CAV filter assemblies

what happens if the glass breaks in the remote outback

You stop.

Then you join the two hoses and bypass the filter, bleed and go.

How the hell would the glass get broken? I put one on after my diesel engine swap a few years back. Great value compared to a Toyota original.

I carry a spare cause I like the inspection idea, however as gerhard said, stop, join and proceed.

The glass is around 8mm thick so would take a bit to crack. I always carry silicone just in case.

I buy my filters for $4 a pop and carry 3 at any one time because they are small and compact.

The CAV system is a great investment. Will pay for itself after 2 filter changes.

Regards
David

Hi Bret, There are 5 rubber seals on a Cav filter compared to 1 on a toyota filter, only 3 are replaced each time you replace the filter. All of these seals can fail,and some times do, recently after using cav filters for 9yrs the small seal at the bottom of the glass failed, took hours & hours to locate the cause of air in the fuel system.

Almost every boat in Australia would have one, including world cruisers, I am sure if they are unreliable they would use something else.

Hi Lucy or for that matter anybody else out there that may be able to help.

I have a 3lt GU Patrol and recently purchased the Delpi unit with the CAV filter as a primary filter to Standard Nissan filter(leave as secondary filtration - and in part as well for warranty concerns). I made the brackets fitted it up oiled the faces of the filter and "o" rings, ran the lines to the fuel line from the tank to the CAV unit, then from the CAV unit to the standard nissan filter. Ie it is on the suction side upstream side of the original filter assembly.

The problem I have (I think???) is that the standard primer on top of the standard filter will not prime the CAV filter unit??????
I have checked everything, connections to tank line, connections to CAV, elbows, bleed screw, drain plug.
I will be speaking to the supplier tomorrow but after failing to get pressure up (40 - 50 -60 pumps on the primer), I reverted back to original setup and it primed after about 6 -8 pumps. The fuel line length has increased about three fold plus the volume of the filter itself.
Anybody else experienced issues like this?
I even prefilled the filter and it still would not prime up. By about 9pm last night I was pretty "shi**ed off with the whole ordeal.
On the plus side, I had an 80 series TD and did a fuel pump ($4300) due to water infiltration/ damage and dirty fuel, and our 60 series has a water trap (standard) and small prefilter and I change them regularly with no drama's so I wanted all the protection I could get for the 3 litre.

Any pointers would be great, I am thinking if this fails I might have to invest in one of those 'facet' in line pumps but ideally did not want to upset the excellent reliability of the 3 lt so far, especially whilst out touring.

No offence but I'm not an idiot and I have double checked all the connections(and their proper direction) into CAV. Maybe I have missed something simple??? I have even checked the integrity of the new hoses as well, post disassembling.

If anybody wants the template/spec for the bracket for the GU, I would be happy to assist as it took a bit of work to suss it out.

thanks in anticipation,

wetfeet

Wetfeet.

Do not despair.

When I fitted mine I started on a Friday evening for a job that should not have taken any more than an hour as I had the CAV units already mounted on the bracket and hoses attached.

So it was remove the OEM pack and bracket, replace with CAV kit, connect hoses, prime and away I go.

Midnight Sunday night I gave up in despair. Could not get any fuel into the first unit - the agglomerator.

I tried and checked everything I could think of, including pressurising the fuel tank to force that green pee through - all to no avail.

MONDAY - rang the supplier who I know very well.

He couldn't believe it and said I'll come around on the way home, which he did.

First thing he did was pull the agglomerator apart (One more step than I did because I didn't know of or about the the next dissassembley step)

Yep! missing seal.

Cut a long story short, the guy who assembles the components for the importer had somehow forgotten to place the seal in this hidden spot.

Anyway once replaced, bingo! fuel starts to Vac up, however there are some leetle bubble streams in the filter glass bowl while the engine is running.

Turns out that all the assembly - disassembly that I had done on Sat & Sun to try and get the mother to Vac/prime the line, had worn/damaged a couple of the seals.

So he said he would fix things and the next day turned up with an envelope full of every size seal used by those units, including the copper seals for the 'banjo bolt' full connections. (last me a life time) (LOL)

Haven't had a problem since.

Soooooo! in your case I'm betting it is leaking air. Less that an ant fart can affect it (LOL)

There are five seals in the CAV unit.

(1) Identify that their are five in your unit

(2) The two large seals that go top and bottom of the filter pack are different in size. Check that you have them in the right configuration.

(3) There is a large O-ring that fits around the centre inlet pipe, between the CAV header and the filter top (approx 16-20mm in dia)

The three seals mentioned in (2) & (3) above are the only ones tha come in the filter box.

(4) There is and must be a seal on the bottom drain plug.

(5) There is and must be a little O-ring seal on the top of the unit where the retaining bolt (around this bolt) where it inserts into the subject unit and holds all the components together.

I am having a guess that (1) the two large seals are A*** about face and/or one of the other three seals is missing or damaged.

(6) Ensure that once you have assembled the unit, that you can blow air through it from one side to the other.

When sealed and unencumbered by any blockage it takes only the minutest of Vacuum to draw the fuel up, into and through a CAV Unit.

You said you 'oiled' the seals. They should go on dry. Firstly hope you didn't use real oil, but diesel. Secondly should go on dry.

Hope this helps

Hi Lucy,

Thanks a heap for the advice, Roachie also came back and it appears I should have removed the pressure side of the Nissan Filter delivery hose, thereby freeing up pressure to be used to suck the fuel thru as opposed to pressurising that remaining fuel as well. See the Nissan service guys advised that there was no bleed screw, the plunger is both (it must have a non return valve) and no need to remove the hose, but in instances like this it obviously doesn't have quite enough suction pressure. I did use engine oil on the seals and they are now soaked in diesel. I will wash and clean thoroughly on the reassembly.

Thanks again.

wetfeet.

Hi guys,
Just another query. If you pull the head off the Delphi CAV units and pay attention to the inlet and outlet arrows on the head, they appear incorrect. Why you might ask???? Shouldn't the fuel go into the glass bowl at the bottom first and then settle out all the crap, flint water etc and then go up thru the filter leaving the rubbish to settle out in the glass bowl and then exit the filter, this also works well for the diesel fuel as it floats on water. the arrows seem to indicate the opposite.

Could someone set me straight. Something to do with the filter??

Presently the crap will settle on the top of the filter.

Roachie any answers??

wetfeet

Wet'ster

I am starting to loose sleep over you. (LOL)

In para (3) of my lengthy post above I gave an inkling what happens.

The fuel comes in the top from the side, down the centre pipe to the bottom of the bowl. (That large rubber O-ring seperates inlet from outlet)

Any solids should stay there including water and the fuel then floats/rises up through the bottom of the filter, out the top into the CAV header via a different route to the inlet and then exits on opposite side to the inlet and goes on its merry way.

I know its an ilusion with tricks, smkoke screens and mirrors, but trust me, it works.

Sleep well

Lucy,
Now don't loose sleep over me!!! Agree with you entirely. The arrows on the filter head paint a different picture if they relate to the fuel flow direction, thats all I'm saying. Hi Flo in Springvale are chasing but can't see a reason why the fuel should go to the top of the filter first.

ta


wetfeet

Hi,
I think they are called Hi Flow, they are in Springvale. We recently purchase two complete assemblies Delphis/ Cav 296 5 micron filters and 10 filters for $165.