Fuel pump rebuild tips

[louis356]

I think I need to rebuild my fuel pump. It doesn't seem to be sucking anything.

Has anyone got any hints/tips that I need to look out for.

My main concern is: do I just take the pump out with gay abandon? or do I need to make sure that 'things are aligned' or anything like that? and do I need any sealant on assembly? like round the edge of the diaphragm?? or is it a clean build.

Is it difficult and do I need three hands to do it?

Thanks in advance for your help.

Greg

[mycar]

No reason why you shouldn't handle the pump with a certain flourish, personally I like to wear a cravat whilst working on the car.

Here's some reading.

http://www.sparkingplugs.com/resources/ ... p+39-2.pdf
http://www.sparkingplugs.com/resources/ ... +pumps.pdf

And the relevant excerpt from the manual.

http://www.sparkingplugs.com/resources/ ... 3-28RT.pdf

Edit :-

The only tricky thing when rebuilding the fuel pump is preloading the diaphragm before screwing everything back together. Here's one solution from the registry annals but with all things 356 I recommend you Check out the 356 Registry Forum.

https://porsche356registry.org/article/80

[Bruce M]

Has the tank got one of those filter socks?
Maybe check that’s not blocked?

[Hugo 356]

Mechanical fuel pump right? I had trouble starting my car after a long lay-up. I suspected the fuel pump, pulled the soft fuel line carb side of the pump and held my thumb over the end of the fuel line while the wife tried to start the car - pressure seemed really weak to me.

Speaking to a long term VW & 356 friend he suggested chucking a small amount of raw fuel down the carb throats, putting the air filters back on and trying to start the car.

Fired up after a couple of goes and has been running great since. Seems the pressure is not strong so as not to overcome the needle valve in the carbs. Moral of the story is not to lay the car up for a long period...

Registry mag has some good articles on fuel pump rebuild if you do need to go that way...

[louis356]

Thanks all

I'm not getting any fuel to the filter before the pump. So I suspect that its not sucking at all.

Full'ish tank as I'm not too sure of on / off reserve thingy and if it should be the bend pointing or the end of the handle (if you know what I mean).

I'll pull the rubber hose and dip in a bottle of petrol and see if that works??? If it sucks and runs that way I know that its a block at tank side? Does my weird heath Robinson idea make sense?

I've just shelled out £80 on a rebuild kit!!

[Bruce M]

Tank strainer. If you have one fitted.

[roy mawbey]

Louis. If the end of the handle is pointing downwards fuel should travel to the fuel pump under gravity feed. I presume you have the later style fuel pump 356B. Have a look at the following link I think itsd your type of pump.

http://www.type356a.com/APG.html

Roy

[roy mawbey]

Louis,

If you have an early 356B your fuel pump will look like the one shown on this link. Again the fuel is gravity fed to the fuel pump so petrol should be present if the fuel tap is in the correct position.
http://www.type356a.com/installation.html

I have a 356A same one as early 356B
Roy

[louis356]

Thanks,

I have an early , early T6. Bottom fuel sender tank. with the early fuel pump.

I'll make sure that the filter is not blocked in the petcock (haven't tried that)

This weekend - here goes, cravat ready!

[neilbardsley]

How can a rebuild kit cost £80? I think it only contains a few bits!

You are right £70

https://www.ebay.co.uk/itm/163419494019

[mycar]

^ That's coming from California, by the time you pay shipping, import duty and handling it might cost more than £80.00.

[louis356]

Roger Bray Supplied the kit.

Do you think I could do this in situ? Looks like most of the tinware has to come off!!

[roy mawbey]

So Louis did you get gravity fed fuel to the fuel pump?

Roy

[louis356]

No, I even jacked up the front of the car to give it some help. I’ve disconnected the fuel line to the pump. Should it be pouring out?

I dismantled the top of the pump and the amount of crap in there

[roy mawbey]

Louis,

Don't suspect the fuel pump till you are certain you are getting fuel to it !! The supply from the tank goes through the 'petcock' ( the item with the turn off handle.) If turning the handle through its 3 positions of 'off, on, and reserve ' shows no fuel and the fuel filter with the wing nut is empty or does not deliver fuel then I would suspect the petcock internals. I had to rebuild mine when it leaked fuel so I can pass on some tips.

From the petcock the fuel rubber pipe travels down behind the floor board to the petrol lines that travel to the back of the car and the connection for the rubber pipe at the steel pipe exiting from the central tunnel. The rubber piping then connects to the metal pipe and then to the fuel pump.

The petcock has a cork gasket with holes for fuel delivery from the main fuel delivery pipe in the fuel tank and the lower reserve delivery pipe. Because the delivery by gravity is copious in quantity its a main blockage you must have its not as though the fuel is passing through a small diameter delivery jet.

I guess the cork gasket might have broken up mine was like brittle wood at over 50 years old. The gasket might have moved to block the delivery holes.

Louis you need the instruction manuals do have them? You can buy a rebuild kit for the petcock I could copy the instruction you will need to drain the tank though.

The fuel pump might just be perfect and not needing work if you can get petrol to it. A full rebuild of that needs care and the instructions. They can leak as I know only to well but the action of this pump made by DVD all those years ago is clever and reliable.

One thought have you tried turning then petcock handle back and forth pushing at the same time towards the part that holds the internals? It might move the gasket. I have drawings of that item too.

Maybe if others don't accept what I am saying they might offer other suggestions.

Let us know how you get on.

Roy