Pagoda SL Group

W113 Pagoda SL Group => Drive train, fuel, suspension, steering & brakes => Topic started by: ola on January 22, 2012, 19:11:24

Title: fuel pump for my 280 se has 3 hoses ?
Post by: ola on January 22, 2012, 19:11:24

fuel pump for my 280 se. the pagoda has 3 hoses. (2 large and one small) which connect these?

Title: Re: fuel pump for my 280 se has 3 hoses ?
Post by: Naj ✝︎ on January 22, 2012, 20:36:55

Hi, Ola

The small pipe is connected with a 'T' piece to the return line.
Not all cars use this syetem, in which case the small pipe on the pump is blanked off with a (4 mm?) screw.

Naj

Title: Re: fuel pump for my 280 se has 3 hoses ?
Post by: wwheeler on January 23, 2012, 05:20:51

I put a new pump on my '68 w111 a couple of years ago. With the old tall pump, it did not have the "tee" in the return line as your picture. I kept the return line routed directly back to the tank as the original set up. But I did not install a screw in the small pipe on the new pump. Should I? There is no fuel coming out now. What is the purpose of the small pipe?

Thanks.

Title: Re: fuel pump for my 280 se has 3 hoses ?
Post by: 280SE Guy on January 23, 2012, 11:26:04

Wallace,

Your new pump should have had the screw already in place.

(https://lh5.googleusercontent.com/-eWgx5oVAIcY/Tx07lpmNxCI/AAAAAAAAA_8/u8a-pswQe-w/s600/fuel-pump.jpg)

The extra line is a fuel bypass hose. From the BBB section 07-11/3 B. Electric Fuel Pump:

The fuel pump (large design) has been replaced by a new fuel pump (small design) with a bypass system. The bypass system prevents fuel vapor lock in the fuel system. The vapor bubbles are forced back into the fuel tank through the bypass connection which is connected to the fuel return line by means of a T-piece (Fig 07-11/7)

Naj, I recognize that fine picture you posted.  ;D

Regards,

280SE Guy

Title: Re: Naj, I recognize that fine picture you posted.
Post by: Naj ✝︎ on January 23, 2012, 12:29:56

Yes, its from the '113 World' Album  ;D

Naj

Title: Re: fuel pump for my 280 se has 3 hoses ?
Post by: George Des on January 23, 2012, 12:59:50

If you are using the small pump to replace the original long style pump, you probably do not need to worry about the tee connection other than just making sure thepump pipe is blocked with a screw and some sealant. Whether you connect to this or not is determined by the fuel injection/fuel distributor set up you have on the car. Joe Alexander has a post somehwere in this Forum where he explains the different diaphrams that are in the fuel distributor and which ones require the tee fitting to be connected. My understanding is that this only applied to later 113s as well as 108 FI models. Hope this helps.

George