changing cav filter - o ring and seal questions

[Burnham Bob]

the cav filter element i have bought has four o rings - two large ones (i think i know which is which!) and two smaller ones - small and smaller. where do the small and smaller ones go? the guy in the car parts shop said i might not need all the o rings supplied........

can someone help before i actually get in a mess? i've searched google and previous posts but there is still room for incompetence and mistakes......

 

[sailor211]

bolt through the middle and vent?

 

[pvb]

The tiny one goes next to the head of the central bolt. The next bigger one fits in a groove on the spigot which the filter element goes on to.

 

[Ruffles]

I've changed the small ones once in over 10 years. Not had a leak yet!

 

[Burnham Bob]

thanks pvb - presumably the small one that goes next to the head of the bolt goes outside the head of the unit....sorry to appear dense!

 

[pvb]

thanks pvb - presumably the small one that goes next to the head of the bolt goes outside the head of the unit....sorry to appear dense!

Yes.

 

[PetiteFleur]

I must admit that I only change the two large seals and so far not had a leak in five years. When I repositioned the filter when I got the boat I did replace them as I did it on the bench which was easy. Fram filter C1191PL has all the seals included.

 

[2Tizwoz]

CAV fuel filter Operators Book price 6d

HERE

 

[SHUG]

This site which was posted last week tells you all you need to know about everything (almost). Filters are on the fourth page or so.
http://www.tb-training.co.uk/CIsys.htm

Also.. remember the useful tip of putting the filter assembly in a ply bag before you unscrew it. Keeps the fuel out of the bilges.

 

[Skylark]

I must admit that I only change the two large seals and so far not had a leak in five years. When I repositioned the filter when I got the boat I did replace them as I did it on the bench which was easy. Fram filter C1191PL has all the seals included.

In situ, it's often quite difficult to get easy access to the little bug gars and I believe there's a chance of doing more harm than good in trying to change them. I agree with the above, I only change the big ones that cry out to be changed.

 

[talltim]

O Rings

The o ring which fits over the spigot (Larger of the two smaller ones) is to ensure that all the fuel goes through the element

The smallest as previously stated is a seal for the bolt

 

[Burnham Bob]

thanks everyone - at least I know waht to expect!

 

[Stemar]

Once you've done the deed, think about doing it again on a dirty night with a hot engine and your crew screaming that the rocks are getting closer.

Yes, I know you we shouldn't get ourselves in that situation and, if we do, we ought to be able to sail off, but there are any number of reasons why that might not be practicable, not least is a steep sea that just stops you short every time you build up a bit of momentum.

I had one block on me in a good F6, killing the engine. It resulted in a rather traumatic entrance into Portsmouth Harbour under sail with the wind unable to make up its mind if it was going to go round the South of Haslar Fort, round the North, over the top or double back on me. Add a ferry or three and stir well...

I now have a pair of spin-on filters from a car breaker and taps from ASAP that allow me to run on one filter with the second primed & ready to go at the turn of a few taps. If I had to I could switch to the spare filter and fit a new one in seconds. My fuel's gravity fed, but if it wasn't I could get the air out with a squeezy ball pump as found on outboard systems.