MCI MC9 Steering Whine

eagle19952 · June 02, 2016, 09:05:23 AM

Quote from: steve.barnett71 on 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??

is there a pressure relief adjustment some where ?

jmblake · June 02, 2016, 09:45:37 AM

Is there anyway to turn them down? The doner bus had a hydraulic fan also.
Jason

eagle19952 · June 02, 2016, 02:19:09 PM

Quote from: jmblake on June 02, 2016, 09:45:37 AM
Is there anyway to turn them down? The doner bus had a hydraulic fan also.
Jason

turning them down may not be the answer, it may need more...there is always a pressure control somewhere... could be shims, could be a screw... could be a spring... but it is not,..... what happens if i do not know...

robertglines1 · June 02, 2016, 05:00:04 PM

Oil ; the book on my 60 series says use motor oil. I had used atf and noticed there were allot of foam with it. Changed over to 10w40 that I use in motor and cleared that up. Don't know if it will be the answer for you guys problem. Again don't know science behind this. Couldn't see where you couldn't adjust pressure on 60series. Seem to remember 2200lb somewhere in the book. FWIW cavation? Bob

sixtyseven · June 03, 2016, 12:03:15 AM

Are you sure the noise comes from the steering box? Sound transmits through hydraulic pressure very good. If it's actually coming from the pump I would suspect what Bob said, cavitation. Mine started making noise like you described. Took a while to find the problem. Turns out there was a piece of rubber from one of the hoses stuck in the fitting coming out of the filter housing going to the pump suction. Just another possibility.

steve.barnett71 · June 04, 2016, 06:28:47 PM

More research today. Noise is definitely coming from the steering box, not the pump. Pump is quiet when turning the steering. I do not think it is cavitation. Did notice that there is a little bit of foam in the sight glass of the reservoir. I think the next step is flushing and changing the fluid. The only question is what fluid to use. The manual for the steering box lists many different fluids and oils that are acceptable.

eagle19952 · June 04, 2016, 07:19:36 PM

Quote from: steve.barnett71 on June 04, 2016, 06:28:47 PM
More research today. Noise is definitely coming from the steering box, not the pump. Pump is quiet when turning the steering. I do not think it is cavitation. Did notice that there is a little bit of foam in the sight glass of the reservoir. I think the next step is flushing and changing the fluid. The only question is what fluid to use. The manual for the steering box lists many different fluids and oils that are acceptable.

how can you think it is not cavitation when foam is a clear sign that it is...?

cavitation the formation of bubbles in a liquid, typically by the movement of a propeller through it.

niles500 · June 05, 2016, 12:52:26 AM

Acts like low fluid, pump is sucking air - fwiw

lostagain · June 05, 2016, 07:53:52 AM

I would replace the filter in the reservoir, and clean the one in the pressure line.

JC

robertglines1 · June 05, 2016, 08:04:25 AM

Cross over guys--from 2 cycle to 50/60 series. I know pumps are in different locations. ? I have does fluid requirements change between these generations? Mixing atf and oil?

jmblake · June 05, 2016, 02:06:31 PM

I used hydraulic oil with my old engine so that's what I used with the 50 series

If I fill mine to the sight glass it will push fluid out the breather but once it seeks its level there is no oil in the sight glass when its not running but with it running it is right in the middle of the sight glass.
Jason

jmblake · June 12, 2016, 06:16:08 PM

We just got back from another short trip and pulled into the drive way and seen oil dripping from the engine compartment and discovered what looks like the gasket that holds the lid on the power steering reservoir has blown

so now I got a big mess of oil film all over everything. I'm going to order new filter and gasket for the reservoir tomorrow so now witch oil should I use

Will one quite the whine any more than the other?
Thanks Jason

eagle19952 · June 12, 2016, 07:45:05 PM

Quote from: jmblake on June 12, 2016, 06:16:08 PM
We just got back from another short trip and pulled into the drive way and seen oil dripping from the engine compartment and discovered what looks like the gasket that holds the lid on the power steering reservoir has blown so now I got a big mess of oil film all over everything. I'm going to order new filter and gasket for the reservoir tomorrow so now witch oil should I use Will one quite the whine any more than the other?
Thanks Jason

every power steering system i ever put 0w30 synthetic in benefited never in a coach but lots of Kenworths and other heavy trucks and every japanese car or truck, Fords and Chevrolet's too...

and in the Arctic it was a lot, run year round.

luvrbus · June 12, 2016, 08:06:28 PM

Jason,you need to check your pressure the MCI 8 was a 1000 psi max and the pump on the 50 series is probably around 1450 to 1800 psi same as mine on the 60 series you shouldn't have enough pressure on the reservoir to blow a gasket

Scott & Heather · June 12, 2016, 08:35:43 PM

On the two strokes, if you ever blow the seal between the pump and engine, you're pouring pump fluid into the engine. So that risk alone has me putting 30 weight oil into my power steering in case this ever happened

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