Some advice please.
engine: Volvo Penta MD7b

The fuel return line on my engine has deteriorated and is the source of a diesel leak that makes a mess and smells so I would like to replace the line if possible. The catch is with such an old engine I'm finding it hard to find replacement parts and they would likely be very expensive. I'm looking at making up a replacement fuel line but i'm no mechanic and want to check that I am not going to be creating a bigger problem for myself.

The part requiring replacement is numbered 47 in the diagram here
www.volvopentashop.com/epc/en-US/Details/PentaPartsCatalog/7742080_036?path=MarineDieselEngines%2F7742080%2F7742080_2300%2F7742080_036

(I found that to be a very helpful web site btw for assisting to understand my engine better)

What I am wondering is if I can source the correct size banjo eye connector (is that the correct name?) for the engine end of the fuel line and use the appropriate hose for the line do I need to have parts 50, 51 and 52 from the diagram?
Is there anything wrong with running the return fuel line straight from the banjo connector back to the fuel tank without the connections in the middle?

My thinking is that the connections are just what is needed because the fuel line when it comes from Volvo is only sufficient to exit the engine. Beyond this point what is needed will be determined by the requirements of any given installation so there has to be a join / connection somewhere in the line.

Thanks for your assistance

no you can replace the fitting with a line ,you can also cut the old swag of the banjo and reuse the banjo and use hose clamps to seal it,make sure you find metric fuel hose to replace it.

Select to expand quote

grich62 said..
no you can replace the fitting with a line ,you can also cut the old swag of the banjo and reuse the banjo and use hose clamps to seal it,make sure you find metric fuel hose to replace it.

Excellent, that's what I was hoping for.

The way you say "metric" fuel hose suggests to me that you are not referring the unit of measurement. So what is metric fuel hose?

The section of hose beyond the Volvo supplied fuel line is just reinforced PVC tubing (rated as suitable for use with diesel). Keeping in mind that this is the return line, not the intake is this ok to use?

Select to expand quote

MattM14 said..

grich62 said..
no you can replace the fitting with a line ,you can also cut the old swag of the banjo and reuse the banjo and use hose clamps to seal it,make sure you find metric fuel hose to replace it.

Excellent, that's what I was hoping for.

The way you say "metric" fuel hose suggests to me that you are not referring the unit of measurement. So what is metric fuel hose?

The section of hose beyond the Volvo supplied fuel line is just reinforced PVC tubing (rated as suitable for use with diesel). Keeping in mind that this is the return line, not the intake is this ok to use?

Hi, suitable fuel line of any origin is just fine, just make sure it is a snug fit on the banjo fittings prior to clamping.

Ok I had an opportunity to get onto the boat and have another look at my problem fuel line today with the benefit of your comments above.

I am now wondering if there is sufficient space to remove the banjo screw without having to also remove the exhaust manifold which is directly above it. I took a couple of pictures today to get peoples opinion (sorry about the side on shots - couldn't get them to upload in the upright orientation).

The exhaust manifold actually has a curved underside. It appears from the photo that there should be enough space to extract the banjo retaining screw but does anybody have experience with the Volvo Penta MD7 engines that can confirm this before i launch into something that very quickly becomes much more than I bargained for and i am in over my head?

If the exhaust manifold does need to come off are there any pointers people can offer about how to go about this? Any common rookie mistakes I should avoid?

Yes i know there is a bit of corrosion showing in the pictures. It's a very old engine.

Thanks for any assistance or pointers people can offer.

I had a 7b for ten years or so. I never had any problems with the fuel hoses. You may be lucky with that banjo fitting. Loosen it with a ring spanner then finish off with an open ender. The thread on that fitting is probably about 12mm long so it's possible there may be that much room. Remove the exhaust if you have to. These engines are pretty basic and apart from the injector pump are easy to work on.

You could also just take the whole hose out and take it to enzed or somewhere similar and they will make you a replacement with new fittings

Having messed around with banjo bolts on my engine, I'd be inclined to give it a go. If you can't get it out, do it up again.

You will need to either re-use those copper washers, or replace them with new washers. I could not find replacement copper washers, but only alloy replacement washers. The alloy washers did not seem to seal well, so I annealed the copper washers (heat and quench, to soften them) and put them back.

The other thing to watch for is if the female thread (metal body that it screws into) is cast iron or alloy. I stripped the thread on a banjo bolt that was fixed to the alloy body of my water pump. The cast iron female threads were fine.

Select to expand quote

Achernar said..
Having messed around with banjo bolts on my engine, I'd be inclined to give it a go. If you can't get it out, do it up again.

You will need to either re-use those copper washers, or replace them with new washers. I could not find replacement copper washers, but only alloy replacement washers. The alloy washers did not seem to seal well, so I annealed the copper washers (heat and quench, to soften them) and put them back.

The other thing to watch for is if the female thread (metal body that it screws into) is cast iron or alloy. I stripped the thread on a banjo bolt that was fixed to the alloy body of my water pump. The cast iron female threads were fine.

Thanks for the pointers Achernar I will keep that in mind when i tackle this job.