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MG MGB Technical - Removing/fitting a fuel pump

I am about to attempt to replace the original SU fuel pump with an electronic one from the MGOC, on my '69 roadster. I have to do this in cramped conditions (I cannot raise the car as I have no axle stands out here in Belgium). Apparently, the pump is a straight replacement. Does anyone have any experience of fitting this type of pump? If so, do you have any hints/tips/caveats? Help! If I don't fix the car, I can't get it home to the UK on Saturday, when I move back permanently. Time is of the essence…

Thanks in advance,

Resh
Resh

Well firstly I wouldn't fit an electronic one, I have recently gone back to points. At least with those you have a chance of effecting a road-side repair i.e. a quick thump. When that didn't work with mine I changed it at the roadside with the car standing on all four wheels. Unless you can run the car for a few miles first to create the slight vacuum in the tank that occurs with the non-emissions and vented cap systems (I assume) or otherwise create a partial vacuum in the tank you are going to have fuel running out all the time any of the unions are loose unless you can drain the tank to below the pick-up. You may well have the usual problems undoing the bolts that clamp the pump in the bracket and bolt bracket to body although mine were OK. Make absolutely sure the power and ground connectors attache firmly to the pump spades as they are pig to get to in-situ, likewise be sure to refit the should be two) vent hoses to the pump body and end cap. Check the new pump runs before fully tightening all the fixings incase it has to come off again. In fact make sure the pump runs before you even start by connecting it to the battery with a couple of flying leads. And don't even think of working under the car if you only have a jack to raise it with.
Paul Hunt

Paul, thanks for your input. I intend to keep and rebuild the SU pump, but it is well and truly fried - the points seize again almost immediately after being freed by a tap to the pump body. My main problem is that I am out in Belgium, and need to get home to the UK (permanently) this Saturday - in the absence of decent tools, replacing the pump (and then having a spare for the future) is preferable to rebuilding the SU pump, or even resetting the points. The points are too far go to limp home on.

My main concern is the fuel line connections - the replacement pump from the MGOC is a PROMOD (or MOPROD? I cannot remember). They swore blind that it is a direct replacement, needing only some spade terminals for the live and earth wires. However, after a look at my workshop manual, at the SU pump, and a look at my new (and very plastic) fuel pump, I am not so sure…

Venting not a problem as the electronic pump is self venting, around the cap - thus only two lines connect to it - fuel in, and fuel out.


Resh.
Resh

Repeatedly sticking is the 'normal' failure mode. They develop a rough and crusty coating that insulates the contacts from each other and can stop them from flipping over. All that should be required is to dismantle the points and burnish the contact surfaces back to a clean dome-shape. My electronic pump didn't use a breather, but the PO left the vent pipe dangling so I was able to fit it to the 'new' (actually old pump off my roadster with burnished contacts) pump. Typical MGOC - how can it be a direct replacement but need different connections? My old electronic pump, the one I had all the problems with, was all-plastic and the comment from my V8 specialist was 'they're crap'. I believe there is a pukka SU electronic pump which may be better, but I still wouldn't have one.
Paul Hunt

Resh - if the MOPROD pump has the same fittings as the SU pump, then the banjo fittings and bolt will go on just the same as on the SU (you only need to insure that the input port gets the line from the tank and the output port gets the line to the carbs). Just be careful that you don't over tighten the banjo bolts as it is relative easy to crack the plastic. If the MOPROD pump has just slip on connections on the pump, they you will have to fabricate something to match. Good luck - Dave
David DuBois

Resh,
My car is a '75 (so might be of limited releavance to you) but to gain acess to the pump it was easiest to remove the rear wheel, you could then work from the side through the wheel arch, and not have to crawl about underneath. A half hour job to rip out a pump, (you'll need a screw driver for the fuel line hose clamps)
I use the past tense, because I got sick of having to so frequently gain acess to the wretched SU pump and eventually bypassed it and put a SUBARU one up in the engine compartment. Not a problem since.
Peter

Thanks for all the advice chaps. Managed the job after much swearing and skinned knuckles, with all of the car's wheels on the ground. Made harder by DPO having gummed everything up with chunky underseal.

The Moprod is great and a straight swap - not noisy once engine on, and the car runs noticeably smoother (a sure sign that the SU needs a rebuild). 400 mile trip tomorrow - wish me luck!

Resh.
Resh

This thread was discussed between 19/08/2002 and 23/08/2002

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