Generic hydraulic pump for fan motor, power steering & hydraulic fluid discussion and questions.

[Superpro14]

Trying to wrap my head around the hydraulic system on my 1999 Monaco Windsor 8.3 DP, when I look at the hoses there is a high PSI hose going to the power steering and a low PSI hose returning to the Tanh. question 1 would be how does the steering box reduce the PSI to the return hose? same question on the fan return hose? question 2 , does the pump put out the same PSI to the power steering as the Fan motor? the pump is very large, with about a 1 1/2" suction hose, the filters could be original and maybe collapsed , will know tomorrow on that, question would be if the filters were plugged would that cause the fan motor to run slow but the power steering still work what I think is normal? I am changing all the hoses in this system as well as the filters and do what ever I deem necessary as I go, besides blowing a power steering hose recently I can't get the fan to run high speed with all the tests for the 2 small lines, remove from valve, plug each, couple them together etc. I have a new Rad (side exit) and am experincing heating issues with new thermosta so my concern is the filters, hoses,pump and fan motor if I can get it running in high speed my valve may check out OK, that will be after I get the Fan to run WO, so an input would be great.TKS

[jacwjames]

Plugged filters could cause lots of problems and starve the pump. 

Although I wouldn't use lower pressure hosing for the return lines it's probably OK as there should not be high pressure on those lines. 

I have a large ~4 gallon reservoir with 3 stacked Nelson filters.  The instructions for servicing is to drain just enough oil to be able to get a hold of the last filter, I would not do that.  I would loosen one of the smaller return hoses and drain all the fluid out to get the level below the bottom of the last filter, there is an elevated sealing surface the last filter seals to.  Once the oil is drained visually inspect the filters especially  the lower one looking for any contamination or metal.  Look at the bottom of the tank.  Clean with a clean rag. 

If the filters and oil looked OK you'll have to turn your attention to the pump and motors.   You might contact a good hydraulic shop and see if they offer field service, they could come and do a pump flow and pressure test on the pump.   The pump may be bypassing internally, could be as simple as a seal or O-ring.

 

Not sure which pump you have but here is the parts page for mine,  Here is the listing on REVRVParts.com  https://revrvparts.com/item-detail?itemId=51293&organizationId=9  it is out of stock.

They show seal kit for the pump for a much lower price.  https://revrvparts.com/seal-kit-po-18766

Whitehouse Products in the UK might be able to provide the pump at a reasonable price.  They are in UK but there prices are good, fast shipping once you set up an account.  https://www.whitehouseproductsltd.com/products/hydraulic-pumps/hyd-gear-pump/non-standard-dynamatic-gear-pumps/dynamatic-no-550-1-36844-159-160    they also show out of stock but worth a call>>> they are the one that supplies others. 

1 Hyrdrualic Pump.pdf

[vito.a]

With a 1999 model you should have a Cummins ISC 8.3L. The engine is electronically controlled by the ECU.  But, do you know which system controls your engine fan speed? 

Most of the electronically controlled engines have a Sauer Danfoss electronically controlled unit that varies the hydraulic pressure to the fan.  This controller is usually located just to the left of the engine (see picture) as you look in from the rear.  The Sauer Danfoss controller is electrically connected to the engine ECU and the dash A/C.  These have a habit of failing but are supposed to go into full speed mode when failed.  

However, some coach builders used the Sauer Danfoss mechanical (wax valve) controller. Usually they are attached to the top of the radiator.  They perform the same function as the electronic system by varying the hydraulic pressure to the fan motor.  

A side note on early Windsor's. For several years the Windsor only had the Cummins 5.9L engine.  When Monaco upgraded to the larger 8.3L engine it took a few years to get the radiator sizing right.  As a result some of the early Windsor's overheat because the radiator is too small.  But this was usually considered to be 1997 and 1998 models.  

Edited September 10 by vito.a

[jacwjames]

My 2002 Windsor has a wax valve. 

He indicates that he has already capped and joined the two lines together with no change in fan speed.   When he capped them the fan should have run wide open. 

I guess it could be the hyd switch, which is suppose to change speed, and/or the motor. 

[Jdw12345]

I would also look at the suction line, unlikely that it would collapse on the inside but it is possible.  If the pump, fan motor etc are internally failing I would think a look inside the filter would reveal that.

[jacwjames]

Here is the parts page for the Hyd fan motor and switch.  REVRVPARTS.com does not show this part.  Doing a search using the vendor number doesn't show any results.  A good shop might be able to cross reference the find a viable replacement if that is your problem.

FWIW, I have quite a bit of experience "helping" troubleshoot and fixing hydraulic systems on large mining equipment.  As Manager of the largest mine in the division I implemented testing protocols to determine the cause of the problem which including purchasing testing equipment to test for flow and pressure.  First thing we'd do is check the flow from the pump and then work from there.  

So I'd suggest you start at the pump since the pump is pretty accessible, looks like it is still available, and there are seal kits available.  If you can't get a tech to do a flow test you can take the pump off and either take it to a shop or take it apart and inspect the inside looking for any type of damage.  These are gear pumps with pretty tight tolerances, rotation of the gears is what creates flow and pressure.  Any scoring on the surfaces will reduce performance.  A shop not wanting to take any chances on problems would probably just source a new pump.  If you take the pump apart and can't find any visual problems I'd recommend buying the seal kit, this would eliminate that side of the equation. 

If you do find major problems with the pump there is a good chance that the downstream components have been contaminated and need to be looked at also. 

 

 

1 Engine Fan Cooling.pdf

[Superpro14]

This is a 1999 and has a Wax Valve and I believe a valve in the fan motor which controls the flow to the motor as the Wax valve closes it stops the flow to the valve in the motor and it increases the flow to the motor and the fan speeds up, if you disconnect the Wax valve hoses and cap them the fan should go wide open(full speed), if you couple the hoses, the valve in the fan motor only lets the fan run slow speed, having done these tests and the speed doesn''t change this is the main problem after I change out the aged hoses which have given me a couple issues. I should have the filters out today  to help me decide the next step in the search.

[waterskier_1]

I used this document from BlueBird for theory of operation.  I think that is what you are asking for, so you can then troubleshoot.  It is NOT a Monaco document, or even depict a Monaco coach.  It IS a very informative document on how the hydraulic Fan Drive System works, in general terms.  

  -Rick N.

hydraulic fan drive system.pdf

[jacwjames]

1 hour ago, waterskier_1 said:

I used this document from BlueBird for theory of operation.  I think that is what you are asking for, so you can then troubleshoot.  It is NOT a Monaco document, or even depict a Monaco coach.  It IS a very informative document on how the hydraulic Fan Drive System works, in general terms.  

  -Rick N.

hydraulic fan drive system.pdf 1.14 MB · 0 downloads

Good document, it does have flushing procedure at the end. 

[dennis.mcdonaugh]

The first time I changed the oil and filter I loosened one of the hoses at the bottom of the tank. The next time I drained the tank with one of these drill pumps. 

[Superpro14]

Thanks to all, very good info, now the work begins, just on a side note, only return oil to the tank which goes through the filters is from cooler, returns from power steering and some of the oil from the fan dump into the tank , are mixed with the suction of the pump and eventually get through the filters after multiple passes through the system, the oil from the cooler passes inside to out on the filters

[jacwjames]

1 hour ago, Superpro14 said:

Thanks to all, very good info, now the work begins, just on a side note, only return oil to the tank which goes through the filters is from cooler, returns from power steering and some of the oil from the fan dump into the tank , are mixed with the suction of the pump and eventually get through the filters after multiple passes through the system, the oil from the cooler passes inside to out on the filters

Interesting, I would have thought all the return oil would go through the filter.  I'll have to recheck mine but I believe all of my return oil does, the suction line is in the middle of the bottom of the tank and the filters are above it. 

Attached is a schematic of the hydraulic circuit.  One thing I notice is that it does show a 2nd filter and labeled as "Matrix".  I do not have that filter or at least have not seen it but will check again. 

Hydrualic Schematic for cooling fan.pdf

[Doug and Nicki]

Moderator EDIT

NOTE.  There is an ongoing hydraulic fluid discussion.  The information requested has been covered, in detail.  This nee topic is now merged into the existing one. Also the OP’s profile has been updated for clarity of the MH year and model.

End of Edit

I have read the previous posts about hydraulic fluid choices but have not been able to see the answer to my question. This is fairly simple. My owners manual calls for HD46, which is 20 weight. I am changing the filter and have ISO 32, which is 10 weight. If I use the 32 just to prefill the filter, this will not be a problem, right?

 

 

 

[Tom Cherry]

• FWIW.  Not ALL Monaco’s are the same.  Early ON, the one pictured here, which is almost 5 Gallons and has the “side” fitting and, presumably, the lower 3 fittings, was used.  In later years and model dependent, a smaller, single filter 2 gallon reservoir was used.  Sometimes, again, depending on the “PTB”, there was also a pressurerized spin on (think oil filter) ADDITIONAL filter.  It always amazes folks.  I BELIEVE that the same ISL 425 used as BASE in the 2008 Dynasty does NOT have the additional filter.  But the Camelot in 2009 has one.

Conclusion…..GO FIGURE.

The BIGGEST mistake is to ASSUME that every Monaco has the OLDER style large reservoir and that it will be AW46.  The owner’s manual was cut and paste.  

Monaco Tech Support stated that my manual, with AW46 was in error because the “shirts” never came to the assembly line…. That Monaco had converted to all ATF in the mid 2000’s.  It has taken multiple topics and posts and reading manuals…..there ain’t NO RHYME or REASON.

• My manual says AW46.  It came (bought it new) with ATF.  
• 2008 Dynasty has AW46….think the manual says same.
• Monaco SUPPOSEDLY switched to ATF due to several warranty failures. The AW46 undergoes a “freezing temps” viscosity change….and there have been “blowout” issues in the system.  Quite costly.  An entire topic addresses this.  Temps below say the low teens are most as risk.
• The 5 Gallon reservoir has THREE filters….
•  The 2 Gallon has ONE.  They are DIFFERENT PN….and NOT interchangeble.
•  There MAY be a pressurized Spin ON on some models….and not the “top” as one would think.
• Elkhart didn’t “play by the Corporate Engineering rules.  They used MOTOR OIL in at least 2 years….maybe 2006 or 07….Manuals say so…owners have confirmed….NOT Straw (HF) or Red (ATF) colored.
• GENERALLY SPEAKING….it is “Safe and Recommended OK Practice” to use AFT in the HF or Motor oil systems…..but NOT Vice Versa.  Many posts debate such as to “totally draining” vs drain the reservoir and replenish with ATF
• TRW recommends replenishing with Transynd or Equivalent.  Their long or extended HD OTR rigs come with Transynd….they did no testing…..they have a contingent of Ex or Former Allison employees…. They also saw a MAJOR warranty cost drop when they “summarily” switched over and required Transynd.  That was the TES 295 (original) spec.  I was told this directly by a TRW tech support and the upgrade to Transynd is documented in their literature. 

[Benjamin]

That's what I'd use in your situation, as long as it's hydraulic fluid in there, not red ATF. 

[CAT Stephen]

@Doug and Nicki,

 

Review this post on the hydraulic fluid topic:

- 

 

[Doug and Nicki]

This doesn’t answer my question. My Rv calls for HD46, not transmission fluid. 

[96 EVO]

7 minutes ago, Doug and Nicki said:

This doesn’t answer my question. My Rv calls for HD46, not transmission fluid. 

Check the color of the fluid in there.

The manual writers and the shop floor weren't always on the same page on this!

[Tom Cherry]

41 minutes ago, Doug and Nicki said:

This doesn’t answer my question. My Rv calls for HD46, not transmission fluid. 

Please scroll up to my post….it covers all the aspects and history of “hydraulic fluid and power steering” in a “general” bullet format.  This is a synopsis based on 15 years of this topic discussion.  Your new topic was merged here….

Redundant postings and information was being posted here that were detailed in the original topic.

Thanks.

[waterskier_1]

As an aside, my 2005 Dynasty has mostly Transynd oil in the hydraulic system.  This was not intentional, but instead because of a hydraulic pump seal problem that went unattended for years.  The transmission fluid leaked into the hydraulic system via the PTO mounted hydraulic pump.  It would then overflow the hydraulic system tank pushing out whatever hydraulic fluid was in there, replacing it with the Transynd transmission oil, which then was low in the transmission, and replaced with more Transynd oil.  I've since replaced the offending hydraulic pump,  and replaced the transmission oil, and filters with more Transynd oil, but didn't bother to replace the hydraulic oil which was mostly Transynd Oil by then.

I think Tom Cherry did some research and found that Transynd Oil was perfectly acceptable for hydraulic oil, at least in the Power Steering pump and system.

Back to your normal programming .....

  -Rick N.

[Superpro14]

I'm not sure how the original post of mine talking pumps, motors ,Filter canister and hoses got added into a post on proper Fluids for different years  so I will keep the original post going hopefully I don't lose any that were posting. So first pic with small hose on right top of cannister is return from valving section of the Fan motor, dumps through the side into the tank. Second pic with the newer hose is return from cooler which goes up through the filters. the smaller hose to the left of the new hose is return from Power Steering. The largest hose on right is suction line to pump which sucks all Oil from the discharge of the filters plus the mixture of the returns from Power steering, bleed off from Valve at Fan. The main flow from the Fan motor goes through the cooler and through the newer hose up through the filters and discharges and mixes with the other returns going to the suction hose. Not saying all systems are the same but that is the way mine is plumbed

[jacwjames]

How big of a tank is that, what is the capacity. 

Mine is 4 gallons, with 3 stacked filter.  Attached is a parts page showing the tank and the fittings, which is similar to yours.  From memory the suction line for the pump pulls oil from the inside of the filters, all the return oil comes in on the outside so it is all filtered.  The bottom filter rests on a platform.  When I drained all the oil I could see the suction line inlet at the bottom.

1 Steering Reservoir.pdf

[Superpro14]

Jim, I would have thought thats the way it should be but is not on my MH, it is also a 3 filter 4 gal tank

[Superpro14]

Jim, do you remember a gentleman had an issue with the bottom of his tank being bent up and he drove it down to straighten the filters, he had some pics I was trying to find and I've looked on both sites and can't bring it up,I was hoping to see where the hose went from the filter tube, looking at my old filters there is only metal cage on outside so I'm thinking fluid inside to out on these. Pic 1 below is new wix filter same number and built the same outside as pic 4, new filter inside second pic is constructed the same as the old pic 3, if you suck Oil from outside to inside on these filters there is nothing to stop the paper element if it comes apart from going through the pump and the system with my system the pump is sucking through the filter and if something happen too the filter the steel cage on the outside retins the element material, opinions welcome tks

 

[Tom Cherry]

Maybe there is a communications issue.  TO THE BEST OF WHAT HAS BEEN POSTED...  Monaco only used the BIG UN and the LITTLE UN.  The capacity was sort of "ILL DEFINED".  The BIG UN has been quoted at 5 Gallons.  If it correctly measures only 4 or 4.X, then it is the SAME ONE.....that has been posted and is in the photographs.  It has the THREE stacked filters.

The LITTLE UN is smaller....and one filter.  It holds "approximately" 2 gallons.  I bought 2 gallons of Transynd the first time I serviced it. I DID prefill the Spin on PRESSURE filter....that my Camelot has...but OTHERS with the LITTLE UN don't have the supplemental filter.  WHY....???  Ask Monaco.  They just "came that way"....like Monaco USED TO in maybe some early 2000's or so....use a Coolant Filter.  That was a BIG MUST DO PM item.

UNFORTUNATELY....we, on the old site...and maybe here a time or two, had folks "adamantely STATE" that there was a Coolant Filter on EVERY MONACO DP made....because...  They READ IT ON THE 'NET.  And we had member do all sort of contortinous moves and searches to NO AVAIL...as they are there....  We have only had ONE report of a member even SEEING A COOLANT Filter on an ISL.  And that was on a FULLY DECKED OUT....FIRE TRUCK....that was in the shop next to his rig.

SO...  BIG and LITTLE.  That is what they are.  The pictures of the double band with multiple drains or fittings on the bottom and a Band Clamp top....are what Monaco used....unless they used it's little brother.  Originally was a NELSON...and that is stamped on many.  Nelson was swallowed up by Fleetguard...and the same filters....same tooling.....make them today...

Hope this helps clarify.

9 minutes ago, Superpro14 said:

Jim, do you remember a gentleman had an issue with the bottom of his tank being bent up and he drove it down to straighten the filters, he had some pics I was trying to find and I've looked on both sites and can't bring it up,I was hoping to see where the hose went from the filter tube, looking at my old filters there is only metal cage on outside so I'm thinking fluid inside to out on these. Pic 1 below is new wix filter same number and built the same outside as pic 4, new filter inside second pic is constructed the same as the old pic 3, if you suck Oil from outside to inside on these filters there is nothing to stop the paper element if it comes apart from going through the pump and the system with my system the pump is sucking through the filter and if something happen too the filter the steel cage on the outside retins the element material, opinions welcome tks

 

We MODREATORS LOVE A TEACHING MOMENT...

The SEARCH feature is unbelievable.  It took 3 quick attempts and HERE is the topic that you referenced.

I tried the USUAL SUPSECTS.....and on the THIRD search, I used...

HYRDAULIC BENT 

Those two key words...in the search box....and clicking on Everywhere and then selecting TOPICS produced this one...as the FIRST hit.

Here are the pictures.

Thanks for bringing that up and also allowing a TEACHING MOMENT or a WORD FROM OUR SPONSOR...  LOL.