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Power Steering pump rebuild DIY

 
Old 04-03-2008, 01:19 AM
  #1  
wsybert
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Default 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)


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
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Old 04-03-2008, 09:46 AM
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Thanks for the writeup and photos!!
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Old 04-03-2008, 11:51 AM
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Post that '964 DIY', boy! -- Post it!
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Old 04-03-2008, 12:55 PM
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FYI.
Here is a pic of the seal kit.
The only items you use are labeled.
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Old 08-27-2008, 12:20 AM
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garrett376
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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!
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Old 08-27-2008, 01:30 AM
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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.
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Old 08-27-2008, 11:43 AM
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We also have a video of the install in our kbase.

http://www.rennbay.com/kbase/index.php?cmd=article&id=9
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Old 08-27-2008, 12:09 PM
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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!
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Old 09-04-2008, 02:18 AM
  #9  
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Originally Posted by wsybert View Post
... it was a "While I am in there thing".
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 **** 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!
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Old 01-30-2010, 11:50 AM
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Originally Posted by Travis - sflraver View Post
We also have a video of the install in our kbase.

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

Last edited by Rocket Rob; 01-30-2010 at 02:06 PM.
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Old 02-02-2010, 03:52 PM
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Old 02-04-2010, 10:03 AM
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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.
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Old 02-04-2010, 03:37 PM
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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!
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Old 02-08-2010, 01:35 AM
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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.
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Old 02-08-2010, 06:37 PM
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Originally Posted by Travis - sflraver View Post
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.........
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