Power steering issue

[Jersey_M3]

Hello all. Turning to this forum for advice as I don’t know how to troubleshoot my issue further.

recently my power steer pump have been making and awful noise and gets very very hot. Like making the oil smoke hot. I turn the car off before anything real bad happens but I’m really stumped on how to fix this issue. I’ve replaced everything and the new pump, still does the same thing. Old pump never broke but I replaced it as a precaution. New pump new lines. New rack.

Is there a line I should disconnect to know for sure the pump is primed. Is there a way to put vacuum on the system to suck fluid through it all?

[sapote]

Have you turned the steering wheel to max CCW and then max CW to fill the fluid and flush the air out with the reservoir filled up?

[Slideways]

Check that all the lines are connected correctly on the PS reservoir, pump and steering rack. Are you trying to bleed the system with car on the ground or in the air?

[Jersey_M3]

Check that all the lines are connected correctly on the PS reservoir, pump and steering rack. Are you trying to bleed the system with car on the ground or in the air?

Car is in the air, I’ve done the full lock to lock to try and bleed many many times and, I even turned the car on to try and bleed it lock to lock. No dice

[sapote]

Check the pump high pressure output line and make sure it's connected correctly to the proper port on the rack. Recently I replaced the two hoses on the reservoir and drained all the fluid, then filled up and ran engine with no issue at all. This was done on E46 325i though but should be similar to M3.

[Slideways]

Car is in the air, I’ve done the full lock to lock to try and bleed many many times and, I even turned the car on to try and bleed it lock to lock. No dice

Either power steering fluid is not flowing to the pump or one of the parts is defective. Does the fluid level fall after trying to bleed air out of the system? The pump should go silent after one or two turns of the wheel as the engine is running.

[bigjae46]

If I had to make a bet, its the pump. The pump is a positive displacement pump with a relief which recirculates pressure from the discharge back to the suction. All PD pumps have a relief to prevent exactly what you are describing. Either you're not getting fluid into pump or its not recirculating. Did you replace the PS reservoir? I'd also check the banjo bolts on the steering rack. One of them has a check valve in it - I think the smaller one. See if it is stuck closed or just replace it.

Then if you can't find anything I'd disconnect the lines and blow air through them to rule out anything being plugged. With the banjo's off, move the rack left to right and make sure fluid spills out. But if a line or the rack was blocked then the pump relief should just recirc and not make noises and stuff.

[sapote]

I agree that it seems the pump output is blocked and the high pressure oil couldn't flow causing noise and heat.

[Jersey_M3]

Im gunna make some air pressure fitting and try and empty the system and blow it out with air, see if there is a blockage somewhere

[Jersey_M3]

After another disassembly I found that oil was getting to my power steering rack but not going through. All other items were blown out and operate freely. Is there a way to manually fill the rack with fluid or manually bleed the rack to get pressure out the other side?

[bigjae46]

There's a check valve in one of the banjo bolts, maybe try replacing that? Should be relatively low cost.

[sapote]

There's a check valve in one of the banjo bolts, maybe try replacing that? Should be relatively low cost.

Why does it need a check valve?

Got the answer: It's a pressure regulator and not a check valve.

[sapote]

After another disassembly I found that oil was getting to my power steering rack but not going through. All other items were blown out and operate freely. Is there a way to manually fill the rack with fluid or manually bleed the rack to get pressure out the other side?

Beside the pump noise and hot, does the power steering assist work -- not heavy but normal feel? I would think if fluid doesn't flow back to reservoir than the rack has no power assist at all.
If anything I think the rack control valve is stuck in the tower -- the part that has the splined shaft connected to the steering column. There are two metal pipes from the tower running to the rack to push the rack internal piston to the left or right as the tower valve detects the steering column direction. You can remove the pipes off the rack but not off the tower, then see if the left pipe shoots oil out when turning the wheel to RIGHT, and the right pipe shoots out when turning wheel to LEFT, with engine idling.

"I found that oil was getting to my power steering rack but not going through."
This is normal in idle mode. Fluid return only during turning the wheel.

I think the pump noise and hot issue is due to the relief valve is stuck and build up too high pressure.

[sapote]

I think the pump oil pressure regulator is jammed and built up too high pressure.

Follow these steps to remove the regulator and no need to fish out the larger spring below it.

https://nam3forum.com/forums/forum/main-forum/e46-2001-2006/189-comprehensive-steering-information-thread

Step 1


If you’re doing this on the car, you will need a 22 mm wrench or socket to remove the banjo bolt and disconnect the high pressure power steering line. Place a drain drain pan underneath for any oil that comes out. I haven’t attempted it on the car, so I’m not sure how quickly it will drain out.


Step 2

Remove the 27 mm hex plug on the pump output.


You will need to use an impact or a vise to secure the pump if you’re doing this off the car.


Step 3

Use a magnetic pick-up to remove the pressure regulator and the spring behind it.

Step 4

Secure the pressure regulator in a collet vise and remove the 11 mm hex plug. Be careful not to lose the small ball or spring hidden behind it, or any shims that may be on the plug.

My instruction: clean the small hole on the 11mm hex plug, ball, small spring, and the inside of the 27mm plug.

[Jersey_M3]

There's a check valve in one of the banjo bolts, maybe try replacing that? Should be relatively low cost.

you sir deserve a medal. This was indeed the issue. Car is fully put back together now. Love this community