O rings on a CAV filter/separater

[cpedw]

I've just bought a replacement filter element for a CAV diesel filter/water separator. It came with 3 O rings, a small one for the assembling bolt and 2 larger (but not identical) for top and bottom of the filter element. Does anyone know which way round these 2 go? Should the larger one be between filter and housing or glass bowl and filter?
I read in a couple of previous threads that it's important to get this right, but they don't say which way round. As I've got a very slight fuel leak at present, I don't trust the existing arrangement to be correct.
All help gratefully received.

Derek

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[philwebb]

I have this separator and from memory the lage one goes at the top
and the smaller one joins the filter to the glass bowl. The time before
last that I changed the filter, the bottom one didnt seem to be a very
good fit and I ended up using the old rubber ring.
Incidentally if you are using the HDF 296 filter check out the filter
that Halfords sells for the diesel Transit - it is a good match.
Regards Phil

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[omega2]

Is this a 296/cav? if so you should have a total of 4 O rings these fit in the following order, small one onto the through bolt, then one about 1/2 inch fit onto the inside of the housing were the bolt comes through, then 2 large ones, one fits the housing in the recess where the filter butts up, and one on the bottom i.e. the alloy base, if you have a glass bowl between the filter and the base you will find yourself one o ring short, even if the kit supplied was complete, this is normal as the trade do not consider us boaties. Not sure which is which but only one will fit snuggly into the housing and the other fits snuggly into the base and you will have to salvage one to put between the filter and bowl. Hope this makes sense. When assembling if you get the lot hanging on the bolt then spin it up until if makes contact on all O rings and check alignment, then get the spanner on it.

<hr width=100% size=1>J HAMER

 

[alb40]

There is no o ring for the bolt, only a copper washer which will already be inplace at the top of the filter (it may be hard to see if it has stuck to the bolt or the housing). If an o ring is put on the bolt it will leak.

The two large o rings go at the top and bottom of the filter and the final one goes in the centre of the filter head and will fit into the centre of the filter when it is assembled

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[rex]

Mine is like Omega2's and has a small O-ring on the bolt. Have never had a leak from it. Anyone know where you can get extra smaller rings as I keep nicking one each filter change so have got 4 filters with no small ring!

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[omega2]

Find an idle diesel fitter and sort through his tool box!!

<hr width=100% size=1>J HAMER

 

[Talbot]

normal replacement filter 'O' ring set does NOT include the ring between the filter and the glass bowl. You need to ask for this seperately. I dislike these cav filters ,as they are a real source of air leaks. I have had problems with an air leak for nearly a year, and earlier this year got totally fed up with chasing the b*gger. I replaced the copper from the tank to the filter, and changed the filter for a Racor 200 from ASAP (this has an integral priming pump as well) Finished the installation, and then thought I had better just check the connection on the tank - It had been made with PTFE tape and was only finger tight - guess that was where my leak was!. I have made up all the connecctions with Locktite's lockseal, and have not had any problems since!.

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[TrawlingAlong]

You might want to eliminate the air and fuel leaks altogether by changing from the cartridge filter and glass bowl arrangement to a screw on fuel filter. You can find the adapter information at http://www.abcprecision.com . Use of this filter will help you eliminate bleeding the line of air each time you change the filter, so long as you prefill the filter with fuel before screwing on the adapter, which attaches permanently to the CAV fuel filterhead.

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