W209 sending unit replacement - desperately need DIY instructions
#1
W209 sending unit replacement - desperately need DIY instructions
Guys/Gals,
I'm down a car and have to get the sending unit replaced in my 06 CLK 500 today. I have been searching for about two hours now (at work mind you) for detailed instructions on how to get the sending unit fuel line clamp off (it is a crimp ring). I have had no luck. Can someone please point me in the right direction here? Specifically - how to get the fuel line off the old sending unit and reattached to the new one. Everything else I got. TIA.
I'm down a car and have to get the sending unit replaced in my 06 CLK 500 today. I have been searching for about two hours now (at work mind you) for detailed instructions on how to get the sending unit fuel line clamp off (it is a crimp ring). I have had no luck. Can someone please point me in the right direction here? Specifically - how to get the fuel line off the old sending unit and reattached to the new one. Everything else I got. TIA.
#3
Well this isn't turning out to be as easy as I thought. Do I have to take the fuel pump out as well, in order to replace the sending unit? I've got the fuel line disconnected from the sending unit and the sending unit itself is pulled out about 8 - 10 inches and then the hoses and various wiring appear to be stuck and I can't pull them any further to disconnect them.
Again, TIA to anyone who can help with this
Again, TIA to anyone who can help with this
#4
Well this isn't turning out to be as easy as I thought. Do I have to take the fuel pump out as well, in order to replace the sending unit? I've got the fuel line disconnected from the sending unit and the sending unit itself is pulled out about 8 - 10 inches and then the hoses and various wiring appear to be stuck and I can't pull them any further to disconnect them.
Again, TIA to anyone who can help with this
Again, TIA to anyone who can help with this
How do I remove this from the top of the fuel pump? This is the new one.
#5
I had the same problem. It's supposed to just be a snap collar, where you push in on the connector, pull back on the collar and it releases. It's like these "shark-bite" plumbing connectors. However, it seems that the seals like to fuse themselves to the nipple and not come loose, and the nipple on the pump gets brittle. I ended up breaking the nipple on mine, requiring a whole new pump. I would remove all the lines you can, then cut this last hose off a few inches from the pump so you can remove the pump from the car. Take it to a work bench and then carefully remove it there. Just cut the connector apart piece by piece if need be.
#6
I had the same problem. It's supposed to just be a snap collar, where you push in on the connector, pull back on the collar and it releases. It's like these "shark-bite" plumbing connectors. However, it seems that the seals like to fuse themselves to the nipple and not come loose, and the nipple on the pump gets brittle. I ended up breaking the nipple on mine, requiring a whole new pump. I would remove all the lines you can, then cut this last hose off a few inches from the pump so you can remove the pump from the car. Take it to a work bench and then carefully remove it there. Just cut the connector apart piece by piece if need be.
Trending Topics
#10
Oh, sorry - I misunderstood and thought you were still having problems attaching the pressure line to the fuel pump. So, you are having problems getting the retaining ring started on the sender unit? Did you get the ring on the fuel pump in place? They are the same - same part numbers and everything. Make sure the sender is installed correctly - there is a dimple that lines up with an arrow on the tank.
The following users liked this post:
abqhudson (09-24-2016)
#11
Oh, sorry - I misunderstood and thought you were still having problems attaching the pressure line to the fuel pump. So, you are having problems getting the retaining ring started on the sender unit? Did you get the ring on the fuel pump in place? They are the same - same part numbers and everything. Make sure the sender is installed correctly - there is a dimple that lines up with an arrow on the tank.
Thanks for your help Rodney.
#12
Glad you finally got it back together. My CLK had the "California" version, which was a giant hose clamp instead of the screw-on ring. I had to use a "Skewdriver" to get to the screw head. It was a major PITA.
#13
Member
Joined: Jan 2016
Posts: 152
Likes: 18
2009 CLK550 convertible, 2012 ,,E550 Cabrio, 2012 Audi Q5
Apparently I have the same version because I screwed that ring around 20+ times and nothing happened so I finally caught on that I had toreally release the clamp I got everything off however getting it back together is another story I can't seem to get the sending unit seated . Is there some sort of alignment issue?
#14
Member
Joined: Jan 2016
Posts: 152
Likes: 18
2009 CLK550 convertible, 2012 ,,E550 Cabrio, 2012 Audi Q5
After an afternoon of frustration I thought I would share what I think I figured out about replacing the fuel sensor gasket. If your car is leaking at the top of the sending unit first check to see if your cover is secured by a plastic ring and a hose clamp around the perimeter. This is how my MY 09 550 was configured, I believe that means it is a California version but I am not sure. In any event the securing ring was clamped on not screwed on. It took me about 1 hour of spinning the securing ring and getting nowhere before I removed the hose clamp and the securing ring came off. I was not able to fully seat the sending unit with the new gasket I purchased so I decided to throw in the towel after another frustrating hour of my life and put the old gasket back in. I was able to tighten the clamp and securing ring much more than it was at the start as evidenced by a smaller gap in the securing ring . I filled the tank and no more leak! I am not sure if this will be a long term fix but for now all is well.
So the moral of the story is , if your car is configured like mine with a clamp around the outside of the securing ring your first action should be to tighten the clamp if possible and see if the leak stops. By the way a 7 mm box wrench is the tool I used.
So the moral of the story is , if your car is configured like mine with a clamp around the outside of the securing ring your first action should be to tighten the clamp if possible and see if the leak stops. By the way a 7 mm box wrench is the tool I used.
#15
The new gasket is thicker, but I was able to get mine in with a bit of grease on it to help is slide in place so it didn't pinch and bind. That ring and clamp is a total PITA to deal with, though.
#16
holy hell yea... those clamps were a pain. i just did mine 2 weeks ago.
those clamps took me a good 25 minutes each on and off. so i had a friend help me.
btw, on my car... the seal wasn't leaking. after replacing the seals... thinking i was done...
i found my housing... the white part. there is a raised part in the middle that is glued. it was leaking from there. i attached a pic of my new part and circled where my leak was coming from. only when tank was full and very light while driving. when i stopped the car, the fuel seemed to continue to puddle. after replacing the seal, i filled up the tank and sat there checking it with everything apart. filling my tank didn't make it leak. it was after driving where i started to notice it.
so lame... i had to take of those clamps twice!!!
i was getting a light gas smell in the garage the morning after i fill up my tank. filling up half way to about 80% didn't make any smells.
when i looked under the car, i noticed white liquid dry marks on the driver side plastic panel. i attached a picture of that also. after this repair, i now know it was fuel making those marks... kinda splashing on my rear portion of the exhaust... super dangerous.
tips, i also used alittle lube on the seal putting it in. wd40. took alittle time. but it did all go in together. i had to also use a double wobble deep socket setup with a small ratchet.
i bought the gaskets on ebay, oem. supposedly... and my gaskets were not just alittle thicker... but it was like 2x to 3x taller! i am hoping i won't have to do this again. i hate touching fuel systems
those clamps took me a good 25 minutes each on and off. so i had a friend help me.
btw, on my car... the seal wasn't leaking. after replacing the seals... thinking i was done...
i found my housing... the white part. there is a raised part in the middle that is glued. it was leaking from there. i attached a pic of my new part and circled where my leak was coming from. only when tank was full and very light while driving. when i stopped the car, the fuel seemed to continue to puddle. after replacing the seal, i filled up the tank and sat there checking it with everything apart. filling my tank didn't make it leak. it was after driving where i started to notice it.
so lame... i had to take of those clamps twice!!!
i was getting a light gas smell in the garage the morning after i fill up my tank. filling up half way to about 80% didn't make any smells.
when i looked under the car, i noticed white liquid dry marks on the driver side plastic panel. i attached a picture of that also. after this repair, i now know it was fuel making those marks... kinda splashing on my rear portion of the exhaust... super dangerous.
tips, i also used alittle lube on the seal putting it in. wd40. took alittle time. but it did all go in together. i had to also use a double wobble deep socket setup with a small ratchet.
i bought the gaskets on ebay, oem. supposedly... and my gaskets were not just alittle thicker... but it was like 2x to 3x taller! i am hoping i won't have to do this again. i hate touching fuel systems
Last edited by faded1004; 06-09-2017 at 11:42 AM.
#17
Member
Joined: Jan 2016
Posts: 152
Likes: 18
2009 CLK550 convertible, 2012 ,,E550 Cabrio, 2012 Audi Q5
Faded1004 says he had multiple clamps, I had only one large hose clamp that squeezed the split securing ring, others have some sort of screw ring. How many different set ups are there? I purchased a tool to unscrew the ring that I assumed held the sensor in place but I did not need it . What I needed was a contortionist to access the head of the hose clamp to unscrew it . Two days after I spent an afternoon cramped into that small area I still have pain in my lower back and shoulders. I am thankful that my 09 is a cabrio, I can't imagine what this would have been with the coupe.
#18
Member
Joined: Jan 2016
Posts: 152
Likes: 18
2009 CLK550 convertible, 2012 ,,E550 Cabrio, 2012 Audi Q5
After many hours crammed into the back seat area attempting to repair the fuel leak at the top of the sending unit by replacing the seal, I discovered that the leak was located at the same spot as represented by Faded1004 in his photos. I decided to try an epoxy repair rather than spending $300+ for a new unit. So far 2 fill ups and no fuel leak. JB Weld to the rescue. Cost $0, it was in my tool box, time 15 minutes. Thanks again to this forum where the epoxy repair was mentioned.
#19
I have the same problem! I narrowed down the leak to the area faded1004 circled in red.
My situation is shown in below pic. Driver's side rear seat.
Also attached is the cover that is over the bolt. I almost broke the plastic piece since I just tore it off. With some more finesse, you can avoid damaging it.
I am going to try the epoxy route. Any recommendations for epoxy? Is JBL weld really the best, or I use some plastic-like version?
My situation is shown in below pic. Driver's side rear seat.
Also attached is the cover that is over the bolt. I almost broke the plastic piece since I just tore it off. With some more finesse, you can avoid damaging it.
I am going to try the epoxy route. Any recommendations for epoxy? Is JBL weld really the best, or I use some plastic-like version?
#22
It's the pressure sensor that leaks. It's not a separately replaceable part, so the whole sender unit must be swapped. Stupid me, when I replaced mine, I meant to keep the bad sender and see if the pressure sensor could be removed and its seal replaced, but I didn't. Maybe an enterprising member who does this swap will take a closer look.
#23
MBWorld Fanatic!
Joined: Feb 2011
Posts: 2,541
Likes: 190
From: Austin, TX
2006 E55, 2012 GLK350 & 1992 190e sportline
It's the pressure sensor that leaks. It's not a separately replaceable part, so the whole sender unit must be swapped. Stupid me, when I replaced mine, I meant to keep the bad sender and see if the pressure sensor could be removed and its seal replaced, but I didn't. Maybe an enterprising member who does this swap will take a closer look.
#25
The epoxy did the trick. No more leaking. I'm not a wizard with the epoxy, which is runnier than I hoped for the first two minutes (5 minute JBL plastic weld), but there is at least a millimeter over everything. I used some metal tape I had and tried to make a dam with it so it would just go where it had to.
After epoxy
After epoxy
Last edited by trikoid; 12-03-2018 at 07:31 AM. Reason: Added picture