Author Topic: Mount of short fuel pump in place of long pump.  (Read 3163 times)

Tom in seattle

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Mount of short fuel pump in place of long pump.
« on: March 27, 2018, 01:10:56 »
Having found that my failing long fuel pump was history I purchased a rebuilt from Bob Youngman, it is a beauty.  The long pump is held in place by a rubber donut which is suspended in a shock mount cage which fits inside the bell cover. You can’t mount the short pump the same way for several reasons.  I was able to use the tall mount components to mount the short pump with some modifications.

First I made a ring out of 1/8 x 1/2 steel which would just fit inside the rubber donut and then fabricated 3 legs which are welded inside the ring and are then bolted to the mounting tabs of the short pump. The ring supports the pump from the inside of the donut and allows the pump to be rotated to allow alignment with the slots in the protective bell.  I had to shorten the upper mount to allow it to fit inside the bell.  The pump is thus double insulated as was the original and aligns in the bell.
Tom Averill
1967 250 SL Auto Euro Spec

Pawel66

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Re: Mount of short fuel pump in place of long pump.
« Reply #1 on: March 27, 2018, 07:24:10 »

Are you going to open the return connector on your new pump (you have it now plugged with a screw) and install the T-connector in return hose?

I think this is a neat and creative solution you came up with!
Pawel

280SL 1970 automatic 180G Silver
W128 220SE
W121 190SL
G-class

Tom in seattle

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Re: Mount of short fuel pump in place of long pump.
« Reply #2 on: April 05, 2018, 16:16:34 »
My old tall pump was not plumbed that way.  The return line is plugged into a separate port in the tank.  Supply fuel comes from another port just below the return line.  Maybe some tanks had a single port?
Tom Averill
1967 250 SL Auto Euro Spec

Pawel66

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Re: Mount of short fuel pump in place of long pump.
« Reply #3 on: April 05, 2018, 16:27:58 »
Tom, we have talked about it in a thread started by me on fuel pump connections.

In essence: the short fuel pump has a return connector. This return connector may or may not be connected through a T-joint with the return hose going from engine to tank.

Wether the return connector on the pump should be connected through T-joint with the return hose depends on the type of the return valve you have in FIP. If the return valve on FIP has a hole in it - it is better to leave the return connector on the pump plugged. If there is no hole in that valve (newer type), the return connector on the pump should be connected to the return hose through the T-joint.

When I asked you this question I did not know that.

I would have thought that in your case you have the older type of valve, with a hole inside and you should not connect the return line from the pump.
Pawel

280SL 1970 automatic 180G Silver
W128 220SE
W121 190SL
G-class

Shvegel

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Re: Mount of short fuel pump in place of long pump.
« Reply #4 on: April 07, 2018, 17:50:31 »
Tom,
There is a part for mounting the short pump.  If you decide to use the later mount you will also need three rubber isolators and three 5mm nuts and lock washers.

https://www.pelicanparts.com/More_Info/1084700281.htm?pn=108-470-02-81-MBZ


Here are the rubber mounts.

https://www.pelicanparts.com/More_Info/1269880011.htm?pn=126-988-00-11-INT

I think you will find the cover over the pump will also not fit.  The later cover is still available.  I am pretty sure the earlier one is not.  You can probably find someone to sell your's to.  Please don't cut your's up as I am sure there are a few people that need the early cover.

https://www.authenticclassics.com/New-Fuel-Pump-Protector-Cover-250SL-280SL-p/auth-006912.htm
« Last Edit: April 07, 2018, 21:50:55 by Shvegel »

Pawel66

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Re: Mount of short fuel pump in place of long pump.
« Reply #5 on: April 07, 2018, 18:27:10 »
I bought my set from MB (bracket, rubber hangers, screws, T-connector, a couple of hoses) and the prices were reasonable. On the hanger I think you use the set of square holes, if I remember correctly...

But again, I do not hink you would need the return line connected as you most likely have the hole in the valve in FIP.
Pawel

280SL 1970 automatic 180G Silver
W128 220SE
W121 190SL
G-class