I'm stumped by a power steering problem

[Busted Knuckle]

OK our '90 model Setra S215 which had sat for 2 yrs after we bought it before we actually got it ready to put into service has always had a growl in the power steering. (heard from the driver's seat and not elsewhere!)
Now it would growl/howl pretty bad on start up but would calm down after a few minutes and was barely noticeable once on the road unless a hard turn or two were made at slow speed. It would always turn fine, just growl some.
But this week-end dad called me and asked me what it meant if it changed from a growl to to a grind like it was eating something?
I told him I had no idea, and asked if it had plenty of fluid. To which he answered yes.
I asked him if it still steered OK? He said yes.

So then Sunday we were together and he asked about it again. I said I dunno, let's look at it.

So we started to check it out and he told me it's getting hard to steer, but then sometimes it'll take off and turn easy.

So we looked it over and I could not find any obvious defects. So we shut it off, and went to check the fluid again. We found the fluid shooting out of the top of the reservoir from tow tiny breather holes in the dipstick top.

I asked dad if he'd overfilled it and he said he hadn't added any at all!
So we drained some out and it quit spraying and seemed to work better.
But once it warmed up again it did the same thing, grinding, hard steering, and spraying out the dipstick again.

OK now a little history when we bought the bus in a package deal where we got our first 45' Setra and this bus and a parts bus too.
We drove this one and the 45'er home 1676 miles door to door, and while they both drove and ran great this one went through 12 gallons of 40W oil and 2 galloms of Lucas.

SO it got parked for a while. Then one week-end Joel from Chattanooga Choo-Choo Express Garage was up at our place and looked it over, discovered the oil leak, and quoted me a price to fix it.
So I drove it down to where he does most all his work (except the occasional road trip to repair a regular customers bus on the road.)
Where he was going to pull the engine/transmission out, separate them, remove the accessory drive gears, remove the accessory drive housing, fix the leak, and reassemble it all (including re-timing the drive gears.
SO I had a replacement power steering pump from the parts bus (identical bus), and asked him to go ahead and change it while he had it off.
Well when we picked the bus up he told us "I didn't replace the power steering pump, because there is nothing wrong with it."

SO my question is was the pump bad and needed replaced, or is the gear box the culprit? 
  BK 

S

[Van]

Hey B... mine been growling at me since I swapped mills in the 15, air is the culprit in mine, sounds like squish/growl, works great some times and pulsy other times. the grinding on yours sounds like the box to me, wish i could be of more help.

[robertglines1]

somewhere in the gray cobwebs of my mind.I remember foaming problems with certain types of atf..10 wt oil was used in certain pumps and did not foam..air will cause the pump to cavitate.

[Hard Headed Ken]

BK

This is probably not the answer, buy maybe it will help someone. I had an Eagle that had a power steering whine/noise. It sounded like cavitation so I thought the pump was starving for oil. I chased that guess for hours. I tried lot of things and nothing helped. I noticed the previous owner had custom built the power steering reservoir and the return line was well above the normal full level. Since the return oil was above the oil level and the return oil flows at a very fast rate the result was aeration of the oil which caused the noise in the system. I moved the fitting for the return below the oil level and within a few minutes the noise was gone. Such a simple thing, always make sure the return is below the oil level.

Ken

[jok]

Hi BK,

I had to replace the 'O' ring in my Vickers power steering pump (1990 Prevost) recently because of a fluid leak. While I had  it apart I also replaced the spring and valve. Prior to replacing those parts I had a whine and weird noises when cold or on tight turns. I have not noticed the noise since replacing the parts. I'm not sure what fixed my noise but maybe this info can help. 

Good luck,
John

[jok]

BK,

I forgot to mention that I also replaced the power steering filter.

John

[Busted Knuckle]

BK

This is probably not the answer, buy maybe it will help someone. I had an Eagle that had a power steering whine/noise. It sounded like cavitation so I thought the pump was starving for oil. I chased that guess for hours. I tried lot of things and nothing helped. I noticed the previous owner had custom built the power steering reservoir and the return line was well above the normal full level. Since the return oil was above the oil level and the return oil flows at a very fast rate the result was aeration of the oil which caused the noise in the system. I moved the fitting for the return below the oil level and within a few minutes the noise was gone. Such a simple thing, always make sure the return is below the oil level.

Ken

Ken,
If only it were that simple, I could move onto collecting the mega amounts some of the competition owes us for helping them out! (of course I'd just as soon be helping them out, than have a lot full of buses sitting doing NOTHING!)
Both lines enter/exit from the bottom of the reservoir, so I don't think that is it.
 BK  

[Sam 4106]

Hi BK,
You said the lines are OK, but have you changed the filter. A severely plugged filter could starve the pump of oil. Just a WAG, but sometimes we overlook the simple things.
Good luck, Sam MC8

[Busted Knuckle]

Hi BK,
You said the lines are OK, but have you changed the filter. A severely plugged filter could starve the pump of oil. Just a WAG, but sometimes we overlook the simple things.
Good luck, Sam MC8

Ah Sam, uh OK go ahead and make me feel stupid! Duh why didn't I think of that? On my way out the door to check it NOW! Thanks;)
  BK 

[robertglines1]

BK did you get my Pm?  Bob

[jok]

Hey BK,
Did you ever solve your power steering problem?

John

[Busted Knuckle]

BK did you get my Pm?  Bob

Yes, and spoke with Shawn and still waiting for him to confirm the trip is a go, although his customer has called us and asked us a bunch of questions and told us that Shawn would be calling to book it. (still waiting )
  BK 

[Busted Knuckle]

Hey BK,
Did you ever solve your power steering problem?

John

Not yet, bigger different problems put that one on hold.
It's on the top of the list of non-emergency items to be dealt with.
I'll update as soon as it is fixed!
  BK 

[JohnEd]

You have a plugged line that feeds the pump.  That restriction may be a filter or screen or collapsed rubber line....but I have solved that problem to many times to believe otherwise.  Two things are the clinchers.....It is worse when the oil is cold and more viscous and difficult to move through a tube.....secondly, that episode of air in the oil and it shooting out the res.  IF the pump is SUCKING REALLY HARD on a restrictive circuit it is prone to ingesting air to replace the fluid it is starving for.  Some reservoirs, as on my Lex, have a screen in the bottom that is UNDER a sheet metal baffle so it looks pristine clean in there....NOT!   Might be part of a rag in one of the low pressure hoses.  Never saw that or even heard of it but it felt right to say

You have two of those buses, right?  Take the res and all hoses loose from one and swap the low pressure side.  If the problem moves that would be a hint.

Good luck

[jok]

BK,

Did you ever solve the problem with your Setra S215 steering?

John