After 22 years, the short hose between the power steering fluid reservoir and the PS pump had turned into hard plastic and began leaking. I replaced it, but in the process lost the fluid in the reservoir and got air in the pump. I followed the directions on page N-6 of the workshop manual, but even so, the PS pump still makes horrible noises when turning the wheel. Is that just air in the pump? And why has the level of fluid in the reservoir increased from when I refilled it before running the N-6 procedure? I put it exactly at the maximum line, but even after most of the foam has disappeared in the reservoir, the level is about 1/2 inch above max. Is that from air in the system?

Is there any way to completely get rid of all air beyond the manual procedure, which doesn't completely work?

Thanks for reading!

 

The process on page N-6 is very typical. That is the correct way to bleed the air from the system. There very well could still be air in the system. When bleeding the power steering pump with the engine off, the pump will not draw air into the chamber. Cycling the steering wheel left and right with the engine off will settle the fluid in the rack and thats about it. Once your level is stablized with the engine off, running the engine will begin bleeding the pump. It may take several turns before all the air is bled out.

On another note, did you get an OEM piece for that tiny hose or did you use something aftermarket?

Matt

 

I replaced the hose on my PS pump with a hose from a local hydraulic supply store.

Yeah, you will need to go lock to lock with the engine running to get all the air out.

Dale

 

Subscribing for any updates...my hose is sketchy too.

 

loop line, or pull rack and delete. car is so easy to steer without P/S and feels so much tighter / road feel

 

Thanks for all your comments.

I did follow all the steps, including running the engine and turning the wheel from lock to lock. I also was careful not to leave the wheel in the fully right or left positions for more than 5 seconds. I probably made a dozen or so lock-to-lock turns with the engine running, but still there seems to be air in the system. Can air get "stuck" in the pump and not cycle back into the reservoir to be bubbled out?

 

No improvement after repeating the lock-to-lock turning with engine running (about a dozen more times). Also, the power steering pump sounds like it suddenly has bad bearings. Level in reservoir is now down to about the MAX level, where I put it when I refilled it before trying to remove air. But things are still noisy, especially when turning wheel while driving. Any further advice?

 

Very strange. Could be the wrong type of PS fluid?

Dale

 

Are there different types? I used Chalet Premium Power Steering Fluid from O'Reilly. I also have STP fluid but didn't need to tap that (yet). There are no specs on either of those products such as ASTM numbers, etc. Have I goofed? What is recommended here on the forum?

 

Supposed to use dexron II ATF (automatic transmission fluid) :P





Matt

 

Yep, I didn't do that, unfortunately. On Monday we will go to the Mazda dealership and have them purge the P/S system and refill it with the proper stuff. Hopefully no damage has been done to the P/S pump and the noise is due to trapped air.

(Interestingly, the text on the back of the Chalet Power Steering Fluid bottle states not to use ATF or any other lubricant in the P/S system due to it causing deterioration of the rubber parts in the P/S system.)

 

Depends if the system is rated for it or not. ATF can eat hoses and seals if they're not compatible.

Matt

 

ive always used whatever was available and havent had any problems with my or any other fd. you definitely have a strange problem. the hose you replaced was an OEM hose? what did you remove to replace it? exactly what you did to bleed your system is what i did/do to bleed mine and it works out for me. you have something fishy going on and im willing to bet it isnt the fluid.

 

Yes, we are the original owners and that hose between the power steering fluid reservoir and the metal tubing that goes to the P/S pump was the original OEM hose. It never leaked before. To remove it, I unscrewed the metal tube section (with the O-ring) from the pump casing, and then after loosening the clamps on the hose, pulled the hose off the reservoir plastic tube. (Nothing was damaged in the process, although all the fluid in the reservoir poured onto our garage floor and had to be cleaned up with kitty litter.)

After replacing the hose and reinstalling it, there have been no leaks anywhere that I can see. I filled the reservoir to the "MAX" line and then did both of the procedures listed in section N-6 of the Workshop manual. There were a lot of protesting noises when the engine was running and I was turning the wheel back & forth; these noises continued later, when driving around corners, and even when going straight noise from the pump sounded like bearings (which never happened before).

Over time, the noises have lessened somewhat, and though the level of fluid in the reservoir had risen above MAX, it is now down to the MAX line again, but the noises are still there.

 

Since that is a low pressure line, it could be sucking in air. I'm really just guessing at this point. Make sure all the fittings are secure and tight.

Dale

 

Apologies to wstrohm for a related dumb question....but since you're going to have it professionally flushed I figured I'd ask in this thread...
Rather than risk trouble bleeding the system after draining it completely, is there any reason I couldn't just syphon the reservoir, and refill a few times to eventually replace all the old fluid? I have a long syphon I've fashioned out of a large medical irrigation syringe that works pretty good for such things. At least it works well for the shifter reservoir. Dextron II isn't expensive. and given the dark color of the crap that's in there, it shouldn't be a problem knowing when it's essentially been changed with clean.

 

@Dale Clark,
I was pretty careful to make sure the new hose was tight and well clamped with the original clamps. I guess it's still possible, though. (The car is now at the Mazda dealership.)

@Sgtblue,
Great idea; that way no air can get in. Unfortunately for me, the hose at the bottom of the reservoir was the source of the leak problem, so I had no choice but to remove and replace it. Be sure to stop the syphon before the fluid drops to the exit tube at the bottom of the reservoir!

 

Mazda dealership was unable to fix the noise problem. They replaced the O-ring at the vacuum port, and said it was (probably) leaking air into the pump. They also replaced the fluid I had used (Chalet power steering fluid) with Dexron. But that didn't get rid of the noise. We took the car back after paying the $120 diagnostic fee, and will try just running the car awhile to see if the noise lessens over time. Wife is not happy.

The power steering pump is no longer available and would have to be replaced by an aftermarket pump (about $1300).

(I am considering working on the pump myself in the future, if things don't quiet down soon.)

 

I don't know why you would even consider an aftermarket pump and that much cash when you can pick a good used pump from the classifieds easily for a fraction of that ridiculous 1300 number

 

And RockAuto.com has a dirt cheap 64$ remanufactured bare pump, that you swap all your brackets and reservoir over to.

 

I don't think the pump is bad; could be wrong, but I think the problem is air in the system that won't come out. I have a couple of ideas to see if that's true, but for the near future we will just drive the car. I appreciate your inputs, though. Thanks for reading!

 

Hopefully driving it will help purge the rest of the way. So in the meantime you can try this if you want. Remove the little strainer from the reservoir fill neck and put the cap back on. Start the engine and turn the wheel lock to lock a couple times. Open the cap and see if the fluid is foamy or filled with small bubbles. If it is, then you may be still sucking air between the reservoir and pump inlet. Check the little hose and double check the o-ring didn't get pinched or cut and that it's the correct ring and not some generic ring that the dealership tech grabbed from somewhere.
If the fluid is clear and no bubbles then the pump may actually have bit the dust.
Unfortunately I have seen it happen right in front of me.... Another tech at work was replacing a high pressure line and a PS fluid cooler line so a lot was drained out. After filling with fluid and trying to purge, the pump would never stop whining, loud. This was on a Nissan of some type. We were joking that he killed the pump but he didn't really do anything out of the ordinary.... It just decided to kill itself

 

I've done this on many cars including my old E39 M5 and my FD RX7 and it was well worth it. No issues and no air enters the system, so its an easy and effective way to change out a lot of fluid.
I used a large 5 inch long by 2 inch round syringe that I found at a hardware store, which made it a lot easier.
I added a neodymium magnet into the reservoir, attached to a length of stainless wire afterwards, so any ferrous wear particles are pulled out of the power steering fluid and held on the magnet- I check it every so often and it is catching sludge and holding it out of the fluid. This may or may not prolong the life of the pump and rack.

As for deleting the power steering and looping the lines... I've never understood why anyone would do that. I've driven one FD with looped power steering lines and the increased effort felt terrible to me, and I felt I couldn't drive that car as fast, as it was too much of a headache, and in carparks with wide tires... It made the car feel like a 'lump' while minivans and SUVs were able to deftly steer around me with ease, which was a bit embarrassing...

 

@Andre the Giant,
I have done what you suggested; initially there was foam, but after several "idling-engine" windings of the steering wheel lock-to-lock, the foam gradually disappeared. Unfortunately the pump noise and weird sounds from the P/S system never went away. That's why I took the car to the Mazda dealer. I had not been able to replace the O-ring at the "vacuum" input since I could not find a suitable size replacement, and the Mazda dealer said the O-ring was sucking air, so they replaced it. The '94 parts catalog does not list O-ring part numbers for that P/S pump, and I don't know what the dealer used. I may be seeing what you also saw on that Nissan, but hope not.

@SA3R,
Since Mazda also replaced the fluid I had used after my hose replacement, it is clear (was before, too) and I have never seen any sludge in the reservoir.

I am going to remove the high-pressure hose connector, since it sits atop the pump at a higher level than the fluid in the reservoir, and see if there is any air pocket there. If the fluid is right at the connector, I will just reinstall it. If there is air, I will use a turkey baster and fill to the connector. There is a "control valve" below the connector that may interfere with my test, but I will deal with that when I get to it. I am also thinking of loosening the drive belt so that I can manually turn the pump shaft slowly both forward and backward to (maybe) let air come up to the connector so that I can purge it. Any comments on that proposed procedure?

Thanks again for your help; I do appreciate it!

 

Don't take this as negative criticism, but you'd be more likely to get an improvement by just driving it around. Opening the system back up is only going to re-introduce air back in.
The pump is either making noise because:
A- the fluid has microscopic air bubbles in suspension which you would have been able to see or
B- the pump is physically making the noise due to some type of damage to the vanes or rotor or internal surface


It's a mystery how the damage could have been caused but it's possible that combination of wrong fluid, run partially "dry" while bleeding, etc maybe caused it.
Never did figure out why it happened to the car at my shop. Had to send the pump back for core right away so we didn't get to take it apart.