Author Topic: Racor Filtration System  (Read 950 times)

Eric Drickersen

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Racor Filtration System
« on: June 25, 2026, 05:17:08 PM »
I see there are a few old posts on repairs and replacement to the now obsolete Racor system used in my 2001 Marquis, but hoping I can get some specific guidance on how to proceed with a repair/replacement. Mine has the plastic bowl (water separator?) attached to the unit, which now appears to be cracked and leaking. I spent some time speaking to Parker Racor techs and they suggested updating to the P790R system. I see obtaining a replacement bowl is not possible, but is there are other recommended mods or fixes for this without going into a full replacement?

Respectfully, Eric
2001 Marquis
C-12

Dan Johnson

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Re: Racor Filtration System
« Reply #1 on: June 25, 2026, 11:44:07 PM »
I had what you have plus a second cat filter. I upgraded to cat primary filter and new fuel line to fuel pump per cat man Dave. I can help with part numbers if needed.
2002 Beaver Marquis Emerald
Cat C-12
Nebraska

Eric Drickersen

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Re: Racor Filtration System
« Reply #2 on: June 26, 2026, 03:28:47 AM »
Thank you! That would be helpful. I also have another filter located along side this unit.
2001 Marquis
C-12

Dan Johnson

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Re: Racor Filtration System
« Reply #3 on: June 26, 2026, 11:45:07 PM »
Filter base  1374367,  5134490 primary (first)  filter,  clear bowl for filter and secondary filter 1R0749. I also had cat make a new line from fuel pump to filter. You will need some fittings to filter base which I got from a hydraulic company. I took a picture but do not know how to post here. Send me your email address so I can send picture of finished job. These are all cat numbers.
2002 Beaver Marquis Emerald
Cat C-12
Nebraska

Eric Drickersen

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Re: Racor Filtration System
« Reply #4 on: June 27, 2026, 01:26:56 AM »
Thanks Dan.
Fred suggested I take a closer look at the plastic bowl to see if in fact it was cracked, or if the o-rings had failed. I did just that, and it looks like it's just the o-rings and seals! I (foolishly) took the mechanics word that the bowl had cracked and caused the leak.
2001 Marquis
C-12

Eric Maclean Co-Admin

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Re: Racor Filtration System
« Reply #5 on: June 27, 2026, 01:13:44 PM »
Eric
Go to the coach assist library where you will find the manuals on the original racor unit.
Here is a link to a new sight glass if you need it but it's usually the "O" rings that are the problem.

https://www.dieselfiltersonline.com/300200-racor-300200-prefilter-w-o-ring-200-mic-discontinued-order-790r30-replacement-unit.html?srsltid=AfmBOorbE0TB-VaCLMX_LLCTWxMlip6hZvqzYsxNX3v-JAlHsL9pUpXn

You may find this past post helpful
https://beaveramb.org/forum/index.php/topic,10706.msg72846.html#msg72846

The "o" rings are a known problem with this system but it is a serviceable part .
I know of at least one other person who has removed the sight glass and threaded the housing to accept a J.I.C. hydraulic fittings so the fuel line could be connected directly by passing the sight glass and coarse screen.

Hope this helps
Eric
« Last Edit: June 27, 2026, 01:41:45 PM by Eric Maclean Co-Admin »
1997 Patriot Yorktown
3126-B
2009 Chevy HHR
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Demco Air Force one tow brake.
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Frank Bergamo

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Re: Racor Filtration System
« Reply #6 on: June 27, 2026, 03:46:21 PM »
If you are going the O-ring replacement direction, the O-rings are different sizes. There are 4 total, two on the ends of the clear pre filter, and two inside the housing opening that holds the pre filter. Very subtle difference in size, so keep track of them when disassembling. Good luck!
Frank & Paulette Bergamo
2018-       : 2007 Marquis Topaz IV  C-15 600 HP Allison 4000
2014-2018: 2002 Marquis Emerald C-12 505 HP Allison 4000
2004-2014: 1986 Executive Diplomat 3208 250 HP Allison MT-643
Grand Junction, CO.
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Eric Maclean Co-Admin

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Re: Racor Filtration System
« Reply #7 on: June 28, 2026, 02:32:24 PM »
Frank is correct there are two different "O" ring sizes used you will need two of each although it's nice to have spares as they are fairly cheap.
They are made of Nitrile so the fuel won't effect them . You should be able to pick them up at your local hydraulic shop.
The numbers are are space standard sizes as follows.

Part # 114  dimensions. .612OD x .103 cross section
Part #208   dimensions.   .609OD x .134 cross section


Eric

1997 Patriot Yorktown
3126-B
2009 Chevy HHR
Roadmaster falcon tow bar
Demco Air Force one tow brake.
The following users thanked this post: Fred Brooks

Eric Drickersen

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Re: Racor Filtration System
« Reply #8 on: June 29, 2026, 04:57:39 PM »
Thank you for the links and valuable advise on the installation. I had seen the pre filter for sale at the link you provided, but seems to be out of stock and discontinued. In any case, I am hopeful it's just the seals. I also see the seal on the elbow attachment is old and deformed; I'll look for that one as well. Are there any other seals or internal components I should service before reinstalling? I totally agree it's an excellent idea to keep a couple of each as spares.
Thanks again!
2001 Marquis
C-12

Frank Bergamo

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Re: Racor Filtration System
« Reply #9 on: June 29, 2026, 09:14:06 PM »
Looks like you have the bases covered. When I replaced the O-rings on my 02’ Marquis, never had another problem with air in the fuel system. Most people will say upgrade to a newer primary fuel system, but in my case, a few O-rings fixed the problem. Cheap fix if it works, if not, then spend the money to upgrade. Your call! Good luck!
Frank & Paulette Bergamo
2018-       : 2007 Marquis Topaz IV  C-15 600 HP Allison 4000
2014-2018: 2002 Marquis Emerald C-12 505 HP Allison 4000
2004-2014: 1986 Executive Diplomat 3208 250 HP Allison MT-643
Grand Junction, CO.

Eric Drickersen

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Re: Racor Filtration System
« Reply #10 on: June 30, 2026, 05:08:55 PM »
Upon closer inspection of the plastic pre filter, I noticed some damage to the area where one of the o-rings seats. It looks like it was damaged by someone attempting to pry it out. In any case, this likely contributed to the leak identified by the mechanic. My first thought is to try to repair it by filling and evening out the seat area. Maybe marine-tex, JB Weld, or fuel tank gasoline-resistant epoxy? Any ideas?
2001 Marquis
C-12

Frank Bergamo

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Re: Racor Filtration System
« Reply #11 on: June 30, 2026, 05:50:52 PM »
Ya, that stuff might work in a pinch, but I would be looking for another pre filter. They are getting hard to find, so it might be time for an upgrade. Good luck!
Frank & Paulette Bergamo
2018-       : 2007 Marquis Topaz IV  C-15 600 HP Allison 4000
2014-2018: 2002 Marquis Emerald C-12 505 HP Allison 4000
2004-2014: 1986 Executive Diplomat 3208 250 HP Allison MT-643
Grand Junction, CO.