Accumulator?

[gofstbuick]

I'm trying to determine accumulator pre-charge pressure, and test my powermaster system, but my Waekon gauge set does not come with the adaptor for the accumulator or pressure switch. The GM tool is $459! So, does anyone know the thread pitch/size on the accumulator or pressure switch (both the same)? I'll make my own adapter.

TIA

PS, please don't try to tell me about the virtues of hydroboost or vacuum assist brakes. I'm really not interested in that arguement on this thread.

 

[gofstbuick]

I found the thread pitch. The size is M12x1.5 (metric). The next problem is there isn't an adapter with that thread pitch to accomodate the brake pressure gauges. This is what I did. I purchased a steel street elbow (1/4 NPT female*1/4 NPT female* 1/4 NPT male). I drilled the top female with a 31/64 drill bit, tapped it for a M12x1.5 helicoil and inserted a M12x1.5 helicoil. On the 1/4 NPT male side, I milled enough material off to use a M12x1.5 die and re-threaded the male side. Leave the other 1/4NPT female side alone. The 1/4NPT female will be used to insert one of the brake gauge adapters and connect the brake gauge. This will allow you to test the pressure switch and to determine accumulator pre-charge pressure. This will also allow you to bleed any air from the booster side of the powermaster (your brake gauge should have a bleed port near the gauge to accomplish this task), without loosening the lines on the master cylinder body. You'll need to use o-rings to seal the pressure switch to the modified street elbow and to seat the modified street elbow to the master cylinder body. You must use a STEEL street elbow, because of the HIGH pressures created by the powermaster booster!!!!
Hope this helps someone.

 

[gordyzx9r]

I went to purchase a new accumulator ball PN18038507 today, the price went up to $200 at the Chevy dealership. Is there any where else to buy these things at a reasonable price?

 

[turbopaul]

Check out the 'other' board under "Cheaper Powermaster Accumulator". Interesting stuff!

Paul

 

[gordyzx9r]

I tried to find the information on the other site, but was unsuccesful. I ended up buying an accumulator through Poston's for $145. ATR had them for $80 or $90 awhile back but when I called them the sales woman said that everything OEM GM has doubled for our cars, so now ATR sells them for the same as the dealership ($199.99). I'm gonna get the car it's own SSN and Visa if this keeps up.

 

[Ormand]

The "other" accumulator is less than $50, from GM partsdirect. It may not last as long as the later model, but for the price difference, I'll take the savings! Part number is 18038506

 

[gordyzx9r]

I'll keep that in mind for the next time. I put in the new accumulator and it dropped my time for the BRAKE light to go off to 5 seconds (from 9 seconds with the one I had on it).

 

[michael evans]

I found the thread pitch. The size is M12x1.5 (metric). The next problem is there isn't an adapter with that thread pitch to accomodate the brake pressure gauges. This is what I did. I purchased a steel street elbow (1/4 NPT female*1/4 NPT female* 1/4 NPT male). I drilled the top female with a 31/64 drill bit, tapped it for a M12x1.5 helicoil and inserted a M12x1.5 helicoil. On the 1/4 NPT male side, I milled enough material off to use a M12x1.5 die and re-threaded the male side. Leave the other 1/4NPT female side alone. The 1/4NPT female will be used to insert one of the brake gauge adapters and connect the brake gauge. This will allow you to test the pressure switch and to determine accumulator pre-charge pressure. This will also allow you to bleed any air from the booster side of the powermaster (your brake gauge should have a bleed port near the gauge to accomplish this task), without loosening the lines on the master cylinder body. You'll need to use o-rings to seal the pressure switch to the modified street elbow and to seat the modified street elbow to the master cylinder body. You must use a STEEL street elbow, because of the HIGH pressures created by the powermaster booster!!!!
Hope this helps someone.

I would like to make an elbow like you have but if you are no longer using the one you made, I will but it from you.