Bad fuel pump? Should fuel pump make a sound?

[jf308]

Bought 64 SL just taken out of "storage" after 15 years.

Cleaned gas tank, replaced all hoses and wires.  New battery.  Oil and fuel filter changes. 
Tried to fire it up for first time today -- NADA.  Engine turns, but doesn't sound like there is any fuel.

Turn of the key to just prior to ignition.  No buzzing, no clicking. No sound at all .  Checked fuse #4 OK.

Where to head next?  I would think that even a gelled up pump would make a noise trying to do something.

Thanks.  John
(newbie to the SL world).

[Bonnyboy]

Getting gelled up may not be the issue.  The vanes on the pump stick to the flat surfaces and nothing moves.  Check the archives and follow the info on cleaning the pump.  It can be taken apart if you are careful and unstuck.  I recall using razor blades and alcohol to unstick my pump vanes. 

[jf308]

Thx Ian...shouldn't I hear a buzz even if stuck?

[Cees Klumper]

No experience with this but if the pump is stuck I think the most you might be able to hear is a very faint tone as with an electric motor that cannot move when current is applied. Have you tested to see whether power is supplied to the pump when the ignition is on if you're concerned about the wiring?

[dirtrack49]

My 66 230SL had sat for 15+ years and the old style long fuel pump that was the original equipment was stuck. The fuel pump does not make any noise that I know of when the vanes are stuck to the bottom of the unit. Do not apply power for too long since it might burn the motor windings. When the pump is operating, it sounds like a fairly quiet water pump like you would have on an aquarium or fountain.

When I removed my pump, I sat the bottom of it where the pancake screws are, in a container full of PB Blaster. I let it sit for about a week. When I went to take off the screws, I tapped them with a screw driver and hammer lightly several times to hopefully break loose 48 years of gunk. Next, take a perfectly fitting screw driver in like new shape, and bear into the screw while turning. If your lucky, you will be able to remove all of the bottom pancake screws without any breaking off. If they do, you can still get them out using several different methods that you will find here on the forum.

Next I soaked the vane and bottom of the pump in alcohol for several days and followed it up with scrubbing with a toothbrush. The only item you may need is the bottom rubber seal. For some reason, I got lucky and the old one still seals. However, I did go to NAPA and found another seal that will most likely work if I ever need a new one.

Good Luck,
Tom L.
66 230SL Auto

[George Des]

If the vane is stuck on these old pumps, be very careful when trying to remove it. If at all possible you need to try to pull the vane straight up rather than rotating it free. There is a small tang on the tab washer that holds the bellows seal stationary on the armature shaft. If you try to break the vane free and the bellows seal is stuck to the mating surface in the pump, you run the danger of breaking this tang. Once the tang is broken, the sealing between the shaft and the inner portion of the bellows will be compromised and you will eventually have a leaky pump. You will then need to replace the tab washer and the rubber shaft seal.

George Des

[jf308]

Pump works now.  Not sure if it was jostling it around, or if it was not too badly stuck.  But it works.  Woo hoo.
Checked electrical connections.... Tried to test pump fed from fresh 5 gallon jug into waste container.  Got rid of old fuel/varnish inside -- then ran a couple gallons of fresh fuel thru it.
Pumped out fine.  Good flow.

I will change out the rubber hoses for Feeder and Return.  What to do with the braided line with the metal fitted connection to the pump output?  It appears to be in good condition -- do I need to change it?  Where would I get that fitting, or can I just use rubber with a clamp?

Thanks.  John

[KevinC]

John,

I bought this item at Pelican Parts ...

113-476-09-26-M20

Its from Cohline, they claim to be an OEM supplier to Porsche and BMW. I WOULD NOT use a rubber hose with a clamp.

http://www.pelicanparts.com/cgi-bin/smart/more_info.cgi?pn=113-476-09-26-M20

Kevin

[dirtrack49]

John,

Make sure the outlet hose with the fitting is the proper length. I purchased one from Autohaus AZ and it was for the newer short fuel pump. If you have the old original long fuel pump, you will need a hose that is several inches longer. I had to special order it from K&K manufacturing to get the proper length hose.

There is an earlier thread somewhere that I brought this subject up on. I will run a search and see if I can find the correct hose number.

Tom L.
1966 230SL Auto

[dirtrack49]

Found the old thread. The correct fuel hose for the earlier long pumps is 111-476-09-26. Part number 113-476-09-26 is for later cars that have a short pump. You might want to check with K&K and see if they can still get this hose special ordered. The 111-476-09-26 hose measures 22.5 inches not including the connector.

I found while bringing my car back to life, as with several other vehicles that I have done in the past, you need to be very careful of what parts you order. Over the years, I have acquired a large inventory of parts that I never could use for the project I was working on. Since I am lazy by nature, I never end up returning anything thinking I may possibly need some item in the future. In reality, it just adds more cost to whatever you might be doing at the time.

Tom L.
66 230SL Auto