MMO in the power steering reservoir

[ChuckBerry]

I took a first look at the power steering fluid reservoir in my new-to-me '99 Crown Victoria Police Interceptor. The fluid was dark brown, and since it calls for Mercon ATF, I knew that the fluid was well past its prime, probably it was the original factory fill.

So, using variations of the turkey baster method, I have been taking the fluid out of the reservoir and replacing it with SuperTech Mercon V fluid. I am doing this once every few days as the fluid circulates around the PS system. I also added a few ounces of Marvel Mystery Oil in hopes that it would clean up some of the stuck on brown stuff inside the reservoir bottle that no doubt is stuck on to other parts of the system as well.

When I initially pumped out the first volume from the fluid reservoir, lots of little black and dark brown flakes came with the fluid. After subsequent removal of reservoir fluid, smaller and fewer pieces are coming out. I can actually see the level of the fluid from the outside of the reservoir, where it was unreadable before from the buildup. BTW I have noticed no improvements in the steering, but it wasn't giving me any problems before I started the drain and fills.

What I am wondering is if the MMO is actually helping in this instance to clean up some of this stuck on crud, or is it just the replacement of old fluid with fresh?

 

[demarpaint]

I had that annoying noise typical of an older Ford PS pump. I did an A-Rx treatment about a year ago and didn't notice much of anything after 3000 miles of using it, the fluid pumped out clean. I decided about 2 months ago to give MMO a shot, and the pump is much quieter now. The fluid pumped out was also fairly clean though, but I stay on top of it.

 

[mechtech2]

Probably both -cleaning from MMO and cleaning from fresh ATF.

It is best to give it as much chance as you can. A lint free rag on a screwdriver -whatever- should be used to mop up as much particulate matter as you can.

I would use ATF alone in your final fills.

 

[hate2work]

IIRC, MMO is 75% solvent, so I think it's definitely helping to clean out the system.

 

[Johnny248]

Didn't ford have a TSB to add limited slip additive to the fluid at some point? I want to say that maybe it was a Lincoln LS TSB, but don't know if it was applicable to any other cars. I do remember that we did a couple of them in the past and it actually corrected the noise.

 

[Johnny248]

Originally Posted By: demarpaint
I had that annoying noise typical of an older Ford PS pump. I did an A-Rx treatment about a year ago and didn't notice much of anything after 3000 miles of using it, the fluid pumped out clean. I decided about 2 months ago to give MMO a shot, and the pump is much quieter now. The fluid pumped out wThe as also fairly clean though, but I stay on top of it.



The power steering flush machines have two hoses, one that sucks and one fills. You run the car and cycle the steering back and fourth. And suck, then add, suck then add, and so on while allowing a little time in between to flush the fluid through. It works great, and in the past I've used a 12volt oil change machine ($10 at the store) to suck the fluid down, and then just poured new stuff in. It is a really inexpensive way to do it, and much faster and I believe to be a better way than the turkey baster technique.

 

[demarpaint]

I have a small hand pump that was used to pump gear oil into a rear or transmission. I empty the PS pump, refill and drive, repeat until I've put about 3-4 qts of fluid through it. It takes me a few days, and hardly any time. I don't want to start disconnecting anything on my older fleet. Certainly not the best method, but it works for me.

 

[ChuckBerry]

I intend to drain/fill another quart through the system over the next few weeks, and then go on a regimen of one reservoir drain/fill per oil change. I think that will be a reasonable interval to keep the system in good shape.

Of course, that means that a small amount of the MMO will stay in the system for years, but considering other stories on the internet about replacing an entire systems capacity with MMO and running on it for years, I don't think it will cause problems.

 

[MolaKule]

Quote:
Didn't ford have a TSB to add limited slip additive to the fluid at some point?


Was this a differential limited slip additive?

I would highly recommend you NOT do that in your PS.

 

[wander2039]

Probably both.. I would of slapped a cheap fuel filter on it before cleaning.

 

[ChuckBerry]

Originally Posted By: Eric Smith
Probably both.. I would of slapped a cheap fuel filter on it before cleaning.


I don't really think that's necessary...it might be more advisable to do a full system flush than a reservoir drain and fill if the fluid is full of large chunks of debris/corrosion, but a power steering system is not like a fuel system with its delicate and tiny injector ports that need to be protected from even miniscule debris. The flakes coming out of my fluid were pretty small, really.

 

[MRtv]

I have recently replaced both my hoses on the power steering pump on my F150. There had been a leak at the high pressure connector on the pump. New hose on and filled it with Castrol Transmax Dex/Merc. No leaks after several thousand miles. Last weekend I did a quick turkey baster suck out of some of the fluid and added two oz of MMO and filled the rest with more Castrol Transmax. No problems so far. Next oil change I will do another baster suck out and refill it again. May not do the MMO on the next one though.