Replacing fuel lines

[meehaja]

I've read the wiki suggesting that 7mm is the way forward, and I've measured whats there currently and it seems to be short lengths of 7mm, some 8mm, some hard plastic hoses (presumably original) some gas hose in the engine bay (cheers for that, I'm sure its perfectly safe! ) and some narrow ish gauge stuff to the breathers.

Looking on Brickwerks confuses me even more, as it seems to imply that 8mm is what i need for the whole length, 7mm is only appropriate for connecting to header tanks and the 5.5mm is also used for breather tanks.

Just Kampers seem to only sell 7mm and 8mm.

If I replace the whole system with one gauge will I lose pressure, if not, which should I go for? I think I'd be happier having one long length rather than chopping and joining plastic hoses then chopping and rejoining again (less joins = less leaks in my mind) also I really need to replace that gas hose, and perhaps replace the garden hose acting as servo pipe as well!

Any ideas?

thanks

[BOXY]

The bore size on industrial hose normally has a +- 10% manufacturing tolerance (even worse for cheap Chinese stuff). So 7mm bore hose could actually be 7.7mm, add to this the amount it can stretch depending on the type of reinforcement used and you might get a 7mm ID hose onto a 10mm spigot. The bore size won't effect the pressure of the system. Measure the OD of the spigots on the tank and carbs and get the hose to suit.

[meehaja]

nice one, thanks... lets hope its not raining tomorrow!

[Keekster]

Where ever you source it from make sure it is the latest modern hose that can take ethanol.eg.
http://www.advancedfluidsolutions.co.uk ... e-95-c.asp" onclick="window.open(this.href);return false;
The older stuff deteriorates way too fast due to modern fuel.

[Oldjets]

meehaja

Not sure which van you have but the folowing info is correct for later vans with DG engine - ealier vans may be slightly different so double check if you can. Info used to be available in the online VAG Cat if you can find it, or even at your local VAG dealer. My local VW van parts guy is very helpful and spent ages cross referencing part numbers for me to see if the various hose sizes were still available.

Anyway, back to the fuel lines: Short flexible piece from the tank outlet to the fuel filter is 7mm internal diameter (i.d.) with a 3mm wall thickness, from the filter to the hard plastic fuel line is 5.5mm i.d., 3mm wall thickness. The plastic fuel line then runs to the back of the van finishing just before the rear bulkhead. Flexible line then runs from plastic fuel line into engine compartment to the pump, then from pump to carb. Another one runs from carb to a non return valve, the other side of the bulkhead, and from that to a hard plastic return fuel line - all these engine bay flexibles are 5.5mm i.d. Feed and return hard plastic lines are 6mm outside diameter (o.d.). The hard plastic line then runs from the rear of van back to the tank but has an odd short flexible hose to join it to the tank inlet - 5.5mm enlarging to 7mm (looks like a special part no. 251201909A.

I haven't done this part on my van yet as I the special hose is obsolete (surprise, surprise). Will probably put another small filter in the line as they have dual diameter fittings.

Have left the hard plastic fuel lines in place on mine at the moment - they were available (at a price) a while back. It would be possible to replace them with flexible pipe entirely from front to back. Just over 2m for feed and about the same for return. Get under and double check with a tape. You would have to make sure it was well secured with rubber lined clips (lots of 'em) at least every 400mm and well out of the way of hot or rotating parts.

Anyone got any advice on an alternative material for hard fuel lines? Kunifer or copper tubing? I haven't be able to find an off the shelf plastic alternative yet.

Hope this is of use.

Oldjets

[meehaja]

Thanks, mines a 2.0 ac but seems to follow the same principle. I've ordered enough 7mm hose to replace the hard plastic lines, but on inspection, they seem in pretty good shape (reasonably new as well) so they may stay put. Its the lines in the engine bay that I'm most worried about as they are orange gas hose!

[croc]

Hard fuel lines - hard nylon from industrial hose suppliers ( eg Pirtek is one).
Replaced mine using 8mm OD, 3m (more than enough, about £3), then proper flex fuel hose from motor factors. Size depends on fuel pump connectors, there's 2 sizes. Filters have stepped connections for both sizes, one filter only!