Servo Pump Replacement: A Helpful Guide

Hello professional thief,

The power steering pump bearing on my wife's 1996 Golf 3 TDI (1Z) has failed. The pump needs to be replaced, and this is after only 115,000 km.
At VW, the pump costs 211 EUR plus installation. But I think I'll get a used one and install it myself.
Has anyone had any experience with this?
Sure, here is the translation of the text from German to English:

'I am particularly interested in the following points:'
Is there a drain plug for the oil? If so, where is it located?
2. Can the oil be reused, or is it better to use new oil? How much of which type of oil is needed?
3. Does the system need to be bled afterwards?
4. Is there anything in particular that one should pay attention to?

Thank you very much for your help.
Greetings from the North!
Eike.

Hi Eike!

I recently had a problem with the steering system, which ultimately turned out to be a minor issue.
Just so you know:

VW recommends replacing the entire system, including the oil, when changing the pump (e.g., due to dry running, jamming, noises, etc.), as any resulting debris could damage the steering gear.
can damage/make leaky.

The hydraulic fluid used is the same type that is used in automatic transmissions.

What problems are you having?

Note: At the time, I had an oil leak (without any oil stains on or around the vehicle!!!!!). VW diagnosed a faulty steering rack. Eventually, I discovered that the fluid was simply evaporating due to a defective seal on the reservoir cap!

Regards,

Andreas.

Hello,
It started with strange noises that sounded like metal rubbing against metal. However, the noise was intermittent and particularly noticeable when listening near the wheel arch on the passenger side.
Following this, VW investigated the problem and removed the two V-belts. The noise disappeared, but returned the moment the V-belt for the power steering pump was reinstalled. Therefore, the belt was removed again, and it was discovered that the power steering pump's bearing had excessive play (the wheel can be easily rocked back and forth). The metallic noise comes from a loose metal ring on the bearing of the pump shaft, which rotates loosely and makes the noise. This part is either corroded or has become detached due to the bearing damage.
My wife has also told me about noises when the steering is turned fully, and she mentioned that the power steering has already stopped working intermittently twice. However, the oil level is sufficient.

The workshop foreman said that a new pump would be necessary. He didn't mention anything else.
Does the pump actually have a plain bearing or a ball bearing?
I can buy an AT pump from a hardware store for 123 euros. I might find one at a scrapyard for 80-100 euros, but who knows how long it will last...

Regards,

Eike.

'I'm also experiencing the noises you mentioned when the steering wheel is fully turned and the power steering fails. That's easily explained: the V-belt is slipping. It happens more often when it's wet and under heavy load (full steering lock), and especially when it's raining, and strangely enough, mostly in right turns. I think I need to replace the belt.'

Hello,

I bought a new pump (AT part) for €129 (24 months warranty) and installed it. The installation wasn't particularly problematic. I drained as much of the old oil as possible and then filled it with new oil (so-called ATF III oil).

'I then started the engine, and the power steering was working. I took it for a short test drive, and after about 1 km, at the first intersection, the power steering stopped working. I then let the engine run for a short time while it was stationary, and the power steering assistance came back.'
After I drove back home, that was the end of the power steering assistance.
I then called the dealer (who has a workshop with certified master mechanics). He said the car would need to sit for a while, as there was likely an air bubble trapped in an unfavorable location that would continue to migrate. However, even letting it sit didn't help. I've now driven over 120 km, and the problem hasn't improved at all.

Does anyone have any ideas on how to bleed the air out of the system? Is there a bleed screw?

Regards,

Eike.

Hi,
In my previous work on power steering systems (though on a Golf II), the system always bled itself automatically. This is also how it is described in the manuals.
Therefore, there is no air vent screw.
Are all the pipes and connections sealed properly? Were new seals used?

Hello Andy,

The pipes are sealed. New seals (the two copper rings at the pump outlet) have also been installed.
It's strange that it worked initially and then stopped working. At first, the pump also made the typical noises that you hear from VW vehicles when you turn the power steering all the way to the stop.
It's gone now too. But the serpentine belt has the correct tension. It can't be the belt. There's enough oil.
At first, I thought the pump might be collapsing the rubber hose that supplies the oil, preventing it from getting enough oil. However, the hose isn't collapsing, even when the engine is running at 3000 RPM.
It's quite strange. I guess I'll have to go to the workshop where I bought the pump. Let's see what they say...

Best regards from OL.

Eike.

I'm experiencing the same problem.

After replacing the steering gear, the power steering worked for a short time. Now, the power steering is not working at all.

Does anyone have any idea what might be wrong? I've already spent a lot of money on the steering system. Is it possible to check the pressure of the power steering pump?

I would be grateful for any help.

Arne.

Hello Andy,

The pipes are sealed. New seals (the two copper rings at the pump outlet) have also been installed.
It's strange that it worked initially and then stopped working. At first, the pump also made the typical noises that you hear from VW vehicles when you turn the power steering all the way to the stop.
'That's gone now too. But the serpentine belt has the correct tension, so it can't be the problem. There's enough oil.'
At first, I thought that the pump might be collapsing the rubber hose that supplies it with fluid, and then it would no longer receive any fluid.

Okay, so if the pump isn't making its usual noises and the belt is in good condition, then it's likely not getting any oil. I would check to see if there's oil actually reaching the pump on the suction side. It's possible that the hose from the expansion tank to the pump is completely empty (which is very likely after disassembly), and the pump isn't able to pump out that much air.
So, try doing the following:
1) Open the lid of the container.
2) Disconnect the hose on the suction side (it's usually only held on with a hose clamp).
3) Wait until the oil stops dripping from the hose.
4) Reconnect the hose to the pump.

Then the pump should also be able to pump out any remaining air.

Good luck.

Andy, I'll try that. Hopefully, it will help me.

I will report back as soon as I know more.

:vomit: ... I disconnected the hose leading to the power steering pump. It was completely full of oil. However, there's a branch in the hose leading to the power steering pump, and one of the branches goes to the steering rack.

Does anyone else have any ideas?
I really want to drive again.

Hey guys,

I've been there too, and I haven't found any air in the pump either. I'm going to the workshop where I got the pump tomorrow afternoon.
Here's a possible idea: How about loosening the outlet (pressure side) slightly, so that the pump doesn't have to work against pressure. Perhaps any air trapped inside the pump will then escape. Looking at the pipes and hoses used, it seems the pump is generating quite a bit of pressure. However, it can't do that if it's only drawing in air. It's similar to a well pump that draws in air...
The question is, what happens if they suddenly get oil again and the pressure increases abruptly. We don't want everything within a 5-meter radius to be soaked in oil .

I will report what caused the issue once I have found the error.

Regards,

Eike.

Hi,

IMO, in cases like these, the problem is likely due to air in the system.
Try loosening the pressure fitting on the steering gear to allow any 'trapped' air to escape.
Loosen the upper nut slightly; place a cloth over it; start the engine; wait until oil flows out; tighten the nut again, and then turn the steering wheel fully from lock to lock several times to pump out any remaining air from the steering system.
Good luck!

Hello Andy,
I was at the repair shop today. The mechanic disconnected the pressure line from the pump and tried to start the engine, but only oil came out.
He mentioned that the rubber seals inside the hydraulic cylinder in the steering gear might be the cause of the problem. According to him, these seals could potentially flip over if there is air in the cylinder, and then the steering is used under load. If that were the case, it would be very expensive to fix.

However, the fact that the power steering assist initially worked and then failed during the test drive contradicts this. If there was a leak, the air should have been escaping for a long time. If the problem were actually due to the rubber rings, the issue should have been present from the beginning, and not only after a few steering movements.

It's also strange that there are no visible flows in the oil reservoir when you apply gas. Before, it was clearly visible how the oil was being circulated.

The workshop has now ordered a new pump, which I will receive tomorrow. Hopefully, something may have just come loose in the 'old' one, and I can fix the problem by replacing it again.

I'll let you know how it turns out...

Regards,

Eike.

YO - let me know if you find out any more details.
I'm really fed up with this crap...

- Arne

Hi,

I installed the second pump this weekend, and sure enough, it works.
I spoke with two mechanics from VW beforehand, and they both assured me that there's nothing to bleed in this process. However, it is recommended that after installing the new pump and filling it with oil, the steering should be turned from lock to lock a few times with the vehicle unloaded (e.g., lifted on a jack) and the engine not running.

'@ Arne: When the pump is running, you should see the oil flowing in the oil reservoir, as the oil is pumped around even without any steering movement. This effect is amplified when you give it some gas. I couldn't see this flow anymore. With the new pump, it was immediately visible again.'

If you can't detect any flow, you should try replacing the pump. You can find used pumps at scrapyards starting from around 80€. I got an AT pump from an accessory dealer for 129€ with a 2-year warranty. It's worth comparing prices!

PS: Of course, you'll also need oil. I used what's called ATF III oil. It costs €6.50 per liter. But one can (1 liter) is enough.

So far...

Regards,

Eike.