Bmc 1.5 fuel filter O rings

[Cattleya]

I have already taken the old filter and top and bottom O rings off and can't remember which O ring goes at the top, one is a little bigger than the other and one has a red spot on the side. Does anyone know which goes in the top housing and which goes under the filter? 

[Tracy D'arth]

They are different sizes and only fit in the correct place in the top groove and in the bowl recess. The top one is the larger diameter and should stay in the groove on its own once correctly inserted. 

 

The smallest o ring goes under the top bolt washer, the next smallest goes in the groove on the central "thumb" in the middle to seal to the inside of the filter.

[Tony Brooks]

Normally the wide one at the bottom - check it against the land on the bottom of the filter element. I doubt you would get that one into the recess in the top housing.

[TNLI]

On 24/08/2021 at 20:20, Cattleya said:

I have already taken the old filter and top and bottom O rings off and can't remember which O ring goes at the top, one is a little bigger than the other and one has a red spot on the side. Does anyone know which goes in the top housing and which goes under the filter? 

Just found this kit a few days ago:

 

Spin On Fuel Filter Conversion Kit (CAV Replacement) (asap-supplies.com)

 

The CAV 296 is a cheap truck filter, so it does make sense to convert it to a spin on unit. Spin on filters are easier to change.

 

For a primary fuel filter, I always fit a Racor 500 FG, although I would confess it's a far cheaper Chinese copy.