Car power steering pump leaks

Addressed to auto mechanics and fellow DIY guys:

My Mazda '97 323 developed a leak in the power steering pump.

Where do you think the leak is most likely to be located:

  1. At the opening on which the rotating shaft rests?

  2. At the pump junction of the input hose?

  3. At the pump junction of the output hose, that goes to the steering gear?

  4. At the edge of the pump halves(?) bolted together?

I bought a repair kit for this pump, it is a collection of rubber O-rings. To be certain, I am thinking of dismantling the whole pump and replacing all the parts corresponding to the repair kit parts; but this approach would take too much time and trouble.

Any suggestions and tips?

Thanks and God bless you.

Susma Rio Sep

PS Pardon the possibly deficient technical vocabulary, but I guess you get the picture.

First suspects would be the hose fittings, followed by the shaft seal.

I saw a lot of leaky shaft seals on the hundred of cores brought back when I worked at the parts store.

Power steering fluid contains flourescents and this makes finding leaks easy. Get yourself a hand held black light, start up the car and have someone turn the wheel back and forth. At full left or right is when your pump will be at maximum pressure and this is where leaks will show up.

Power steering pumps require specialized tools to repair. Unless you have some, you would be much better off buying a rebuilt unit for your vehicle.

And as a temporary possible fix, you can buy power steering fluid with an additive that makes the seals swell up and, at least temporarily, reseal.

It strikes me as a poor approach to try to figure out the most likely leak point from others’ experience when it’s relatively easy to actually find the particular leak on this car.

Thoroughly clean the pump and connected parts of all the oil (power steering fluid) that is on them. Aerosol brake cleaner, available at auto parts stores, should work nicely for this. With the pump clean and dry, start the engine and watch carefully to see where the leak point is. Remember you need to catch it when it starts to leak–once the oil spreads around and gets everything oily it’s hard to tell exactly where it leaked from.

If you don’t see any leakage within a minute, turn the steering wheel briefly (engine running) to pressurize part of the system and reinspect.

I wouldn’t disassemble the pump unless I were absolutely sure it was needed and I had the tools and expertise to do it properly.

The most common leakage point on power steering pumps is the shaft seal.

Thanks, guys. And God bless you.

I guess the shaft seal is the #1 suspect. Removing the cover through which the shaft protrudes to the outside might be within the capability of a DIY owner like the undersigned. Otherwise, getting a rebuilt unit on a possibly trade-in deal might be a more feasible and economical alternative.

Susma Rio Sep

Racer says:

"Power steering pumps require specialized tools to repair. Unless you have some, you would be much better off buying a rebuilt unit for your vehicle."

Racer, please tell me, if I may impose on your goodness, what are the specialized tools used for in the repair of the power steering pump, what are they supposed to be used for.

My parts store told me that pump repair of leaks usually involves changing rubber seals, and all of them are in the repair kit I bought.

Are the specialized tools you know about intended to get something done easier and in less time, or are they such as without them one patient and averagely intelligent and resrouceful guy can’t do the repair himself?

I have removed and dismantled a transmission housing and disassembled all its gears and other parts – all by my lone self, just for the curiosity, but really in order to replace the main shaft seal to stop leakage – all without any special tools, but two alligator lifts of the two tons household capacity. Do you think I can manage a power steering pump without specialized tools?

Thanks for your information, and all other guys here.

Susma Rio Sep

What they did not tell you is that to replace those seal that you bought you will have to have some flare nut wrenches to remove the threaded lines (or run the risk of ruining them and the pump), hand tools to remove the pump from the car, and at least one puller, or impact wrench to remove the pulley off the pump.
Then depending on the construction of the pump you may need another puller to disassemble the pump.

Then you can replace the seals and re-assemble.

If I were you I would pony up for a rebuilt. Then all you have to do is to remove and replace the old pump.
If you do the work and the pump still leaks afterward, you are screwed. If you buy a rebuilt and you have a problem, you get another under the warrenty.

I knew someone that rebuilt PS pumps and he had a lot of tools I don’t have, and I have enough tools to fill 3 roll-a-way/chest combos. You would require a fork type puller to remove the pulley. A standard gear puller that grabs the outside of the pulley will not work, it will bend the pulley before removing it. You may also require a set of bushing drivers and feeler gauges. And you will need at least a 2 ton press to reinstall the pulley. You will not be able to hammer it back on without damaging the pump. You will also need the press to R&R any bearings.

And don’t forget the shadetree mechanic’s rule, if Chilton’s or Hayne’s don’t show you how to do it, don’t. I have a Haynes that covers your car and it does not show how to rebuild a power steering pump, just how to R&R it. I have been working on cars since I was a wee lad and I have never rebuilt a power steering pump. It is something I leave to the experts.

Oh, I would also like to add that the guys in the parts store get paid to sell auto parts, not fix things. Of course they are going to tell you that you can fix the pump. They would try to sell you a muffler bearing if you thought you needed one. There is a reason they stand behind a counter retrieving parts for customers instead of making lots more money working on cars.

**They would make a lot more money selling a new pump rather than the rebuild kit. So what’s your reasoning?

And that reason is?

Almost certainly the pulley is held on with a nut, rather than pressed on as with most domestic models. The shaft seal can be replaced by removing the pulley, then prying out the seal, and pressing or driving in the new one. This has to be done very carefully–if the shaft gets nicked, it will likely leak even with a new seal, probably worse than before. If the new seal is distorted during installation, it may well leak. It’s not hard so much as tricky. If there’s enough room to work, it may be possible to do it without removing the pump from the engine.

My Mitchell’s manuals, written for professionals, don’t have any info on Mazda power steering pumps. I wouldn’t even attempt to disassemble one, because I have no way of knowing if there is a need for special tools or if there are critical specifications that must be seen to. It may be easy, or it may quite complicated, but without knowing one way or the other it’s big gamble to tear into it.

Find the leak. If it’s the shaft seal, you can probably replace it successfully. If it’s in the body of the pump, my counsel is to get a rebuilt pump.

Thanks to all you guys and God bless you. Special regards to Racer for his patience.

I just put in some time every now and then to work on the pump. So far I am at the stage of removing it from the engine block. The anchoring attachment of the pump is also in charge of tensioning the belt driving itself and the aircon compressor, powered by the engine shaft. Pardon the deficient technological language.

I usually work up to the point when I calculate that it woud be on diminishing returns should I continue on; at which I point I put back everything and drive the vehicle however limping to the experts. So far I have not had to call in a tow truck.

The way I look at this peculiar model of a power steering pump – and it is a first time, like several of my jobs, it does not seem to look formidable. The cover of the pump is not at the front where the pulley is situated, but at the back secured by four bolts. It’s really enticing to get this pump off the engine block and have a good look at it, and open up the back cover to penetrate into its innards – but not necessarily to disturb these innards. That should be fun. Anyway I still have the use of two other working low budget low profile cars.

Sometimes when I could not or would not do a procedure for its being to difficult or beyond my modest arsenal of tools and I.Q., I would proceed to a good shop with the gadget or assembly and beg on my knees the guys there to help, for a consideration of course, but sometimes free for the camaderie from their part.

Again, thanks to all you guys, and specially to Racer.

Susma Rio Sep

I have just removed the power steering pump from the engine block.

It took me four sessions of work, each lasting maybe around two hours of after office evening. Well, it was challenging and fun; though I wished those design engineers, sons of their mothers and God love them, would just have the common sense to put the contraption on the engine block in such a way and manner and in a position; so that guys like me could remove them easily and quickly.

Now I think I can put it back on the engine block in twenty minutes at most, having mastered the knowledge and the maneuvers of its removal.

This Mazda '97 323 power steering pump (KYE 7607 9-2) is no bigger than the typical size of an adult pig’s heart. Go to the meat shop and look up a pig’s heart.

It does not look so formidable. There is the input opening and the output opening, and a protruding shaft ending in a pulley wheel. Now, the cover of the pump is at the other end of the shaft, and secured to the housing of the pump by four bolts. Pardon the non-technological vocabulary, I just employ whatever words I can command.

My suspicion is that the leak must be occurring at the input opening which is sealed against leakage with a rubber O-ring, kept in place by a tubular plastic attachment, the ending to the input rubber hose coming from the fluid reservoir. This spot seems to me the most leak-prone of the pump. The whole attachment to this input opening is secured by one small bolt on the side fastened into the housing of the pump. What do you think? I will try changing this rubber O-ring and return the pump back to the engine block – then observe as I put the car back on duty.

Racer says:

I hope Racer you don’t get annoyed, but do you think I can get a hand held black light in the average hardware/electrical shop? I am really an ignoramus here; but a flashlight that emits a beam of black light, wouldn’t blocking light from getting to the spot in question be the same?

I am not inclined to suspect leakage from the opening on which the shaft rotates, because the rubber sealing ring there usually lasts years and years, as witness the similar sealing ring at the end of the big main driving shaft of the engine. But one can never tell.

I once changed that one also, in a car which had been going on for some fifteen years when a leak developed there – believe me. You can change that seal ring from the outside world, without opening up any part of the engine block.

But that is the suspicion of most you guys here in regard to power steering pumps; and you are most probably right. I will take a gamble just the same, a luxury of my stubbornness, and laziness.

Back to the power steering pump, what about the output opening? It is sealed with two copper rings, one on each side-end of a hollow bolt that serves as the conduit connecting to the rubber hose, for the pressurized fluid to rush to the steering gear below linking the front wheels. Leak proof condition can always be obtained and secured by a good tightening of this conduit-bolt(?).

I don’t think I will open up the pump and have the luxury of looking inside, to satisfy my peeping curiosity. I will just presume that the leak does not happen at the seam between the housing and the cover, because it’s quite well secured with four bolts. What do you guys think? Besides, the pump is working right, otherwise.

Well, guys here, do you have further suggestions and tips…? I really appreciate your time and trouble to share with me your knowledge and experience. God bless you.

Susma Rio Sep

PS: Pardon me also, you guys here, but I am just one son of my mother who have this itch of always trying to patch up things myself, instead of buying a rebuilt substitute. If you have this kind of an itch, you will understand.

So, I have removed the power steering pump from the engine block and have dismantled all the parts except one assembly, which I think does not have any part to change inside. It has not been a very tough job, requiring special tools and special knowledge. I guess this model is not the types that sons of their mothers engineers designed to be terribly difficult to disassemble, requiring special tools and special knowledge.

My repair kit consists of nine rubber O-ring seals and one steel wire ring clip. I can see that only eight seals are found in the pump, so only eight of the repair kit seals will be used. I called up my supplier, asking him to look up his books of parts and diagrams. And he told that only eight seals appear to be present and thus should need changing, all to play safe. What of the extra one which I can’t and he can’t account for? So we agreed that maybe the pump in question can take either of two seals depending upon the manufacture batches for which the kit supplier therefore put one of each size.

I will report back when I have re-installed everything back and tried it. If it still leaks, then it’s all my fault; and I will just have to get a rebuilt unit, and hope that I can trade in the failing one.

Susma Rio Sep

My car is a Mazda 323 Familia 1997.

The power steering pump is easy to rebuild to fix leaks. You don’t need special tools and special knowledge.

Buy a repair kit which consists of O-ring rubber seal replacements. Tie with a piece of colored strand all the old seals to be replaced, to know which are the old ones which the new ones. If you get them mixed up, then you will have a hell of a time figuring out which are the old ones which the new.

Also take careful notes and diagrams as you work to record which parts are assembled where and how; then you will know where to return them properly.

There is no need whatever to use a puller to remove the pulley wheel or any stuck gears in the pump shaft; because nothing has to be pulled off or apart with a puller. But take care not to leave any nicks on any smooth shiny surface, specially the shaft being held by the main seal.

If anyone need more help, write me at my email address:
Susma Rio Sep

PS After rebuilding and remounting, there was no leak anymore but there was no power steering either. I had to take off the pump again and dismantle it again to a good extent.

I found the trouble, a mistake I made in putting back together the pump: placing the spring of the relief valve at the back instead of at the front of the valve assembly. Placing the spring at the front of the valve assembly keeps the relief valve open permanently; the correct location is at the back, so that when pressure is excessive, the pressure pushes the valve piston backward against the force of the spring, opening up the relief aperture.

Well, there is one analogy I thought I’d never see.

Glad you got it working.

Here I am again, for all you guys who might derive some use from my experience.

After some days of duty with my Mazda, what did I see but leaks again!

Upon very careful examination, the leaks come from the linkage between the banjo connection from the pump output joining it to first segment of the high pressure rubber hose.

Solution: replace the hose segment leaking at the coupling point.

Go to the yellow pages and look up hose suppliers and service, specifically those doing hydraulic systems. You can even see some shops with the list of service including power steering trouble-shooting, crimping service.

Canvas for the best and the thriftiest shop, and the most honest.

I found one who changed the leaking hose segment, parts and service, for only some 10 dollars. No need to change the other segment. A dishonest(?) operator will insist that both hose segments must be changed, charging you more than double (this guy wanted to do it this way for 30 dollars plus).

How to remove the high pressure hose assembly, use your mechanic intelligence. If you need help, email me at

Susma Rio Sep