Hydraulic System Service and Maintenance?

[Bill Sprague]

There is a couple posting on a Facebook Beaver group about a failed hydraulic system.   The initial symptom was balky steering.  The diagnosis is that either the pump or fan motor started coming apart and there are metal flakes in the entire system.   

The system has to be replaced to get rid of the metal contamination.  Estimated costs are approaching $40K!  It's an '06 Patriot Thunder.   

I know of one other Beaver owner/member that had to do the same thing.  His costs were close to that, but were covered under an extended warranty. 

My point in starting a topic is to raise the question of service.  On our '04 Monterey there was a filter and a sight glass.  I added a little power steering fluid a couple times and changed the filter a few times.  Other than that, I took power steering and radiator cooling it for granted!

My point in starting a topic is to raise the question of preventive maintenance.   I recall little from the books I had.  Should the system be flushed?  How would you do that?  Is there a higher grade of fluid that should be used?  Should the filter be cut open and inspected?

[Jeff Watt]

Bill,

Thanks for the information. As I’m not on/use Facebook, I don’t see any of those posts.

I’m somewhat concerned regarding this issue as my coach has started to have a stiff/balky steering at low speed. I thought maybe fluid level, but it is good. Also thought maybe when the fan is on, but this isn’t always the case.

As far as maintenance, I changed the hydraulic filter about 2 years ago and maybe 7500 miles. I’m not sure what to do to diagnose further.

Any other information, maybe somehow from those that had the major repair, would be appreciated.

Jeff

[Gerald Farris]

Jeff,
Most of the C13 equipped Beaver coaches of your vintage have 2 hydraulic pumps. One powers the radiator fan and the other one powers the power steering system. One is engine driven and the other is driven by a PTO on the transmission. The problem arises from the fact that a common fluid source (reservoir) is used by both systems, and if a pump fails and causes excess fluid contamination, the other components in the system including the fan motor and other pump can also be damaged. Therefore, if you are having a power steering assist issue, especially if you can duplicate it, you should have the system checked by a qualified technician. 

Gerald     

[Jeff Watt]

Thanks Gerald,

The clarification on two pumps is useful as I though only one pump. I’m not a tech, but do they do a pressure test on the pump(s)?

Replication should be easy - it’s doing it almost all the time.

I guess I better have it checked before off on a trip this fall. Seems to run (steer) ok at higher rpms, but on a highway there isn’t a lot of steering inputs so hard to tell if any resistance.

Jeff

[Gerald Farris]

Jeff,
Yes, a system pressure test is one of the first test that a technician should do when diagnosing a power steering system complaint like the one you have.

Gerald 

[Hal Grimshaw]

how often should we have the filters changed and is there a better grade or brand of fluid to use???/

[Scott Shearer]

When we got our 06 Thunder the clog indicator on the hydraulic filter base was tripped. I replaced the filter, still tripped the clog indicator. I opened the original filter and it was by no means clogged.

I contacted tech support at MP Filtri (the OEM filter supplier). Their response was that the filter spec’d by Monaco was undersized. They recommended using a CSG150A25A filter. 

The following is from tech support.
The CSG150A25A is a 19 um absolute media (glass) filter. It is 10 ¼” long and flows 42 gpm.

The original (OEM) CSG100P10A filter is a 10 um paper element. It is 6 ¾” long and flows 34 gpm.

The absolute media filters are 99.9% efficient whereas the paper media filter is ~50% efficient. A 25 um absolute filter will generally out perform a 10 um paper element.

www.mpfiltri.com

[Mike Shumack]

Thanks for the info. That got my wondering about my hydraulic filter.

My coach is a year older and uses the LHA hydraulic filter (SPE 15-10). I tried to look up the specs for this filter but it looks like LHA is out of business (at least I cant find them). There are cross-overs to other brands like Lubra-Finer LFP1652 and Donaldson SP15. These are short filters (5.6" high by 3.7" diameter).

However the OEM spec for both our coachs is a filter rating of 10 microns. Going to a filter with 19 micron filtration may improve flow but it is a good idea?

So if your filter is undersized at 6-3/4", it make me think my filter is really undersized.

[Jerry Emert]

Scott, thanks for info.  What is your source for these filters?  Just looking around internet briefly there are a lot of replacement filters not so many made by Filtri.  Thanks again.
Jerry

[Jeff Watt]

Gerald, I’ll defer to your knowledge although my manual shows only one pump - granted the manuals are often covering a lot of coaches. Do you know which pump runs the power steering?

Scott, did you replace the filter with the larger and higher micron unit? If so, is there any difference?
Does the use of a 19 micron compromise the system vs the 10 micron?

I shouldn’t use my memory for recalling service - I looked and the hydraulic filter was replaced 4 years ago and about 22Kmiles -  oops   First on the agenda to do list. Four years and 22K miles makes me think I need to drive more.

Jeff

[Jerry Emert]

Do we know which models/years/engines have this problematic hydraulic pump/system? 
Thanks
Jerry

[Scott Shearer]

Our 2006 C13 powered Thunder has the two hydraulic pump system that Gerald described. Both the engine driven and the PTO driven pump share the same oil reservoir. It appears that the only the return line from the cooler is filtered, the engine driven power steering pump does not appear to be filtered at all.

[Scott Shearer]

Jerry,
I purchased my replacement filter directly from MP Fitri US (Quakertown, Pennsylvania). MP Fitri is an Italian company that specializes in hydraulics. MP Filtri is what is spec’d in my owner’s manual and is what was on our coach when we purchased (I’m sure it was the original CSG100P10A filter).

http://www.mpfiltri.com

Jeff
The technician that I talked with at MP Fitri US said that he had fielded a number of calls from owners of Monaco built coaches. His recommendation was, that if you have the room, use the 19 um absolute media filter (CSG150A25A). He said that a 25 um absolute (glass) media filter will out perform a 10 um paper filter both in flow and filtering capabilities.

Prior to contacting MP Filtri tech support, I had research the issue and found several discussions. This led me to research absolute media vs paper media filters, my findings supported the technician’s recommendation to change to the 19 um glass media filter. I found several articles that discussed absolute media filters vs paper filters. Most indicated that an absolute media filter is 99.9% efficient where a paper filter may be only 50% efficient.

Tech support at MP Fitri US was very helpful and easy to talk with. I would recommend talking with them if considering a filter change. I’m only know what I’ve read and was told by tech support, certainly not experienced in hydraulics.

http://www.mpfiltri.com

[Jeff Watt]

Does the hydraulic reservoir have any filters in it? I don't see any mention of it in the manual, however on some other forums there is a mention of one or more filters in the tank.

Taking it in next week for diagnosis. Hopefully only a filter. Maybe the PS pump needs some work and/or its lines, and as Gerald and Steve have stated it is separate from the fan pump.

I do have a Blue Ox Tru-centre steering unit, but this stiff steering has only been noticeable lately.

Jeff