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MG MGB Technical - Fuel pump flexible pipe modification

73B Roadster.

I have recently had the flexible braided hose, that connects the fuel pump to the copper pipe running to the engine bay, deteriorate and leak. This pipe failed almost overnight. Looking at the way the factory design works, could a rigid copper pipe, banjo, unions etc, like the input to the pump, be implemented on the output of the pump, thus eliminating a weakness in this pipework? The unions on the fuel pump for for both input and output look identical.

There would need to be a union between this pipe and the forward going pipe but this could be a rubber sleeve pipe and clips over the copper pipes butted together which would be way more reliable than the flexible pipe. Additionally, simpler to fix on the roadside if required.

Any thoughts?

Best

Richard.
Richard Thompson

Richard - Remove the leaky flex line from the banjo fitting (a bit fussy, but considerably less expensive than a new flex line. Get some 1/4 inch fuel injection line a bit longer than the existing line and a couple of hose clamps (forgotten the name of hose clamps on your side of the pond) and make your own flex line. I have done this on several cars with no problems. Cheers - Dave
D.W. DuBois

Richard,
Three things,
1. Not a fan of braided fuel lines as you can't examine the important bit, i.e., the rubber, to see if it's cracking.
2. A flexible allows for a bit of movement of the pump, which is not rigidly mounted.
3. Use the latest specification fuel injection hose.J30R6. Much more resistant to modern fuels.
Do as Dave suggested.
Allan Reeling

Dave, Alan,

Many thanks for the suggestions.

I had not thought of separating the existing leaky pipe from the banjo and fitting better pipe back onto the banjo. This also maintains the compliance of the pump mounting where as fitting a rigid copper pipe would reduce it.

I'll search for J30R6 pipe; I have clips.

Thanks again.

Richard.

Richard Thompson

Hi Richard
Before you use J30R6 best to read: http://www.vehicleservicepros.com/on-the-vehicle/powertrain/fuels/article/12044377/modern-fuels-require-modern-fuel-hose
J Hughes

Looks like the really ethanol proof stuff is R9. R6 is "tolerant".
Allan Reeling

J Hughes,

An interesting read, thanks.

Richard.
Richard Thompson

Hoses don't deteriorate overnight! Yes one day they may leak when they didn't leak the previous day, but that's not the same thing. Just replace it with suitable fuel hose. Having solid pipes both sides could well cause problems with sealing unless that are both exactly aligned to the pump. Having at least one flexible connection eliminates that. FWIW RB cars have two hoses on the pump.
paulh4

Hi Paul,

Good points, and reflects my thoughts. I was not aware that the RB Bs had flexible pipes on the input and output.

Obviously when BL made that production change the cost of the flexible pipe on the input was less than the equivalent copper piping, giving a production cost saving.

'Overnight’ was intended to convey the fact that this issue manifested itself in a short period of time, such as between my bi weekly drive of my B, as it is not my daily driver. (must get out more!)

Best

Richard.
Richard Thompson

This thread was discussed between 04/06/2017 and 09/06/2017

MG MGB Technical index

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