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MG MGB Technical - Another SU Pump Issue

fuel pumps one is probably for David, but I
C R Huff

This is the same problem I'm having. From what I gather, it means the pump is drawing in air somewhere, or as you say the non return valve isnt working. Burlen fuel systems do rebuild kits for these pumps so if your going to be taking the pump out to try and fix it, I'd get this kit. Replacing the gaskets and seals as well as the valves would be a prudent move in my opinion. It also comes with new points and a new diaphragm. That should eliminate the problems I reckon. I'll be doing my pump in a couple of weeks so I can give you my advice and pitfalls from a novices perspective doing the job for the first time and how I overcame them.
Ross Kelly

One of the Reed Valves (In, Out) is probably

They're made of a thin plastic and they develope
a hairline crack before they totally go kaput.

They're easy to change, once the pump is out
of the car.


Less likely (but not out of the realm) is that the
diaphragm might have developed a crack and
is leaking.

The Bentley Manual gives detailed instructions
on how to replace and adjust the diaphragm.


In both cases, no special tools are required.
Daniel Wong

Thanks Guys,

I probably won't do a full rebuild because I already have another new pump plumbed into the car, and it would start doing the job anytime I swap the wires over to it.

I don't have the Bentley, but now that I know what I'm looking for I suspect that I can find it. Do most of the MG parts supplies have the valve available?

Hmm, come to think of it, I might have a Bentley for my Spridget.

C R Huff

An air leak on the inlet side of the pump or a bad check valve (or some debris trapped in it) will cause the problem you are experiencing. It could be a torn or cracked diaphragm, but those are very rare and if it is the diaphragm, you would see fuel leaking out from th event tube or the edge of the diaphragm. Cheers - Dave
David DuBois

Thanks David,

I'll have my self a look-see.

C R Huff

This thread was discussed between 17/06/2008 and 18/06/2008

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