MG-Cars.net

Welcome to our resource for MG Car Information.

Recommendations

Parts

MG parts spares and accessories are available for MG T Series (TA, MG TB, MG TC, MG TD, MG TF), Magnette, MGA, Twin cam, MGB, MGBGT, MGC, MGC GT, MG Midget, Sprite and other MG models from British car spares company LBCarCo.

MG Midget and Sprite Technical - Heater switch refurbishment

A clone of Cedric's heater tap thread. Only heater switch this time.

I have a working heater switch. The push you pull me and twist style. Bought as a second hand item but when I come to fit it I realise that the inner wire has at some time snapped off and is now too short.

I have been trying a repair job. First attempt was to solder an extended piece on the end, using welding wire. It seemed to work ok, but the tiny soldered butt joint wasn't strong enough and it broke free (like queen). I may try the same, but weld although I think that will probably just burn the wire away.

Another possibility is that at the top end the inner wire terminates with a round ball that engages with the switch mechanism. I may be able to replicate that with solder on the end of new length of welding wire.

But, does anyone know whether replacement inner wires are available? Moss et al don't list just the inner wire.
GuyW

If there is enough length in the cable, cut away the outer sheath to expose the remaining inner wire.

Otherwise maybe grind the ends of the wire at an angle to increase the surface area of the joint and use braze rather than solder or weld.
Chris at Octarine Services

Guy
Never seen the inner wire sold but its just piano wire so can be purchased from Model Shops or the like. I don't know the gauge so will need measuring.
Bob Beaumont

I can't ever remember seeing the inner cables for sale. I remember talk of the complete assembly being available at one time but can't remember seeing any evidence.

The complete assemblies were different parts numbers for different models whether it was just the length that varied I don't know.

Do remember which way the cable relates to the fresh air flap orientation. ;)

The relevant Driver's Handbook, if you refer to it, will tell you the factory settings and how they'd operated - or you could have another permanent curry-hook.

Nigel Atkins

There's a heater control cable for an MGB for sale on ebat atm. It's 35" long so could be cut down if needs be. £4.25 + £1.95 p&p.
http://tinyurl.com/ydc429yk



Jeremy MkIII

Chris, the outer was already marginal for length, but I have fixed that. Yes, brazing it should work better than solder.

The welding wire I have is the correct gauge and is as stiff as piano wire. I am going to try putting a lump of solder on the end of that and shaping it into a ball, as original. I have lots of spare inner cables from various sources, with assorted fitted ends but none on rigid wires.

Then I thought maybe someone sells this stuff!
GuyW

Fixed now. Put a bit of braze on the end of a welding rod of the same guage as the original wire. Shaped it into a sphere with needle files until it fitted and it works just fine.

How does one value these things? Together with yesterday's abortive attempt I will have spent a better part of 3 hours which makes it an expensive repair! If the wire were available to buy it would certainly cost less than a fiver, probably half that!
GuyW

Well done. As this part is not available, you could set yourself up as a refurbisher! Help pay for the rebuild!
Bob Beaumont

Kind of related.
Does the MK1 dashboard use the two extra metal supports between the bulkhead and the lower edge of the dash? And if so where do they attach at The bulkhead end? I assume they screw to the lip of the rearward facing flange, but how far apart, or doesn't it matter?
GuyW

Guy I spent a couple of hours polishing some very tarnished water jet nozzles. One came out great, the other was too bad to rescue, all the plating had gone. So £7 from ebay gets me a new pair.

I had more luck with my instrument bezels.

Some you win, some you loose. :)






Chris Madge

It looks good Chris. What an improvement. I must admit, despite some of my more recent questions on here about anal details of assembly of my Frogeye, I am not usually one for fussing about the small stuff. On my other 1275 car, under normal circumstance a well used "daily driver" I barely notice how dirty the dial faces get. Then maybe once every few years it will suddenly occur to me that they need a wipe over! But when one does spend a bit of time the do clean up very well and look so much better. Yours looks really smart!
GuyW

Guy, Yes you do need the two lower dash supports to stop the lower edge flapping about. Your correct that they are secured to the flange. they are spaced the same as the mounting in the dash. Mine was originally held by self tapping screws but I replaced them with 4 BA screws and nuts
Bob Beaumont

I will need to identify where the mountings on the lower edge of the dash are then. Currently they must be covered by the vinyl that someone has glued over the dash and folded over the edges!

I would guess that they more or less match the width of the centre bulkhead forward of the transmission tunnel?

I should add that the bulkhead flange doesn't have the screw holes in it either as I replaced that panel too. As far as I recall, there wasn't much of the old flange left anyway!


GuyW

The stays on the dash end are held by two 1/4" cross head set screws along the lower edge. I had a look at mine and they are in a vertical line below the choke and starter knobs so yes approx the width of the centre bulkhead
Bob Beaumont

But Bob, Guy's gone all anal on us - I#m pretty sure crosshead screws were never used in the factory for this application, just old-school slot-head (horrible things). As an aside when did Phillips screwheads enter mainstream mass car production in UK, sometime during the mid to late sixties maybe?
David Smith

Hi Dave

Interesting, that was what mine had before I restored it. Its the same type of screw used to retain the heater box or the bonnet stays. It seems cross head Phillips or Pozi drive type seemed to be on cars from the early 60's certainly in the smaller sizes holding things like brake line and washer line clips. If I recall the door hinges also used pan cross head screws.
Bob Beaumont

David, I share your hatred of slot head screws. They are terrible in all fields and applications! :-)
Malcolm Le Chevalier

Presumably cross head screws came in with powered drivers. Holding a powered driver into a cross head screw is quite tricky! When did fitters on the assembly lines stop doing up screws by hand (or hammer)?
GuyW

Different dash I know but I've been meaning to fit the two straps to my dash for nearly 13 years but haven't and it's fine. I actually bought the straps a few years ago.

I've had a while where the choke cable was catching and pulling the dash and I thought that wouldn't be good for the dash but it did no harm, and I'd have thought as the earlier dashes where less contoured there'd be less flex with them.

I don't know if it's because mine's a Heritage shell but I can't see how you'd get a drill and drill bit in to make a hole for the self-tappers in the flange and the flange doesn't seem deep enough anyway unless the screw goes in at 45 degree and through the other panel (or perhaps it's me?).

Nigel Atkins

Just fitted mine Nigel. Including drilling the holes in that flange. No difficulty at all other than getting my ageing carcass back out from an upside down contortion in the footwell. Perhaps that's what you meant?
GuyW

Yes that too definitely - but, the flange sticks out at 90 degrees to the panel, the flange is very thin so how do you get a drill in there to get a straight hole (top to bottom of flange) through the flange and without the drill chuck scraping the panel?

BTW the original chrome trim on the dials is good enough to leave a long time between wipes without permanent tarnish, a damp (microfibre) cloth and then a dry one or if there's already condensation or rain on the dials you only need the dry cloth.

Nigel Atkins

You make it sound much harder than it is Nigel.
Firstly, as the thing attaches by the corner of the centre bulkhead and the side of the footwell, there is clear access to get a drill in there. That's drilling upwards, not " top to bottom of flange" of course.
Secondly, if you are picky about the flange angle you will find it's an extrapolation of the sloping footwell lid, so is angled upwards slightly and not a true horizontal, so aiding drill chuck clearance.
And thirdly, you would of course make a mark with a centre punch to stop the drill bit wandering when you first start it allowing the drill to be at 82.5 degrees to the flange, rather than 90 degrees, wouldn't you?
GuyW

I've found my original dash support straps, confirming cross head screws. The car is a 1958. The flange on the new shell needs drilling like yours Guy. I will paint them of course!


Bill Bretherton

All nicely labelled I see Bill, complete with papyrus name tags. How long ago was that?
GuyW

It's masking tape, my default choice for labels. Done in late 2012/ early 2013. Dash painted but not fabric covered yet.
Bill Bretherton

Guy,
I took it that the straps go straight (at 90 degrees to dash face) across to the flange as it photo A ignore the fixings in the photos as it's just a quick mock up but I assume the ribs face the floor?

And I've yet to polish the dash this week so it's not sparkling like usual.

This way the points of drilling on the flange are against the panel behind the centre console even if you angle the drill a bit.

Do you mean to move them outwards (towards the doors) for the flange drilling give more room for drill, as in photo B?

I'd got my spirit levels and set squares out for the installation expecting strict angles.

I find on my car (to my wonky eye) that the flange angle isn't an extrapolation of the sloping footwell lid as there seems to be angle that brings it to nearer horizontal. There are waves to the horizontal edge of the flange, you can just see one in photo B but I could try to take a clearer photo of the wavey flange if you want but that area was roughly sprayed black by someone before me so might not show up well.

I can't use automatic centre punch as it decide to stop being automatic a while back, but if fixing is as photo B I could use it with a hammer or if as photo A I'll use a long nail or long drill bit and hammer as a centre punch (or use my standard centre punch if I want to be boring).






Nigel Atkins

Joke, Bill. Papyrus and hieroglyphics.
GuyW

Guy, Phillip's screws were first used by General Motors on Cadillacs in 1936 and most American companies were using them by the end of the decade. Earliest use I can find over here on cars suggests the mid fifties and they are Posidriv which of course is the mark2 Phillip's.

Trev
T Mason

Trev, would that be when powered drivers came in then, in America, - 1936?

I can imagine the british car industry being populated by engineers who insisted on using "proper" screwdrivers - hand operated!
GuyW

Nigel,

Mine are as shown in photo B right on the corner. They were the original holes as the flange was in good shape when the car was restored. I have mine mounted with the ribs upward but I don't suppose it matters. Note the dash panel screw should be inserted so the head is showing not the nut to avoid any potential knee scrapes.
Bob Beaumont

Guy, dont know if that's when powered drivers appeared but I gather mass production was the reason. General consensus seems to be that GM were the first but I have seen some suggestion that Ford used them on the model T but evidence of that seems a bit vague.

Trev
T Mason

Thanks Bob.

Can you just confirm the following as it seemed counter intuitive to me as I was thinking the small hole on the strap went to the flange as to confuse me more the car came with one strap fitted only to the dash with a 3/16" setscrew and nut through the larger hole on the strap and the strap was straight without end bends.

So to summarize, I use a No.10 self-tapper, from below, through the dash to the small hole in the strap.

Then a No.10 self-tapper, from above, through the larger hole in the strap to a pre-drilled hole in the flange.

Do you also use a shakeproof or other washers?
Nigel Atkins

All the crosshead screws, that I've noticed, on my MGs have been Pozidriv not Phillips, at least some of them seemed factory fit but they might not have been.
Nigel Atkins

Hi Nigel
The self tapper is only used at the flange end and it goes in upwards. Ie through the strap and then into the flange. At the dashboard end there is a pan headed pozidrive set screw. This goes through the dash then through the strap and then a spring washer and nut.
Your photo showed the set screw going the other way with the nut visible. This is a potential knee scrape
Hoe this makes sense.
Bob Beaumont

Bob,
that does make a lot more sense, you finally got me there, thank you.

I'd only seen the self-tapper screw pictured loose and dash board end (but having it that end didn't make sense to me).

I originally had my post with a list of options but it got long and Sod's Law I kept getting interruptions so going away and back to computer so I deleted a lot.

I did originally expect to use a 3/16" UNF setscrew and only had the nut at the bottom for a quick mock up.

As very short length 3/16" UNF setscrews have been unavailable for a few years now, from local shop and at shows at least, I'll use a short hexhead and washers and nyloc.

I found that 58-64 Spridgets used straps with part number 14A4706 and later Spridgets used AHA7763 but that for the last 10 years one part is made to cover both, I bought these a few(?) years ago. -

https://www.ebay.co.uk/itm/293541301910
Nigel Atkins

Ah Ha An Ashley Hinton part. It will fit ok as his products are generally good quality.
Bob Beaumont

Uhmmm, not necessarily for heater taps now, and perhaps not for these straps, having had two taps leaks I can be fairly certain about those but I throw in benefit of doubt about straps as I'm in a rare good mood.

I had to cut the straps behind the small hole to flange fixing as it pushed the strap too far out to line up the screw to the hole I made.

If the holes and different lengths of tails behind them had been transposed everything (on my car?) would have lined up without alteration (and the strap ribs would face up, not to floor).

Also, assuming it's correct, if I'd known that the holes were supposed to be at the U shaped cut out in the bottom sheet of metal (of the two sheets that form the flange) as marked in photo then I'd have understood the seconds of easy drilling out required.

Guy will be pleased to know I got my automatic centre punch working again by service work, clean and lube.

And I was pleased to find again my really short (4") offset double ring (3/16", 7/16") spanner as it's so useful and easy to hold in tight spaces. I've no idea when I got it and from where but I wish I had a set of them.



Nigel Atkins

You are making a meal of this Nigel! After my initial question it took me just 10 minutes to fit them both. All done and finished with 36 hours ago.

Photo is for you Nigel!


GuyW

Yes Guy but you weren't working on my car with the straps I have and looking up to a dash with black on black and a very big hot extreme backlight (the sun in a cloudless sky) so not seeing the u-cut.

Once I saw the location of u-cuts it was seconds to drill, I/m not sure you'd have been much quicker than me at it.

To drill as photo B in second photo on passenger side just to get the drill means removing and putting back T-bar bonnet cable, the heater trunking, and a very awkward metal parcel shelf with three wood spacers that even you would find takes a little time and patience.

Of course you're not listening are you.

Once I knew what was what I done the work a lot faster than 10 minutes but Guy probably took his time as I know he enjoys farting about on the car whereas I don't.
Nigel Atkins

A bit late now Guy but I managed to fix one recently by fitting a new cable with a quick blip on the TIG welder, so far so good. I used a stainless bike cable, cheap cables are galvanised making soldering or TIG trick/impossible.
Paul MkIMkIV

Thanks Paul. My fix seems to be ok for now at least. Plus someone from here kindly sent me a spare as well.

On rethinking this, I believe the problem wasn't that the original cable had broken or been cut. I think the switch was maybe from a later car. Although the unit is the same, the exact cable run on a Frogeye is about 1" longer as the heater control knob is positioned 2 1 /4" further over to the left. The switches are quite hard to come by and if looking for one for an early car it's worth bearing in mind that there is this difference.
GuyW

Guy I have a feeling its the other way round. The spridget has a longer cable. I have a spridget one on mine and its too long. The frog and spridget part numbers are different. I think I saw somewhere the relative lengths but can't find it now.
Bob Beaumont

Bob, it's actually rather more complicated.
The cable length needed for cars with the updated dashboard, but still having the square box heater is shorter than the MK1 Sprite version because of the revised position of the switch on the dash, requiring about an extra inch of cable. Then when the heater box was changed to the tear drop style a much longer cable was needed as the air flap was repositioned to infront of the fan housing.

There was yet another variant about this time with an air flap right at the front of the air duct, next to the rad. Then of course there will be the LHD market ones too!
GuyW

Does anyone have the relative lengths of the heater control cable for a Frogeye. Mine does seem too long. (replaced when the car was vandalised a couple of years back)
I am refurbishing the heater with new foam etc so a chance to correct the length. I don't think its a straight run from the dash to the heater casing but there is a curve in it.
Bob Beaumont

You are right, Bob, there is a curve to it as the control knob is off to the left. But a cable that is too long will either mean that the outer extends too far in front of its clamp, impeding the operation of the flap valve leaver. Or the curve between the bulkhead and the clamp will be forced into a longer arc which adds resistance to operation of the cable. I fiddled around with mine for a while to get it right. Its quite a fine tolerance.

As mine is now installed, its not so easy to measure it. Plus mine is now not as original anyway, but if you need a dimension I could measure the length from where it emerges from the bulkhead grommet.
GuyW

Thanks Guy, Mine curves behind the dash as you say and then again the bulkhead side. It works ok if a little stiff (its well lubricated). I am sure I have seen a measurement for the two types of cable but I'm dashed where! The length the bulkhead side would be useful if you get a mo.
Bob Beaumont

Bob, on the bulkhead side mine measures 9.5". That's the outer, which is trimmed off 1/4" beyond the forward face of the outer cable clamp. It comes through the correct bulkhead grommet hole at an angle, as in the photo you posted a few days ago. This length has only a very slight curve to it.

Behind the dash it curves rather more and there is 4.25" between the bulkhead and the end of the hexagonal shaft of the switch. This all seems to work ok with mine, but bear in mind mine is not original!

I have no doubt that if the push pull switch was nearer to the steering shaft, as in the binnacle dashboard MK2 cars, AND it still used the square heater box, then the heater cable would be slightly shorter than the Frog one. But on later cars with the tear drop heater boxes the cable would be rather longer again maybe by another 2 to 3 inches.
GuyW

Thanks Guy, That's helpful.
Bob Beaumont

Exciting moment today when turning on the lighting switch on the dashboard makes the rear lights come on! First time that has happened for at least 36, and probably 40 years!


GuyW

its such a great feeling when the end is so clearly in sight............
Bob Beaumont

Yes, but the front end is not in sight yet, just the rears! One step at a time!

And the number plate light just needs its 2 bulbs, which I don't have in stock so that will have to wait a while.
GuyW

Anyone mentioned Venhill for universal cables: https://www.venhill.co.uk ?

Enjoying the chat about machine screw head types and the difference between a Phillips head and Pozidrive. Go BBS!

Cheers
Mike
M Wood

I hadn't thought of Venhill for this application Mike. Doesn't it need to be a push/pull type like a Morse or Teleflex cable, rather than the more usual Bowden type which relies on (for example) a spring return?
Perhaps they do them as well, I've never noticed. If they do and the quality equals the throttle cables I've made up it sounds like a good idea to me.
Greybeard

For that application it needed to be a stiff solid wire, not a cable. I don't think they list that. Venhill site looks good, if somewhat expensive, though their search engine is a bit clunky!
GuyW

Bob, I'd have replied last night but internet trouble. My cable from the back of the switch (includng the solid portion) to the END of the INNER cable is 20 inches. The portion of inner cable showing is 2.25 inches. The tape rule is to indicate dimensions at switch end.





Bill Bretherton

Thanks Bill As its chucking it down I was planning to spend the afternoon in the garage!
Bob Beaumont

Adding up and deducting to make measurements comparable Bills 20", less the 2.25" of bare inner cable, = 17.25"
Whilst mine, before I extended the outer, was about 15.75, so 1.5" shorter.

Bill's is, I think, off his original MK 1 Sprite. Mine is of uncertain parentage and I suspect is from a MK 2 or a MK 1 midget. I added 1.25" to the outer to get it to reach the clamp and then made up a longer inner to suit.
GuyW

Guy, my 20" does include a solid portion on the back of the switch as I said. And, yes, it is what I removed from the Frogeye so assume it to be original. The switch seems to work. Note there is a ferrule with set screw to hold the inner to the heater lever. First time I've looked at it for a few years!
Bill Bretherton

Bill, yes I added the length for the solid portion to my earlier measurements to make them comparable.
GuyW

This thread was discussed between 20/04/2020 and 28/04/2020

MG Midget and Sprite Technical index

This thread is from the archive. The Live MG Midget and Sprite Technical BBS is active now.