DIY Rebuilt Power Steering pump pre '81

by Gerrit Dreesen

Hi,

since there is no service kit available for the power steering pumps for the early 928 ( before 1981), I decided to
challenge myself and luckily it was a success .
Here the necessary parts and the cost :
bearing : SKF 6004/C3 : inner diameter = 20mm , outer diameter = 42 mm, width = 12mm 7,62Ä
retaining rings for bearing : A20 Stainless Steel - Din 7993 : inside diameter 17,7 mm 7,73Ä
oil seal ring : FREUDENBERG 20x42x7mm (72 NBR 902) 14,22Ä
oil O-ring seal1 : VITON 80 SHORE : inner diameter = 66 mm (outer diameter = 71 ), thickness 2,5 mm
oil O-ring seal2 : VITON 80 SHORE : inner diameter = 67,95 mm (outer diameter = 73), thickness 2,62 mm
25,4Ä

total = 54,97Ä ( $61)

Hopefully it will help other 928 enthusiasts:-)
here some pics:

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Can you tell me how to remove this top seal? I canít tell if itís a simple rubber seal or if itís a shield on top of a bearing. Do I have to push out the shaft with a press?

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Seal is made of rubber so you need to remove it with a screwdriver. Just be careful not to scratch the axe or the housing of your pump in which the seal is set.
When you have removed it, it will look like this :

Gerrit

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Got it, though it wasnít easy. There's a metal plate underneath the rubber which made it very difficult to remove without causing collateral damage. What are the two Vitron 80 Shore o-rings for? I currently only see one large o-ring for the back plate (which is held in with the spring clip).

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here is a picture with the location of the 2 O-rings :

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I havenít seen that second seal because I havenít gotten that deep. Which leads me to my next question: how did you get this casing piece removed from inside the back? Does it simply pull out? I havenít pulled on it too much yet and thought Iíd check with you before I do.

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It should come out when you pull. But the O-ring will make it sit tight..

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This pump sure likes to fight me. Any suggestion on how to remove this other retention ring that sits on the shaft? I already got the outer snap ring out.

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Not this way. You first need to remove the whole ax (incl bearing) from the pump housing. Like this :

And then remove the retention ring to replace the bearing. The retention ring only serves to hold the bearing on its position on the ax.
Next you can put the whole ax back :

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Unfortunately I've not been able to get to that disc with the splines. The plate that sits above it (where that lower o-ring is) doesn't want to budge

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I know that the plate above the lower disc is set with 2 separate pins on which it slides,
What you can do is heat up the case of your steering pump with a heating gun. This could expand the case a bit, loosen your plate inside the lower o-ring.
Gerrit Dreesen.

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I spent a few minutes trying to figure out how to remove the pump gear without disturbing the small blade elements but finally gave up and went to bed. After having slept on it, I now think Ill place a small rubber band around the outside perimeter of it to retain the blades into the wheel before i remove it.

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Try using a magnet to keep them in place.
__________________
Gerrit Dreesen.