Long Fuel Pump Overhaul

[Pawel66]

I have embarked on an adventure - rebuilding long fuel pump for my Ponotn. Yes, I know, it is a long shot, but I thought - if I brake it, it will be my pump broken .

I have two questions:

1. We have the black plastic seal in the pump housing. I have it new to be installed. I noticed its inner diameter is bigger than the shaft of the pump, so it would not seal the shaft. Is it ok? Or I got the wrong part? I do not remember what was the diameter of the one I dismantled. On the other hand I received the parts from a reliable source...

Do not know what to think about it.

2. I have attached picture with the shaft of my pump and parts that go onto it. I had two cap washers there, one of them, I guess, fitted instead of shim (the upper one). Is it correct what I have there? Shall I keep this second cap washer instead of shims?

Please kindly help if I may ask.

Pawel

[MartinK]

The "plastic ring" is the counterpart of the mechanical seal. The diameter has to be wider as the shaft. A mechanical seal consists of two parts. One part is pressed firmly into the housing, while the other rotates with the shaft. Be absolutely careful with the both parts. If the surface of one of the parts has a scratch, it is unusable and fails.

[Pawel66]

Thank you!

That is exactly what I was after.

Understand the need to be careful - I see the mating surfaces, I understand bellow needs to be undamaged. I have a applicator for the plastic seal, it came with the kit.

Thanks again!

[rwmastel]

The diameter has to be wider as the shaft.

Which do mean?
- as wide as the shaft?
- wider than the shaft?

[mauro12]

Is there a place around europe that rebuilds these long pumps ?

[MartinK]

https://www.sl-oldtimer-service.de/

WhatsApp him.

[Pawel66]

I put the pump together and tested it.

Runs very quiet, pumps fuel like hell, I think more than 1 liter per 15 seconds.

No fuel is dripping from the drain nipple when the pump is running

However

When the pump stops or when I was priming it before start - there was fuel dripping form the drain nipple.

What did I do wrong? Is it the question of the oring on the shaft not fully sealing the bellows seal (I have a new bellows seal)? I did use 5x1,25mm oring, so slightly oversized.

Or is it something else?