Mep-803a Diesel leak

[chilbun28]

I notice I'm getting a drip of fuel running down my metal canister of the fuel filter housing. I changed the filter along with all new o-rings along with the large one which appears to be the one leaking. I removed the filter and oring, inspected it, and replaced it along with rubbing a little grease around the o-ring before tightening the canister. At first it appeared to no longer leak but started again. I applied more torque on the center bolt which helped but I don't want to over tighten. Should I just replace the oring with a new one and start over? Anyone have a certain o-ringthey would suggest?

 

[Ray70]

Unfortunately those canisters are prone to leaks no matter what you do. 99% of the time it's a matter of getting the o-ring ( actually it a square cut ring ) into the groove without it twisting or otherwise getting out of position.
Take the bowl off again and make sure the seal is in the groove and lying flat.
reassemble the bowl taking care to push the bowl up into the groove for the seal while tightening the center bolt, don't rely on the bolt to guide the bowl into position.
If its still leaking, double check with a paper towel to see if the leak is at the bowl seal or where the center bolt seals to the bottom of the bowl.

 

[Mullaney]

I notice I'm getting a drip of fuel running down my metal canister of the fuel filter housing. I changed the filter along with all new o-rings along with the large one which appears to be the one leaking. I removed the filter and oring, inspected it, and replaced it along with rubbing a little grease around the o-ring before tightening the canister. At first it appeared to no longer leak but started again. I applied more torque on the center bolt which helped but I don't want to over tighten. Should I just replace the oring with a new one and start over? Anyone have a certain o-ringthey would suggest?

.
You need some sort of "slick-um" on that quad ring. Yeah diesel fuel could work, but the stuff made in the last ten years or so isn't nearly as slick as it used to be. Like @Ray70 mentioned, grease will work. Silicone or Vaseline might be another idea to keep you from "rolling the ring" when you install the filter. Square rings are more difficult than round when you use them (IMO).

Also, have you looked at the bottom canister to make sure that the bottom isn't deformed?
Looking for "cranked down too tight" by the last guy who changed the filter?

.

 

[chilbun28]

I'm curious if the ring that came with this filter is possibly not a square ring and possibly part of the problem. I plan on looking at it this evening when I get home. I might find the part number and order several spares just to have.

 

[87cr250r]

I generally don't recommend using petroleum greases to lubricate o-rings. Buna-N o-rings first swell and the harden over time when exposed to petroleum oil. Normally, an o-ring is only exposed to oil at its edges but when coated with grease the entire o-ring is exposed which accelerates the deterioration. Also, EPDM o-rings used in cooling system components will be destroyed by petroleum greases. Silicone and PTFE greases are more universal and don't accelerate the deterioration of the rubber.

 

[chilbun28]

Thanks for that explanation. I was unaware of that.

 

[Light in the Dark]

You will want to check the sealing edge of the filter canister too.. if it has any burs, distortions, or tweaks of any kind... its never going to seal right again. Ask me how I know. Do you have the internal spring, and sealing washers in place on the bolt as well?

They are available new on the big auction site and elsewhere (complete with the mounting base, which you can just throw away) if you need new.

 

[Light in the Dark]

USGI MEP-802A, 803A, 812A, 813A Fuel Filter Assembly 284359, 2910-01-110-8184 | eBay

The top cover is female threaded to accept 1/4" BSP male unions at either side.

www.ebay.com

 

[chilbun28]

Yea, I have the spring in the bowl along with the new seals that go on the bolt.

 

[chilbun28]

Fixed. I pulled off the can and removed the ring gasket. It looked fine with no cuts or pinched areas so I reinstalled it. I didn't allow the can to rotate as I tightened it and made sure the ring stayed in its grove and the can seated directly into the gasket. I turned the ignition switch on and let the fuel pump charge the fuel lines/filters. It's dry as a bone. I'm pretty sure my issue was from the can not seating directly onto the gasket and it was slightly cocked on the housing.

 

[Guyfang]

Very common. Thats why I always turned the can as I was tightening it up. Seemed to keep the can centered.

 

[Light in the Dark]

Ive had good luck using a nut runner on my screw gun, and hold the canister body up and tight until the bolt seats, then just finish with a socket wrench. The twisting of the can body can sometimes distort the gasket.

 

[jmenende]

Very common. Thats why I always turned the can as I was tightening it up. Seemed to keep the can centered.

I must disagree here. I used to turn the can and what would often happen is the O ring slipped out of the groove and got pinched thus causing a leak. What works for me is using a little axle grease to keep the O ring squarley in place and tighten the bolt wihile holding the cup in place. Most problems occur when not seating the flat O ring properly as was stated before.

 

[Ray70]

Seems we all have different ways of conquering the problem. Whatever work to stop the leak... go with it!.
Seems a spin-on final filter would have eliminated a lot of grief!.