CAV filter change

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Caladh

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..don't laugh. Having owned my V34 for 9 years I think it's about time I changed said filter. I do others on a regular basis ! I see the small tap on the bottom and presumably drain out existing, undo the bolt, remove glass bowl and filter and replace with a new filter. Do I then operate the lift pump to refill or how else do I refill the "bowl" ? Thanks in anticipation.
 
can anybody tell me how much to tighten the central bolt please. Mine always seems to be weeping - somewhere - whenever I wipe my hand around the CAV it always smells of diesel. The Orings/gaskets are replaced and all mating parts wiped clean.
 
Where is the filter?
A - is it between the tank and the lift pump?
B - Is it lower than the level of fuel in the tank?

If the answers are both "yes" - and they ideally should be, once you have changed the filter and replaced the diabastrical rubber "o" rings properly, turn on the fuel tap at the tank again and open the bleed screw at the top of the filter housing.
The flow of fuel down from the tank will displace the air in the filter unit.

Tickling the priming pump will simply draw air into the system....

If you've managed to get air into the system anyway, it will need to be bled at the fine filter between the lift pump and the injector pump. This is when the hand primer is used.
Then, depending on the engine in question, there are more bleed points to be used in the correct sequence.
Everyone should know how to do this at sea, as a wee bubble of air in the wrong place will prevent an engine from starting just when you need it most.
 
Helpful

Caladh said:
Thanks for the info. - very helpful. Looks like I'm not the only one looking at this issue !
Click to expand...

Wonderful I thought it was only me.
I love this site for all this good stuff

Now I know what to do. Have only been putting it off for 5 years - on the principle that it ain't bust.
But I felt the same way about the heat exchanger and it was only a small drip - for a while, then it got going.........
 
A lot of people seem to complain about the CAV filter. There certainly are easier ones to change but at a price. The only real problem with the CAV with glass bowl is that CAV do not supply 2 of the seals that fit between base and bowl and between bowl and filter. Contact CAV and they woll send you additional seals FOC.

When doing the change have plenty of absorbent paper to hand and take your time. Do make sure that you remove the seal at top of filter. It is recessed into the upper housing. Can be tricky to remove. I use a sail makers needle. Stick it into seal, incline needle and remove seal. Dry the recess and smear a little grease into recess and carefully fit a new seal. fit new seal on long central bolt, hold new filter in place, insert long bolt, place bowl up against filter, hold in place, fit base plate and locate long screw and start in thread. Tighten by hand and then further with spanner to nip the seals. I think it is supposed to be tightened to 13nm but have neveractually used a torque wrench for this purpose. Just reasonably tight. Fill with fuel and check for leaks. Tighten a little further if necessary.

This has taken longer to type than it will take you to change the filter!

With regard to the extra seal required the quick answer is to buy 2 filters and later get extra spares from CAV
 
There are plenty other compatible filters I'm pretty sure the last ones I obtained had enough gaskets. I've always found a smear of grease on the gaskets gets them to seat a bit better.
 
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As people say they are a 'B******' to change! I always put a container underneath to catch spilt diesel(and you will spill some!) and use rags etc. I've thought about the 'spin-on' type filters but they are expensive......... ASAP used to do a conversion kit to 'spin-on' but I don't think they supply it anymore.
 
You can also buy a new CAV filter head for c. £10 which accepts spin-on filters such as the Delphi 496a, as fitted to Land Rovers and the like.
I'll also jump on my small soap box and say that not all filters are equal - if at all possible fit the Delphi HDF296 filter (if staying with the bolt on type), they only cost a couple of £ from a site such as:
http://www.ssldieselparts.co.uk/fuel-filters-fuel-filter-delphi-bolt-c-7_242.html
(no association)
A diesel system engineer who I have considerable respect for views pattern filters as one of the main causes of pump and injector wear.
 
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I am about to jinx my next filter change...

I have never found any of the difficulties listed in previous posts. I like the glass bowl so I can see whether there is a problem. Light aircraft have drain points built into their fuel lines and a sample is taken off each before every flight to check for condensation in the fuel. Of course, they have the advantage that the fuel is gravity fed to thes drains.

I always make sure the fuel level in the tank is higher than the top of the filter. Close off the fuel taps at the tank and the filter outlet. Change the filter, cleaning every component carefully, and then open the bleed screw and let it refill itself. Mind you, I have a vested interest in keeping my CAV filter as I bought a dozen filters (genuine Delphi) from bankrupt stock.

Rob.
 
I also have the dreaded CAV filter, but have no problems in changing it. A light smear of grease on the new gaskets is a good idea. I tighten the central bolt hand tight ans then turn the filter and the bowl independently until they feel loose agan. Then tighten a little further and repeat. When no more free play can be eliminated this way tighten the central bolt gently. This prevents leaking and diesel smell.
 
alan17 said:
As a car mechanic I have changed many CAV type filters and if you have the type with a glass bowl I have yet to come across a make with enough rings. I have tried Crosland, Lucas CAV. Fram, Coopers and many others.
Click to expand...

Baldwin filters supplied mail order by In-line Filters come with a full complement of rings.

After trying various ways of reducing the mess, I now hold a plastic kitchen measuring jug (flexible, good handle, £0.40 from Asda) under the filter then remove the centre bolt letting everything fall into the jug. Very clean and simple.
 
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