300SEL Fuel Leak

1965 - 1972: 250S, 250SE, 300SEb, 280S, 280SE, 280SEL, 280SE 3.5, 280SEL 3.5, 280SE 4.5, 280SEL 4.5, 300SEL, 300SEL 6.3, 300SEL 3.5, 300SEL 4.5
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knodes
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Joined: Sun 10 Jul, 2005 11:56 am
Model you own: w109
Location: Brisbane

300SEL Fuel Leak

Post by knodes » Sun 10 Jul, 2005 12:45 pm

Hey fellow Benz lovers,

I have a small problem which I’m hoping one of you 108/9 knowledge ponds may be able to assist in solving.

Yesterday, as I was about to head off on my weekend drive, I noticed a fairly steady leak of petrol from the rear fuel pump of the car (69 300SEL 3.5.) It is still running and isn’t noticeably underpowered; however I have no desire to drive her anywhere until this issue is resolved.

Upon closer inspection the leak is coming from where the power leads join to the pump (See attached image if it works). However no cracks are immediately visible; that’s not to say they are there though.

Can anyone tell me whether?
1. The small cap which the power leads attach to screws into the pump, and thus there may simply be a deteriorated seal at fault?
2. If I could use the same fuel pump from a 280SE 2.8 or 3.5 of similar vintage if the issue is terminal?
3. If using a simple sealant would in your opinion provide a decent temporary fix?

Being a poor uni student, I’d love to save the AU$500 it will cost to get a replacement pump!

Thanks in advance for your help.
John


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bruceT
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Post by bruceT » Sun 10 Jul, 2005 1:53 pm

Welcome to OZVETS John.

Just a point regarding BBCode. If you disable it in your post, the features won't work. So that your pic would display, I had to re-enable BBCode.
Cheers
Bruce

http://oztayls.blogspot.com/
http://oztayls-shesha.blogspot.com/

Past Benzs:
1976 W123 300D (Running on SVO (Straight Veg Oil) since June 2006-Sold in Nov 2008)
1982 W126 280SE - Unregistered (Free to a good home!)
1993 W124 300D (running on 100% used cooking oil, no conversion and no glow plugs!)

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O319-coach
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Post by O319-coach » Sun 10 Jul, 2005 3:34 pm

Belive it or not the electric motor that runs the pump is submersed in fuel at all times. This is why you never test run one of these pumps out of the car. Anyway the reason there is fuel leaking out from the electrical connection is that there must a be a bad seal in there somewhere. These pumps can be pulled apart and worked on however given the possible consiquences I certainly do not reccomend this. Give us a call on 1300 787 300 and i will do you a good price (much better than $500.00) on a new pump.

There are several reasons why the d-jet V8's had a habit of burning to the ground this is one of them.
John Green
Independent importer of discounted genuine Mercedes-Benz parts.
Restorer of Concours winning cars.
Sponsor of this forum.
http://www.mbspares.com.au Toll free phone 1300 787 300

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Les Orth
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Model you own: w220
Location: Tamborine Mountain Queensland

Post by Les Orth » Sun 10 Jul, 2005 10:37 pm

Hi John,
I replaced a similar fuel pump in my 280SE 3.5 and was quoted $450 to purchase the pump from a local Mercedes parts dealer in Brisbane. I checked around and was able to purchase the same pump directly from a bosh supplier for $124. I then contacted the local mercedes specialist workshop who quoted the $450 for the pump and told him the price I could get it for, whereupon he said he would supply the pump for the $124 price quoted and fitted it charging around $80 for labour, being $204 all up for the job. I've found it pays to shop around. By the way Mercedes Benz of Brisbane quoted me $650 for the same pump.
regards,
Les

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ADow
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Post by ADow » Mon 01 Aug, 2005 6:52 pm

There are several reasons why the d-jet V8's had a habit of burning to the ground this is one of them.
What are the other causes John?

(G'day Les - great to hear from you again).

Alastair
Alastair
1971 280SE 3.5 - Don Ottavio - sold
1980 300D (formerly daughter's) - Heidi - sold
1999 C200 Elegance (currently daughter's)
1981 300D (son's) - Hektor
1998 Puma Clubman with 225 RWKW SR20DET - Percy
http://www.youtube.com/user/adow77

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O319-coach
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Post by O319-coach » Mon 08 Aug, 2005 1:17 pm

Basically anything to do with fuel lines and leaks. The drain hole at the back of the block tends to get blocked so any leaking fuel just pools in the valley waiting for an ignition source. Get some compressed air and blow out the drian from below. You can see the exit just above the starter motor.
John Green
Independent importer of discounted genuine Mercedes-Benz parts.
Restorer of Concours winning cars.
Sponsor of this forum.
http://www.mbspares.com.au Toll free phone 1300 787 300

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ADow
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Post by ADow » Mon 08 Aug, 2005 1:32 pm

Welcome back to Oz - did you come back from Germany with a couple of container loads of spares?
Alastair
Alastair
1971 280SE 3.5 - Don Ottavio - sold
1980 300D (formerly daughter's) - Heidi - sold
1999 C200 Elegance (currently daughter's)
1981 300D (son's) - Hektor
1998 Puma Clubman with 225 RWKW SR20DET - Percy
http://www.youtube.com/user/adow77

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