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Author Topic: Hydraulic System Filter  (Read 611 times)

Dennis Belfils

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Hydraulic System Filter
« on: April 11, 2019, 03:26:50 PM »
Just prior to leaving our Winter Home, we had a Boss shop change oil, lube & replace the Cat fuel filter. Since we do not know if the P O replaced the hydraulic filter & we had one we thought it would be a good time to. The filter is located left side of the engine compartment, below the reservoir & cooler. Before the Tech could get the old one off, we lost 2-3 qts of fluid & he quickly spun it back on. We could not find a way to isolate the filter. Crimping the line was discussed, but no one wanted to risk damaging the hoses. Are we looking at a complete fluid change to replace the filter or did we miss something?
2006 Monterey Montclair IV
Cat C-9 400HP

David T. Richelderfer

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Re: Hydraulic System Filter
« Reply #1 on: April 11, 2019, 03:33:56 PM »
The Monaco Engineering Dept would recommend turning the coach upside down to reduce the oil loss.  Of course, you should dump the waste tanks first.  Another brilliant design, eh?  No shutoffs on the oil lines?
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Dennis Belfils

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Re: Hydraulic System Filter
« Reply #2 on: April 11, 2019, 03:44:56 PM »
Your reply made me laugh. Thanx ;D
2006 Monterey Montclair IV
Cat C-9 400HP

Frank Bergamo

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Re: Hydraulic System Filter
« Reply #3 on: April 11, 2019, 03:49:33 PM »
The only way to replace filter if you don't want to crimp lines that I know of is to quickly remove old filter, then install new one. Then top off fluid in tank that was lost with new fluid. A bit messy, but try to put something under filter to catch leaking fluid. Hope this helps.
Frank & Paulette Bergamo
2019-       : 2007 Marquis Topaz IV  C-15 600 HP Allison 4000
2014-2019: 2002 Marquis Emerald C-12 505 HP Allison 4000
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Grand Junction, CO.

Dennis Belfils

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Re: Hydraulic System Filter
« Reply #4 on: April 11, 2019, 04:08:58 PM »
I can understand why no valves were installed as if they were not reopened, it could cause a big problem, but the filter location was poorly thought out. How often should the hydraulic fluid/filter be changed? Maybe it's just time to do so....
2006 Monterey Montclair IV
Cat C-9 400HP

Mike Shumack

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Re: Hydraulic System Filter
« Reply #5 on: April 11, 2019, 06:25:41 PM »
The manual says to change hyd fluid every 12 months or 15,000 miles - but more realistically I'd say change it every 5 years. There is not an "oil contamination" worry with the hyd system like you would get with a transmission (wearing friction discs) or for engine oil (combustion gases) but there can be moisture in the tank so an oil change is still needed at some point.

One trick I heard of is to put/tape a vacuum cleaner hose on the hyd tank filler opening (not touching fluid). The vacuum on the tank will keep the oil in the tank from draining quickly (if at all) when the filter is removed and it will not suck up any oil in the vacuum cleaner.

Here is an example https://www.youtube.com/watch?v=Kp1SpNpXwlE
- Mike

'05 Beaver Patriot Thunder, Vicksburg, CAT C13  525HP, Allison 4000MH, HydraLift

Bill Sprague

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Re: Hydraulic System Filter
« Reply #6 on: April 11, 2019, 07:04:01 PM »
The only way to replace filter if you don't want to crimp lines that I know of is to quickly remove old filter, then install new one. Then top off fluid in tank that was lost with new fluid. A bit messy, but try to put something under filter to catch leaking fluid. Hope this helps.

If you have everything ready, gloves on, etc., you can be quick enough to only loose a cup or two.  Having a helper with a finger to plug the hole can keep the flow to a minimum. 
Bill Sprague
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Jerry Emert

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Re: Hydraulic System Filter
« Reply #7 on: April 11, 2019, 08:57:12 PM »
Just replaced mine a few months ago and the same thing happened.  I found that the fluid is slippery!!!  As I was scrambling to get new filter on the fluid leaked all over the new filter making it very slick.  I was actually laughing as I tried to turn the filter with very little friction to help get a grip! Had a ball doing it but lost about a quart.  I was ready for the loss after reading several forum posts on it. 
Jerry, Chief USN Retired
2003 Patriot Thunder Lexington 40' 3 Slides
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Stan Simpson

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Re: Hydraulic System Filter
« Reply #8 on: April 12, 2019, 08:17:48 PM »
Mike, that's a pretty neat trick with the wet vac.

I recently changed mine. Had a bucket underneath, but the old one slipped out of my hand, and fell in to the fluid, along with the dirt from the filter. I had to quickly turn the new filter on, and replaced the fluid that got out. Didn't want to put dirt from the old filter back in.
Stan Simpson & Becky Glover & Moe the cat
2005 Monterey Laguna IV
C9 400 Cat
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Bryan Beamon

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Re: Hydraulic System Filter
« Reply #9 on: April 12, 2019, 10:16:58 PM »
Dennis, not sure if your 06 Monterey is the same as our 07 Contessa Cat C-9 400hp, but our hydraulic reservoir has 3 drop in filters as well as a spin filter. I have found that if I first drain the reservoir, add new drop in filters, then change the spin on filter and then refill the reservoir the mess of hydraulic fluid is minimal. The spin on filter is only changed every 3 years and I change the hydraulic reservoir every 2 years ,fyi
C & Bryan Beamon
2006  to present
2007 Contessa 42ft Cat C-9 400hp
1996 to 2006 97 Beaver Patriot Camden

Dennis Belfils

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Re: Hydraulic System Filter
« Reply #10 on: April 15, 2019, 03:57:45 PM »
Thanx Byron, I will look to see if mine is the same. Plan to do a complete change in any case.....
2006 Monterey Montclair IV
Cat C-9 400HP

Roy Boles

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Re: Hydraulic System Filter
« Reply #11 on: April 16, 2019, 04:21:36 AM »
    I had the problem of hydraulic oil filters springing leaks. I got really good at changing that filter. After finding the problem I added a ball valve between the tank and the filter. No more filter leaks so I haven’t tried the valve yet.
'98 Marquis Diamante
C-12/Allison 4000

Dwight Lakusta

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Re: Hydraulic System Filter
« Reply #12 on: April 20, 2019, 03:12:00 PM »
SPEED! It also wouldn’t hurt to change out some of the old oil with new anyway. Whatever you loose, just top up with new. Should loose more than a quart or two.
2003 Beaver Marquis Ruby 40, 3 slides, C12, 505HP. Current unit.
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2000 Monaco Windsor, 40, 2 slide, 8.3 ISC, 330HP.