PM Rebuilt, Still pedal will hit the floor

[jshot]

Very Frustrated
Just bought this 87 GN with PM.When i first got it wouldn't stop worth a darn. would stop but not enough for an emergency stop. So i rebuilt the PM with the Kirban Kit and a new Accumulator and new brass Proportioning valve.

Bench bled, Gravity bled, then 2 person beed. Also adjusted rear drums. i did not push the pin in on the proportioning valve while bleeding.

Stops a little better but pedal does nothing until half way then works but will hit the floor. I am thinking 80% braking. Seems to pass all the tests in the Powermaster book i got from Kirban.

getting frustrated, just like everyone else. More bleeding? thinking about buying a reverse bleeder.
I do have to push a little hard to get it to the floor, but i am thinking it should never hit the floor. and stop better

 

[TurboTGuy]

Maybe a dumb question, but did you change the brake SWITCH?

 

[jshot]

Maybe a dumb question, but did you change the brake SWITCH?

the electric one for the pedal? Yes i did. not the vacuum one tho.

 

[pacecarta]

the kirban oring kit wont fix an issue on the brake hydraulic end of the powermaster , it only replaces the orings on the booster portion

 

[TurboTGuy]

^^^^ This is the man to talk to.

 

[jshot]

the kirban oring kit wont fix an issue on the brake hydraulic end of the powermaster , it only replaces the orings on the booster portion

OK so any ideas on the issue?

 

[pacecarta]

i had one here recently ,,felt the same as you describe , 2inch no feel then it felt like something but not great car was lucky to stop
replaced soft lines pads, prop valve bled .. no improvement .. went vac conversion, i didnt rebleed system just connected lines and burped the bubbles in the master before bolting to the booster and the pedal was perfect ,brakes are solid
i had the unit rebuilt (kirban kit following RC book) and it operates as it should on bench but havent been able to test brake side on a car

 

[jshot]

i had one here recently ,,felt the same as you describe , 2inch no feel then it felt like something but not great car was lucky to stop
replaced soft lines pads, prop valve bled .. no improvement .. went vac i didnt bleed system just connected lines and burped the bubbles in the master before bolting to the booster and the pedal was perfect ,brakes are solid
i had the unit rebuilt (kirban kit following RC book) and it operates as it should on bench but havent been able to test brake side on a car

OH DARN...

 

[pacecarta]

did you follow the RC book?

 

[jshot]

did you follow the RC book?

Yes. the only concern i had was when finished lapping the valves with fine lapping compound the surface was a dull finish not a shinny mirrored finish like they way they came out, but i believe that potion is for the boost. otherwise it went very well. that is why i am thinking bleeding more. a lot of threads on here about bleeding and re-bleeding for hours.

 

[jshot]

did you follow the RC book?

i can do some 60-0 distances tonight. any thought on numbers that should be ok. so far found 200 ft on the forums?

 

[Hahny]

I had experienced the exact same thing with the braking when I first purchased my GN and I told myself there is no way in hell that I would be driving this car around, until I got the braking lined out on it. Do yourself a favor and ditch the "Scaremaster" and look into either converting over to vacuum or hydroboost like I did and never look back. IMO-this was one of the best upgrades I have made to my car. Good luck!

 

[jshot]

Maybe a dumb question, but did you change the brake SWITCH?

i did not replace the one on top of the MC

 

[pacecarta]

book say it should travel 2,25" with 100# applied ..what i had was with almost no pressure it would move that far and assume thats what you have going on as well...still havent tested the one i have that has been rebuilt ..have to bolt it up to a car to find out if oring kit fixed it

 

[jshot]

book say it should travel 2,25" with 100# applied ..what i had was with almost no pressure it would move that far and assume thats what you have going on as well...still havent tested the one i have that has been rebuilt ..have to bolt it up to a car to find out if oring kit fixed it

I do have 2.25" of travel. but using force with my hand. not sure how much tho. i am able to push past that with my foot to bottom out. Luckily i have been able to contact a local guy who has owned many GN's. i am taking the car to him for advice. maybe i am paranoid. my last car was a 66 beaumont (chevelle) and it would stop on a dime 4 wheel drums.

 

[jshot]

i went out and did a couple of 60-0 stop test. and i'm at 225 - 230 with a little fade at the end. depending how accurate my paces are.

 

[michael evans]

I bleed my system three times and used two big bottles, was very much fustraterated. Someone told me what to do. At first I thought it was strange but it worked.

Turn the car all the way off and push the brake pedal several time until it gets hard (about 10 times).

After I did that, the brakes worked great.

 

[jshot]

I bleed my system three times and used two big bottles, was very much fustraterated. Someone told me what to do. At first I thought it was strange but it worked.

Turn the car all the way off and push the brake pedal several time until it gets hard (about 10 times).

After I did that, the brakes worked great.

thanks. I have already done this. this is to bleed the pump/accumulator i believe.

 

[NOKA72]

why did u change the prop valve. Was there an issue. Maybe try the old one again. I’ve seen that before.

 

[jshot]

why did u change the prop valve. Was there an issue. Maybe try the old one again. I’ve seen that before.

i changed it beacause it was the original one. and also i didnt want that to be the one thing i didn't change and end up being the issue