Main Line Fuel Leak--Not Pump or Filter
10-26-2013, 03:43 PM
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Main Line Fuel Leak--Not Pump or Filter
My son was driving my wife's '99 ML320 (129K) last week and complained of a chemical smell. I went to check it out and quickly found gas profously leaking from around the frame rail forward of the left wheel well. I gave it some time to dry out and got it in the garage while I serached this invaluable forum for clues.
A couple days later I pulled the fuel pump cover and left rear wheel well liner fulliy expecting to see a failed hose in the vicinity. Nothing--it was dry as a bone. I then pulled the rocker panel liner and saw what look like a corroded fuel line just forward of the frame/body connection in front of the left rear wheel well. Disconnecting the fuel pump I put some air on the line and it was obvious where the leak was--in the main supply line by the plastic support barcket just forward of the body to frame bolt by the wheel well.
Pulling the line I was more than surprised to see it heavily corroded. I live in the Mid-Atlantic and this is not a snow car. We do get some snow and ice but not a lot, and when the weather is bad, my wiife won't drive.
Replacing the filter and fuel line is a given. For the line, I'll need to research OEM versus making my own (I've done brake lines and have the flare tool and tube benders).
What I'm wondering is whether I should also do the fuel pump. I can find a compatible aftermarket fuel filter for my old pump, and there is no indication of leaks. My view if to leave it alone. Plus this is the third repair in three weeks (lock actuator and sunroof)--I hate the idea of putting more money into it than I have too.
Thanks to everyone for your advice.
Kontoboy
A couple days later I pulled the fuel pump cover and left rear wheel well liner fulliy expecting to see a failed hose in the vicinity. Nothing--it was dry as a bone. I then pulled the rocker panel liner and saw what look like a corroded fuel line just forward of the frame/body connection in front of the left rear wheel well. Disconnecting the fuel pump I put some air on the line and it was obvious where the leak was--in the main supply line by the plastic support barcket just forward of the body to frame bolt by the wheel well.
Pulling the line I was more than surprised to see it heavily corroded. I live in the Mid-Atlantic and this is not a snow car. We do get some snow and ice but not a lot, and when the weather is bad, my wiife won't drive.
Replacing the filter and fuel line is a given. For the line, I'll need to research OEM versus making my own (I've done brake lines and have the flare tool and tube benders).
What I'm wondering is whether I should also do the fuel pump. I can find a compatible aftermarket fuel filter for my old pump, and there is no indication of leaks. My view if to leave it alone. Plus this is the third repair in three weeks (lock actuator and sunroof)--I hate the idea of putting more money into it than I have too.
Thanks to everyone for your advice.
Kontoboy
10-27-2013, 08:58 AM
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Here is the part # for the fuel feed line. This is not a DIY repair as a lift is needed and the body and frame have to be separated to install the line
10-28-2013, 12:20 PM
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And in the unlikely event I need another 1/4 inch of room between the frame and body I have a 10 ton hydraulic wedge head that will let me separate the two.
I ordered the line today and will have it by Wednesday. I decided to go with OEM even though I could of spliced a section of 5/16 fuel line in with two compression fittings for under $15. I bought the new filter and lines too (Mahle for $190).
Kontoboy
11-01-2013, 06:13 PM
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Picked up the new fuel line today at my local MB dealer. $212 w. tax--Ouch. When I first saw it I was a little worried--it had a big 90 degree bend in the middle of it that shouldn't have been there. The parts desk was ready to order me another but I decided to bend it straight on top of the parts counter rather than wait until next week for a new line.
As expected the line went back in sliding it from the front wheel well back. It took about 45 minutes to get it in place and reattach all the stand-offs and clips.
New fuel filter (($190 online) was an easy install--15 minutes or so. Then it took about another hour to check for leaks, reinstall the wheel well and rocker panel liners, glue in the pump cover and reinstall the rear seat!
Drove around the neighborhood and all looks good.
I'm still perplexed when the fuel line would rust out in 13 years. I lived in upsate New York in the 70's and 80's where roads were routinely salted and never had these problems.
Kontoboy
As expected the line went back in sliding it from the front wheel well back. It took about 45 minutes to get it in place and reattach all the stand-offs and clips.
New fuel filter (($190 online) was an easy install--15 minutes or so. Then it took about another hour to check for leaks, reinstall the wheel well and rocker panel liners, glue in the pump cover and reinstall the rear seat!
Drove around the neighborhood and all looks good.
I'm still perplexed when the fuel line would rust out in 13 years. I lived in upsate New York in the 70's and 80's where roads were routinely salted and never had these problems.
Kontoboy
