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Pelican Technical Article:

Steering Rack Rebuild

Steve Vernon

Time:

2-4 hours

Tab:

$70

Talent:

***

Tools:

10mm wrench, 6mm Allen, circlip tool, punch, hammer, various sockets for pushing seals in place, lots of cleaning fluid, floor jack, jack stands, wheel chocks, safety glasses, torque wrench

Applicable Models:

Porsche 944 Turbo (1986-89)

Parts Required:

Rennbay steering rack-rebuild kit, steering fluid

Hot Tip:

Clean everything well

Performance Gain:

Proper performing steering rack

Complementary Modification:

New tie rods

The power steering rack is a constant source of leaks on the front of the Porsche 944 and 951. Thankfully, Rennbay now makes a complete kit for rebuilding yours. If you can remove the rack from the car you can rebuild it. Most people just buy a new part when something wears out but this is your chance to rebuild your rack, save a lot of money and look like a professional mechanic for doing so. You will need to remove the rack to rebuild it. Removal of an old and leaking rack is a very messy job. Removal is not that difficult but add some extra time if your steering rack is really dirty. Please see our article on rack removal for additional assistance.

If your rack has been leaking there is a good chance it came off the car looking like this.
Figure 1

If your rack has been leaking there is a good chance it came off the car looking like this. The first thing you should do is give it a good cleaning. Cleanliness is very important when rebuilding these. Even though you are going to clean each component start with a clean outside.

The Rennbay kit comes complete with everything you will need to rebuild the rack.
Figure 2

The Rennbay kit comes complete with everything you will need to rebuild the rack.

To begin disassembly you will want to remove the breather tube.
Figure 3

To begin disassembly you will want to remove the breather tube. The ends are plastic and will just pull out (red arrows).

The two lines are held in by four banjo bolts; use a 6mm Allen.
Figure 4

The two lines are held in by four banjo bolts; use a 6mm Allen. Making sure it is properly seated in the bolt head, remove the four banjo bolts (red arrows, two shown).

With a nice clean stripped down rack you can begin the rebuild process.
Figure 5

With a nice clean stripped down rack you can begin the rebuild process.

You do not need to remove the small plate at the base of the housing to rebuild the rack.
Figure 6

You do not need to remove the small plate at the base of the housing to rebuild the rack. However, if yours is giving you trouble remove the two 10mm bolts (red arrows), the gasket and the spring (yellow arrow). Note: this gasket is not included in the rebuild kit.

Remove the top cover to the housing by pulling the plastic piece off (yellow arrow) and then removing the three 10mm bolts (red arrows).
Figure 7

Remove the top cover to the housing by pulling the plastic piece off (yellow arrow) and then removing the three 10mm bolts (red arrows).

Inside the housing will be a thin washer (red arrow).
Figure 8

Inside the housing will be a thin washer (red arrow).

Below the thin washer will be a thick washer with a beveled edge over a bearing (red arrow).
Figure 9

Below the thin washer will be a thick washer with a beveled edge over a bearing (red arrow). Note the orientation of the bearing and washer when removing for reinstalling later.

You are now going to pull the pinion shaft out from the housing.
Figure 10

You are now going to pull the pinion shaft out from the housing. You may need to wiggle the shaft and pinion to get it free. There are two washers and a roller bearing on the bottom of the pinion (red arrow) that may come off with it or stay in the housing. Make sure you get the three pieces out.

Next, you want to separate the rack tube from the housing.
Figure 11

Next, you want to separate the rack tube from the housing. There is a ring on the tube that you will need to use a punch and hammer and turn the ring (red arrow) until you can separate the two.

With the ring unscrewed you can slide the tube off the rack and housing (red arrow).
Figure 12

With the ring unscrewed you can slide the tube off the rack and housing (red arrow).

You can now pull the rack out from the housing in the direction of the red arrow.
Figure 13

You can now pull the rack out from the housing in the direction of the red arrow. The sleeve will remain on the rack for now.

To remove the sleeve (red arrow) from the rack you will need to remove the series of circlips, washers and gasket from the rack (yellow arrow).
Figure 14

To remove the sleeve (red arrow) from the rack you will need to remove the series of circlips, washers and gasket from the rack (yellow arrow). The sleeve cannot be removed from the geared section of the rack.

The end of the sleeve next to the geared section of the rack will have a circlip and Teflon washer (red arrow) and a rubber O-ring.
Figure 15

The end of the sleeve next to the geared section of the rack will have a circlip and Teflon washer (red arrow) and a rubber O-ring. Sometimes the O-ring remains in the housing. Do not forget to remove and replace it. Do NOT lose the Teflon washer; there is not one in the kit.

You need to remove the sleeve to replace the seals on it.
Figure 16

You need to remove the sleeve to replace the seals on it. To do this you will need to remove the series of circlips and washers on the rack; you are going to be replacing some of the components as well. Begin by using a proper circlip tool and remove the circlip. It is very important that you do not scratch the rack while performing this work so be smart and use the right tool. Remove all the clips and washers keeping track of the order they came off in.

In the rack there are grooves for the circlips.
Figure 17

In the rack there are grooves for the circlips. The center groove is for the two rubber O-rings (red arrows) with the metal washer and Teflon washer sitting over the rubber O-rings. Remove the circlip, washer, larger washer with the Teflon O-ring, the two rubber washers, metal washer and other circlip. Remove the Teflon O-ring from the large washer and replace it with the new one (yellow arrow). Install the two new rubber O-rings when reassembling. The large washer with the Teflon O-ring will sit over the rubber O-rings. Remove the sleeve from the rack.

Remove the seal on the sleeve along with the bushing inside (red arrow).
Figure 18

Remove the seal on the sleeve along with the bushing inside (red arrow).

The bushing has a beveled edge (red arrow).
Figure 19

The bushing has a beveled edge (red arrow). When inserting it into the sleeve make sure the beveled edge is pointing down in the tube.

Insert the beveled edge facing down into the sleeve.
Figure 20

Insert the beveled edge facing down into the sleeve. Then insert the new seal lip side facing up (red arrow); if you insert this the lip side down the rack will leak. Use a socket with the diameter of the seal and press it into the sleeve until it seats below the edge of the sleeve (red arrow). Reach in and try and move the Teflon bushing. If you can move the bushing the seal is not seated enough (yellow arrow).

Make sure to reinstall the Teflon bushing on the other end of the sleeve (red arrow) and replace the rubber O-ring (yellow arrow).
Figure 21

Make sure to reinstall the Teflon bushing on the other end of the sleeve (red arrow) and replace the rubber O-ring (yellow arrow).

There is a Teflon bushing and seal at the end of the rod housing (red arrow).
Figure 22

There is a Teflon bushing and seal at the end of the rod housing (red arrow). Remove the old seal and bushing by pushing them out the long end of the tube.

The new bushing and seal must be installed from the long end of the tube.
Figure 23

The new bushing and seal must be installed from the long end of the tube. The bushing does not have an orientation but the seal must be installed face up (red arrow). Drop them in the tube. Reach in through the bottom. Make sure the seal is facing the right direction. Then use the appropriate sized socket and push the seal in place. Again, reach a finger in. If you can move the Teflon bushing the seal is not seated correctly.

There is a seal that sits in a machined recess in the housing.
Figure 24

There is a seal that sits in a machined recess in the housing. Removing this seal without scratching the housing can be challenging so just take your time and work cautiously (red arrow).

With the old seal removed insert the new seal lip side out or facing you.
Figure 25

With the old seal removed insert the new seal lip side out or facing you. Push it in place using the appropriate sized socket. The seal should sit just below the machined lip inside the housing (red arrow).

Replace the O-ring from the side of the housing that faces the rack tube (red arrow).
Figure 26

Replace the O-ring from the side of the housing that faces the rack tube (red arrow).

The pinion has a series of four rubber and Teflon O-rings that you are going to replace (green arrow).
Figure 27

The pinion has a series of four rubber and Teflon O-rings that you are going to replace (green arrow). It also has the series of washers and bearings on each end (red and yellow arrows).

On the pinion there are four grooves; remove the Teflon O-ring (red arrow) and then the rubber O-ring (yellow arrow) from each groove (green arrow).
Figure 28

On the pinion there are four grooves; remove the Teflon O-ring (red arrow) and then the rubber O-ring (yellow arrow) from each groove (green arrow). Do this for all four grooves.

Insert new rubber O-rings in each groove (red arrows).
Figure 29

Insert new rubber O-rings in each groove (red arrows).

Place the new Teflon O-rings over the rubber O-rings in the grooves (red arrows).
Figure 30

Place the new Teflon O-rings over the rubber O-rings in the grooves (red arrows).

On the geared side of the pinion there is a large beveled washer that sits against the housing.
Figure 31

On the geared side of the pinion there is a large beveled washer that sits against the housing. When inserting the washer make sure the beveled side of the washer (red arrow) faces the base of the housing.

When placing the thin washer, roller bearing then beveled washer on the pinion they must sit in the recessed area.
Figure 32

When placing the thin washer, roller bearing then beveled washer on the pinion they must sit in the recessed area. If they sit on the hat (red arrow) they will be damaged when you tighten everything down. I like to apply grease to the bearing and washer to help hold it in place.

The eight small O-rings go in the banjo bolt fittings (red arrow).
Figure 33

The eight small O-rings go in the banjo bolt fittings (red arrow).

The two smallest O-rings are for the breather tube fittings (red arrow).
Figure 34

The two smallest O-rings are for the breather tube fittings (red arrow).

Remove the old seal from the cap on the top of the housing.
Figure 35

Remove the old seal from the cap on the top of the housing.

Replace the seal in the same manner as the other ones.
Figure 36

Replace the seal in the same manner as the other ones. Make sure the lip of the seal is facing in towards the pinion (yellow arrow). Replace the rubber O-ring on the cap. You are almost done. Grease everything up and carefully reinstall everything in the reverse of removal. Make sure that the O-rings are lubed and stay in place when reinstalling. If you have any misgivings about having put this back together incorrectly, remove the piece and reinstall it. Things will be tight with all new O-rings and gaskets.

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