How To Diagnose Problems with Your Imperial's Power Steering Fluid

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Question from Olin (1955):

I have a slight power steering leak on my 1955. I have done the brake fluid thing on another car and it worked well. In reading in the manual (when all else fails, read directions) it says this car should have ATF Type A which I'm told is no longer available. What should I be using?

Reply from Bill:

I think that is what it says for our transmission too, I "assumed" that ATF-3 is ok, that is what I have been adding.

Question (1966):

My '66 convertible is leaking power steering fluid at a fast rate......what would the first logical steps be for a non mechanic?


From Dick:

Step one: determine the source of leakage. You have 6 choices, in order of likelihood:

#1. fluid reservoir - Feel under the metal can into which you pour fluid to replenish it - if you feel wetness at the raised edge of the reservoir right behind the pulley, you need to replace the "O" ring which seals the reservoir to the pump casting. This is very easy to do but you must remove and disassemble the pump to do it, so if that sort of thing isn't your bag, take it to your mechanic. The "O" ring costs a few cents, but he will probably charge you around $150 labor.

#s 2 through 5 - . Hoses - you have two hoses, and each one has two ends. Inspect and feel around each end of each hose.

#2. Most likely culprit is the return hose at the pump end - this is the end with the strap type clamp on it, right on the small pipe attached to the reservoir (the metal can thingy to which the cap is mounted). This hose is cheap and easily replaced, however when you remove it you will lose most of the fluid from the system, so be prepared for a mess, or else suction the fluid out of the reservoir first.

#3. Next most likely place is the other end of this same hose - it is connected to the smaller of the two connections on the steering box (the dirty cast iron thingy at the lower end of the steering column). Again, this hose is cheap and easily replaced. - just take the old one into your NAPA store and have them make a new one for you.

#4 and #5 are the other hose, the pressure hose. This is the one that is bolted to the pump, not held with a strap clamp, and its other end goes to the larger of the two connections on the steering box. This hose is not cheap, and will have to be special ordered, most likely, although I found that Carquest stores keep one in stock. This is also easy to change, but you need to have some experience with compression fittings, and I'd advise you to take it to a shop if you are not comfortable with this type of thing.

#6. The steering box itself may be leaking - this is not a job for the faint of heart - this is a complicated mechanism which is directly related to your safety, I strongly recommend you let a pro take care of this problem. You can have the steering box rebuilt by NAPA or probably other auto parts stores.

If you feel there is any danger at all of fluid getting on the exhaust system of the car, do NOT drive it until the leak is cured (danger of
serious fire!), or until you take the belt off the pump and drain the reservoir to prevent fluid from hitting the engine. You can then drive the car, but it will steer VERY hard, so be prepared. You can cut the belt to remove it, as you will no doubt be replacing it anyway. Save the old belt for a size sample. It will not hurt the car to drive it without power steering, as on your year car, that belt does not power anything else.

From Rodger:

For the dumb non-mechanic they use some oatmeal to soak up the extra fluid that is leaking out. Or they can go to NAPA for a ring/seal kit. With the kit in the hand ask a friend for the all American tool kit ( aka 5/8, 9/16,
1/2 and a 7/16 wrench ). Take a couple of holding bolts off and the hoses too. Take the pump apart so that you make exchange old stuff for the new NAPA stuff.

Question from Brad (1966):

For 1966, did the power steering system use power steering fluid or transmission fluid? My LeBaron has tranny fluid in it and I'm thinking that may be why it leaks. I know my '63 Caddy used tranny fluid, but I'm not sure on the Imperial.  Either/or. Doesn't really matter. They're compatible and mixable, and the seals and rubber parts aren't damaged by either one or the other.


From Mark:

 It probably leaks only 'cuz it's old....

From PEN:

I have to respectfully disagree with Mark. On your '66, use Chrysler type power steering fluid, indicated on the bottle for that application, only in your power steering. Never put transmission fluid in your power steering. The reason is that transmission fluid will cause the system to overheat, cook the neoprene o-rings thus leading to leaks, and cause the power steering pump to wear out prematurely due to abnormal heat expansion of the moving parts. Power steering fluid, on the other hand, is designed to absorb and carry less heat, thus protecting those parts in systems that were designed for that product. Earlier Chrysler systems, such as in my '55 Imperial, and in other makes such as my '70 Ford Pickup, require transmission fluid in the power steering. They were designed for its use, but your car was not. These fluids are not interchangeable.

From Peter:

It has long been my understanding that, while many people claim ATF is appropriate for use in the power steering system, it is not meant to be there.  While both fluids are mineral oil based, the additives (anti-foaming agents,  anti-oxidants, swell agents, etc.) really make a difference. Topping off a low PS system with ATF won't hurt, but at some point the concentration of PS fluid will drop too low (if you keep topping off). The box in my 70 was seeping at the input shaft and pitman arm. After flushing the system and filling it with power steering fluid, the leaks stopped. BTW, the shop manual for my 65 Monaco calls for #2084329 power steering fluid.

I've been using Valvoline Synpower synthetic power steering fluid. It came recommended by AGR who made the high performance box and pump for my 4x4. It seems to have cut the heat and foaming way down.

From Rick:

My Imperial service manual indicates "to restore level, if necessary, add sufficient hydraulic fluid specially formulated for minimum effect on rubber hoses. Such a fluid is available under PART NUMBER 2084329, Power Steering Fluid".... note: rubber hoses have gotten better over the years and yes some folks still use tranny fluid but I've found the hydraulic fluid I needed when I was faced with rebuilding my power steering box...ironically someone had filled the reservoir with what looked to be tranny fluid...that and diminished maintenance contributed to its demise.

Question from Brad (1966):

What fluid SHOULD be in my power steering system.   After thoroughly reading the FSM power steering section I came across the following statement in bold print: DO NOT USE TYPE F AUTOMATIC TRANSMISSION FLUID.  So, this should quell any heated discussion in the future, at least as far as '66's are concerned. Any other years?  I'm not sure it's not power steering fluid in my '66 right now. IF Chrysler power steering fluid for these cars is the same color as ATF, then it may be. However, if the fluid should be clear like the new stuff, well, I definitely need to flush and refill. 'Cause my fluid looks exactly like ATF.

By the way, I priced a power steering pump at AutoZone. They DO stock them for $50 w/exchange.


From PEN:

The correct power steering fluid for your car should look clear. The automatic transmission fluid is red. If you drive your car like a new car, I would definitely flush and refill as soon as possible. However, if you only drive it a couple of miles every week or two, not enough to really get the power steering hot, then you may not have to worry about hurrying to make the changeover. Anyway, you are going to have to replace the power steering pump reservoir o-ring seal, which you have said is leaking. I think you can still get a seal kit for these, without having to get a rebuilt pump and seal kit as a combo. When you do that, that would be a great time to make the changeover in the fluid. And then, and then you will have the opportunity to deal with the power steering pump mounting brackets, which have been such a joy to so many of us for so many years. For lack of a better word, it's called initiation.

From Mike:

Chrysler was pretty specific about using power steering fluid as opposed to ATF. Not sure when this changed (my '59 DeSoto owners' manual actually called for ATF, but by the mid-'60s this spec had changed, and I understand '87 and newer MoPars use today's ATF in their power steering systems). I have actually seen a product on the shelves in some auto parts stores marked "Chrysler Dodge Plymouth Power Steering Fluid". This is not a MoPar-sourced item but I have used it with no problems; haven't needed any for a while so regrettably I have no manufacturer's info.

From Norm:

The 1961 FSM for Imperial lists "Power Steering Fluid" as the fluid of choice for cars of that year. Modern fluid designations such as you mention, are probably indicated for modern Mopars, not specifically for the stuff we drive.  But they probably will do the job. Just as an aside, these systems are not as delicate as you may think. I once made the mistake of pouring engine cleaning solution in to the power steering reservoir of my 79 Cordoba. The can looked like the power steering fluid can I was using at the time. Anyway, I flushed out the stuff by opening the return hose and running the car in short spurts and replacing the fluid with the right stuff until I was sure all the bad stuff was gone. That was about 7 years, 75,000 miles and no problems ago.  My sister is still driving the car.

From John:

Maybe they were saying don't use type F as this is what was used by Ford at the time & Chrysler used type A suffix A. Type F was also not supposed to be used in the transmission on a Mopar.  Yes I have also seen the power steering fluid for Chrysler vehicles at Pep Boys. I believe it is intended for early '60's Mopars.

From Mark:

You DON'T want type F transmission fluid in the power steering. That concoction was for Fords with C-6 and C-4 transmissions (and maybe the FMX?), and should only be used in those applications. Dexron, Dexron II and Dexron III, the ATF specified for use in GM, Chrysler, Daimler-Benz, later Fords and other products, however, IS acceptable (and sometimes REQUIRED) as P/S fluid.

From Santi:

I read somewhere that you should NEVER put ATF in the power steering reservoir because of the high pressure and temperature it experiences in the power steering system. ATF is apparently not made to take pressures or temperatures in that range and therefore doesn't do well and doesn't help the power steering system. Anyway, I think you can even get power steering fluid in Khazakstan so why not put the right stuff in the next time you go to the gas station.

Question from Tony (1959):

The book says to use automatic transmission fluid Type A for power steering.  I note there is power steering fluid available that says "For MOPAR prior to 1988" and is yellow, rather than the red tranny fluid. What is best for my IMP? I have a steering gear seal replacement to do now, so I'd like the very best for it.


From Mike:

Chrysler didn't start using the yellow stuff until '62. I guess they didn't think there are enough '61 and earlier out there to mention that part. Dexron III/ Mercon is sort of a great-grandchild of Type A, and will work just fine for Type A applications.

From Norm:

We always used Trans type A suffix A in the power steering systems of old cars. if a spec today calls for Power Steering fluid, I use it. If it calls for Type A, Suffix A, I use Dexron-it is made to be used anywhere you needed the earlier stuff, so it must be ok. See, No Big Words.

Question from Denis:

Been reading the talk of the listings about this and Have both years, and hove no Idea what's in them to start with? Does it matter if you mix something else? Steering fluid, tranny fluid, dextron III ?

Reply from Rodger:

The trans fluid will work, can do a job on your seals/gaskets.

Question from Rob:

I am still having trouble with the fluid super heating on my '66 Crown. Here is my problem:

I had a new pressure side PS steering hose made up for my '66 Crown as a preventative repair. The old one was checked and appeared to have been repaired at one time as it was stepped down 1/2 in to 3/8 in hose. The return hose gave out some time ago and it seemed reasonable the pressure side would soon follow. I had no problem to replace hose (and the fitting at the steering box end) at the local hydraulics shop. However, after replacing the hose, filling the reservoir, starting the car and cycling the steering wheel side to side to purge air bubbles I discovered to my surprise the hose was hot. I stopped the engine and topped up the fluid and started cleaning up the mess thinking (smugly, I must say) this was a rather simple project completed. One last test for leaks, I thought, and done. WRONG! After about 2 minutes the PS hoses became hot enough to actually burn my hand when I moved them to check for leaks. A trip to the shop to examine the old hose for a flow control/check valve confirmed there was none, as suspected. I surmise the fluid become so hot because of excess pressure. There must be a valve or some such device in the system somewhere, but where to start? Can anyone help me out? I don't want to start taking apart components of the system at random on speculation. Please email directly or to the list with any suggestions. Apparently, as Dick B pointed out, what I thought was a cobbled together repair was actually the correct hose arrangement for this application. Unfortunately, we damaged the original hose and had to make up a new copy. The folks at the shop assure me it is a duplicate of the original with the step-down the same distance from either end (hose size) although the overall length is about 1 inch shorter due to the new coupler at the steering box (small) end. I jacked up the front end and turned the wheels back and forth (about a million times !) to bleed the air out of the system. To no avail !!! I still have over heating fluid. In under ten minutes at idle ... engine running, car in park, did not cycle steering ... the hoses became too hot to hold. There is a 'hissing' sound emanating from the steering box when the wheel position is at dead idle. Would this indicate air still in the system? Is there some other method to bleed the system? Could someone look up the precise stock hose size (inside diameter/length) so I can be absolute certain the new one is correct or advise a NOOSE part number (NAPA ??). ANY comments and ALL suggestions are welcome. This problem is all the more frustrating since cutting up the old hose searching for a 'check valve' we discovered it had only superficial surface damage. In other words, there was nothing wrong with it to start with!!!


From Bill:

There is a factory power steering fluid cooler which mounts on drivers side using 1 or 2 existing bolts & is connected in the return line & helps the heating problem a lot. We bought a new '69 NY'er, a new '80 Vogue Motor Home [last of the Dodge m. h. chassis], both had the factory cooler, neither had or have excessive power steering fluid heating.  I put one on each of my cars, Mopar & other brands. The cooler looks like a mini-mini- mini transmission cooler but mounts in the area of the a/c compressor & gets plenty of air flow. A trip to most any wrecking yard & you'll find more of these than you can use, I also see them at car parts swap meets & most people selling them don't have a clue what they are.

From John:

Since all the Imperials & big Chrysler products used this same hose from about 59-66 you would likely be able to get one at your local Napa. There are usually 3 hoses listed, all have same thread size . the biggest difference is on the end that goes to the box.  The metal piece on that end on one is a 90 degree angle to clear the autopilot if so equipped.  This is the hardest one to find at the parts store.  The straight up one is what you usually will find & should work, if no autopilot will easily work. with a bit of effort & more $$, can probably locate one through a vintage source such as Mitchell Motor Parts, Arizona Parts ,Len Dawson etc.

Another thought is what do you have for a return hose?  Some people substitute a piece of heater hose when they can't find the correct hose.  I read an article on this & the article said that since a heater hose isn't made to withstand hydraulic fluids, the hose will "slough off" from the inside & start plugging up the works. Gates makes the correct hose for this application.

Flushing should have been done after installing the new hose.  The easiest way for this is to put the PUMP end of the return hose into a gallon plastic jug & start and let drain, will drain rapidly & refill & drain once or twice more then reconnect return hose & refill with FRESH fluid. Also be sure to use power steering fluid, never transmission fluid.

From Roy:

Sounds like an obstruction in the steering gear is causing excessive back pressure and creating the heat. If there is no pressure on the steering wheel, the fluid should freely flow through the steering gear until the wheel is turned and the valve inside the steering gear directs the hydraulic fluid to do its work.  Try removing both hoses from the pump, drain as much fluid from the hoses by lowering them over a pan, and then blow through the pressure hose. You should be able to easily blow the remaining fluid out and hear a gurgling noise, if not, there is something wrong

From Leo:

Check your new hose for obstructions. When the hose was made up, they may heve peeled some of the rubber inside when they installed the fittings. If it's a straight hose just hold one end up to a light, you should be able to eyeball it. Apply air pressure from both ends, see how the flow is. The easiest way is to get another hose, no big deal. You may have gotten some dirt into the steering box when you swapped hoses.

From MStout:

Sounds like the spool valve is out of adjustment, causing the restriction.

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