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MG MGB Technical - Inline fuel pumps

My 1975 MGB has chronic fuel pump issues and I've replaced them at least twice. Most recent failure of my SU style pump was due to corroded contact points. I cleaned the points and the pump is working but making noise. Does anyone have a recommendation regarding inline pumps which appear to be much simpler and less expensive?
JD Joe

All pumps are 'inline', and after-market types need various work to connect them to the existing lines and for mounting.

SU pumps are usually very reliable, even the points types, and should run for many tens of thousands of miles before even those points need attention. About the only thing that happens is if the car is not used for many months when the points can oxidise and need 'tickling up' to get it going again. Even new pumps come with a slip of paper saying to clean the points before returning a pump as faulty. As a 75 presumably a rubber bumper the points are relatively easy to access from the boot/load space. And as such they should be better protected there then chrome bumper points.

If your points are giving problems with the car in regular use then there is something else causing it, which may or may not affect a different style of pump. Do you have the two vent pipes connected and are they clear?

Pretty-well all points make a noise, some like the SU should only click when the carbs need fuel, other after-market types clatter away all the time and drive people nuts, apparently. If your SU is clicking all the time then the inlet one-way valve may be stuck open, possibly with dirt/corrosion from the tank, which can cause all sorts of problems. Have you checked the fuel supply for debris?
paulh4

Where is the pump located in a rubber bumper car? Part of the issue with the earlier cars is the awkward location of the pump, which discourages maintenance. When I next have to replace one I was thinking of relocating it to one of the vacated battery boxes. My battery is now in boot. I fiddled about with SU pumps for years in various cars, the points for which were expensive, even back in the Seventies. The final straw was a pump playing up in northern France on the way back from Le Mans. Tapping it with increasing frequency got me onto the ferry. At Folkestone I made the classic error of kidding myself it now OK and got on motorway where it failed completely and after much angst, petrol everywhere, car got transported back to Bath. Enough, I cried and bought a cheap Moprod replacement. That's now been on twenty years, and maybe tempting Providence, with no problems. It's the only bit of aftermarket electronics I've got on the car.
Peter Allen

JD I know traditionalist disagree but I'd always bin the points type of pumps and having the SU label on them nowadays just seems to mean higher cost for no better build.

If you can get them on your side of the pond fit a Hardi or similar make/model pump, they're a fit n' forget, no more farting about with cleaning points, servicing or carrying a hammer in the car.

Decades ago I lost a day's work because a SU pump packed up on my B and since then a classic new to me, along with checking/changing the battery(ies), as soon as possible I bin points pumps and points in the ignition.

I fitted my (Q&H) Hardi style pump to my midget 12.5 years not touched it since.

Yes at some stage I will have to think about when I should replace it before it packs up but I haven't and won't be crawling under the car getting filthy fiddling with points. As you can tell I'm not the type of owner that enjoys "playing" with the cars I only enjoy driving them, I've had enough roadside repairs to last me two lifetimes.

I had a cube type Facet pump in a classic and it was a horrible noisy thing even when fitted on the rubber bobbins.
Nigel Atkins

As said above the RB pump has electrics end in the boot under a black metal cover, see attached.

CB is not so convenient to get to the electrics end, but then it is much easier to change if you have to. I had to change mine by the roadside when the points failed and as I had come to a halt on soft ground I couldn't use the jack. But despite not having touched the pump it all came undone even the mounting bracket with the car standing on its wheels, and the new one back on. I didn't even get any leaks, with the correct filler cap with vent and sprung valve the the tank develops a small vacuum while running - noticeable as a slight gasp when filling up part-way through a journey, and that was enough to stop the petrol siphoning out. Back home I decide to change the flex hose as it was really ratty and without that vacuum petrol dribbled out all the time.

My V8 came to me with a Moprod, which kept short-stroking and causing fuel starvation, and unlike a points pump when they fail you are stuffed. I cleaned and adjusted the points on the pump I had taken off the roadster and put that on the V8 and it has been fine ever since. I haven't binned the Moprod as it is a potential spare, but since another SU came my way it isn't even that any more. With the plastic body you have to be careful tightening the unions.



paulh4

In 12 years I've had 2 SU pumps go down. The first one was points type and I repaired it . But after that experience I plumbed in back-up pumps on both my V8's, both Facet cubes. Easy to do with a simple change over switch. The second failure was an electronic which gave up after only 8k/3 years. The back-up got me home and is still functioning. The SU was replaced with a Hardi.
Allan Reeling

UPDATE
Thanks to all of you who replied. Quite a few excellent tips.

Turns out there was carbon debris (the size of oatmeal flakes) inside the pump body. I also trimmed the ends of the hoses and installed new clamps.

It clicks like it should and stops within a few seconds when the lines are full.

The actual model pump is an Auto Pump AP115 made in New Zealand. I plan to keep it as a backup and install a real SU with points. (Now that I know how to access the points from the boot instead of pulling the entire pump.) Really appreciate paulh4 setting me straight on that!

You folks are great. Thanks again.



JD Joe

Each to their own but that's just hair shirt time to me. :)

And I've never understood this having back-ups and carrying spares, wheres it all end, surely you'd need to carry a spare engine, g/box rear axle too, or tow a complete spare car behind.

JD,
whether it's supposed to have one or not I'd try adding a foam seal between the rad and the panel (forget its name) behind the rad to fill in that big gap to see if it helps with cooling the rad and engine. If it doesn't not much spent and easily removed.

Nigel Atkins

I don't know what precipitated the comment about the foam seal, but prior to 1977 and the forward-mounted radiator they should gave one, and the rubber seal across the top of the radiator diaphragm. Mine always had the rubber strip but after many years - without any cooling problems - I decided to fit a foam strip and was surprised how much difference it made on the gauge in hot weather. Logical, it's a big gap and air under pressure will find it easier to go through that than the rad.
paulh4

>>I don't know what precipitated the comment about the foam seal<<

Paul, doesn't JD's photo show on your device, even my my wonky eyes can't miss the gap in the photo.
Nigel Atkins

Didn't look at the picture.
paulh4

Are we talking between the rad and the diaphragm? My '72 looks the same as JD's.
Peter Allen

Yes (I couldn't remember if it was called a diaphragm or not, thank you).

I wasn't thinking of if the foam not being there was correct or not to factory original rather that the addition may serve a useful function. Factory changes were not always improvements.
Nigel Atkins

As you say Nigel, each to their own. It also amuses me to do it!
I carry spare bulbs and fuses and some spanners and tape. Does that mean hair shirt as well??
Allan Reeling

Spare bulbs and fuses I can understand, they don't take up much space and don't weigh much and you never know when they might be need - mainly for other people's cars like the spanners.

But back up pumps! Well if they're already fitted and wired I suppose they can stay but it's still a bit prickly shirt. :)

Carrying a spare loose fuel pump though deserves prickly underpants. :) - but of course, again each to their own, if you enjoy it and it harms no one else then enjoy!

Nigel Atkins

I've always carried a spare pump on long journeys, and it got me going again when the existing one failed about 60 miles from home without having to call for assistance. And an alternator. What's the point of having them and leaving them at home? In 50 years I've only once had to ring someone for any help and that was when a roadster battery failed suddenly. Only on one other occasion have I ground to a halt anywhere. But then I'm just lucky.
paulh4

Paul, agree on the carrying of spares, and those in particular. Plus having a fair selection of tools. However, the reality always seems to be that one's in the wrong place when it happens eg motorway hard shoulder, or worse motorway without hard shoulder, or wearing best bib and tucker. I do recall in days of yore fixing a vehicle wherever, such as dismantling a motorcycle carb at the kerbside, or stripping down a car dynamo in a pub car park. Then there's the keeping going, but be damned - returning from Beaulieu years ago on wet evening in overheating car and topping up the radiator every few miles with rainwater from ditches and puddles. It transpired rad was totally silted up with limescale etc and needed a re-core.
Peter Allen

We call that (diaphram) panel the radiator support panel here
If you are going to fill the gap with foam it needs to be a nice dense foam otherwise the air will go straight through it

JOE
Looking at the pic of your engine, I notice it has a weber carby on it-- well just to be safe, some of these webers have an issue-
I tied to blow your pic. up for a look but can't quite get it big enough before it goes fuzzy
The problem with them is that 'some' of them have a pressed in brass fuel line fitting and others are screwed in---The pushed in brass ones have a habit of working out of the housing resulting in fuel getting pumped all over the engine bay while you're driving along--not recomended
Might pay to check and see if it's a screwed in or pressed in one
If it's pressed in, the fix is to bump the fitting hard into the housing with a small hammer, drill a tiny hole " 1mm -ish"through the the housing and brass fitting and drive a little pin in to lock them together

willy
William Revit

Now an alternator is a step too far for me. That is a very heavy item, why not balance it out with a spare starter motor.

If you think an item is so suspect that you need to carry a spare why not replace it with a reliable fully functioning item so you don't need to carry the spare.

By statistics batteries are a/the major cause of breakdowns so statistically you should always carry a spare battery(ies). I suggest keeping it/them in the passenger footwell that way the navigator can rest their feet on it and have a constant reminder that the car is subject to unreliability so they'll need to keep fit for pushing duties. :)

By what Willy has put a supply of small jubilee clips need to be kept too.
Nigel Atkins

Hmmm ... I got a spare gearbox in the garage doing nothing, now if I ditch the spare wheel ...
Brian Shaw

We had a really "animated" discussion on the MGA Forum some time ago about carrying spares.

It had me on the one hand carrying lots of spares to cope will almost all likely breakdowns and then at the other extreme, there were those who just carry a credit card to pay for any repairs that are needed. I'm afraid that I am in the Paulh4 and Peter camp when it comes to carrying spare parts, well maybe a bit more extreme! :^)

I won't repeat it all here but here is the link to the discussion if anyone is interested.

https://mg-cars.org.uk/cgi-bin/or17?runprog=mgbbs&access=&mode=archiveth&subject=6&subjectar=6&thread=201603281631069225

Cheers
Colyn
Colyn Firth

I carry a small tool roll, some bulbs, insulating tape and a length of wire, but no spares. They have very rarely been touched and I've never had to change a bulb at the roadside. The wire could double for electrical repair or to suspend a broken exhaust, but again it hasn't happened. The one time I needed to tighten an exhaust clip on the BV8 at Zeebrugge I found I needed a metric spanner, which of course I didn't have. Fortunately someone else did. I've been driving since 1965 and lack of spares hasn't been a problem yet......

A pal doesn't even have a spare wheel in his MGB V8 Roadster, giving him a much more useful boot. The car has covered 70,000 miles all over Europe without a puncture. Talk about tempting fate !!!
Mike Howlett

Diaphragm foam seal is AHH8887, although not apparently fitted to Mk1 cars.

"topping up the radiator every few miles with rainwater from ditches and puddles"

Not long after I got a Scimitar GTE I was taking my new boss to the wilds of Lincolnshire when a heater hose split. I taped it up and put a Jubilee clip round it, looked through the field gate where we had stopped and saw a water bowser. Climbed over the gate and found a fertiliser bag stuffed in the hedge, so put some water from the bowser into that and we both carried it back to the car. That got us to the next garage where I bought a hose that I could make fit, and that got us home. Boss said he was impressed. After the third (all different) hose failure in as many months I decided to change the rest of them en-masse - I think there were about 12 altogether, and had no more problems - with the hoses at least. It took me a year of fixing things before I could go on any decent journey with any degree of confidence, but I and it always got each other home. The fan-belt is another story!

"why not balance it out with a spare starter motor"

You don't need a starter motor to start the car in most cases. Who said anything was suspect? I 'won' them in various ways, and as I say it would be silly to have them at home when you needed them hundreds of miles away. I weighed the tools and spares once - came to the equivalent of a third 'standard MGB' person i.e. about 150lb.

You can be as dismissive and sarcastic as you like, Nigel, you won't stop me doing what suits me nor make me embarrassed about it.
paulh4

Not trying to do either Paul, and as you put it wouldn't work anyway. Not sure I'm being sarcastic, more mockery but yes taking-the-Michael, to put it politely. I find classic car ownership laughable in many ways most of which includes me too, I've never understood this preciousness to the particular vehicle or general subject.

I supposed I became a little desensitised to Mickey-taking when I owned three Skodas in the mid-80s when the Sun-reading sheep would tell me very joke they'd read or heard about Skodas - and some of them were very funny and less obvious.

Some Triumph owners think MGs are the poor relative, some MG owners think the reverse is true, 'big' Austin Healey owners know both are wrong, but they all look down on Jap cars. All have many faults and some/most are a bit rubbish (apart from the Jap cars of course) so why worry who owns what. German car owners think they have quality engineering but we all know better, Jap cars are usually the best. :)
Nigel Atkins

To be a bit more serious - if classic cars are to continue other than as static museum pieces then we need to encourage much younger buyers and owners. They are more used to reliability and if they get the idea that classics regularly breakdown and you need to carry loads of spares all the time this puts them off and gives the wrong impression.

Owners can carry whatever they want in their vehicles, it's their choice, if you want to tow a trailer of spares that is fine (you will of course need spares and tools for the trailer too).

Even our modest models of classic ("vintage") cars are already tremendously over priced (valued) so to put more obstacles in the minds of young potential owners will have them buy more modern classics and the likes of our models will disappear as us elderly owners get too old to drive our (already over precious) classics.

For decades there have been fewer (less?) owners to more classics so less actually used (owners with more than one classic and driving all less) so the spread of ownership is narrower and getting nearer to terminal decline (elderly owners die).

How's that for lightening the mood. :)

Anyone at the NEC tomorrow or over the weekend pop over and catch me out with the spares and tools I carry, we're in Hall 5, you can't miss us we have the cars that actually get used for their design purpose.

No mickey-taking please.

You can't miss me I'm tall, athletic, good looking with dark hair. :)

Nigel Atkins

3 Scodas - ha ha ha , ha ha ha ha ha
lol
willy
William Revit

This thread was discussed between 19/03/2019 and 21/03/2019

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