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Power Steering Pump Removal
 
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Pelican Technical Article:

Power Steering Pump Removal

Tom Morr

Time:

3 hours3 hrs

Tab:

$499-$625 (pump), $16 (pressure hose)

Talent:

***

Tools:

7mm socket, 8mm wrench, E12 Torx socket, Torx bits, 14mm wrench or socket, 17mm line wrench

Applicable Models:

Mercedes-Benz R170 (1998-04)

Parts Required:

Replacement pump, reservoir, and/or hoses, power steering fluid

Hot Tip:

Siphon as much fluid out of the reservoir as possible

Performance Gain:

No more squeaks or leaks

Complementary Modification:

Replace the hoses, check the drive belt

As with any part that's constantly in motion, power steering pumps eventually wear out. Afflicted SLK owners then get to decide whether to replace the entire reservoir/pump assembly or buy a new or rebuilt pump and transfer the existing reservoir to it.

Regardless of which repair route you choose, the old parts need to come off. So, the focus here is on removing the pump/reservoir assembly.

For SLKs that have the ZF pump, you must unbolt the pulley while the pump is still on the car. (Luk models have a pressed-on pulley, which requires a puller for removal.)

Our project car, a pre-facelift 2000 SLK230 Kompressor, has the ZF pump. It doesn't have the optional self-leveling suspension system and the accompanying tandem steering pump. I decided to remove the pump and its mounting bracket as one assembly instead of attempting to pull just the pump and reservoir. The air conditioning compressor and lines impede access. Removing the pulley and undoing the Torx-headed bolts that secure the pump, reservoir, and bracket are easier with the entire assembly out of the car. Two hoses and three bolts does the trick.

Cleaning the grime off the inner fender and plastic lower engine cover and wheel liners will help reveal any future steering leaks. Also, the steering system will eventually self-bleed any air that entered while replacing the pump. Typically, this takes about 30 miles of driving.

An alternate method is to jack up the front tires, turn on the engine, leave the transmission in Park, and slowly steer from lock to lock several times. Top off the fluid to the proper level. Repeat the process until the fluid reads the correct level on the dipstick.

The torque spec for the power steering pump bracket bolts is 25 Nm.

First, remove the belt.
Figure 1

First, remove the belt. The tensioner can be slackened by using an 8mm box wrench and a cheater pipe. (Please see our drivebelt how-to for additional details.)

A potential mess can be minimized by sucking as much fluid out of the reservoir as possible.
Figure 2

A potential mess can be minimized by sucking as much fluid out of the reservoir as possible. The "Thanksgiving" method is affordable and effective, by using a Thanksgiving baster to suck up the power steering fluid. We de-coupled the intake tube and moved it aside to improve access, while also protecting the MAF sensor from any minor spillage, dust or debris with a clean rag.

Even after de-basting the reservoir, some fluid will drain when the lines are removed.
Figure 3

Even after de-basting the reservoir, some fluid will drain when the lines are removed. If you don't want it to accumulate on the lower engine cover, remove the cover (please see that how-to for details) and put a drain pan under the car. The pressure hose (arrow) takes a 17mm wrench on its fitting. A line wrench is the preferred tool.

The return hose (arrow) can be removed by using a flat blade screwdriver or a socket (7mm in this case) on its clamp.
Figure 4

The return hose (arrow) can be removed by using a flat blade screwdriver or a socket (7mm in this case) on its clamp. Plug the hoses to keep dirt out.

A ground wire runs from the back of the steering pump to the car's fender.
Figure 5

A ground wire runs from the back of the steering pump to the car's fender. Its retaining bolt takes an E12 Torx socket (arrow).

Two long bolts having E12 Torx heads (arrows) secure the steering-pump bracket to the engine.
Figure 6

Two long bolts having E12 Torx heads (arrows) secure the steering-pump bracket to the engine. Once these are out, the pump can be slid out toward the fender.

The Torx-headed bolts (arrows) that mate the bracket, pump, and reservoir are easier to access once the assembly is out of the car.
Figure 7

The Torx-headed bolts (arrows) that mate the bracket, pump, and reservoir are easier to access once the assembly is out of the car. The pulley on the ZF pump is retained by a nut that takes a 14mm socket or wrench.

Backside bolts are difficult to get tools on while in the car.
Figure 8

Backside bolts are difficult to get tools on while in the car. The air-conditioning compressor and lines don't leave much wrench room.

This return hose shows signs of leakage.
Figure 9

This return hose shows signs of leakage. Most parts stores sell cut-to-fit lengths of power steering return hose, so replacing it is cheap leak insurance. In general, we recommend using new clamps whenever the hose is replaced. Purchasing new hose clamps is also inexpensive insurance.

Inspect other power steering hoses (arrows) for signs of leaks or deterioration and replace as necessary.
Figure 10

Inspect other power steering hoses (arrows) for signs of leaks or deterioration and replace as necessary.

Clean any spills, dirt, and debris off the fender and area around the power steering pump and hoses.
Figure 11

Clean any spills, dirt, and debris off the fender and area around the power steering pump and hoses. This will make any future leaks more obvious.

Use fresh power steering fluid.
Figure 12

Use fresh power steering fluid. Dispose of the old fluid properly.

Check the fluid level on the dipstick.
Figure 13

Check the fluid level on the dipstick. The level will go down as air bleeds out of the system.

The steering system will self-bleed during the normal course of driving.
Figure 14

The steering system will self-bleed during the normal course of driving. An alternate method is to jack up the tires and slowly steer from lock to lock with the car running and the transmission in Park. Check the fluid level and add as necessary until it remains at the proper level on the dipstick.

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Comments and Suggestions:
Ohioref Comments: Completely removed and replaced the power steering supply lines. Tools needed were: 19 mm line wrench, 17 mm line wrench, screw driver, and 17&19 mm sockets. Replacement lines were $105 and $26 from md dealership. We jacked the car up removed the under engine cover tray. It was manageble but difficult to get the lines removed. Replacement was also difficult as the lines connect in very tight spots. We reccommend replacing the 17mmpressure line first then the 19mmreturn line. Total time was near 1.5 hrs. Which would be less if we had the correct tools to start this project. We thing the Claw Wrench would be the correct tool for this project. Your site helprd us greatly. Thank you.
June 12, 2016
  Followup from the Pelican Staff: Thanks for the additional info and feedback. We appreciate it.
- Nick at Pelican Parts
 
Ohioref Comments: Do you have any hints on replacing the POWER STEERING HOSES ON THE SLK230 '98. The one pressure hose has a pin hole in it which is the cause of all the leaking. I tried to get the hose NUT off but I can't seem to get the wrench on it and there is lil if any room to get torque to loosen it. Is it best accessed from top or below? Do I need to remove anything to get to the nuts on the hoses?
June 2, 2016
  Followup from the Pelican Staff: Use a Crows foot line wrench with a universal socket to break it loose.

We don't currently have that tech article. If we get a chance to perform the procedure, we will be sure to document it.

I would grab a repair manual. It will have the procedure, special tools and torque specs.

Give our parts specialists a call at 1-888-280-7799. - Nick at Pelican Parts
 
Ohio ref Comments: These directions were spot on. After getting a replacement pump and hoses and clamps as suggested it took about 1.5 hours. We had a little issue getting the bracket back into the slot but other than that we had no problems. Savings from MB dealership $725.00. Thank you as my 1998 slk230 is back to full power.
May 25, 2016
  Followup from the Pelican Staff: Thanks for the feedback. Glad we could help. - Nick at Pelican Parts  

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