Powermaster issues

[IL KIM]

Hello. Trying to get 2 remaining issues resolved so I can enjoy driving my 85 GN again and looking for advise. One issue is the brakes. I searched through the Powermaster topics and don’t really want to go to vacuum brakes, but to get the PM system working.


Issue I am having is intermittentLy the PM motor will not turn on leaving the inboard reservoir full and hard brakes with brake light. I went through the PM Diagnostics from GNTYPE.org and ended up on step 2 where it took 13 seconds of motor running till brake light went off, I bought and replaced the accumulator ball as recommended. This did not solve my intermittent issue. The diag chart basically says if the ball didn’t work the get a now PM.


When the issue happened, I tried disconnecting the main harness connector and jiggling with no luck. I also tried jiggling the pressure switch connector and the motor did not turn on. However tapping the motor with an 8mm wrench made the motor turn on and suck the fluid down. Any advise out there before I buy a remanufactured one from Kirbans or from GBody where I got the accumulator ball?


I don’t know if I can take the black box apart to look at electrical connectors on the motor housing.
Thank you. 

[Steve Wood]

No help from me.  I'm strictly a vacuum brake kinda guy

[ULYCYC]

Could be the motor and or pressure switch, most likely switch.  I don't have a clue whats available these days and sure prices are crazy. At this point in time I would do a conversion to vacuum or hydro-boost. 

[IL KIM]

Hey, another Avatar I recognize from the past.  Thanks for your input Steve and Ed.  I thought it might be the pressure switch but when I had the issue and I jiggled the connector and tried removing/reinserting, the motor still did not start up.  Per diagnostics flow chart, if you disconnect the pressure switch and the light comes on, the system should be good.  Intermittent electrical issues are the worst. 


Is the vacuum or hydro-boost better (pros and cons) for reliability and function?  I read the vacuum conversions may have issues with turbo cars running roller cams/rockers or more pedal apply is needed?  Have not read up on what a hydro-boost system is. 

[Steve Wood]

vacuum is only a problem if you have a big cam duration wise.  My roller cam is 210 degs durartion and the brakes work very well.

The earlier hot air cars had a hydroboost system.  People love them but I don't.  If you lose hydraulic pressure, you lose both the brakes and the steering at the same time.

[ULYCYC]

I found over the years not to trust diagnostic flow charts for powermasters, coils and maf sensors.  Having a known good one on hand works best to prove your find.  I agree with Steve and prefer vacuum brake setup.

[earlbrown]

I've got a 215/220 roller and my vacuum kit works just fine.


the booster has a check valve that stores maximum vacuum it sees.  I don't care what cam or engine you have, any time you do a throttle chop, the manifold vacuum goes through the roof.  That's how the booster gets charged.


  As far as actual powermaster advice goes....    the only tidbit I release is ''toss it''.


Even if you fix it, it's going to break again.

[Shimy87]

another vote for vacume system, PM is a headache and potential disaster 

[Scoobum]

Vacuum for the win. Replace the 3 flex hoses with SS lines from Russel. Flex hoses...well.. .they flex.

[IL KIM]

Thanks guys. Who is “Russell” please? The hydroboost system looked pretty straight forward but if there with no backup when a hose or steering pump goes, then potential disaster.


I’ll start looking into vacuum system now with all the input above before giving up on the Powermaster system that worked for me for 35 years. It would cost me $750 to get it rebuilt with little labor on my end.

Thanks everyone for your advice.

[Steve Wood]

http://www.russellperformance.com/mc/brake-clutch-hose/domestic.shtml

[earlbrown]

I just mailed out a set of Russel SS brake lines from my eBay store. Was that you Kim?

[IL KIM]

Sorry for delayed response.  Been a little busy with moving kids into college. Hopefully won’t be moving them back home anytime soon.

Thanks Steve. I’ll look again or call Russell’s but did not see RWD Regals or our years on the link.
Earlbrown; no that was not me but what is your eBay seller name?  I can peruse your store!

Thanks all.

[Steve Wood]

Believe I bought mine from Earl

[earlbrown]

Earlbrown; no that was not me but what is your eBay seller name?  I can peruse your store!

It's earlbrown. 

https://www.ebay.com/itm/162432664157