964 - Power Steering Pump Rebuild

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Originally posted by WSYBERT at Rennlist He was gracious enough to provide the text and the pictures.

This is a very easy DIY. I say easy, because my engine is sitting on a stand in my garage now. So, getting the PS pump out of the car with the engine in the car, may not be so easy. You will have to decide that.

1) Remove the PS pump drive belt. Note: I removed mine by removing the lower drive pulley bolt, and removing the drive pulley. You may be able to remove the belt once you remove the 4 nuts holding the pump in the housing.

2) Remove the PS pump from its housing. It is held in place by 4 nuts (takes a 13mm socket). See the first picture (sorry for the quality).

3) Place the pump on a work area (preferably covered with a towel of some sort. You will get PS fluid on this area) with the toothed pulley facing down.

4) Put a matchmark on the housing and remove the 4 bolts holding the housing together. The matchmark will help you orient the halves together later.

5) Pull the two halves apart. You may have to tap them with a rubber mallet to get them apart. Keep the pulley side facing down.

6) Once you get the halves apart, you will see the internals of the pump. 3rd picture.

7) The internal pump seal gets replaced. This is a two piece seal. Remove the old one, by gently prying it out. Assemble the new one. The hard piece goes on the outside of the rubber. Once you assemble the two pieces of the seal, put them into the seal plate.

8) Gently pry up on the seal plate (The plate that holds the seal you just installed). It has a some good surface tension, due to the oil and very flat surfaces, but it will come off easily. Plus there are two dowels that help hold it on the inner pump housing.

9) Once you have the seal plate off, you will have to remove the snap ring that holds the shaft in place (pic 4). I used two small screwdrivers, and worked them around the ring until I could pry it off. If you distort it a little, don't worry. I did, and bent it back into place. Once you re-install it, it is captured inside the pump wheel, so it's not going anywhere.

10) Now that the snap ring is off, the pump shaft will slide out of the housing. Gently pull the pump shaft out. Keep ahold of the assembly on top (inner pump housing and pump wheel).

11) You are going to want to keep the inner pump housing and pump wheel together. I placed my palm over the housing and wheel, then turned the assembly over. Once it is upside down, you may have to pry a little on the inner pump housing, as the dowels will hold it in place. Once the pump wheel and housing are in your hand, you will want to put them somewhere out of the way. I used a small flat piece of wood, and turned them over on to it. Don't worry if a pump vane or two come out and fall on the floor... yes a couple of mine did.... just take a look at them and place the shiney side out. I also took a look at another ones wear pattern, to verify I had them back in the way they were.

12) Remove the pump shaft seal, by prying it out. You can use a screwdriver, but I had a seal puller which worked well. (Sorry, no pics here, I forgot) Shaft seal location is in pic 2.

13) Put the new seal into the housing. I placed mine in the housing and used a flat piece of wood and a mallet to tap it into place. I also used a little oil on the housing bore to assist in the installation.

14) Now you can start re-assembly.

15) Once you have the pump shaft back in, and the pump wheel and inner pump housing back in place, re-install the snap ring. The snap ring, once installed, will need to be compressed into the groove, and the pump shaft will need to be pulled from the pulley end. This will allow the snap ring to seat itself into the counterbore of the pump wheel. (I missed this on mine. The pump halves will not go back together unless the snap ring is pulled back inside the pump wheel.

16) Place the seal plate back on top of the wheel and housing assembly.

17) Install the new housing o-ring in the groove in the outer pump housing.

18) Re-install the 4 housing bolts. Torque _____ ?? (Haven't looked for it yet.) Note: A pump like this will eat seals, if not lubricated. Add some PS oil to the pump and turning it by hand to lubricate everything, before putting it back in.


Any comments or suggestions are welcome.

Fred (Fred's 964), thanks for the tip on sourcing the seal kit.

You can find it HERE (No affil). It is shown as a kit for a 944, but it works on the 964. Also, you will not use all the seals in the kit. Only the shaft seal, the inner odd shaped 2 piece seal, and the housing o-ring.

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