Developed a fuel leak from right rear. Wife forced to take it to dealer. Dealer quickly says $450 for a fuel pump, 2 seals, and some "cheap line." Only 46,000 miles on a 1996 car. Not sure if this chassis model has one pump or two and I am out of town without chassis number. Tried "eautorepair.net" to try to find a schematic as to whether the pump(s) is/are internal to the tank or not. IMO that website is worthless. Cost me $7.99 to find out. Logic tells me that if the pump is leaking then it is external to the tank, otherwise it would be leaking into the tank, no? In my experience these pumps do not usually leak: they may fail, but not leak. BTW, this dealer is notorious for simply replacing the offending part without checking its operation. They are usually quite perturbed when you insist on keeping the replaced part, often saying there is a core charge.

Two questions. First, assuming pump is external to the tank, how difficult is it to acces and replace if need be? Second, other than at a fitting, any idea how these pumps can leak?

Thanks

I am not sure where the fuel pump on the 320SL is. But, if the clamp on your fuel line was loose like on my 88 260E, then we may have the same problem. The fuel was leaking on my car after the engine was cranked up. I can see the fuel dripping on the ground. After jacking up the rear wheel and carefully securing the car, I slid behind the passenger side rear wheel and tightened up the clamp over the fuel line using a screwdriver, I did not even have to take the cover off.

Fuel leaks from the pump body are common. Not as common as outright failure, but o-ring body seals as other rubber items are often affected by no use. A 40k 320SL isn't getting driven much and failures of rubber products (the body seals are undoubtably rubber although there is no way to tell without distructive disassembly) is common after 10 years.

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Steve Brotherton
Continental Imports
Gainesville FL
Bosch Master, ASE Master, L1
33 years MB technician

Steve,

Thanks for the info. In the case you suggest does it usually require replacement of the pump, or just the seals? If so, should a normally competent mechanic be able to perform the operation assuming a pump external to the fuel tank?

Thanks again.

Charlie Warner

" (the body seals are undoubtably rubber although there is no way to tell without distructive disassembly) "

The pump has no servicable internal parts. There are plenty of external ways it could be leaking though and non of it is sophisticated. Most any one can do it.

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Steve Brotherton
Continental Imports
Gainesville FL
Bosch Master, ASE Master, L1
33 years MB technician

Thanks Steve.

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Charlie Warner
Fatto Gatto Racing