Detailed Powermaster Question - Reaction Piston O-Ring?

[DMan]

Hey all,

Does anyone know if the 'reaction piston' in the powermaster requires an o-ring?

The reaction piston is a small, 1.5 " long stainless piston - fits inside the power pistion assembly.

it looks like its got a groove cut for an o-ring but I can't tell for sure.. mine 'appears' to be missing the o'ring..

please confirm if you can. Thanks!

 

[zeus87gn]

Hey there,
If you still need the answer, it appears to me that the reaction pistion (itself) does not need an oring. Had to get out the book on that one.

Don't get the reaction piston confused with the reaction group. It includes the spring loaded body and a disc. I do believe the body w/spring does have a seal on one end. It's not easy to tell from the pics in the manual.

The reaction piston may have an oring within the body it sits in. I would have to pull apart my spare to know for absolute certain on this. I can this evening if you need to know.

HTH

 

[DMan]

Hey thanks zeus

Yeah it would be interesting to know if there's an oring inside the body the piston goes in.

I took a unit apart and it looks like all I need is a reaction disc. Good luck finding one though.

However- Karps does sell rebuild kits for the powermaster (no hard parts). $100.

 

[zeus87gn]

Karps is down to $100??!!
Much better than the last time I called them a year or so ago.
Even if it is only the seals, it's almost a fair deal.

I will look at my spare P/M this evening and let you know as soon as I can.

 

[POWERBRAKEBOB]

Hydroboost Conversion

No, There Is No O-ring Around The Reaction Pin. We Have Ground Down The Tip Of The Reaction Pin, To Increase The Valve Opening, Making The P/m More Sensitive, And Increase The Boost Pressure. The Rubber Disc Controls The Valve Opening, By Holding Back The Reaction Pin Movement. For Those Who Are In Love With Their P/m, We Have New 12v Motor Pumps Available For $295.00

 

[DMan]

Thanks Zeus and Bob

Bob - do you have any reaction discs available for sale? I think thats all my unit needs..

 

[POWERBRAKEBOB]

Hydroboost Conversion

Yes, I Do Have Those, What Else Do You Need?

 

[DMan]

I think thats all I need. Please pm me with price and availability.

Another nice-to-have would be the metal line that mates with the high-pressure hose from the pump on one end, and threads into the check-valve housing on the cylinder. These usually rust and seize up. Can you make up one of these, or can I make one myself? What is the cost?

Thank you.

 

[zeus87gn]

No, There Is No O-ring Around The Reaction Pin.

Agreed. I checked my old unit over the weekend. There is also no oring within the spring body it seats into. Didn't get back online until this morning.

For Those Who Are In Love With Their P/m, We Have New 12v Motor Pumps Available For $295.00

Little steep on the $$, eh?

Dman,
If you have gone far enough to pull it down to find this you may as well put a fresh seal/oring kit in it. Clean all the parts well with denatured alcohol to remove the old funk. Lube with fresh brake fluid on reassembly.