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1986 Mercedes 560SL
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7 Posts
Discussion Starter #1
Hi, first post and I am a new member here and could use some help.

I have a 1986 560sl and I have replaced the 3 fuel lines on the left side of the car...only problem is I did it in sections all at once. I don't think I did it...but I may have mixed up the lines between the 3 as the car is not firing up now and i put in about 25 ft of new line. Before I go and disconnect all the lines again...

Can anyone provide a picture under there 560sl of the fuel lines below the left side firewall and the lines before the axel? All my fuel line brackets rusted through so I had to remove them all.
 

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1986 Mercedes 560SL
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7 Posts
Discussion Starter #3
Thanks Robert, very helpful link! I traced the lines and my fuel sender is definitely in order and so is the return...still unsure why it won't start but at least I know my lines are in the right spot.

The 3rd "other fuel line" I am not sure what it does but I will keep searching through this link...I replaced a 4 foot section of it but have no idea what it is! just that it was rusted through and leaking.
 

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1978 450SL--117K
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1,374 Posts
It's an area I haven't messed with yet, there should be a return line that returns excess fuel to the tank. Have you checked to see if any fuel is getting to the injectors? Have you checked the fuel filters? is the pump running?

I know a lot about injection--for diesels, not these. I would work my way back from the front to the rear to see where it is or isn't flowing. Did you try using a bit of ether to get it started? I believe these cars have a safety feature which shuts off the pump if the car is not running. Diesels have a manual pump to prime the system.
 

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1986 Mercedes 560SL
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7 Posts
Discussion Starter #5 (Edited)
Thanks Robert, very helpful link! I traced the lines and my fuel sender is definitely in order and so is the return...still unsure why it won't start but at least I know my lines are in the right spot, guessing I still have a lot of air in the lines but after looking at the diagram and the car there is a bleeder on the fuel cooler?

Is the fuel cooler connected to the a/c compressor in anyway? The sender is the line coming from the filter and the return I can trace from the engine bay as shown in one of the diagrams, but there is a 3rd fuel line that runs into the engine and I repaired this line under the car but I can't seem to trace it anywhere to see where it goes into the engine bay...I am not sure what this line is
 

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1978 450SL--117K
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1,374 Posts
Thanks Robert, very helpful link! I traced the lines and my fuel sender is definitely in order and so is the return...still unsure why it won't start but at least I know my lines are in the right spot, guessing I still have a lot of air in the lines but after looking at the diagram and the car there is a bleeder on the fuel cooler?

Is the fuel cooler connected to the a/c compressor in anyway? I've never even heard of a fuel cooler before. This car is complex.
Again, I am no expert, others are. I believe the fuel cooler referred to is the low pressure A/C line headed into the heater box where the evaporator resides.
 

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1978 450SL--117K
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squirt some starting fluid into the air intake--with the air cleaner assembly open. If it is air in the lines, just gently squirt enough in to keep it running--assuming it will start with starting fluid/ether. Once running, it should self prime the system working the air out.
 

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1986 Mercedes 560SL
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7 Posts
Discussion Starter #9
Sounds like a plan, the pump is running. It is running when the key is in "on" and primes then and it remains running while the starter is going.

I think your right about the a/c fuel cooler, there is a bleeder there but that is for the a/c system not the fuel system. I will try to get the car to go with starter fluid tomorrow.

Thanks for all your help, sorry for the double post confusing. I will post results of what happens.
 

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1978 450SL--117K
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Sounds like a plan, the pump is running. It is running when the key is in "on" and primes then and it remains running while the starter is going.

I think your right about the a/c fuel cooler, there is a bleeder there but that is for the a/c system not the fuel system. I will try to get the car to go with starter fluid tomorrow.

Thanks for all your help, sorry for the double post confusing. I will post results of what happens.
No problem. And yes, it is a complicated car--for it's day.
 

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1986 Mercedes 560SL
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7 Posts
Discussion Starter #11
the mystery line runs to the trunk...I'm assuming that is where the charcoal canister is...from the diagram it connects to a bunch of valves under the motor i can't really see but that's my guess.
 

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R/C107 Moderator
1986 560SL: '84 500SL: '84 280SL 5 speed: other 107s
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32,353 Posts
Charcoal canister is mounted under the left front fender. You have to remove the inner fender liner to access it.
 

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1978 450SL--117K
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Charcoal canister is mounted under the left front fender. You have to remove the inner fender liner to access it.
That's what I thought. But, since I have had no fuel issues--yet, I don't know much. My guess is, is that the ether worked--else he would have been back on.
 

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1986 Mercedes 560SL
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Discussion Starter #14
Hey Folks, thanks again for your help, the car starts now which is good. I have 3 fuel leaks, all on my sender line.

I double flared every fitting accept for one existing compression fitting...and the 3 leaks are coming from the double flare fittings and not the compression fitting.

The fuel lines on these cars are thicker...and they didn't flare well so I do not recommend trying. I even used a Blue-Point flaring tool, the lines are just too thick to get a good double flare so learn from my mistake!

I can take a pic of the factory mercedes 5/16" line next to a 5/16" replacement line if you would like to see.

Also, The fuel lines are "no longer available" from the factory. Looks like my next step is to use compression fittings and get rid of my flared lines...I have no other options at this point, just an update, thanks again for the quick help.
 

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1978 450SL--117K
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Thickness should not be a problem when flaring. The thickness of your pipe is no where near as thick as 2" copper water line and we flared that all the time--until we started welding it to save money on the gigantic brass fittings. Weld was better for that anyway.

Flaring is a tricky deal. It must be flared all the way out, but w/o cracking the metal. I would check, with the flaring tool, to make sure it is properly flared. If you like, take a pic and I will give you my opinion of the flare you have made.
 

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R/C107 Moderator
1986 560SL: '84 500SL: '84 280SL 5 speed: other 107s
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32,353 Posts
Also, The fuel lines are "no longer available" from the factory. Looks like my next step is to use compression fittings and get rid of my flared lines...I have no other options at this point, just an update, thanks again for the quick help.
Have you checked the Classic Center for availability? I checked a dealer site for the long fuel feed line 107 470 93 64 it showed 84.00 MSRP and 60.00 their price. The Classic Center would have the final word on availability.
 

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'89 300TE, '79 450SL, '01 ML320
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If they're leaking at a factory connection it's likely because Mercedes uses bubble flares, not double flares.



Fish
 
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