Author Topic: Hydraulic pump leak  (Read 5524 times)

Don Forsyth

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Hydraulic pump leak
« on: April 18, 2024, 10:39:59 PM »
I have a 2005 Beaver Monterey Laguna IV w/Cat C9  400. I noticed the other day a puddle under the rear just about the battery location. I crawled under to find that the large hydraulic line that connects to the pump had loosened and was dripping. I lost about a gal of fluid. Which makes sense because my power steering started groaning. Originally the elbow of the line was horizontal and up near the frame and tucked away. When I found it, it was hanging down vertically. I pushed it back up as tight as I could by hand and then put a pipe wrench on the fitting. I thought that fixed it until a few days later when I noticed a new spot on the ground. The fitting is still leaking. I can't tighten it anymore and was wondering it maybe the nut turns on the front of the pump. So not wanting to create more problems I thought I would reach out and see if anyone was familiar with this and how to tighten it. Having trouble attaching picture.
2005 Monterey
CAT C9 400hp

Frank Bergamo

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Re: Hydraulic pump leak
« Reply #1 on: April 18, 2024, 11:19:20 PM »
The fitting that goes into the pump housing is a O-ring fitting. Rotate the elbow fitting where it lines up with the hose fitting then snug it down. That should fix the drip. If not, then back out the nut to access the O-ring and replace O-ring and reassemble. 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
2004-2014: 1986 Executive Diplomat 3208 250 HP Allison MT-643
Grand Junction, CO.

Don Forsyth

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Re: Hydraulic pump leak
« Reply #2 on: April 19, 2024, 02:28:20 PM »
Thank you Frank,
If I do wind up replacing the o ring I assume I will have to drain the pump and reservoir. Is that true?
2005 Monterey
CAT C9 400hp

Eric Maclean

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Re: Hydraulic pump leak
« Reply #3 on: April 19, 2024, 03:55:55 PM »
Don
As Frank pointed out the hydraulic fitting in question is what is known as an ORB ( O ring based fitting) . They are designed to be treated in and don't tighten up on the threads like a pipe thread does instead the stay loose in the valve block which allows you to position the fitting to the desired angle to allow hose connections to be where you need them.
One the fitting is threaded in and positioned correctly the jamb nut is tightened against the O ring which seals and locks the fitting in place.
It is common for the vibration from the running engine to loosen these type of fittings
As Frank pointed out if simply retightening the jamb nut doesn't solve the leak you may have to remove the fitting and replace the O ring.

Eric
1997 Patriot Yorktown
3126-B
2009 Chevy HHR
Roadmaster falcon tow bar
Demco Air Force one tow brake.

Frank Bergamo

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Re: Hydraulic pump leak
« Reply #4 on: April 19, 2024, 04:55:51 PM »
Very little should leak out if you need to replace O-ring. First, snug up the nut, that should take care of your drip.
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
2004-2014: 1986 Executive Diplomat 3208 250 HP Allison MT-643
Grand Junction, CO.

Don Forsyth

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Re: Hydraulic pump leak
« Reply #5 on: April 20, 2024, 01:31:08 PM »
Okay, I'll try to tighten again. Maybe I need some leverage. I just about gave myself a hemroid trying to move that nut. It won't go in either direction. It is snowing here now, so I will go to the storage lot next week to see what I can do.
Thank you,
2005 Monterey
CAT C9 400hp

Frank Bergamo

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Re: Hydraulic pump leak
« Reply #6 on: April 20, 2024, 03:27:27 PM »
You shouldn’t need a bunch of leverage on the nut. If it’s that tight, and still drips, then the O-ring needs replacing. It’s the nut up against the pump housing that we are talking about, not the hydraulic line fitting nut.
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
2004-2014: 1986 Executive Diplomat 3208 250 HP Allison MT-643
Grand Junction, CO.

Don Forsyth

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Re: Hydraulic pump leak
« Reply #7 on: April 23, 2024, 02:01:09 PM »
Yes, that is correct. The nut at the housing. What in confusing me, is that the elbow that threads into the nut. So in order to change the O ring, I will have to disconnect the nut on the supply line from the elbow. Then remove the elbow to get to the nut to replace the O ring. Any idea of how much fluid will come out. Just so I have a big enough tub to catch it all. I tried to attach another picture of the supply line and elbow.
2005 Monterey
CAT C9 400hp

Frank Bergamo

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Re: Hydraulic pump leak
« Reply #8 on: April 23, 2024, 04:22:52 PM »
Yes, disconnect the supply line nut from the swivel fitting, holding the swivel fitting with a wrench as you are loosing the supply line fitting. This keeps it from twisting and possibly breaking off. After the supply line fitting is off, then loosen the nut up against the pump housing and remove fitting from housing. As far as fluid leaking out, you will probably loose some, have a pan ready and possibly something to plug the ends. Hope this helps, good luck! This is what you have, https://www.discounthydraulichose.com/6801-06-06-38-jic-male-x-6-saeorb-male-90.html?gad_source=1&gclid=CjwKCAjwuJ2xBhA3EiwAMVjkVKvt6Ae8TIYh97B7nKLLa-9TdBe8eLwgHb0MiwKA25iaj_qrDhVWbhoCTOQQAvD_BwE
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
2004-2014: 1986 Executive Diplomat 3208 250 HP Allison MT-643
Grand Junction, CO.

Eric Maclean

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Re: Hydraulic pump leak
« Reply #9 on: April 24, 2024, 01:17:47 AM »
Don
Being the larger of the two hydraulic hoses tells me that is the supply line from the hydraulic reservoir if there is no shutoff valve at the reservoir then expect the entire capacity of the reservoir when you disconnect that line . ( Check first to see if there is a shut off valve at the reservoir) I doubt it but you never know.
1997 Patriot Yorktown
3126-B
2009 Chevy HHR
Roadmaster falcon tow bar
Demco Air Force one tow brake.

Don Forsyth

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Re: Hydraulic pump leak
« Reply #10 on: April 24, 2024, 02:25:59 PM »
Frank, thank you for the link. That really turned on a light. That makes perfect since now, that coupling would have a flared fitting at the supply line. Apparently the end with the straight tread, threads into the housing and the nut acts like a lock nut but with the O ring sealing it.

Eric, thanks for your input. That's a good idea, I will look along the supply line for a shut off. But I got a feeling there isn't going to be one. Last thing I want is 10 gallons of fluid on the ground.

I had to replace the fluid about two years ago. I had it in the shop to replace the engine compressor. It got really cold here in Denver and when they started it to put in the shop it blew out the hydraulic cooler. Unexpected repair. If I remember correctly the fluid was about $300. I found a new radiator because they could not repair the old one. That was over a$1000. Again, thank you for your help. I will let you know how it turns out.
2005 Monterey
CAT C9 400hp

Don Forsyth

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Re: Hydraulic pump leak
« Reply #11 on: May 10, 2024, 02:58:46 PM »
Sorry for the long delay, but I finally was able to get back to the storage lot and change the O ring on the hydraulic line. It was a little challenging to say the least. The nut on the pump is 1 7/8", and the nut on the line is 2". I only have a pipe wrench a spud wrench to work with. The access is not great, the wrenches were really hard to manipulate in the areas that I need to access. A 5 pound persuader helps too. Just to give the fittings a little love tap, and a cheater bar. I was going to buy a tapered plug but didn't and wished I had. I put a clean 5 gal. bucket underneath to catch the oil. Once I had the compression nut loosened the fluid started run out into the bucket and down the side of the engine. Thanks to the wind. I had a good rag at hand and when I had the line completely off, it was like someone opened the floodgate. I stuffed the rap into the end of the hydraulic line and it held back until I could get the elbow fitting out and change the O ring. The O ring was square but tapered on one edge. After running to the hydraulic store and finding out that the O ring was supposed to be round and the old one was just smashed. I could have picked it up a Ace hardware.

Reassembly went really quick, but by the the time I got the hydraulic line reconnected I had 4 gal. of hydraulic fluid in the bucket and about a quart on the ground and tools and me. Pretty messy job. But it is done and no more leak.

For anyone that is going to tackle this job, I would highly recommend you get a 1 7/8" Jam Nut wrench, I should have, but window of opportunity now and I had to take advantage off it. Also get a Tapered plug. Both items will run you about $20.

Thank you everyone for your input and suggestions. It would have been alot harder to do this job without them.
2005 Monterey
CAT C9 400hp
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