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MG MGB Technical - Fuel Leak Found, need help!

Greetings all,

I have fuel dripping from the clear plastic hose that goes from the fuel pump to the rubber grommet in the passenger side wheel arch area. Does this mean I need a new fuel pump? The fuel pump is operating normally, other than this leak.

Thanks in advance.

Steve

Steve

Do you mean the little hose that comes out of the plastic cap and is a breather for the part of the pump where all the electrics live? If so, then your diaphragm could be holed and letting fuel through. That could be nasty if there's a spark from the contacts.....
Miles Banister

I agree with Miles. Sounds like the pump diaphragm has a hole in it.

The good news is that you can get this part from the regular sources (Moss, Victoria British, etc...),
for about $30. The "fly inthe ointment" is that you'll have to ascertain the length of the metal stem on
the diaphragm before ordering the part as there were 2 versions of these. This means that either you
have to know the part # ID codes of SU fuel pumps - or you'll have to disassemble your the fuel pump
and measure the stem yourself (- safest bet).

Fortunately, disassembling and putting back an SU pump is a fairly straightforward affair if done
carefully.

I may also recommend that you also replace both intake and outlet reed valves on the fuel pump for
good insurance. These things are made of paper-thin plastic and if the diaphragm is old and worn,
chances are the valves are too. Make note of their orientation before removing the old valves.
Victoria British has these.
Daniel Wong

Daniel, Miles;

Thank you.

I forgot to mention that it's a '78 RB roadster.

I just found it last night, and didn't have a chance to crawl under it to see exactly where it tied in to the pump, but I just assumed it was part of the evaporative or venting system (one of the ystems I havn't researched yet). The hose appears to be about 1/8" Dia, and is clear (yellow); I pulled the end that's towards the wheel well out of the rubber grommet, and could see raw gas dripping slowly with the engine running.

Now the big question; the hose is hanging pretty far down, and away from the exhaust. Is it safe to drive home? I'm still at work. I'm OK with the occasional drip to the pavement, but is there any loose gas close to the pump that could ignite?

Thanks again,

Steve
Steve

Steve. If it were me, I would replace the pump and have the old one rebuilt by David DuBois who posts here sometimes. As to whether to drive the car home (assuming this is not already overcome by events) you have been driving the car in this condition and have not had a problem. I have had similar minor fuel leaks which did not prove to be a problem. The explosive part is the gasoline vapors. Which generally do not build up when you are driving. All this being said, I would get a ride home, order a new pump by next day air or purchase one locally (make sure it is not too high a pressure--about 1.75 psi max) and not drive the car until the problem was corrected. What we can get away with in ignorance sometimes catches us when we are aware of a problem. Les
Les Bengtson

Made it home!!, but...

I think it's time to put it up on jackstands for the winter, and start the numerous winter rehab projects.

WHY?
1. The weather... it's been beautiful here in N.W. Indiana, but it can't last long.

2. When I went to start it to go home from work, I needed a little choke ('78 is SU converted with manual choke); Somehow, I managed to catch the turn signal arm with my sweater (it's getting cold here), and I jammed something in the switch: THE BRIGHT LITES CAME ON, and stayed on, EVEN WITH THE LIGHTS NOT BEING TURNED ON!, and even when I shut the engine off.

They wouldn't go off, no matter how I worked the light switch and/or the turn signal/brights switch, although they would go off in 1 position in the middle of the travel range of the switch. I had to force duct tape into the front and back of the turn signal switch to hold it in a certain position to keep the brights off; I took the main road home (the straight way) because every time I used the turn signal, I BRIGHTED anyone in front of me. Good thing I hadn't had too many cold soda's.

I take this as a sign, maybe, that it's time to start the winter projects.

I'll be replacing the fuel pump, learning about the SU system, rebuild front and rear suspension, REPLACE TURN SIGNAL SWITCH, etc.. etc.. etc..

I hope my wallet holds up!!

Thanks to all on this forum.

Steve

Steve

Steve of NW Indiana -

You sound about as haphazard as I am -LOL. Your escapade encourages me to go on. I thought only I was that fortunate to break things without any malice aforethought. I too shall have a few "cold sodas", I usually fare better that way

jolly good mate

Gary
gary n. hansen

This thread was discussed between 08/11/2001 and 09/11/2001

MG MGB Technical index

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