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Cat 303.5 leak from Hydraulic fluid filter cover

Kekoa512

Member
Joined
Jan 24, 2025
Messages
20
Location
Honolulu
Hydo flows out when it’s pressurized after I removed the cover and reinstalled. I took it off again, cleaned up the o-ring and mating surfaces, and reinstalled. Still leaking.

Hoping this is just an o-ring issue? It seemed like it may be a little loose, not a snug fit into the groove it’s supposed to sit in. Anything I’m missing before I replace o-ring?
 

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Kekoa512

Member
Joined
Jan 24, 2025
Messages
20
Location
Honolulu
I’d call it a big weep. It didn’t do it before I took the cover off; only after I put it back on so im hoping it’s just an o-ring issue
 

Kekoa512

Member
Joined
Jan 24, 2025
Messages
20
Location
Honolulu
@Nige that's the bummer, I don't have a serial number. Sorry for the delay, I thought i had sourced the right o-ring but i was wrong. I know it's the o-ring/seal under the cover to the hydraulic suction strainer and I THINK my rig is an old 303.5D CR or just CR. Do you know the exact name of that cover I'm talking about? Hoping i might find the o-ring if I know what CAT calls that cover
 

Nige

Senior Member
Joined
Jun 22, 2011
Messages
38,491
Location
G..G..G..Granville.........!! Fetch your cloth.
Do you know the exact name of that cover
Cat will simply call it a cover. The problem is that without looking the cover up by machine Serial Number getting the correct Part Number is somewhat of a lottery.
I thought i had sourced the right o-ring but i was wrong.
Did you buy a Cat Part Number.? If yes, what P/N did you buy.?
 
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