs. But like most, they were ignored or maint. was delayed.
Why should my master cylinder wear out any faster than ANY master cylinder out there??????
Since I do proper care and maintenance I don't expect it to happen any sooner than yours. It's been going strong now more how many years? Geez 23 now.
And if a master cylinder goes bad, I don't care what braking system it is, it's not good.
Dave. You mention the term plain Joes. Believe me, a plain Joe cannot afford to go through a busy intersection with no brakes.
In any form of racing, safety must always take priority to building boost at the line. That should not even be up for discussion. Why would you even consider such a compromise?
Don't think for a minute that it's impossible for the brakes to completely go out on you without warning. That would be a very big mistake. Remember, I work on these things. I see PMs being a major issue with these cars. I also have a street driven GN. It has already been through the PM episode. My wife was driving it when it first showed failure. No brakes, period. Another, 'luckily no one was in front of me' story. Before I fixed the brakes, I drove it around a bit just for testing. The brakes would work fine for a good length of time and when you just started getting used to the brakes working and stopped being overly cautious, guess what. Adrenaline rush!!! Not fun at all.
Dave, you really need to get your head out of the sand on this one. Try this next time you're out and about in your GN. When you come up to an intersection or stop sign, miss the brake pedal when going for the brake. I guarantee you will get the same sensation of a failed PM.
In any form of racing, safety must always take priority to building boost at the line. That should not even be up for discussion. Why would you even consider such a compromise?
Don't think for a minute that it's impossible for the brakes to completely go out on you without warning. That would be a very big mistake. Remember, I work on these things. I see PMs being a major issue with these cars. I also have a street driven GN. It has already been through the PM episode. My wife was driving it when it first showed failure. No brakes, period. Another, 'luckily no one was in front of me' story. Before I fixed the brakes, I drove it around a bit just for testing. The brakes would work fine for a good length of time and when you just started getting used to the brakes working and stopped being overly cautious, guess what. Adrenaline rush!!! Not fun at all.
Dave, you really need to get your head out of the sand on this one. Try this next time you're out and about in your GN. When you come up to an intersection or stop sign, miss the brake pedal when going for the brake. I guarantee you will get the same sensation of a failed PM.
Why should my master cylinder wear out any faster than ANY master cylinder out there??????
Since I do proper care and maintenance I don't expect it to happen any sooner than yours. It's been going strong now more how many years? Geez 23 now.
And if a master cylinder goes bad, I don't care what braking system it is, it's not good.
I've seen 3 PM units where the master cylinder was the problem. No rebuild kits available. You will have to make the switch at some point. From a safety stand point alone, sooner would be much better than later.
Maybe, but I'll keep mine up and running for as long as possible.
Head in the sand? Not really, just practical, and not one to abuse maint. schedules.
I'm not sure what you mean by "In any form of racing, safety must always take priority to building boost at the line. That should not even be up for discussion. Why would you even consider such a compromise?"
What compromise am I making? Please don't insult my intelligence(what little there is left). ANY brake system can fail at any time for any number of reasons.
I, like so many others can't afford an electronic trans brake like you can at the track. Therefore, I like so many others launch on a foot brakes.
You on the other hand can afford to drive an incredibly expensive full race car at the track with all the bells and whistles as far as power and safety goes.
Pardon me for saying so but if anybody is out of touch (head in the sand) with the "commoners" like many of us, it's you.
We must make due with what we have.
I like being able to lauch with as much boost as the tires/track will hold (15+ lbs of boost).
Try that on a vacuum brake or manual brake car, let me know how it works out for ya.
Head in the sand, indeed.
Head in the sand? Not really, just practical, and not one to abuse maint. schedules.
I'm not sure what you mean by "In any form of racing, safety must always take priority to building boost at the line. That should not even be up for discussion. Why would you even consider such a compromise?"
What compromise am I making? Please don't insult my intelligence(what little there is left). ANY brake system can fail at any time for any number of reasons.
I, like so many others can't afford an electronic trans brake like you can at the track. Therefore, I like so many others launch on a foot brakes.
You on the other hand can afford to drive an incredibly expensive full race car at the track with all the bells and whistles as far as power and safety goes.
Pardon me for saying so but if anybody is out of touch (head in the sand) with the "commoners" like many of us, it's you.
We must make due with what we have.
I like being able to lauch with as much boost as the tires/track will hold (15+ lbs of boost).
Try that on a vacuum brake or manual brake car, let me know how it works out for ya.
Head in the sand, indeed.
No rebuild kits available? Look harder.
If they are available, and I'll admit that I didn't look real hard, how do you rebuild a worn out master cylinder? Economically?
Dave. You are completely missing my point. I'm not even thinking about my race car in this discussion. Don't really understand why you are. I'm strictly thinking about people's safety here. Whether on the race track or on the street. The vast majority of cars that I work on are every day drivers, so I don't think I'm really that out of touch with the average joe, as you put it.
I just think that compromising one's safety and that of the racer in the other lane just so that you can build better boost at the line is plain crazy. I'm sorry if you view that as being out of touch.
OK, I'll concede, It's obvious you've got to have the last word on this and you're convinced that everybody running the PM is compromising everybody else's safety.
Not true. But hey, to each his own. You win, I'm done.
Not true. But hey, to each his own. You win, I'm done.
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