Air bubbles in pipes. Bleeding the system?

[darkchild101]

I was changing my fuel filter as well mm as the extra filter for the wvo debris still in the tank. After I cleaned the prefilter and stuff and when I started the car I noticed loads of bubbles especially into the wvo filter. Bubbles into pipe going into prefilter and even in pipes out of the main fuel filter

How do I purge the air in the system? The car is not responsive at all and struggles when I put the foot down

 

[Triv]

Did you replace the o rings on the filters?

 

[television]

As above the whole system must be air tight or the bubbles will never go away.

 

[darkchild101]

Did you replace the o rings on the filters?

Triv the fuel filter came with its own o ring and I never changed the prefilter but just washed/cleaned it. However I think there now is a litle leakage on pipe going into prefilter. Is there an o ring I can put on the prefilter? I dont remember there being one ever

The nut and washer fhingy that close prefilter look like bent. Went to the breakers today and couldn't find anything?

 

[Triv]

Yes there is an o ring on the prefilter. If there is air bubbles going into it, then I suspect that you've disturbed the plastic fuel pipes and the o ring seal on one of the pipes is letting air past. Just moving those plastic pipes can cause this.
The o rings are cheap enough to buy and replace but if you break a clip whilst dismantling it, you'll probably need to buy the whole pipe with the clip and new o ring attached.

Edit: Because you've run wvo through it, all the o rings will be knackered and need replacing. I forgot you'd experimented with that.

 

[darkchild101]

Yes there is an o ring on the prefilter. If there is air bubbles going into it, then I suspect that you've disturbed the plastic fuel pipes and the o ring seal on one of the pipes is letting air past. Just moving those plastic pipes can cause this.
The o rings are cheap enough to buy and replace but if you break a clip whilst dismantling it, you'll probably need to buy the whole pipe with the clip and new o ring attached.

Edit: Because you've run wvo through it, all the o rings will be knackered and need replacing. I forgot you'd experimented with that.

Where can I buy an on ring urgenty please. Think will look into into replacing the clear pipes. Is there a recommended type of pipe and o ring?

 

[spock500]

You can buy a full set of O ring from Derek [Silver Saloon] he has an ebay shop.

Not sure if he posts on here but he is on the MB forum [the other one].

If not MB sell them but imo they are not very good, poor fit.

 

[darkchild101]

You can buy a full set of O ring from Derek [Silver Saloon] he has an ebay shop.

Not sure if he posts on here but he is on the MB forum [the other one].

If not MB sell them but imo they are not very good, poor fit.

Done search for user by that name came up blank

 

[Triv]

http://forums.mercedesclub.org.uk/member.php?u=4267

 

[darkchild101]

http://forums.mercedesclub.org.uk/member.php?u=4267

I am thinking replacing the pipes and o rings and worried about the connections. Anyone got diagram of the pipes please

Also going to post picture of my set up as I had to add an extra filter for wvo contamination as well as a inline bulb primer

 

[Triv]

Interestingly, Television (Malcolm) has a diagram of the fuel system. He emailed it to me a couple of years ago however, by all accounts he's serving a ban for some inane reason and so can't help (how grown men act like children over a keyboard is beyond me and that goes for all involved) and my email has been hacked and taken over by some moronic spammer, so I have no access to it and can't help you either!
There are plenty of other members with these cars who may be able to help but as you've altered the system, I'm not sure how much help can be given without photographs of your actual set up.
I suggest that you go to your dealership armed with the vin number of your car and order a complete set of clear plastic fuel pipes equipped with the o rings and clips. That way, you can't go wrong.

 

[yorkshire1]

fuel system

Still having trouble DC......
diagram of system

http://mbworld.org/forums/attachmen...-fuel-lines-what-else-change-out-fuelflow.jpg

Im in the process(but havent had time as yet) of replumbing the C250 fuel system whereby it is pressurized rather than under vacuum/suction.. basically you take the tank feed directly to the lift pump (via an inline prefilter if you wish) then the pressure outlet is fed to the preheater then the rest follows suite this will I believe totally eliminate all the 605/606 air issues for good

the O ring quantity/sizes are

8x(2.5x8)
3x(2.5x10)
1x(2.5x12)
1x(2.5x18)

either source from MB or any half decent hydraulic supplier preferably use Viton as they are unaffected by the veg oil however the compound itself is harder and will under certain circumstances still pass air due to the high viscosity of veg oil in the feed pipes and the tendency for negative pressure

 

[Triv]

That's a great post. Thank you.
I've wondered about pressurising it too but my thoughts were along the lines of adding a Facet fuel pump down near the tank. Just to help the lift pump a bit.

 

[spock500]

Mechanical lift pumps on these are hugely powerful, this is what happens if the vent gets blocked

 

[yorkshire1]

facet

That's a great post. Thank you.
I've wondered about pressurising it too but my thoughts were along the lines of adding a Facet fuel pump down near the tank. Just to help the lift pump a bit.

yes thats an option however Im not overly keen on adding extras especially somewhere relatively inaccesible

Ive never got to the bottom of where exactly the fuel pipes go to/from in the tank, my favourite is nice sized hosetail fitted near bottom of tank and big bore hose to lift pump (oh and a return back to same area of tank) estates anyway

 

[darkchild101]

Whats the part number for the prefilter o ring? Went to eurocarparts yesterday and bought mm prefiter, they didnt have o ring and said would be in today. Called today and they never had it

 

[darkchild101]

Still having trouble DC......
diagram of system

http://mbworld.org/forums/attachmen...-fuel-lines-what-else-change-out-fuelflow.jpg

Im in the process(but havent had time as yet) of replumbing the C250 fuel system whereby it is pressurized rather than under vacuum/suction.. basically you take the tank feed directly to the lift pump (via an inline prefilter if you wish) then the pressure outlet is fed to the preheater then the rest follows suite this will I believe totally eliminate all the 605/606 air issues for good

the O ring quantity/sizes are

8x(2.5x8)
3x(2.5x10)
1x(2.5x12)
1x(2.5x18)

either source from MB or any half decent hydraulic supplier preferably use Viton as they are unaffected by the veg oil however the compound itself is harder and will under certain circumstances still pass air due to the high viscosity of veg oil in the feed pipes and the tendency for negative pressure

So no extra gear needed then? Sounds great

 

[yorkshire1]

part number

Whats the part number for the prefilter o ring? Went to eurocarparts yesterday and bought mm prefiter, they didnt have o ring and said would be in today. Called today and they never had it

Its only an O ring if needed easiest option is merc dealership Itll be pence

 

[yorkshire1]

tools

So no extra gear needed then? Sounds great

No thats it,apart from a little something between the ears,
prefilter O ring, black Immobilizer valve O ring (bolted to side of injection pump),and all the clear pipe O rings just dont rive at the pipe unions when dismantling, push the white clip in to disengage locking mechanism and wiggle to pull out of socket

lubricate all O rings with fuel/oil before refitting or they may not seat properly especially the one on the back of the black immob valve


also if youre doing the immobilizer valve O ring youll also need a splined key use the right type/ size or itll strip the head cos theyre only shallow then youve got a (another) problem

 

[darkchild101]

Its only an O ring if needed easiest option is merc dealership Itll be pence

Went eurocarparts and they had ordered wrong thing. The guy behind counter goes to back and says they no longer sell the o ring even though its on their website. Then went Mercedes dealership at Newbridge and they dont have them in stock but he can order one from Coldstream dealership near England and will be here Monday at £2.85. Thought let me try local indie at Pumpherston, even he doesnt have it.

How can something so small be that hard to get