MCI MC9 Steering Whine

steve.barnett71 · May 31, 2016, 09:17:53 AM

Recently purchased a 1982 MCI MC9 conversion. It has what I would describe as a "hydraulic whine" when you turn the steering wheel. What should I look for? Is it a major concern?

Utahclaimjumper · May 31, 2016, 10:53:36 AM

Wrong weight oil or out of oil.>>>Dan

eagle19952 · May 31, 2016, 11:45:15 AM

yes it is a major concern.

TomC · May 31, 2016, 06:41:05 PM

My Sheppard steering with 15W-40 engine oil whines when it is cold. Once warmed up it makes a light whining sound, but nothing much. Some whining is normal for any hydraulic pump. Good Luck, TomC

Utahclaimjumper · May 31, 2016, 07:18:50 PM

5 or 10 weight oil,, or ATF will do the job nicely and quiet it down.>>>Dan

luvrbus · May 31, 2016, 07:28:58 PM

MCI's have 2 filters 1 in the reservoir and 1 on the pressure side of the power steering they probably have never been serviced the one in the reservoir is a throw away type the pressure side is cleanable service those and it will make a difference

steve.barnett71 · June 01, 2016, 01:12:06 PM

Thanks for the replies. I will check the level (as soon as I locate the reservoir...lol) and filters.

Also, just to clarify the noise comes from the area of the steering box in the front of the bus not the pump.

goutoe · June 01, 2016, 04:16:00 PM

I noticed the first time out this spring with the bus I had a noticeable whine I narrowed it down to the steering ( I have sheppard steering ) It was cold around 40 degrees the whining stopped when it warmed up, I checked the fluid level it was a little low, I added a little over a quart of 10w40 motor oil, it quit but still a little noticeable when the wheel is held against the stop.which I think is normal.>>>> John.

steve.barnett71 · June 01, 2016, 05:59:08 PM

Did a little research and need even more advice now. This bus has been repowered with a series 50 detroit. The reservoir has been relocated and the lines extended. That doesn't concern me much but when I messaged the previous owner to ask what oil he used his reply was "any power steering fluid" I have several trips coming up in the next couple months. What should I do now??

eagle19952 · June 01, 2016, 06:16:51 PM

when in doubt...use 0w30 synthetic... at least i do.

Utahclaimjumper · June 01, 2016, 06:43:10 PM

It seems a little late to "discover" which engine it has,, and other changes,, looks like you have an education in your future.>>>Dan

jmblake · June 01, 2016, 06:46:20 PM

I just repowered with a 50 series and now I also notice a whine in the power steering

It does seem to have more psi than my old pump so I thought maybe my old pump was just wore out put I'm not sure now.

steve.barnett71 · June 02, 2016, 03:11:54 AM

I did not just discover that it has a series 50. I knew that going into it and researched the engine and transmission extensively.

I just discovered the power steering system changes and was looking for advice on what to do about the fluid.

I am sure that I have lots of learning to do...but that is not a bad thing.

steve.barnett71 · June 02, 2016, 03:15:27 AM

jmblake , The previous owner of my bus also says the whining started after the repower. Maybe higher output pump is causing it??

luvrbus · June 02, 2016, 06:18:02 AM

Could be to high of pressure and flow, hydraulics whine when to much oil is being bypassed through the valves that is why they whine against the stops