How To Diagnose and Repair Noises Coming From Your Imperial's Steering

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Question from Tony (1956):

I have a question. On my '56 Imperial whenever I am stopped and turning to back up or pull forward the power steering unit squeals like it is out of  fluid. It only does it then no other time. Now last year I had to remove the power steering unit to get the generator rebuilt. After I put the power steering unit on it started the squeal stated above. I did flush it out again, disconnect the hose and turn it over. I then put new fluid back in and it still did it. Any ideas?


From Roger:

Tighten the belts. If the pulley can be turned by hand and slips you have found your problem.

From Jim:

A hydraulic whine or groan would be the pump. A real squeal may just be a loose or oily belt or a glazed pulley. That's especially true if the squeal has a pulsating sound as in "chirp - chirp - chirp."

From Dick:

Check your belt tension - especially if your ammeter darts toward discharge when you hear the squeal!

Question from Tony (1956):

I am the one that had the whiny power steering unit on my '56 Imperial. I did purchase one off a fellow Imp owner and put it on and still had whine. I then put new hoses on, high pressure and return. I also purchased the > rubber piece that goes between the generator and the power steering unit and put it on. I also flushed out the power steering fluid and put in transmission fluid and it still whines when I turn. 

The only thing I could think is, that I put on another worn unit, or my first unit was good and I introduced a second unit that was worn. Does anyone have anymore ideas?


From Dick:

Most of the replacement pressure hoses omit the flow restriction orifice that is there to prevent noise from the pump, because the people making the hoses are not engineers and think it is there simply as a size reduction fitting.

If you have a replacement pressure hose that does not include this device, you will not be able to get rid of the noise without removing the belt from the pulley!

You need to obtain a correct original power steering pressure hose, even if it is no good, so you can retrieve the flow restriction orifice and have it used in making a correct new hose.

The flow restrictor is incorporated in the size reduction fitting. On the ones I took apart, the restrictive orifice was 0.070" diameter, but this was not for your model car, so I don't know that it would be the correct size for your car. However, you could start with that and see if it cures the noise without unduly slowing the assist function, then fine tune it from there.

If the hose you have is original to the car, and it has the reduction in size, located about 1 foot or so from the lower end, it is probably OK, as long as it does not leak.

If you are not sure it is the original hose, then we can only guess as to whether it is part of the problem you are having.

Of course there are other possible sources for power steering noise, but the fact that you had changed the hose triggered my previous response, as the usual result of doing that is to cause the whining noise from the pump.

I'm thinking you also replaced the pump, right? What is the condition of the replacement pump, if you know? This might come down to finding a similar car without the noise, then swapping parts until you discover the offender!

This is very likely an acoustic resonance problem, and sometimes seemingly obscure changes make a big difference - for instance on another (non Mopar) car I own, I discovered that I still had a moan from the power steering system after doing every thing I knew, and then found that looping the pressure hose in a full 360 loop (it was a little too long anyway) cured the noise! I'm not sure if the cure was because of the added loop in the hose, or because it moved a portion of the upper section of the hose away from a part of the body that it was touching previously. (Not that it matters, but this is on my 55 Hudson.)

From Denis:

All your belts must be the proper ones and at the proper tension or a whining noise can occur. Have you tried turning the steering while the car is not moving and listening under the hood for where the noise is coming from? It is unlikely to have 2 pumps with exactly the same noise problem.

From William:

On the more modern power steering pumps, the "orifice" is in a screw-in fitting near where the pressure line screws into it on the back of the pump. If the orifice is too large, it can cause an overboost situation where the wheel will turn if you breathe on it the wrong way. It's the size of the orifice that determines the amount of boost the system has. On the Saginaw pumps, there were basically two diameter orifices--one for cars and one for light trucks, with the cars having the larger/higher boost orifices, at least back in the 1960s, and the heavier cars probably having a slightly larger one than the lower level and lighter weight vehicles. Just a few thousanths of an inch difference in the hole diameter can make a bigger difference than you might suspect.

The distance of the orifice from the pump may well have something to do with reducing a harmonic caused by the fluid flow in the hose, so making sure all of the dimensions are "dead on" from the production hose is important.

Question from Tony (1961):

I have a persistent buzz from the steering on my '61 LeBaron. I was convinced the problem was in my p/s pump, but having replaced it, the noise is still there. Now I am no longer sure. When I try to locate the sound in the engine bay it is difficult to pinpoint but it is definitely much more audible in the driving compartment. The sound is most noticeable when the wheel is being turned but you can hear it to a lesser extent all the time. It also increases in pitch and volume as the revs increase. Despite the noise, the power steering works perfectly well even at a standstill. Does anyone have any ideas? I would like to drive my Imp in the silent splendor it was designed for.


From Dick:

Very likely the pressure hose from the pump to the steering box has been replaced with a hose which does not have a noise suppression orifice in it. Many cars have a special fitting on the hose about 8 inches back from where it terminates on the steering box which contains a restrictive orifice of about 0.070" to stop an acoustic noise which resonates under the hood when the pump is working hard. If you can locate an original hose to borrow, try just switching hoses to see if this eliminates the noise. I'm betting it will. Then, you know what to look for, and possibly you will need to find an NOS hose, unless a high quality aftermarket hose is still available. I have been through this exact scenario with 3 of my cars, and each time I lucked out and found a good original hose to bail me out. The noise is very noticeable on Packards especially.

From Hubert:

I had a similar buzz on my '55 DeSoto. I didn't know really what was the problem, but I solve it when I changed both hoses (pressure and return). I expect that the old pressure hose was too thin, so the pressure was too high, making a 'resonating' noise. (Are you sure that your pressure hose has the right diameter ? ) Another idea is that the pressure hose was getting blocked with something like old filter paper, because when I bought the car, the filter in the power steering oil tank was partially destroy.

From Ron:

Does the sound change when you turn the steering wheel? The noise may be in the steering box and is telegraphed up the steering column. You can always remove all drive belts and start the noise? Install 1 belt and noise? Install the next noise? Install the next belt and so on. This is the best way to isolate accessory noises from engine noises.

Follow-up question from Tony:

I have examined the power steering pressure hose and there is a metal reduction union about half way along. Could this be the noise suppression device you mentioned? If so, can they fail? Unfortunately, finding a spare hose to test the system is a remote possibility in this part of the world. For what it's worth, when I bought the car about 4 months ago, it had only done about 80 miles in the previous 5 years. I was wondering if the long period of inactivity might have caused the seals to deteriorate in the steering box, although I would have expected that to be accompanied by faulty p/s operation.

Reply from Dick:

Yes, this is where the noise reduction orifice is located. I don't think it could be worn out, but it is possible that your hose has been replaced with one from a different application. I guess without any access to another hose, you are probably going to have to live with the problem until something else happens to tell you what is in trouble. I think since your power steering is working fine, and assuming you are using the correct fluid (Dexron III, currently, NOT "power steering fluid" unless it is specially labled for older cars), there is not much else in the way of possibilities for the noise source. If the pump has ingested air during its long time out of use, it might just improve with use as the air is slowly worked out of the system. Be sure not to let the fluid get below the correct level in the reservoir, and just drive it.

Question from Dieter (1955):

My steering is very smooth but it makes, what I call, a groaning noise.  On every turn --  makes no difference left or right she complains until she is put in a straight direction. Then every sound disappears and all is quiet just like new. My power steering pump is connected to the other end of the generator and the reservoir is as full as can be. Can't put too much more in there because fluid will escape through a small breather hole on top of the lid. Any one got any ideas how I can correct this annoying moaning/groaning noise?


From Dick:

I have a couple of ideas: In no particular order - -

Possibly there is air in the system. Have you turned the steering wheel to both stops a couple of times? If that doesn't help, I think you have pump a problem.

If there is a filter in your fluid reservoir, try removing it to see if it maybe is restricting the flow of oil into the pump.

If that doesn't do it, make very sure the mechanical setup is OK. I'd listen to the various bearings in the generator and power steering pump to make sure where the source of noise is. Perhaps when there is a load on the pump, the generator bearing begins to make noise.

If you eliminate all those problems, and the noise appears to emanate from the high pressure hose outlet from the pump, your pressure relief valve is chattering, and you could try cleaning it carefully, or replacing it with a spare if you have one.

Another thought, and probably the most likely one to pursue: I have to ask, have you replaced the pressure line on this car? If you have, I'll bet you a dollar that the new line doesn't have the restrictive orifice in the hose, about a foot from the steering control valve, that the original hose had. Try reinstalling the original hose - my guess is your noise will miraculously vanish.

From Norm:

I would add one more test: with the car on a lift (frame type) I would turn the wheels through the full range of motion left to right, etc. If the same "moan" presents itself, you may have a bearing or bushing problem, not an hydraulic one.

Follow-up question from Dieter:

I can' t tell if I have the original or a replacement pressure line.  I left everything the way it came from the prior owner and bought the car with the noise. 

Reply from Dick:

OK,  to identify a replacement line without the restrictive orifice, inspect the pressure hose about 1 foot back from where it connects to the steering control valve. If it has a metal fitting there, and a decrease in line diameter, it probably has the orifice (but we don't know if it's the right size). If it is a plain rubber jacket all the way from the pump to the control valve, you know for sure that it does not have the restriction. Many aftermarket hoses omitted that nicety, and the result is always a noisy power steering pump.

Question from Rob (1981-1983):

My '83 just developed a clicking in the steering column area, sounds like the blinkers only random. Any ideas what this could be? Also the headlight covers won't go back down, it made a noise for a week & that was it. Any ideas would be appreciated

Reply from Ed:

It sounds like your headlight door relay was clicking on and off, probably due to an overload on the doors motor. Have you checked the doors for freedom of movement? A few years ago, I was staying with friends, and when I parked my '81 in their garage with my headlights on, a tennis ball hanging from the ceiling (used as a parking guide for their cars) got caught in one of the headlight doors when it closed, unbeknownst to me. In the morning, when I was driving to work, with the headlights off, I could hear that same clicking. It was the sound of the relay popping as the doors kept trying to close but could not due to tennis ball! Finally the ball got THROWN free, and everything went back to normal! It sure sounds like you have a similar problem, although it's not likely to be a tennis ball!

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