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MG MGB Technical - Fuel pump rebuilt

The rebuild kit I ordered for my SU fuel pump arrived a couple of weeks ago from Gower and Lee. It was the proper SU kit. The problem I was having with my pump was that it was ticking continuously even without the engine running. It wasnt starving the engine of fuel but I reckoned it would only be a matter of time before it would, or it would burn itself out. Either way it was going to have to come out. Saturday I got under the car and pulled it out to fix it once and for all. It wasnt totally straightforward. Firstly the instructions that came with the rebuild kit were completely useless and spoke in riddles about how the wiring for the points was done. It was with the help of, of all things, the haynes manual that I got the points in and wired up. I broke a wire in the process so I had to solder that. For the pump end of things, it was a nightmare getting the dome shaped cover with the four screws off. Eventually I got the screws out with a vice grips and butchered the screws in the process but it couldnt be helped. Under the other dome shaped cover where theres one bolt holding it down with a cork gasket underneath, the cork gasket was in bits. I obviously got a new one with the rebuild kit but there was bis of cork everywhere. I thoroughly cleaned out the pump body and replaced all the bits and put it back together without incident. I bench tested the pump just to make sure it was working then put it back into the car. When I turned on the key it started clicking like mad again, the way it had done before, but once I took the car to a garage and put some fuel in it and took it for a good drive, by the time I stopped the pump had setled down to a tick - tick - tick, about once every second when idling. I turned off the car and it slowed to once every 15 seconds. So for 40 I sucessfully rebuilt my fuel pump and it only took me around 2 or 3 hours.
Ross Kelly

Ross,So would you reccomend Gower and Lee for rebuilds? I will be doing mine pretty soon.Thanks,Rich
Rich Osterhout

I'd certainly recommend them over Burlen, who just dicked me around from the start. I actually cancelled my order with Burlen by phone and called Gower and Lee, who had the kit in the post that same day. Whats more, its the exact same kit but its cheaper. Its the proper kit that comes with absolutely everything needed to do the rebuild, including new points and condenser, new valves, diaphragm and all gaskets and seals. The instructions that come with it as I said are useless but the kit is top quality.
Ross Kelly

E-mail me direct at SUfuelpumps@donobi.net and I can send you an assembly and adjustment procedure. Cheers - Dave
David DuBois

I got that off you David. Thanks again. It was your manual combined with the haynes manual that got me through it in the end actually.
Ross Kelly

Actually, that was aimed at Rich, I just forgot to put his name on it. Cheers - Dave
David DuBois

It shouldn't click more than once every 20 secs with the ignition on but the engine stopped, but 15 secs is obviously better than it was. If it was still clicking away like mad when you first powered up after the rebuild it seems like there was still debris inside or the inlet valve wasn't seating properly, and although its better now may still not be fully closing.
Paul Hunt

Well with the way it is I can live with it to be honest. The points that I took out of it were in a bad way as well so the rebuilt will greatly improve the reliablilty of it on the whole. I reckon the seals weren't seated properly at first. As for cleanliness, I went so far as to wipe down the work surface I was using and wash my hands before I touched it once it was cleaned, then I used a soft clean cloth to give the pump body a wipe before reassembling it, so I dont honestly think it could be cleaner if I tried, short of assembling it in a cleanroom. I think over the next couple of hundred miles it will get better as the seals seat properly.
Ross Kelly

Ross,

Did you replace the rubber fuel line between the tank and the pump? If the hose is deteriorated and cracked, the pump maybe partially pumping air into the system and not pressurizing allowing for the rapid ticking.
Kimberly

Yeah all the fuel lines have been replaced. In fact the entire fuel system has now been either rebuilt or replaced!
Ross Kelly

When I started my car today my fuel pump started ticking away like mad again. Im starting to think there could be a very small hole in the metal pickup pipe in the tank which is allowing the pump to draw in air from the tank. The engine still running fine. When I got home I checked the hose coming from the tank. I kinked the hose and the ticking stopped and didnt restart until I started the engine. When I turned off the engine again it was back to clicking like mad. I tried kinking the pipe again but it didnt do anything the second time. So has anyone any suggestions on this one?
Ross Kelly

A hole in the pickup pipe will cause ticking/fuel starvation when the fuel drops below a certain level. So if sticking another gallon in stops it, then it is a likely cause.

However kinking the inlet hose between tank and pump simply acts like another valve (albeit a no-way valve in that case) in the line so the problem could still be with the inlet valve in the pump sticking open. If you can disconnect the inlet pipe from the tank and place it in a very small container with petrol i.e. something you can see the level changing in, and if the level is going down *and* up when the pump is clicking like mad, then the inlet valve *is* sticking open.

New seals/valves should not get better over the next 100 miles, they should be spot-on from the word go. There could be debris in there, whilst old tanks, pipes and hoses could cause rust and rubber debris this souldn't happen with all new, but new stuff can have factory debris in it. New seals and valves in the repair kit could also be faulty, and one mustn't rule out the possibility of incorrect assembly.
Paul Hunt

I arrived home last night on the back of a towtruck. It seemed like fuel starvation was the problem. Even with the engine running the pump was only pulsing every 3 or 4 seconds and sounded different too, as if it was dry. So rather than spending time working on my camper van which was the intention for this weekend, I've to get the bloody fuel pump out again.
Ross Kelly

Aaagghhhh! It was something so stupid and yet I only found out what it was after I had the fuel pump out and cleaned and adjusted again. It was a kinked fuel pipe! The pump had twisted in its mounting and kinked the outlet pipe. Anyway, its probably as well I took the pump out and cleaned it. It was still quite dirty inside so I gave it a much more thorough cleaning and now it only ticks every 30 seconds or so when the engine is off. Happy days!
Ross Kelly

This thread was discussed between 21/07/2008 and 27/07/2008

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