Carpokes Porsche Forum

New today, power steering pump groan when sitting still in the driveway.

I rebuilt the leaky pump maybe five years ago. Wasn't too hard. Prior to the rebuild it had groaned at full lock, and also leaked.

This is new, though. It groans just sitting there idling. Groans like crazy if I even touch the steering wheel. It's full of fluid, but it doesn't look like the fluid is circulating. Usually you can see some fluid turbulence in the reservoir when you remove the cap, but not now.

Ideas anyone?

• I remember reading about a non-replaceable filter at the bottom of the reservoir. I've never replaced the PS reservoir, so that's a 250K mile filter.
• The supply/return lines are connected and not kinked or crushed.
• No leaks. Nothing "wet".

Anything else come to mind before I start throwing parts at it?

Thanks in advance.

I have a not-very-old reservoir from my 928 that I had to replace (as a condition for the warranty on my rebuilt rack on that car), that you are completely welcome to. It has <2000 miles of power steering recirculation on it, if you want it.

Going through what could fail (there may be more than this):
- Blocked line
- Pulley disconnected from shaft
- Shaft disconnected from internal thing that holds all the little vanes
- Little vanes are all stuck in their housings and not pushing the ATF around

I'm not totally sure how to diagnose those things separately, but I think it all starts with removing the pump (maybe after you change the reservoir).

PM me and I can send you the old/new reservoir, if you're interested.

Good luck

PM sent, at least I think it sent.

Many thanks to @Zirconocene for the PS reservoir!


While I had the reservoir removed (and the fluid drained), I took the opportunity to inspect the internals of the PS pump. I had replaced the seals in 2018 and posted about a "groan after rebuild" on RL. At that time I discovered that the new hourglass-shaped seal had been sucked toward the little openings.

The same was true now in 2023 (circled here in green)...
This is how it's supposed to sit.
The PS pump is currently quiet and operating normally. No leaks. No noise. Nothing unusual.

My working theory as to how this happened is this...

• PS Reservoir has restricted flow due to gunk in the 250k mile filter
• In lieu of a constant supply of fresh fluid, PS pump sucks the hourglass seal into the ports
• Ports get blocked by seal further starving pump of fresh fluid
• PS Pump groans

Anyone else have ideas?

Did you confirm the old reservoir was blocked/clogged? Pour a little fluid in and see if it flows out normally? If it was clogged, your theory sounds good to me...

At some point we'll have to have our engine bays open together; that color scheme in yours is very similar to what I have going on in mine. (I'll post pictures later, but it's a funny coincidence)

I'm glad I was able to help out.

Cheers

Zirconocene wrote: Wed Jul 19, 2023 9:03 am At some point we'll have to have our engine bays open together; that color scheme in yours is very similar to what I have going on in mine. (I'll post pictures later, but it's a funny coincidence)

Some engine compartment p*rn (taken last fall when putting everything back together)...

Tom what do you think about a small 3D printed piece in there to keep the seal from doing that?
Make it shorter than the height of the channel, and fit in between that. Could keep the seal from collapsing.

Unrelated, but here's an older picture of my engine bay. I'm pretty sure the only update since then is new blue spark plug wires.
Jinx!

stitch2k1 wrote: Sat Jul 29, 2023 7:40 am Make it shorter than the height of the channel, and fit in between that. Could keep the seal from collapsing.

I'm gonna try this. After a couple days of working properly and maybe 50 miles total, my pump started groaning again as I pulled into my driveway.

I'm gonna take the pump off the car again. I'm sure I'll find the hourglass seal sucked into the ports again.

I think there is enough clearance along the inside edge of that seal to slip a thin plastic strip, like the tail of a zip tie, in the areas adjacent to the two ports. I'm gonna try that.


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