Power Steering pump rebuild DIY
 

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.

19) :biggulp:


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.



Bill

Thanks for the writeup and photos!!:cheers:

Post that '964 DIY', boy! -- Post it!

FYI.
Here is a pic of the seal kit.
The only items you use are labeled.

This is fantastic!! Bill, thanks for the post!

If I might ask - where did your pump leak? Mine just seems to squirt the valve cover somehow and leak onto the exhaust.

Thanks for the instructions, and especially the link to buy the parts. I really appreciate it! ;)

The pump itself did not leak... it was a "While I am in there thing". The kit was so cheap that I decided to rebuild the pump. The suggestion came from another RLstr.
Is your shaft seal and o-ring ok? Maybe it is coming from there (#6 and #5). I had a leak from around #6 and it ran down the inside of the belt housing onto the heat exchanger. Made a mess under my wheel well and on the inside of my wheel. The o-ring was hard a brittle too, so I would guess some was coming from there too.
It is not an extremely tough job to get the pwr steering pump off with the engine in... I had to replace the shaft seal again, b/c I messed it up when I put the pump back on while the engine was out. So , the 2nd time was with the engine in... not hard, just takes some patience.
If you need any help, PM me.
Bill

We also have a video of the install in our kbase.

http://www.rennbay.com/kbase/index.php?cmd=article&id=9

Great video, Travis! I am surprised how many people don't know this is rebuildable... I know several 964 guys that bought new pumps when they started leaking! Shame!

Ok, just did my pump a few minutes ago. I must say, anyone who rebuilds their engine or is in there to replace the camshaft seal and o-ring which is quite common, this is a "MUST DO while in there thing". It is such a pain in the arse to do this with the engine in place - and to think I've had my engine out three times in the past couple years... and this kit was $25 or so! Geez. 5 quarts of engine oil drained later (mostly on the floor), and power steering fluid filling my undertray, I was able to sucker that thing out of the corner of the engine bay. What a pain and what a mess! And it's just so easy with the engine out of the car!

Just a couple things I noticed - there are actually cast-in orientation marks on the pump body and nose cone, so there is no need to use a pen to make "match-up" marks. Also, your step #15, sentence #2 is crucial - that the snap ring has to pop into the slot. I didn't do this at first, and was wondering why, once the pump was reassembled, was so hard to turn by hand. Well, I read your post and realized I needed to pop it into the groove, and all is well now. Otherwise a no brainer. I had to watch Travis' video to confirm that the plastic piece that surrounds the rubber gasket does indeed face upwards since I didn't pay attention upon disassembly - seemed counter-intuitive.

Hopefully my engine is now leak free... thanks again for this great post!

Travis - Is the video still on your website? Link above doesn't work and I tried searching your site without success. I purchased your seal kit and am about to start on the pump rebuild.

Never mind, I found it on your instruction sheet with the seals. Doh! http://www.rennbay.com/pump.wmv

Travis,

Just got the kit today, preparing to put in after work. Great thread, glad I saw it while I had the engine out. Probably saved me a lot of trouble down the road.

Very interesting! Thanks for the post!

Has anyone had any problems with the vanes and rings? Are parts available and if so, why wouldn't you replace them while you're in there.

I grew up working in the oilfield using a machine my Dad invented to straighten pipe - tubing, casing and drillpipe, 1 1/2" - 12" diameter. The pump is almost identical in function and components to two hydraulic pumps my Dad incorporated into his machines.

I became proficient in rebulding these pumps in the field and always carried spare parts to the job sites.

The seal system in my Dad's pumps was different from our p. s. pumps and never failed. The wear items in them were the vanes in the slotted rotor and the oval shaped ring.

The vanes in my Dad's pumps were not symmetrical. The edge facing the ring was angled, and if I recall (38 years ago) the sharp edge faced the direction of rotation. So I was surprised when you said that if any fell out, to just put them back in with the shiny side out, without consideration for any angle on the edge of the vanes. My Dad's pumps would not develop adequate pressure if you mis-oriented the vanes. Also, when the edges wore down, the pump would not work. Maybe our p. s. pumps are not required to develop as much pressure as the hydraulic pumps I used, and there is no angle on the edge of the vanes?

The rings also wore out. You could tell a bad ring by running your finger around the oval shaped interior surface of the ring. You could feel irregular ridges in the surface which, I guess, caused the vanes to float between the ridges and lose pressure, as the fluid would escape past the vanes.

Wouldn't hurt to check both these components while you're in there.

Finally, + a big 1 on getting at that pump while the engine's out, I got the engine back in my car over the weekend, then tried to go back to resolve an issue that developed with the p. s. pump last night. I got so frustrated that I gave up after a while. Will make another go of it tonight. Dropping the engine a few inches helps.

Again, great post and Thanks!

The veins on these pumps have a rounded edge to the outside not a sharp angled one. Because of the variable assist (pressure / RPM controlled) in the steering systems, bypass on the rounded veins doesn't matter as much as in a closed loop hydraulic system like you are talking about. The sharp leading edge on the veins would give you much more consistent pressure (not needed here) but they would wear the pump and wear out themselves quickly as you experienced.
Having seen the insides of hundreds of these pumps, I have never come across one with worn veins. Most have bad low/high pressure seals (the funky looking ones) that let the fluid bypass and noticeably reduces steering assist. That and leaky case half seals that like to drip fluid everywhere.

Thanks for the explanation. Never too old to learn.........

Finished my rebuild today with the rennbay seal kit. Anybody know the torque on the 4 case bolts?

This is fantastic!! Bill, thanks for the post!

If I might ask - where did your pump leak? Mine just seems to squirt the valve cover somehow and leak onto the exhaust.

Thanks for the instructions, and especially the link to buy the parts. I really appreciate it!http://www.ardm.info/ht3.jpghttp://www.ardm.info/jh88.jpghttp://www.ardm.info/dh6.jpghttp://www.ardm.info/ht7.jpg

I torqued mine to 17 ft-lbs. I didn't know the official specs so I used the torque for a generic 8mm bolt. The pump has worked fine for 2 years without any leaks.

Thanks Rob. I arrived at around 18ft-lbs last night based upon the table here so your information confirms that.

Here a a couple of photos from my rebuild. 1st picture shows what is required when you pop the retention ring back onto the main shaft. It has to then recess into the counterbore on the piece the holds the vanes.

The main seal that needed replacing on my pump was the main shaft seal. It is beat to crap in the photo because I was trying to pull it out and destroyed all the rubber. It has an insert molded metal collar and the seal was an SOB to remove. In the youtube video it just seems to easily pop out. Not the case on mine. I actually put some penetrating oil on it and left it overnight then pried it loss with a screwdriver the next day after several tries. I was scared to damage the pump by applying too much force. I was just about to put it in the oven at 300F to loosen up the press fit when it finally popped free. You can see the new blue seal in the background that I then popped into place with a socket that fit perfect to tap it in gently back into the pump.

Great thread. Over $700 for a rebuild pump on Pelican with a core exchange. Or use this $20 seal kit and do it yourself.

Power Steering Pump Binding
 

I am having a problem with the pump shaft binding after the pump is reassembled.
I have had it apart numerous times, made sure the snap ring is seated properly, read WSYBERT's thread, watched the utube video of a 944 pump rebuild but as soon as I tighten down the 4 housing bolts the pump shaft binds.

What really dumb thing am I doing wrong?-it's not that hard

Maybe some of the veins are not in correctly, rounded side facing out?

I have attached a photo of the pump showing the veins. I have just been examining each vein under a magnifing glass and I cannot see the one side has a more rounded edge more so the the other side.
I can see that there is one way the veins do not go - the pump will not turn at all if they are insert the wrong way.
I am sure the answer is there and when I figure it out I will kick myself.
The colour on the veins is the flash from the camera and is not do=irt or contamination.
https://rennlist.com/forums/attachme...1&d=1346912139

Power Steering Pump
 

Could the be the answer?
I was looking at the photo that RicardoD posted above my last post - It looks like I may have the outer part of the pump in the wrong way.
Should the V mark be showing or not?

The v was showing on mine. But the hole wasn't, can you flip the ring over? Is their a v on the other side?

One thing to note is that there is lots of endfloat on the shaft and if you push it in i guess it may bind, does it bind if you pull the shaft out and turn it?

I'd love to help but have not suggestions to offer. My pump did turn freely by hand when I was done. I hope you resolve your problem soon.

What are the symptoms for determining if a rebuild is required? Is it just leaks?

There is only a" V" on one side. I am sure that when I disassembled it that the V was showing.

I have just pulled the pump apart for what seems like the hundredth time and completely reassembled it. The pump shaft was definitely binding on the end of the shaft. I pulled out the main seal and then gently reinserted it. It looks like that I may have pushed this seal in too far when i first installed it into the housing causing the top of the pump shaft to bind inside the pump.

It now is turning much more freely so will reinstall and hope for the best.

Thank you everyone for your suggestions.

Hey Travis,
Have you ever seen the problem shown below? Each time I replace the face seal it gets sucked into the vane energizing holes? What causes this?

Thanks!

https://cimg2.ibsrv.net/gimg/rennlis...452b879bfd.jpg

I rebuild another pump today from my C4. Great thread. Won't have it back in the car for a while so I hope everything went back together ok.

Just followed your instructions, worked like a charm, hardest part was getting the snap ring off.
Did it in 1h45min, pump out, changed all the gaskets, pump back in, that is with the engine in the car :D

I also did my steering rack, but my steering wheel is still much harder to turn than a C2? This is when standing still. I thought i had a worn pump seal or rack, but now all is rebuilt.
Using CHF 11S, would a different viscosity ATF? be better?
The one i used have a cst of 21.9, i see Dexron 3 is 44cst

Resurrecting an old thread.. I had this exact same problem today. Did you ever figure out what was wrong?

I am having the exact same issue with my 944. I reseated it twice (since I had no power steering) with it just being squished over the holes a little bit, but the third time it was completely sucked into the holes. I bought a new kit for a new gasket, but I don't want to ruin that one too. It looks fine when installed, then looks wadded up when pulled back out.

Just to update, I talked to Travis and he thinks it was the feed line collapsing and the increased pressure is sucking the seal into the holes. I replaced my feed line after reseating it the second time, but still no luck. Looking at the reservoir, I get no fluid flow with the car on. Best guess is after getting sucked into the hole multiple times, it weakened/ruined the seal. So hopefully with a new feed line and new seal, it will work.

The screen in the bottom of the reservoir can get plugged. I replaced my reservoir and normal flow returned. My pump was making some noise when cold, then I discovered the issue with the reservoir (screen) .

YMMV

Thanks for the write up and pics. Great info.

Whish I would have known this when I had my engine out for reseal.

I've had a leaky pump for a while now. I recently replaced all the tubes which seemed to help for a while, but now it's leaking worse than before. Say, it's almost using more power stearing fluid than fuel! So today I decided to have a go at rebuilding the pump.
However, as can be seen from the photo, I have encountered some difficulties. The lower left nut has rounded and the lower right bolt appears to have broken off. So i don't know how I'm going to get though this. Any suggestions are welcomed!

https://cimg1.ibsrv.net/gimg/rennlis...93385b4572.jpg

There are a few approaches for a rounded nut- chisel, cutting wheel, etc. There are specialty sockets for this that may be worth trying too. The broken stud will need drilled out (use a press or a guide to keep the bit from wandering into the soft aluminum threads). A left-handed drill bit, or an ez-out might be enough to remove the stud. It shouldn't have any torque on it or corrosion.

Related plug- I have my rebuilt pump in the classifieds. $150 including all of the mounts, brackets, pulleys, and related ancillaries- https://rennlist.com/forums/market/1110197 I didn't have any issues with the rubber seal mentioned above and I ran it for a few thousand miles.

Update: In the end I was able to get the broken bolt out from the back (actually front of car) using a ratchet. Theoretically there isn't enough space to take it out the back, but as it loosens the pump moves forward (that is towards the rear of the car)
Whereas, after trying many different methods, I was fortunately able to get the rounded nut off with a 1/2 socket.

My seals all appeared to be ok (but I replaced them anyway) so I guess my pump was leaking because the broken bolt wasn't keeping it all tight enough.

I dropped the rear nuts and a washer down into the belt area, after a couple of hours with a mirror and magnet I gave up trying to retrieve them, I guess they'll find their own way out.

The only thing of particular interest was that the shaft bore had 2 worn grooves on it. Has anybody elses had this? Should I source a spare pump for when this one will eventually wear out.

Cranked her up and all is well, a satisfying little project and another leak free 964 :bigbye:

https://cimg3.ibsrv.net/gimg/rennlis...c7d247c7b7.jpg