Fuel line clips... what's correct? - PeachParts Mercedes-Benz Forum

landev · #1 02-09-2008, 04:33 PM

My '96 E300D is proving to be an ongoing headache... I fixed the leak from the supply line to the fuel tank to remedy the "no start" condition. Seemed that all was well and fine... then it started to snow.

As we got 4' of snow over the week, I just left the car in the shop and have been driving my pickup. I noticed a few days ago the odor of diesel in the shop, then discovered a 3' diameter puddle of diesel on the floor. "Damn... I must not have gotten the leak fixed" thought I, so ordered another supply line from the dealer ($48!!!) in preparation for this weekend. Today, I pulled the intake manifold off (again) and discovered that the supply line is not the problem, but that there is diesel dripping from the injection pump where the clear fuel lines connect and are held with white U-shaped clips.

When I bought the car, I was told by the previous owner that he had replaced all the lines so that he could run biodiesel if he wanted. I recall he stated that the white clips were not properly installed when he got the car... that instead of the clips being pushed in fully, they should be pulled out to seal correctly. The upshot is that he pulled the clips at all connections where they had been previously pushed in fully.

I went through the manual and can find nothing about the correct position of those clips. My question is: "Should the clips be pulled out or pushed in to fully seal the lines?"

I am currently experimenting and have pushed the clips in so that they are fully seated. I then stuck a paper towel under the fitting to see if there is still leakage. So far, the drip has stopped.

What's correct?

...Update...

Just had another look... still leaking! Bummer!!!

Thanks in advance!

-l-

TMAllison · #2 02-09-2008, 05:08 PM

The horseshoe clips are spreaders. They are pushed tightly closed (ie: make a ringer) for removal.

When installing the fuel lines you should feel or hear a dbl click as both sides seat. With new orings it can be difficult to get enough pressure on them to compress the new orings.

Parrot of Doom · #3 02-09-2008, 05:15 PM

Terry is spot on. Clips in to release, clips out to seal.

This way if a clip breaks you're not going to have a leak.

landev · #4 02-09-2008, 05:40 PM

O.K... got it.

The next question is about getting the leak stopped. I've spent 45 minutes or so patiently trying to figure out where the leak is. As near as I can tell, it is coming from one of the connectors on the injection pump. I've tried to find the part in the Star manual, but it doesn't show and identical pump, so I'm lost.

There is a small black (appears to be plastic) module which is mounted to the driver's side of the pump. Fuel lines are connected to this black module on both top and bottom. It seems that the connection on the bottom of this black module is weaping a drop about every 8-10 minutes or so. I am guessing (hoping!!!) that there is an O-ring that needs to be replaced. Does anyone know how to define the part(s) I need to get this sealed up? Is this just a generic O-ring?

Thanks!

-l-

raMBow · #5 02-09-2008, 05:57 PM

Sounds like you need the Shut-off Valve O-ring replaced. I too thought my fuel line change and viton had not worked, but I had not replaced the aforementioned item. Two screws hold it in. Worked like a charm afterward, hope that is all you are faced with.

raMBow · #6 02-09-2008, 06:00 PM

http://http://www.peachparts.com/shopforum/showthread.php?t=177588

TMAllison · #7 02-09-2008, 07:52 PM

Link is messed up...this one works http://www.peachparts.com/shopforum/showthread.php?t=177588

Line 74, connecting to the bottom of the SOV is one of the difficult ones in my experience to get seated tightly. I've "gently" used a pair of channel locks on that one previously to get it to seat. Second is the oring behind the SOV may indeed be the culprit.

If it is the SOV oring, you really dont even have to disconnect any fuel lines. You can pull it out far enough away for the IP to get the new oring on. I've done all my fuel lines and SOV by removing the windshield washer bottle and reaching under.

http://www.detali.ru/cat/oem_mb2.asp?TP=1&F=210225&M=606%2E962&GA=722%2E608&CT=M&cat=19T&SID=07&SGR=120&SGN=04

raMBow · #8 02-09-2008, 11:13 PM

for fixing the link.

Jeremy5848 · #9 02-10-2008, 01:07 AM

I had my '96 E300D apart to replace the #2 glow plug and found four broken plastic clips that hold the FI lines. While replacing those I noticed that the horseshoe clips are indeed in the "out" position on all lines. Since I have no leaks, I assumed that they were correct and left them as they were. It's nice to know that this is correct.

Jeremy

landev · #10 02-10-2008, 12:50 PM

Rambow,

Where is the shutoff valve O-ring located (link doesn't seem to work... I'll poke around some more)? At this point, I would like to replace any and all seals that might be causing the problem. I'm losing my sense of humor with having taken the intake manifold as many time as I have in the past few weeks, so would like to make sure all is well before re-installing it again. Sure seems that the leak is occurring at the black module (is that the shutoff) where the bottom seated fuel line connects.

Funny how this major leak only started after I fixed the supply line leak. I'm guessing some pressure dynamics have occurred as a result of fixing that initial leak.

Hmmm....

-l-

TMAllison · #11 02-10-2008, 12:57 PM

The SOV oring is behind the SOV. It has a nipple that is approx 3/4" long that inserts into the IP and is sealed with a 2.5mm x 12mm oring. SOV is the black plastic valve on the side of the IP. Its held in place with two torx cap bolts. Its a 5 minute job if you've got the IM off.

landev · #12 02-10-2008, 01:00 PM

Terry,

Thanks!

I think I found the relevant link on the parts.

Is it best to replace the fuel lines (as suggested in the link) while I'm in there? I'd prefer (of course) not to replace a bunch of parts that don't need replacement, but really would like to get this car back on the road (it's been down 9 weeks out of the past 12!!!)

THanks again!

-l-

TMAllison · #13 02-10-2008, 01:13 PM

The lines themselves are very durable although they do yellow with age making it more difficult to see bubbles whan a problem arises. The entire set is on order of $60-70 from the dealer.

The orings are really the only parts that deterioate. Those parts are NOT avail from the dealer.

landev · #14 02-10-2008, 01:21 PM

OK... after having viewed the exploded diagram more closely, I am guessing that the shutoff valve is probably the culprit. As I was exploring the leak, it seemed that a drop of diesel would just appear at the firewall bottom corner of the SOV every few minutes. I wiped the entire valve off numerous times between drips, but could not really see where the leak was. Touching my finger to the fuel line connector at the bottom of the SOV proved that there was diesel there... but I'm guessing it may have collected there from the SOV O-ring. Perhaps I have leaks in both places?

A further question...

While I was awash in diesel, I decided it would be a good time to replace the fuel filter. I had a Mann replacement on the shelf and noticed that they supplied 2 O-rings with the filter. After removing the old filter, I can only see where the larger of the O-rings is installed. Where does the smaller O-ring seat?

THanks,

-l-

TMAllison · #15 02-10-2008, 01:27 PM

The 96 and up use one small oring on the shaft of the fuel filter bolt.

The 95 has a kill switch/button combined on the bolt and uses the other small oring.

Use a mirror and flashlight to look up under the SOV after its cleaned for your drip.