power steering pump problems

[72 K20]

When I bought my K20 almost two years ago the steering sector seals were shot and the pump was shot from lack of oil. I rebuilt the sector and got a reman pump cartridge from napa since they couldn't get a complete pump with the return line in the right position. Got the pump together , filled it with fluid, started the engine, turned it back and forth a couple of times ,shut it off and refilled the reservoir , started the truck and had nothing.Removed the pump exchanged it at napa, that one grenaded internally upon startup,, literally broke the cartridge in pieces. Got the third pump and all was golden,,,,,,, until about a week ago. I noticed a growl while driving and thought possibly was low on fluid altho I have not seen any leaks. Checked the fluid ,, full,, hhmmmmmmm,, but foamy. This pump has worked great until now,, only about 3 thousand miles.

Called napa,, they said to call customer service. Called them , tech says I need to vacuum bleed the pump. I said What ?

He said to take an old reservoir cap, drill and tap for a hose barb and pull it down to 15 inches of vacuum with the motor idling, maintain that for 10-15 minutes and it would be cured. I asked why it would be messing up after almost 2 years of service.
He said that he couldn't explain that. He said that maybe it's from sitting. I told him that my other trucks don't do it and neither did this one until recently. He said again
I can't explain that.

I've replaced and installed at least a dozen GM power steering pumps over the years and have never had this problem whether it was a new or working used pump.

Have any of you experienced this ?

Thanks for any and all comments !!
Have a great day !! Tom

[ole dollor]

like you i have never heard of this before, you do have to bleed them when you change one out, i always jack the front wheels off the ground and fill the tank and crank it up and turn the wheels from stop to stop. let its set awhile and do it again. do this until all the air bubbles are out..some time you have to let it set a while to get all the bubbles out...that's the way i have always done it...

[Andy4639]

Don't want to Hi jack but I just took my pump off the truck to repaint it and was wondering the procedure here. I need to fill the pump up and turn the wheel lock to lock several times to get the air out right.

Is this with the pump cap on are off? Check level and top it off if need be right?

[PAWS 72]

when I replaced mine and refilled I turned the wheels lock to lock about 4 times each direction with the motor off then started and done the same thing and then checked the fluid. Haven't had any problems since.

I did have the same problem with the return tho. I just took the pump out of the new housing and put back in the old housing and returned for core charge.I did get about 5 different pumps ordered but they all were the same.

[Andy4639]

Originally Posted by PAWS 72

when I replaced mine and refilled I turned the wheels lock to lock about 4 times each direction with the motor off then started and done the same thing and then checked the fluid. Haven't had any problems since.

I did have the same problem with the return tho. I just took the pump out of the new housing and put back in the old housing and returned for core charge.I did get about 5 different pumps ordered but they all were the same.

Good info. I will try this first. Thanks!