Length/sizes of rubber->viton fuel hoses?

[MonsieurBon]

Hi folks-

I am working on replacing all my rubber fuel hoses with Viton hoses so I can feel safe running B100 (100% biodiesel). In the engine compartment I see the following (lengths approximated):

5" rubber from solid fuel supply line to prefilter
2" rubber from prefilter to primer pump
7" plastic? from primer pump to main filter
7" plastic? from main filter to IP
8" rubber from main filter to tank return line

So do I need to replace those clear plastic lines as well?

What are the specs (OD, ID) on the lines? How do those convert to standard, rather than metric? McMaster-Carr doesn't have that wide a selection of metric hoses.

After this, I'd like to try to replace the hoses that attach to the fuel tank itself. Can I just get under the car to do that, or do I need to pull the tank?

Since Viton is mighty expensive, I'd like to be as exact as possible.

Thanks so much!

[Stevo]

MonsieurBon

I replaced the plastic one from the hand pump up to the secondary fuel filter. Its handy for observing air bubbles. I used plastic hose from the building supply. Get various sizes, its cheap & good for brake & clutch bleeding.

The rest of the hoses are 8mm except for return hose (or is it vent, anyway its ONE of the 2 on the driver side of the tank) . The injector return hoses, you want the real thing, fact is you can get all these things that will be the proper equipment for your car from Fastlane. Ok which ones did I forget?

[The Warden]

Originally posted by Stevo
The rest of the hoses are 8mm except for return hose (or is it vent, anyway its ONE of the 2 on the driver side of the tank) .

I'm 99% sure it's the vent hose. You CAN get an 8mm hose on there; it just takes quite a bit of work...fortunately, a perfect seal isn't as important on the vent line as it is on the return line.

BTW, I replaced both of those hoses (along with the fuel intake hose) with OEM hose from the dealer about a week before I found out that normal rubber hose and biodiesel don't mix. So it looks like i get to replace them again when $$ allow...I really want to start running biodiesel...

[MonsieurBon]

McMaster-Carr has 8mm ID/10mm OD "Firm" viton hose for $6.03/ft.

I'll go measure how much I need in the front in the next few days and report back.

Are the rubber hoses that connect to the tank the same ID/OD?

It sounds like even the softest Viton doesn't bend easily, so I might need to order a few barbed 90 degree adapters.

thanks!

[MonsieurBon]

So what is the ID of the return rubber line?

thanks!

Check out this stuff...
http://www.usplastic.com/catalog/ca...e=Tubing&Page=1
Any thoughts on which to go with?

[soypwrd]

If I may be so bold as to suggest;
Just change out the inter-injector return lines and keep an eye on the rest. If any lines begin to fail they will begin to sweat fuel, not fail altogether and at once. I believe if you replace all those lines you are suggesting you`ll be doing more work than needs to be done. From what I`ve researched, the only lines that are a problem are the inter-injectors and possibly the fuel filler neck.

Jeepers, viton is expensive!
I heard some talk about NEW MBZ fuel line being B-100 safe...
Any thoughts on this? (it still says nitrile)

I suspect it is 5 feet of injector return line, anyone know for sure?

MonsieurBon, here is a handy page for metric/inch conversion:
http://www.plumbingstore.com/metric.html

Look at this stuff, TeflonŽ PFA Tubing,
http://www.usplastic.com/catalog/default.asp
Less than 1/2 the price of viton!
I wonder if it bends....

[soypwrd]

Originally posted by thevegmyster
..I suspect it is 5 feet of injector return line, anyone know for sure?

Just replaced mine with some shorts lengths I had and I suspect it only took two feet, but I`d get three feet just to be safe.