Tall Fuel Pump Rebuilding (Bellows Seal)

[PeterPortugal]

Hi All,

I have had goes previously at rebuilding the tall fuel pumps and sometimes it was successful and sometimes not. The unsuccessful attempts have always been fuel bypassing the bellows and leaking out of the pump body.

I just came across this YouTube video (in Japanese I think) which is quite useful for anyone attempting a rebuild. The info in the Technical Manual is excellent but this video has a detail I haven't noticed on the board - the correct length to stretch the bellows to before installation. Supposedly 21mm. I am not sure whether this can be verified but in the absence of any other advice it is maybe worth considering for anyone doing a rebuild.

Link to Youtube and picture attached.

https://www.youtube.com/watch?v=f5VbKUzFvHc

Regards

Peter

[Pawel66]

Thank you!

Very useful.

[PeterPortugal]

Hi Pawel, it is a really good resource. If you watch the end of the video he tests the pump successfully for an hour off the car. However, once installed in the car it leaks from the overflow pipe. The creator of the video puts this down to back pressure being present on the pump once installed. This increases the differential pressure across the seal and any small flaws in the rotating (bellows) or static (ceramic ring) parts of the seal are exposed.

This is the difficulty with these pumps and may have been one of the drivers for Bosch to develop the short version which doesn't have the seal.

He also has some comments about the quality of components in the aftermarket kits which are worth noting.

[MartinK]

I replaced the bellow seal Into a radial seal ten years ago without any issues until today.

[PeterPortugal]

Hi Martin,

Can you tell us where it is possible to buy this alternative seal?

Thanks

Peter

[MartinK]

Sorry, but it is ten years ago. It is a FKM/FPM radial seal. (inner diameter) × (outer diameter) × (height). I milled out the casting and pressed the seal with some fuel resistant sealant into the casting.

[stickandrudderman]

https://www.sl113.org/forums/index.php?topic=35830.msg261741#msg261741

Not sure if anyone ever followed up in this lead.....

[66andBlue]

Sorry, but it is ten years ago. It is a FKM/FPM radial seal. (inner diameter) × (outer diameter) × (height). I milled out the casting and pressed the seal with some fuel resistant sealant into the casting.

Perhaps I can jog Martin's memory a bit. 
Reply #23: https://www.pagodentreff.de/diskussionsforum/threads/benzinpumpe-getauscht-motor-ruckelt.12501/page-2

http://www.agrolager.de/product_info.php?products_id=31000006

[MartinK]

Thanks, did not have this post on the map. 

[ja17]

I believe Authentic Classics is now offering new reproduction brass bellows seals for the long fuel pumps!

[mauro12]

Vintage Europe parts in USA offers a new reproduction of bellow seal . I guess the most difficult thing was to obtein this small but critical part .

[PeterPortugal]

I don't know who the supplier was (it was somewhere in the US) but the maker of the video was scathing about the quality of the parts in his rebuild kit, including the bellows.