Author Topic: Fuel Pump Mounting  (Read 5373 times)

Hargus

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Fuel Pump Mounting
« on: May 19, 2009, 22:23:54 »
I have installed a new "short" fuel pump replacing another one that had lasted for more than the 21 years I have owned my '66 230SL. Although I was a MB mechanic in an independent shop in the mid 70s I certainly don't remember much about the fuel pump mounting (and that would have been the tall pump anyway). The last person to install a short pump on this car apparently didn't either. This may explain why the outlet hose is dangerously close to the sub-frame and night wear over time. They used the old tall pump mount bracket that bolts to the sub-frame and used the rubber mounts from that to the 3 finger circular mount plate, which they bolted to the pump proper with screws. From a picture at the the SLS site (link below) I see that the round rubber mounts should screw into the pump and be bolted to the 3 finger circular plate. What I can't determine is how it is bolted to the sub-frame. A couple of questions for the more knowledgeable out there:

1.  Is the old long mount retained?
2. Does the 3 finger circular mount plate bolt directly to the subframe or is there another plate I need to get?
3.  Pictures would be a real help!

Here is the illustration that I've found most helpful up to now
http://www.sls-hh-shop.de/popup_image.php/pID/2474/imgID/0

Here is a picture of the pump presently mounted incorrectly:



waqas

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Re: Fuel Pump Mounting
« Reply #1 on: May 19, 2009, 22:54:24 »
... This may explain why the outlet hose is dangerously close to the sub-frame and night wear over time.

The rigid elbow for the return hose should not be pointing up. It should be loosened and then pointed to the side (left side, toward the wheel). This should give you more clearance.

Quote
1.  Is the old long mount retained?

Yes. The goal is to make sure the gravity-fed nature of the setup is maintained. The feed line of the pump should be at or slightly below the bottom of the fuel tank.

Quote
2. Does the 3 finger circular mount plate bolt directly to the subframe or is there another plate I need to get?

I've seen both kinds of setups. However, I do believe that the correct setup ought to be to connect the new plate directly to the old mount plate, followed by the rubber mountings, and then the pump. The new plate has several choices of holes to use for mounting (this will be clear once you've removed the plate).

Quote
3.  Pictures would be a real help!

The following image is taken from our Technical Manual (page: http://www.sl113.org/wiki/Fuel/FuelPumpRebuildLater). Note that the perspective from which the photo has been taken is different from yours.

« Last Edit: May 19, 2009, 22:59:59 by waqas »
Waqas (Wa-kaas) in Austin, Texas

Hargus

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Re: Fuel Pump Mounting
« Reply #2 on: May 19, 2009, 23:34:50 »
Thanks for the quick response. I knew I'd seen a picture somewhere on the site but couldn't locate it again. I think I'll tackle re--mounting it next week after a trip to Miller's to get a new factory type fuel outlet hose. Of course I used medium locktite on the bolts so I'm in for a fun time! If I look hard at the picture I linked it appears that the fuel line is pointed towards the other, passenger's side wheel. Perhaps this is not a 113 shown?

waqas

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Re: Fuel Pump Mounting
« Reply #3 on: May 20, 2009, 01:17:45 »
Definitely a 113 shown. The hose goes up and above the axle, and then to the hard line along the driver floor.
Waqas (Wa-kaas) in Austin, Texas

SteveK

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Re: Fuel Pump Mounting
« Reply #4 on: May 20, 2009, 01:29:53 »
I really like he cut away fuel pump cover in the pic above.  When I bought my Pagoda the PO had just put in a new pump but did not replace the cover.  I have it but it's pretty ugly having been brutally modified with a cutting torch to allow the a shorter pump. (He told me someone had done this in an earlier fuel pump replacement.)  I think I'll get out the grinding wheel this weekend and do the curvy full cut out and mount the cover! :)

Naj ✝︎

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Re: Fuel Pump Mounting
« Reply #5 on: May 20, 2009, 06:29:13 »
Here's a better? Picture.
The original mounting brackets are used to mount tripod circular plate to.
This is a 230 SL where the pump is slightly differently mounted to the 280 with the 82 litre fuel tank.
« Last Edit: May 20, 2009, 06:30:49 by naj »
68 280SL