CAV filter connections - fuel bleeding problem

flyingscampi

flyingscampi

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I've replaced my fuel tank and had trouble last night trying to bleed fuel through to the secondary filter on a Volvo 2002.

The new tank draws fuel through the top of the tank unlike the old one which was from the bottom. Currently I only have 20l of fuel in a 91l tank.

I've started the siphon through to the CAV filter Ok with fuel coming out of the bleed screw but I can't get fuel to come out of the bleed screw on the secondary filter by pumping the manual lever (about 10 minutes of trying).

I ran out of time last night to try taking things apart but I'm wondering if the problem could be down to not having enough fuel in the tank (the CAV filter is below the tank) or the connections on the CAV filter:

The filter has four connections which are marked with a two pairs of in and out arrows. I have linked the filter up with both in and out connections on one side of the filter instead of one on each side as before - this shouldn't cause a problem should it?

Is there any other reason why I can't draw fuel to the secondary filter?

Should I try turning the engine over?

/forums/images/graemlins/confused.gif
 
Are you sure that the lift pump cam is not held at the top of its stroke? If it is then any amount of pumping the lever will achieve no result. Try turning the engine over half way with a spanner or the alternator belt and see if this helps.
 
DSC_3251.jpg


Here is the top of the filter before I changed the connections - the inlets are at the bottom and the outlets at the top. Surely it wouldn't make any difference to have the inlet and outlet on the same side?
 
the filter(s) maybe dry. try topping the filter bowl(s) up with fuel first it will give the manual pump something to pull against. Just a thought..Good luck
 
Agree with Viking, you will be pumping a long time if you did not pre-fill the filter before you screwed it back.
Fill Filter, bleed, then kick engine over,
Mike
 
my cav is above the tank. First time tried pumping via the lift pump for ages and nothing. re fitted the CAV making sure all seals were correctly fitted, bolt hand tight "and a bit" ( smashed a few glasses before) and pumped away ... engine primed in no time you can feel the thing pull the fuel through.... check the cav seals.
 
I had the same experience. It took about 20 mins, with the cam in the right position, before the fuel came. My fingers were nearly raw! I think you can fit a suction bulb, with non return valve, in the line to make it easier.
 
I have to say that I have used in and out on the same side many times. One of the problems is that the lift pump are not powerful enough to pull the fuel through tne filters, especially on engines derived from small plant engines wich normally have a gravity feed .
 
My primary filter is above the tank and to get fuel up to it I used to (a) make sure the tank was as full as possible, then (b) blow down a tube temporarily stuck in the tank vent. This worked but, not having piper's lungs, resulted in me seeing stars! An air pump would be better...

When I had the system apart a couple of years ago to fix a leak I took the opportunity to include a primer bulb. Life is now much easier.
 
[ QUOTE ]
The filter has four connections which are marked with a two pairs of in and out arrows. I have linked the filter up with both in and out connections on one side of the filter instead of one on each side as before - this shouldn't cause a problem should it?

[/ QUOTE ]

mmmmmmm you would think it ok - but I would be inclined to work as CAV may have intended - opposite connections not same side. ?? Maybe someone has done this as well and it works ?

But as to lift pump - as another says - the lift pump may be on it's stroke when engine stopped. Turn engine a touch so pump comes off stroke and then try again. Must admit my pump is very temperamental for this.
 
Well this one was bleeding obvious, I wasn't pushing the pump lever hard enough - twit.

It happens when you're tired after working for 12 hours and letting your imagination run riot /forums/images/graemlins/blush.gif
 
I called ASAP supplies and they told me there is no problem putting inlet and outlet on one side of the CAV filter.

Well it works anyway /forums/images/graemlins/grin.gif
 
blow down a tube temporarily stuck in the tank vent. This worked but, not having piper's lungs, resulted in me seeing stars! An air pump would be better...
*************************************************

I do likewise using the dinghy pump nozzle in the fuel filler and pump slowly , the vent ensures pressure is not to high.

This may be the only way when the filter is high up.
 
I see that another has used same side and it works - that's good to know for future !

I'm betting lift pump stroke or just not man enough ..

Both diesels I have had to bleed - my boat Perkins and the truck Mercedes ... hand pumping is a pain as it takes ages. I have to admit I like the idea another did of adding a pump that actually pumps !! in the line.
 
Fill Filter, bleed, then kick engine over
*********************************************

Easier said than done with the CAV filter as it is in three sections so cannot be filled until the three sections are assembled to the head and tightened. Hence the easiest way is to pressurise the fuel tank either with a dinghy pump or I have done it just blowing through garden hose stuck into the filler with rag sealing the joint. /forums/images/graemlins/laugh.gif
 
[ QUOTE ]
My primary filter is above the tank and to get fuel up to it I used to (a) make sure the tank was as full as possible, then (b) blow down a tube temporarily stuck in the tank vent. This worked but, not having piper's lungs, resulted in me seeing stars! An air pump would be better...

When I had the system apart a couple of years ago to fix a leak I took the opportunity to include a primer bulb. Life is now much easier.

[/ QUOTE ]

The primer bulb you used ? Is that a normal outboard one designed for petrol ? Interested as I have a few laying around in the box ...
 
Yes, bog standard outboard primer bulb and hoze. Works fine.

No doubt someone will now point out that all fuel pipework has to be metal to comply with something or other... /forums/images/graemlins/frown.gif
 
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