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Power Steering Pump Rebuild
 
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Pelican Technical Article:

Power Steering Pump Rebuild

Steve Vernon

Time:

5 hours5 hrs

Tab:

$5 to $50

Talent:

**

Tools:

30mm, 22mm socket, 17mm flared nut wrench, three prong puller, impact gun, Philips head screwdriver, large C-clamp, fluid pump

Applicable Models:

Mercedes-Benz W123 (1977-85)

Parts Required:

Rebuild kit

Hot Tip:

Follow procedures for filling and bleeding the system carefully

Performance Gain:

Good power steering pump

Complementary Modification:

Power steering fill and bleed

The power steering pumps on the W123's and 616 and 617 engines can begin to leak over the years, the nice thing is that Pelican sells a rebuild kit. Depending on the kit you buy, the rebuild kits basically supplies the parts to replace the O-ring, washer and seal that are the cause of the leaks. If your pump is leaking make sure to carefully look at it and get a kit that includes the parts you will need.

You will need to remove and drain the pump to replace the flawed elements which means that you will need to fill and bleed the system afterwards. Please make sure to follow the bleeding instructions carefully and do not just pour some fluid in and drive off.

We have removed the fan and shroud for photographic purposes but you do not need to remove these to perform this work.

Over the years your car may have been serviced by multiple people including previous owners and this can lead to parts replaced with different size fasteners and hardware. The sizes of the nuts and bolts we give may be different from what you have so be prepared with different size sockets and wrenches. If something is different on your vehicle please let us know and share your info to help other users. If you have any questions or comments or even a different procedure you would like to share please leave it below and please leave your vehicle information.

You are going to have to remove the pump and disconnect the lines so begin by sucking as much fluid as you can from the power steering reservoir.
Figure 1

You are going to have to remove the pump and disconnect the lines so begin by sucking as much fluid as you can from the power steering reservoir.

With the fan and shroud removed you can see the four drive or V-belts.
Figure 2

With the fan and shroud removed you can see the four drive or V-belts. The power steering belt (red arrow) is the most forward belt but you can also see both the A/C compressor belt (yellow arrow) and the two water pump alternator belts (blue arrow). You are going to need to remove the power steering belt but the others can stay.

Use a 13mm socket and loosen the two bolts on the right side of the power steering pump (red arrows).
Figure 3

Use a 13mm socket and loosen the two bolts on the right side of the power steering pump (red arrows). Use a universal joint on the upper bolt mounting bolt and a regular socket on the lower slider bolt, also do not remove the nuts or bolts yet, just loosen them.

Use a 13mm socket and loosen the slider nut on the left side (red arrow).
Figure 4

Use a 13mm socket and loosen the slider nut on the left side (red arrow). You may hold the bolt head on the rear of the pump.

Use a 13mm socket and working between the two upper lines completely loosen the tensioning bolt (red arrow).
Figure 5

Use a 13mm socket and working between the two upper lines completely loosen the tensioning bolt (red arrow).

You can now push down on the power steering pump and slide the belt off the pulleys (red arrow).
Figure 6

You can now push down on the power steering pump and slide the belt off the pulleys (red arrow). Once the belt is off go back to all of the nuts and bolts and remove them so you can remove the pump from the mount.

Figure 7

There is a piece on the rear of the pump that rides in the threads of the tensioner (red arrow); do not lose this piece when removing the pump and do not forget to install it when putting everything back together

There is a supply and return line attached to the pump that you will need to remove.
Figure 8

There is a supply and return line attached to the pump that you will need to remove. While the one line can be disconnected at the hose with a Philips head screwdriver or by using a 19mm flared nut wrench (red arrows) the other line needs a 17mm flared nut wrench for removal (yellow arrow). Do not try and take this line fitting off the pump using a standard wrench, if you round it or strip it the line will be difficult to remove and expensive to replace. Even though you have drained the fluid be prepared for fluid to escape and catch and dispose of it correctly.

With the pump off you will need to remove the nut holding the pulley on.
Figure 9

With the pump off you will need to remove the nut holding the pulley on. Basically the only way to remove this nut is to use an impact gun and a 22mm socket

Use a three pronged puller and separate the pulley from the shaft.
Figure 10

Use a three pronged puller and separate the pulley from the shaft.

The large O-ring inside the rear cover can be a source of leaks.
Figure 11

The large O-ring inside the rear cover can be a source of leaks. There is a metal ring that holds the plate in place as the cover is pushed outward by a spring inside (red arrow).

Thread the shaft nut onto the end of the shaft to protect the threads and then use a large C-clamp and compress the rear plate inwards.
Figure 12

Thread the shaft nut onto the end of the shaft to protect the threads and then use a large C-clamp and compress the rear plate inwards.

Once the plate is compressed you can remove the metal ring.
Figure 13

Once the plate is compressed you can remove the metal ring.

Now you can remove and replace the O-ring inside the body of the pump (red arrow).
Figure 14

Now you can remove and replace the O-ring inside the body of the pump (red arrow).

There is a single seal on the pulley shaft; remove the Woodruff key and then use a seal puller to remove the seal.
Figure 15

There is a single seal on the pulley shaft; remove the Woodruff key and then use a seal puller to remove the seal. Another trick is screw a couple of drywall screws into the seal and use them to pull it out. Do not force anything metal (like a screwdriver between the seal and the shaft of housing, if you nick or mar this area the new seal will probably leak.

Clean and inspect the seating area of the seal.
Figure 16

Clean and inspect the seating area of the seal.

Install your new seal and use the appropriate sized deep socket over the shaft to press in in place.
Figure 17

Install your new seal and use the appropriate sized deep socket over the shaft to press in in place. Reinstall the Woodruff key.

The cooper washer sealing the nut to the pressure relief valve can also be a source of leaks.
Figure 18

The cooper washer sealing the nut to the pressure relief valve can also be a source of leaks. You will probably need to place the pump in a bench vise as these then to be really "on there" use a 30mm socket and loosen the nut. The nut is under pressure from a spring behind it so use care when removing it.

Clean the mounting surface and install the new crush washer.
Figure 19

Clean the mounting surface and install the new crush washer. Installation is the reverse of removal. Remember to fill and bleed the pump once it is installed. Please see our article on power steering flush and fill for additional assistance.

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