Need Specs on two 4 in fuel lines at diesel tank - PeachParts Mercedes-Benz Forum

cchkaiban · #1 08-09-2007, 12:20 AM

1982 300TD
My fuel lines have both started leaking. Does anyone know what size they are? Exterior diameter and interior.
Thanks.

tangofox007 · #2 08-09-2007, 12:27 AM

ID is 7.5mm. 5/16 will also fit.

cchkaiban · #3 08-09-2007, 09:19 AM

This is probably elementary, but I find that I have to ask...
I can only find 7mm or 8mm.
Which should I buy?
Thanks..

vstech · #4 08-09-2007, 09:31 AM

depends on quality of hose. all else being equal, go 8mm. if the 7mm hose is a better hose, go 7mm.
either one will work fine.

vstech · #5 08-09-2007, 09:32 AM

prepare for a LOT of fuel to drain out when you do it though...

cchkaiban · #6 08-09-2007, 10:51 AM

Thanks for your advice...
charles

Richard Eldridge · #7 08-09-2007, 11:15 AM

Even when your gauge says your tank is empty, it isn't. Even when the motor runs out it isn't. Wear gloves and a shirt you dislike. It will be all stinky unless you are running biodiesel.

If you are running biodiesel, put Fido on a leash.

If you cut the tube to fit before you start, then clamp the old line near the tank replace the line at the front of the car first, then you might be able to slip the new line on the tank with minimal mess.

There is no rule that everything must be allowed to drain.

tangofox007 · #8 08-09-2007, 11:29 AM

Quote:

Originally Posted by Richard Eldridge

If you cut the tube to fit before you start, then clamp the old line near the tank replace the line at the front of the car first, then you might be able to slip the new line on the tank with minimal mess.

There is no rule that everything must be allowed to drain.

I replaced those same lines just a few days ago without draining the tank. I don't think that I spilled more than a pint of fuel. But you need to have a plan of attack. And have a helper standing by just in case you drop something or need a hand.

I made a "cap" by plugging a short piece of hose, which I temporarily put on the tank nipple after cutting the old hose off. (Don't expect the old hose to pull off effortlessly!!!) I removed the tank end of the hose first, then installed my temporary "cap" to stem the flow of fuel. Then I had plenty of time to cut the other end of the hose off and cut the new hose to match the length of the old hose. Installation was in reverse order-tank end last.

Biodiesel300TD · #9 08-09-2007, 11:31 AM

The best way I have found to change the fuel lines at the tank, and it works great you will only drip out what is in the fuel lines, nothing will come out of the tank if you do it right. We put fuel lines on a lot in the shop I work at so I have done this many times, and it works with a nearly full tank.

If you have a shop vac. Pull the cap off the filler neck. Then stick the shop vac hose into the filler neck a little ways. Not to far you don't want to suck up and fuel. You just want to create a little vacuum in the tank. Turn the shop vac on and make sure you aren't sucking up fuel. Then crawl under the car. And take a catch pan with you. Pull the hose clamps off one of the fuel lines you are removing. And break the hose loose on the barb so it will come off easily and slowly, not all at once with a big jerk. Then take one end of the hose off and be ready with the catch pan. If you have the shop vac setup good, no fuel will come out of the tank, but the fuel in the line up to the front of the car will drain. The slight vacuum in the tank pulls air through the hole in the tank instead of it draining all over you and the floor.