The PowerMaster Bleeding Procedure

[zeus87gn]

Originally Posted by dentmasters01

I can get one full pump out of mineo and on the start of the second pump, it starts the motor again. I have a brand new acc. on it and after depressurized it runs for 14-15 sec. on start up.

It sounds like you might have air somewhere in the system.
14 sec on pump up isn't too bad, that's what mine has been running for a while now.
I didn't remember to check my time over the weekend, let me try again tonight.

How long does the pump run when it starts on the second pump?

[dentmasters01]

ok, I just tested it out and after pump down, it takes about 14 sec. to pump up, like I stated before. I apply pressure for one full stroke and at the start of the second stoke the motor cycles on for 5 sec. and turns off.

One thing I noticed. I cycled the acc. about 5 times the other night and removed all the air out of it. I drove the car about 2 miles sunday (to test out my new tires on the street) and its been in the drivway eversince. After the above test I decided to pump the acc down again and there is just as much air in it now as the first time I did it a few days ago ?? Its a brand new, out of the ac/delco box acc. any ideas??

edit: I do remember I didn't bench bleed the powermaster when I installed it on my car last year. could there still be air in it that getting in the acc.?? I have, however, blead the lines extreemly well at all corners.

[zeus87gn]

Mmmm, this is a tough one.

Originally Posted by dentmasters01

After the above test I decided to pump the acc down again and there is just as much air in it now as the first time I did it a few days ago ?? Its a brand new, out of the ac/delco box acc. any ideas??

Ok, brand new out of the box GM. Sounds like a second generation acc, right? It would have the nut embossed on the outside and surounded by a yellow printing. Those haven't been made for probably pushing 5 years now (guestimate). It is possible that your "new" acc may have outlived it's shelf life and the diaphragm is leaking nitrogen. I don't know the materials of the diaphragm, but they don't last forever.

Originally Posted by dentmasters01

edit: I do remember I didn't bench bleed the powermaster when I installed it on my car last year. could there still be air in it that getting in the acc.?? I have, however, blead the lines extreemly well at all corners.

Bleeding at the corners will not get all the air out of the low pressure side of the master cylinder. Bench bleeding is the best method of doing this. Even so, what little air is in there won't make it back into a pressurized acc and even if it did won't be enough to cause frothyness.

My best suggestion for you is to try a known good accumulator. If you know a fellow TR owner that has a good setup that would allow you to try his, you can make a solid determination if the acc is at fault. If the same thing happens with a known good acc, the problem lies elsewhere.

Z

[dentmasters01]

ok, if the acc is leaking, and the car sits for oh lets say 3 days. Should it cycle on and pump up apon initial "key on" for the first time??? Mine doesn't. Another thing. On "pump down" my peddle get hard after only 6 pumps. ??

[zeus87gn]

Originally Posted by dentmasters01

ok, if the acc is leaking, and the car sits for oh lets say 3 days. Should it cycle on and pump up apon initial "key on" for the first time??? Mine doesn't.

It may not initially cycle.....yet. When it's pumped up, it's going to reach a balance in pressure (equilibrium) each time the diaphgram decides it wants to leak. If that balance point is more than the set point of the switch, it wont run. As the nitrogen slowly leaks out of the acc (and into the fluid chamber where you will see it on pump down), there will be a point where it will run on startup.

Remember, this is just my theory thinking you have a pinhole type leak.
That is why I recommended you try a known good acc.
It sounds to me like you acc is slowly dying.

Originally Posted by dentmasters01

Another thing. On "pump down" my peddle get hard after only 6 pumps. ??

This just adds to the above thoughts. There isn't as much back pressure (nitrogen charge) left in the acc to leave you the reserve you would normally have. If you were to watch it, you will most likely work down to only a pump or two and by then you acc will probably be dead.