i have the GDP big line MK2 kits on both of my trucks and they did not come with that center o ring is it something we should have
hope to hear from the guys a GDP on here
thanks
sid

 

I just picked up the CAT 0750. I was going to ask the same question. Can a regular o-ring be used or does it have to be a flat rubber ring like Fleetguard uses?

 

I've been running the CAT filters for almost two years now without an o-ring. No o-ring comes with the filter or head aside from the large outer rubber gasket on the filter itself.

 

Thats odd, when I got my Glacier kit it came with a flat o-ring installed on the center post of the filter head. The oil filter uses one so I never thought about the fuel filter not using one. Heres a link to the flat o-ring from Glacier: http://www.glacierdieselpower.com/pr...?pf_id=255622S

I looked through the installation instructions on the Glacier site and they don't mention the o-ring. I just assumed that if it was on the post that I should use it. I swear I remember something mentioning the o-ring. I have the copy of 8 lug magazine that covers the Glacier installation, maybe it mentions it. Its out in the garage and covered in diesel. I can't see why they sell it if they don't want you to use it though. Also if you look at both the F/W separator and 2u kits they list the o-ring in the "Parts we suggest column".

When I put on the Fleetguard and the CAT filters I used the o-ring. They tightened up just fine each time and I didnt have any binding or anything else.

I also seem to remember the filter head center post is only threaded so far and that the ring takes up the remainder of the space between the threads and the filter head.

 

Same here. We've had about 10 trucks that all come factory with the same fleetguard filter head and Cat filters, none of which ever use that fleetguard o-ring. I did install one with that ring (forgot to remove it from a previous fleetguard filter) and it stripped the bottom 1/2 of the threads. It leaked so I tightened it more and when it fell off I noticed that ring was still there. I figure if they were supposed to be used, they would be with the new filters.

I wouldn't use it with a Cat filter.

 

Well I went out and measured the depth of the filter from the outer sealing ring to the threaded portion of the base. The Fleetguard is right at 3/16" and the CAT is right at 1/8". The o-ring is about 1/8".

I don't think a 1/16" difference is going to matter on this flexible o-ring with this application. When I tightened it down I never had any problems. I ran the filter up to hand tight and then went 1 extra turn as the filter suggested and everything is running fine. No leaks or anything. I'm not going to worry about it.

For what its worth the Fleetguard 2u filter doesn't come with an o-ring either. I think its specific to the filter head.

On the other side there are a lot more threads on the CAT filter as the CAT head is aluminum and the Fleetguard head is steel. So you would have more thread to stop fuel.

 

maybe the guys from GDP will respond this is a good question
thanks

 

Now for the real question; is a flat o-ring really an o-ring?

Nick.

 

I think they are closed down until the 18th of this month for inventory.

 

JohnnyH,

Where are you getting your fuel from?..........Thats the worst filter i've ever seen.

 

Unless I am on the road with the RV I always buy from Hess. Very busy station and have never had any problems. You are not seeing dirt but rust that formed in that filter. I have never seen a drop of water during my random draining of the water seperator. I'm confused how this happened. I just hope nothing went through the injectors. The truck is running fine.