I put a section of viton fuel line on a 300sd and one end leaks. As I have used this fuel line before with no problem I am wondering what I did wrong. I have replaced the return lines before so I was wondering if there is a trick. It is the correct size.

Did you cut off the old line and nick the barbs on the connection?

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Charles
1983 300D, bought new, 215k+ miles, donated to Purple Hearts veterans charity but I have parts for sale: http://www.peachparts.com/shopforum/showthread.php?t=296386

No I pulled it straight off. No tool was ysed to nick anything.

Viton lines leak with WVO and diesel fuel.They don't leak with Bio.

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1999 w140, quit voting to old, and to old to fight, a god damned veteran

I am burning diesel so I guess I better go back to the old lines.

I disagree. I have 50k miles of WVO oil use with my viton lines, and no leaking. A new hose shouldn't leak despite the type of diesel or alternative diesel fuel. Over time biodiesel and veggie will degrade regular rubber and cause it to leak. But none of those fuels will cause leaks with viton, atleast not for many years.


To the original poster, no need to switch to another hose material, diesel will not make viton leak.
If your using and old piece of hose, sometime you have to cut off a portion of the end to get a fresh piece of hose to clamp on. Theytend to get compressed with the pressure of the hose clamps and then they don't seal as well.

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I heard from Mercedes source today and he explained that they no longer sell the viton hose as they had a number of complaints of leaks, I boughgt this hose a year ago and just used a piece. There are no clamps to worry about so the easiest thing for me to do is just change it. Thank you for your comments.

He must be getting the wrong size. I worked for Greaseworks for a while and we sold hundreds of viton hose kits while I was there and had maybe one or two had leak problems. Usually it's user error that causes the problem. Either the hose gets cut some how, the barb gets damaged from removal, or the hose gets stretched over a barb that is too big and it tears. Get viton from greaseworkds their hoses don't leak. Justin sells injector return lines separate from the full kits.
One of the issues with viton is that it's soft and really isn't meant for automotive use. I've got viton lined 30R9 hose my rigs, much more durable, but you can only get solid viton for the injector return lines. Normal hose will work just fine, and will work for several years even with biodiesel use, but it won't outlast viton.

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I installed all Viton hoses last summer and go back and forth between Biodiesel and straight diesel. No leaks at all.However when I first installed my rerun lines
I had 2 that seeped so I cut 2 new ones a little longer and have not had a problem. I believe that the Viton hoses are stiffer or whatever but they can not be bent as much as the originals. Redo them longer and I bet you will be okay.

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92 500E Silver 66k
82 Porsche 911SC 84K
68 Cadillac ( Gone Now )
03 Suburban Z71 200K
85 300SD 217k From Original Owner ( Dad )

OK, good. Did perhaps some of the old hose stay stuck on one of the bards and prevent the new hose from sealing?

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Charles
1983 300D, bought new, 215k+ miles, donated to Purple Hearts veterans charity but I have parts for sale: http://www.peachparts.com/shopforum/showthread.php?t=296386

Seriously, redo the leaking ones and make the radius of the bend less severe( ie a little longer than the one installed)

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92 500E Silver 66k
82 Porsche 911SC 84K
68 Cadillac ( Gone Now )
03 Suburban Z71 200K
85 300SD 217k From Original Owner ( Dad )

I second this motion. When they are stretched too far the hoses tend stretch causing the diameter to decrease, as well as kinking the hose some, both of which will reduce the flow capacity and can cause leaking.

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