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littledog
5th August 2008, 10:34 PM
Hi Everyone, Has anyone had any problems with a CAV style filter leaking from where the cartridge meets the main housing ass'bly.
This is a new unit out of the box, it was pre-assembled and tightened as far as i am aware as tight as it should be.
I have replaced the fuel filter ass'bly on my hilux 2.8lt with this CAV filter and found that it is leaking from the top seal when the vehicle is turned off, and it is allowing air to suck in when the vehicle runs. The vehicle runs for about 20 - 30 seconds and then dies (even with revving). I have had to change the housings back to the original so that i can run the vehicle but I wish to pursue the CAV filter idea. (the vehicle runs fine with the original housing and filter)

So 1, Can anyone tell me is this a common thing with this style of filter?
2, How tight is tight enough? (this one is tight enough that if you turn the bolt with a spanner, the bottom drain cock turns)
3, is there anything that i can do? I have checked the rubber seals and they look ok (no nicks or anything like that)

Cheers Sam

Captain Echidna
5th August 2008, 10:52 PM
Perhaps anyone who has managed to succesfully get a CAV to not leak either air or fuel can enlighten us how its done? The only ones I have seen not leaking are on a shelf waiting to be purchased.....

Qwarla
5th August 2008, 11:24 PM
A common fault with the CAV is people put the wrong 'O' ring in the wrong places. The 2 that fit above and below the element are NOT the same size and this is the usual place people stuff up.
Apart from that it is always possible the top housing is warped. Being new, I'd be inclined to take it back.

The through bolt can be done up fairly tight. The thread will bottom out so over tightening it should not be possible.

83Patrol
5th August 2008, 11:25 PM
I smear a bit of fuel on the seal before assembling - don't know if it will help in this instance though.

By CAV-style, do you mean a copy - one of those generic no-name housings that's painted light grey?

When I was doing my conversion, that was the first thing I bought, but as soon as I really examined it and saw the cheap looking build quality I returned it. Sales guy tried telling me it was a genuine Delphi - the filter that came with it did have Delphi printed on it (although in very poor print quality so I have my doubts), but the housing was definitely not.

I noticed you're in Vic. Are you in Melbourne? BSP Diesel in Campbellfield sell the genuine Delphi CAV assemblies for only about $15 more than the cheap copies. Seeing as they also give you 2 brass hose tails, it ends up being around the same price.

Maybe give that a try, money permitting?

littledog
6th August 2008, 12:39 AM
Im not sure if it is a knock off or not, it is an ally housing, but it is not painted. It did come with delphi filter. I didn't assemble the unit, so don't know if it was put together incorrectly. I think that I will be returning it to where i purchased it from.

Thanks for the comments guys and gals.

Sam

littledog
6th August 2008, 10:55 AM
Ok, So i contacted the supplier of the filter assbly, he said that the bolt that tightens the asslby together may be slightly too long which means that the filter will not tighten properly ( he has seen this before). He suggested to cut 1/4 inch off that bolt to give better tightening ability. He also said that the seals may be no good, but if the bolt shortening doesn't work he will send a known good filter assbly in exchange. I think i will take him up on the offer.

thanks for the comments everyone

Sam

Fitian
6th August 2008, 11:41 AM
Who is this supplier?

The bolt does not need to be cut or shortened.

The pipe nut connected to the glass bowl only needs to be adjusted down a little for the bolt thread to go all the way down into it.

O rings should be smeared with oil not fuel.

The wide O ring goes on top of the element and the other goes at the bottom.

The O ring that goes under the bolt head should be also smeared with oil.

After tightening - hold the glass bowl and the filter head and check if they turn. They should not.

83Patrol
6th August 2008, 11:59 AM
O rings should be smeared with oil not fuel.



Oops, that's what I meant - veggie oil being the fuel we're using.

Sorry if I caused confusion, Littledog...

Fitian
6th August 2008, 01:23 PM
I knew this is what you meant. I just wanted to make it clear it is oil not diesel or other fuel.

Good on you mate

have a good day

littledog
6th August 2008, 02:17 PM
I got the unit from Wagga tractors.

I have pulled the unit to pieces and cleaned it. Lubricated the seals with oil and reassembled. The housing and bowl do not move when i try to rotate them.

I am not following the idea about the pipe nut, this unit has a bolt which goes into an ally rod which is threaded on the end. This threaded end goes into the ally drain cock assbly which locates through the bottom of the glass bowl. I cannot see how this bottom part could be adjusted as it is a one piece component except for the plastic drain plug?

I will test it tonight and see how it goes. hopefully the oil on the seals will make the difference. Thanks for the assistance

Sam

Matt
6th August 2008, 04:10 PM
Do not forget the two larger rubber seals are different sizes, the smaller of the two goes onto the glass bowl, the larger seals at top of filter.

Matt

Fitian
6th August 2008, 04:26 PM
I am not following the idea about the pipe nut, this unit has a bolt which goes into an ally rod which is threaded on the end. This threaded end goes into the ally drain cock assbly which locates through the bottom of the glass bowl. I cannot see how this bottom part could be adjusted as it is a one piece component except for the plastic drain plug?

Sam

Sam,

I think what you have got is a copy not an original CAV.

It should work if it is made to specs though.

Good luck

littledog
7th August 2008, 10:31 PM
Thanks Fitian,
I have sorted the problems (i think). I disassembled and cleaned all parts. Reassembled using oil on the seals, this seemed to make a better seal. vacuum tested the unit and found that all the bolts blocking the other inlet and outlet holes and the bleeder hole on top were all leaking air substantially. Refitted them all with plumbers tape and retested. Vacuum tested ok, no leaks. Fitted to car and bled system through. Started car and drove it. No hiccups or power loss. The old OEM filter must have been pretty blocked (or the OEM housing leaking air as well) because the idle rpm on the car had been dropping off and now is back up to where it should be.

I hope that the CAV filter ass'bly can take some vibration and so forth because I am taking it bush this weekend.

Also dose anyone know how well standard plumbers teflon tape reacts with diesel and biodiesel?

If it fails then it will be back to square one.

Thanks again for everyones help

Sam

Qwarla
7th August 2008, 11:28 PM
Also dose anyone know how well standard plumbers teflon tape reacts with diesel and biodiesel?

Thanks again for everyones help

Sam

Sam I am fairly sure that teflon thread take is totally inert to diesel and bio.
It should outlast your vehicle.

Captain Echidna
7th August 2008, 11:35 PM
The threads on the CAV filter are tapered, if you have a paralell thread (not discussing the same topic in another thread silly) it wont seal as well as a tapered one, however it wasnt my problem.

littledog
8th August 2008, 12:12 AM
Captain,
These were the bolts that came in the unit, I have contacted the supplier to see what more permanent solution they can offer.

Sam

Captain Echidna
8th August 2008, 12:15 AM
Sorry, My mistake.

Tony From West Oz
8th August 2008, 01:44 AM
The CAV units should have parallel threads in the internal threads as they are also used with Banjo fittings. If adding hose barbs to the CAV's then you should use tapered thread to hose barb adaptors, to reduce the potential for leaks. As discussed, thread seal should be used with these.

The original bolts should have been supplied with crush washers, which provide the seal between the filter housing and the bolt head. Thread seal should not be necessary.

Regards,
Tony

littledog
8th August 2008, 10:24 AM
maybe that goes to show that it is a cheap knock off then, the washers that are on it are thin aluminum washers, but i couldn't get the bolts tight enough to form a seal. They just kept leaking air, there was a visible gap on one side of the washer where it didn't sit flush with the bolt and housing. It was like it was sitting lop sided or something. Anyway we will see what the supplier says.

Sam

Fitian
8th August 2008, 11:18 AM
the washers that are on it are thin aluminum washers, ....

Sam

Sam,

You still can use the aluminum washers "not the same old one" and get them to seal.

Place a wet & dry sand paper on a flat surface and run the wash in round motion both sides. This will get the washer to have a smooth flat surface.

Do not over tighten the bolt until the washer is deformed.

littledog
9th August 2008, 09:39 PM
Sorry, the gap was about .5 - 1 mm no amount of wet and dry will fix that.
The washers haven't deformed. If i remove them they are still flat. When they are tightened up the washer is snibbed up on one side and has a gap on the other. It is like the inlets have been tapped crooked.

Sam

Fitian
9th August 2008, 09:48 PM
Sam,

If this is something you are going to face every time you change the element, then you better off getting a better quality filter housing.

Can you post a photo of the filter you have? Or post a link of where you bought it from " if the link has a photo"

Maybe I'll be able to give you better idea/fix

Thanks

Nuddy
10th August 2008, 02:32 AM
I bought CAVs from WaggaTractor and I think they are genuine Delphi.
I bought genuine barb fittings (taper seat) with them and had no trouble with leaks there nor at the element. One did leak at the blanking plugs and I fixed it with thread tape.

littledog
10th August 2008, 01:49 PM
Troopy,
I got my barb tails from ENZED and they have the tapered end like you got. Sounds like what I have done is the normal thing. I had (maybe incorrectly) assumed that the pre-assembled bits would not need to be altered. Anyway, I don't think that changing filters will cause me much grief now that i know to lubricate the seals with oil. If the sealing tape on the blanking plugs doesn't degrade then i think that i will not have any more problems.

Sam