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[924RACR]

Just rebuilt my PS pump last night, using the $20 rebuild kit from Rennbay (also sold by Paragon IIRC). Pretty easy, didn't take long; biggest PITAs were a) removing it from the car (not challenging, but messy) and b) cleaning the housings off. All that leaking plus dirt and years equals a LOT of crud!

Procedure is pretty simple, really, just a matter or replacing the seals that are in the kit (note that the kit is designed to rebuild multiple pumps, so you have left-over parts). Naturally, this should be performed on a clean, clear surface.

You remove the pulley first (3 bolts), then separate the housings with the 4 bolts holding them together. Impact is ideal for this, but can clamp it in a vise if needed. Be sure to note the relative position of a) the double-ended stud used for pump mounting, and b) the brace plate for the tensioner.

Remove the large o-ring that seals the cases together.

Remove the hammerhead shaped seal on the back of the impeller housing - which is a the very back of the nose section, behind the shaft - along with it's retaining clip, noting the orientation of the seal; flat side goes towards the pulley side.

The impeller housing then comes right off the front housing of the pump; it may lift right off, but mine required a little light prying with a flat-bladed screwdriver. Be gentle here, don't get it cocked to the side and don't damage the alloy of the housing!

As the impeller housing comes off, the impeller will be exposed. It's got many little pump vanes; these are loose and will fall all over the place if you're not careful.

Remove the small circlip holding the impeller to the shaft; prying gently with a small screwdriver will accomplish this, but don't overdo it and distort the clip - you need it again for reassembly! Then the impeller can be lifted off the shaft and put aside.

The shaft will then push out the front of the housing. Then remove the front (nose) seal on the housing - it can be pried out with a screwdriver, since it'll be replaced. Just don't scratch up the housing.

This is a great point to clean all the parts, most notably the outside of the housings. Dish detergent works surprisingly well, in high concentrations, and is much easier on your hands than other chemicals...

You can also, if the inside of the pump was dirty, remove the spider clip in the back housing, piston, etc., and clean all of those; mine was not dirty, so I skipped this step (nothing in there to replace).

For reinstallation, start with the nose seal; lube lightly with ATF, and press it in straight... usual deal of a socket and gentle, square tapping till seated. Then insert the shaft, again with a coating of ATF. The impeller hub then gets coated with ATF and placed on the end of the shaft (note that the beveled side, unless I'm sorely mistaken, gets placed facing the pulley) and secured with the small circlip. This is usually easier to do without the impeller blades in place, installing them after the impeller hub is secured.

Note when reinstalling the impeller blades, which you should do now, that they have a flat edge and a curved edge. The curved edge faces outward, away from the shaft, when assembling.

Once all the blades are in place, the impeller housing is reinserted.

After the impeller housing is in place, install the new hammerhead seal and retaining clip, again noting that the flat side of the seal goes towards the impeller (towards the pulley) and then the clip secures the seal. Continue to lube all with ATF.

Then the o-ring is placed in its groove on the housing, with a little ATF, adn the housings reassembled. Note to line up the small port on each housing, at the outer edge of the circular cavity, with each other. Use loctite on the bolts, and torque to 20Nm.

Then of course install the pulley, using a little loctite. Reinstall, reattach the hoses, and fill up w/ ATF verifying no leaks. Start the engine, and cycle the steering side-to-side lock-to-lock to flush/bleed the system out. Verify again no leaks, and top off the system to full per the dipstick.
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Vaughan Scott
Webmeister
'79 924 #77 SCCA H Prod racecar
'82 931 Plat. Silver
#25 Hidari Firefly P2 sports prototype