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MG MGB Technical - Fuel pump: over-wintering

As I’m about to set my B down for the winter, I wanted to ask for tips to prevent a problem that I have experienced when taking the B out of winter set down in March.

I have an unheated garage and over the last two years, every March, I have experienced a problem where the fuel pump will not work after the winter set down. I have solved this problem by removing the contacts in the SU pump and cleaning them, with some 400 grit paper, to remove what I believe to be oxidation on the contact surface. Thereafter the pump runs fine for the rest of the year.

My question is, what could I do to prevent the contacts in the fuel pump corroding so that I don’t have to remove and clean the contacts next March?

One thought I had is to tie-wrap a poly bag over the contact-end of the pump to prevent the circulation of damp air.

Suggestions welcome.

Best

Richard.
Richard Thompson

I'm surprised they oxidise so quickly. My new pump came with a slip of paper saying to clean the points before returning a non-operating pump. One can imagine the storage time of those could be many months, but then it's in a more benign environment when boxed. I have a spare pump that's only tested once a year if that and has always worked. Also an unheated garage, but brick wall and felted roof which would be 'drier' than concrete and asbestos, for example. It is also kept in its box. Neither of mine have ever failed, but then the longest they have sat is perhaps three months as I use them all year round when road conditions are suitable.

I helped a pal resuscitate a barn find where the pump didn't work and just bridging the pump contacts to power the solenoid two or three times was enough to cause the contacts to self-clean and get it running. Easy on an RB as that was, less so on a CB.

Other than that just turn on the ignition once a month and I'd have thought that would be enough.
paulh4

I too am surprised - you seem to have been unlucky although it's difficult to draw conclusions from such a small sample. The advice for all who plan to hold on to their classic pride and joy is to run a small de-humidifyer all year round in the garage. Cost less than £100 - mine takes out a pint of moisture every week until the temperature is close to freezing - then it sits as an iceball on the outside and needs defrosting.
Roger Walker

It's sudden increases in temperature and humidity that can cause moisture to condense on to a cold car, but even so no bodywork or paint work for 32 years and counting.

Shutting them up in an unventilated space is one of the killers, a humidifier may well help in that situation.
paulh4

I suspect that tie-wrapping a poly bag over the contact-end of the pump is akin to shutting it up in an unventilated space. The bag may serve only to trap moisture, not exclude it. JMHO. Jud
J K Chapin

Thanks for your comments.

I have brick/asbestos roofed garage that is remote from home, and has no mains power (I only have a 12v car battery for lights) so dehumidifiers aren’t really an option for me; one of the joys of living where the housing stock is circa 1905 when houses with garages was a mere concept.

Jud,
I do wonder if you're right about trapping moisture in, but thinking about it, I could place some silica gel in the bag.

Richard
Richard Thompson

Silica gel - that's a good idea. I think you can by silica gel in bulk. Jud
J K Chapin

Evening all,

I thought that I'd post a follow up to this post I made in November.

Today (6-3-22) I tested the operation of the fuel pump, after no running since November (...I know - shame on me), and it worked fine. I over wintered it with a small bag of silica gel inside a polythene tied over the contact end of the pump. This I tested with a remote battery connected between to the + of the pump and chassis before installing the batteries. Had the pump not worked I would have had better access to the points with the batteries out than in.

On the face of it this has some merit as a preventative measure, in that I did not need to dismantle the pump contacts and clean them.

Hope this is interesting

R
Richard Thompson

Hardi fuel pump, fit and forget.
Nigel Atkins

I have a spare points pump in the garage that hadn't been run for a couple of years, and that ran as it should when tested on the bench.

There are some questions about Hardi, primarily chattering far more than SU, varying from pump to pump. Timing the clicks with the ignition on and the engine off is a useful indication of float valve condition, with the SU they shouldn't be more frequent than once every 30 secs once the initial burst at switch-on has finished. Several people reported that theirs click every 2 or 3 secs, and Hardi themselves say "HARDI Pumps stop working if no fuel is needed - should not click than" (sic).
paulh4

Well my Hardi pump has been fine and as you know others have reported the same with decades of use.

I agree with you that some of the reports of issues might be suggesting issues elsewhere in the fuel system. Not all MG and classic car owners have their cars (or investments for some) in the best of order with old and worn parts and components fitted as the cars are sometimes used so little and so timidly which given the true condition of some is probably best. Some are very shiny paint and added chrome with old crumbly and porous bits under the shine.
Nigel Atkins

Interesting commentary.

I'd not come across Hardi before. I'll investigate.

R
Richard Thompson

Every S.U fuel pump I have seen comes with black electrical tape over the seam where the plastic cover meets the fuel pump body. If you are removing this cap to service the points, I suggest making sure that the seam is sealed as well as possible to limit exposure.
Glenn Mallory

This thread was discussed between 03/11/2021 and 23/04/2022

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