pump always kicking on

[ed39]

how often is the brake pump supposed to kick on??? everytime im braking i always here the pump kicking on and off and even when im driving it just seems like it is bleeding down some ware. i have a brand new accumulator. how often should the pump kick on and should it be kicking on this often for me..how do i go about fixing this cause it really pulls the alternator volts down

[Keller]

Not with every brake apply. See the diagnostic chart.

[ed39]

i looked at the chart and that didnt help me at all i talked to my boss who knows alot about these units. he said the accumulator i had another one tried that and it didnt work and now im back ware i started. now the pump is constanly on and dose not seem like it is holding any pressure. could the pump not be putting out enough pressure. could this be true? or is it bleeding down enternally/??

[Keller]

I'm not sure 'enternally' is a word. Internally? (Maybe etenally in this case?)

Anything is possible. An internal leak is possible. Going through the test procedure step by step should reveal the problem.

How many miles on the car?

[turboadict]

Mine started to cycle more and more often even without brake application. It got to the point where it cycled every few seconds and I stripped down the powermaster unit (the main body under the resevoir). There was an O ring in there that had failed causing an internal bleed down. Can't remember the exact size of the O ring, I have it written down at home somewhere.

When I get home I'll post the size.

I'm sure that if I had left it alone it would have developed into the problem you discribe.

[turboadict]

Well, couldn't find the O ring size, probably wouldn't matter anyway, if there is a failed O ring you should be able to get one matched up no problem.

If you get a piece of 1/2 inch clear tube about 8 inches or so long, you can test for an internal leak.

Pop the top off of the resevoir and you will see two holes in the bottom of the large side - closest to the passenger side. Place the end of the tube over these holes in turn, if fluid rises up the tube while the pump is running you have an internal leak and you'll have to go through the unit - the instructions are on the website. Have fun.

If you can find one, I used the rebuild kit part # 18020067, contains all you need. Or...... could just be the one O ring like mine.

Hope this makes sense and is of some help.

[ed39]

is it worth fixing this problem or am i in it for a few hours of labor... i have a vacum unit waiting around doing nothing would it be easier to swap the units out cause these power master units are very trouble some. can the engine make enough vacum for the vacum brakes to work or do i need an auxliary pump or something to hold the pressure


sorry about the typo haha guessing about 170k miles on it

[zeus87gn]

Yes, you have an internal leak IF 1 - there is no fluid leaking out and 2 - if you test and find results as turboadict has described.

Rebuilding the PM is just as time consuming as converting to vaccum. Just keep this in mind...If you are in boost, you have no vaccum unless you have a pump and a canister to hold it.

IMO, you should fix the PM. Orings can be found, and so can the rebuild kits. Highly superior if kept in good working order.

[ed39]

is rebuilding the pw hard to do im not familar with this system at all and can i do this in a few hours or all day event?

ps ware can i get a rebuild kit?

[zeus87gn]

To do the job right, you will need the book...and follow the directions to the letter. I believe Kirbans and Poston has it. I also believe the kits can be had from Brian at gbodyparts.com. If not, there are sources that can be found. Check the vendor lists here and on turbobuick.com.

Did you run the diagnostics? Are you sure you need to rebuild? It is not just a simple thing. You have to take you time and be anal about the quality of work you put into it. These are your brakes, not a place to skimp. The PM is a d@mn good system if serviced properly. Use denatured alcohol and lint free rags for prep and cleaning.

I took my time and spent an entire weekend getting the whole brake system back into shape. I now have trustworthy brakes. Only thing I am short at the moment is SS braided flex lines.