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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 TD TF 1500 - TF temp gaue, bulb & capilliary

I'm anxious to resolve my temperature gauge issue.
If anybody has a complete TF temperature gauge assembly in any running condition, I would be happy to pay any sensible price.


Gord Clark
Rockburn Québec
Gord Clark

Hi Gordon

Contact https://www.westvalleyinstruments.com/ and they can fix it for you.

Frank
TF1414
Frank Cronin

Thanks Frank. I've already been in contact with them. But my car won't be accessible, 'till late April so I need a gauge now.

These units are becoming scarce. I'm hoping there's someone out there, who can help.

Gord Clark
Rockburn, Qué.
Gord Clark

Gord, if you're up to it, the temperature gauge system is not very difficult to repair. I've done two of them. No heavy lifting. Easily done by folks our age. Bud
Bud Krueger

Gord

I am not sure what you mean by any working condition. I have this one that does not work. If you are interested, shoot me a pm with an offer.





Rick

Hey Rick,

That's what I'm looking for. I can send that to West Valley and they can repair it for $175 or even might try repairing it myself, as Bud has suggested.

The issue is that I can't remove the bulb. Abingdon are out of plugs, so I'm stuck if I want to drive the car whilst its being repaired.

Please contact me at gord@gordclark.com. I'm prepared to pay anything sensible.

Gord Clark
Rockburn, Qué.
Gord Clark


Gord:

Moss is showing this plug as in stock:

328-040
PLUG, water outlet
TF (XPEG engine)
$17.99

This is in their on-line catalog under COOLING SYSTEM....item 32


Jim


Jim Rice

Take care with the plug. The tapping for the temp gauge is US pipe but the heater one (late TF) is BSP and they have different pitches.
Ray TF 2884
Ray Lee

Gord, I sent a suitable plug a few days ago. You should have it early in the week.
Cheers, Hugh
H.D. Pite

Hugh's dah man!
Christopher Couper


Ray:

Maybe my aging brain cells are not what they use to be, so a bit confused on your comment. If the TF's came from the factory with the gauge, capillary and the bulb installed in the thermostat housing, and were tapped as US pipe, why would there be the different BSP threading as well for that same hole on a TF?

I ask as I'm going to need to have my temp gauge assy. repaired too, and was going to buy that plug from Moss in order to drive the car while the gauge is being repaired.

Cheers,

Jim
Jim Rice

I do not have a clue why they are different, but they are. The 1500 TF's had a heater outlet at the stat end of the engine and the 1250's had it at the back of the head.
I should have said they have the same pitch but different OD's. I had the same problem when I was training in the 1950's with instrumentation fittings.
On my TF the heater outlet is BSP as I have standard UK fittings screwed in to the stat housing.
Ray TF 2884
Ray Lee

Also should have said late TF stat housing had 2 tappings, one for the heater and another for the temp gauge alongside each other.
Ray
Ray Lee

Mine is an earlier engine. XPEG852. Only the one tapping for the temp gauge.


Jim Rice

I think I've got things worked out. One kind member of this forum has offered me a non-working unit and I'm going to try to repair it.

I'm grateful to Hugh Pite for the plug (which I will be returning). There is no way to run the engine w/o closing the hole.

Barney Gaylor offers a repair on his web-site, see:- https://mgaguru.com/mgtech/dash/dt102a.htm If this works, I'll have a unit available which I'll offer on then forum.

Many thanks to all for your help.

Gord Clark
Rockburn, QuP.
Gord Clark

Courtesy of Rick in Ohio, I now have another TF temperature gauge, and like mine, it doesn't work; but I'm going to do my darndest to repair it.

However, I don't really know why my gauge stopped working, but I'm starting with the assumption that the ether has escaped the capillary tube.

Before I attack the bulb, what other issues could cause the gauge to fail?

Gord Clark
Rockburn, Qué.
Gord Clark

Gord,
Read through this before you attempt the repair as I think it is an easier way to go about the capiliary repair.
https://mossmotoring.com/lab-coat-lessons/

Regards
Declan
Declan Burns

Many thanks Declan for the heads-up on that article on repairing a bulb-type water temp gauge. I just wish I had the equipment that Dr. Neumeier has. He makes it look easy.

Gord Clark
Rockburn, Qué.
Gord Clark

Hi all:

I wanted to reactivate this thread and ask if any of our UK or Australia members could inquire at a local plumbing supply houses who might carry plumbing plugs.

I'm back to the threaded plug needed for when the temp gauge fails and the gauge, capillary, and bulb need to removed to be repaired. That's going to leave a hole to plug.

Moss no longer supplies the cap nut (P/N 361-075 - third reference) which is item 49 on page 19 of their catalog. Abingdon shows the plug as a catalog item, but they have no idea if or when they may get them. So....Moss did provide specifics on the plug (see picture). I was wondering if any local plumbing houses may carry something similar to the sample plug picture in the dimensions noted from MOSS. 3/8 BSP 19 TPI.

I know it's a long shot...but wanted to ask anyway.

Thanks,

Jim






Jim Rice

Jim,
There are two types of BSP thread. BSPP which has a parallel thread and BSPT which has a taper thread. The listing states just BSP but the photo shows clearly a BSPT thread. They are readily available in Europe for pennies. If you cannot source one in USA I can get one for you. The problem is that it takes approx. 10 days at present via airmail to USA.
You could use the BSPP but you will need a seal. E.g the bung in the base of the fuel tank would fit as it is 3/8" BSPP. Surely somebody in USA would loan you such a bung.
Worst case scenario-any decent machine shop worth it's reputation should be able to make such a plug in a few minutes.
Regards
Declan
Declan Burns

Jim,
Here you go. 4978K358 from Mc Master Carr on stock.

Regards
Declan


Declan Burns

The TF water outlet that included a fitting fo a heater started with XPEG-1000.

Lonnie
TF7211
LM Cook

DeClan:

Thanks for the info! I think I'm going to order a number of 3/8 plugs in varying thread and head styles. They are all pretty inexpensive (under $4 each US) as it's still not clear if I would need BSPP or BSPT. The 1st photo (of a photo) is the plug that Abingdon would sell if they had it. There is also a fiber washer that is sold for this. That leads me to believe the Abingdon plug might be BSPP. On the other hand, the second photo is of the fitting currently in the thermostat housing. As you will note, it does not sit flush with the housing, nor is there any kind of washer. There are threads still exposed and there appears to be thread tape or pipe dope that was used. In this case, I think the threads may be BSPT. I know from doing some plumbing here, the U.S standard pipe threads fit very similar to the second picture of the installed fitting. I did find another source here in the U.S that sells BSPT & PSPP with a square drive end, hex head, and a recessed Allen Wrench drive. I'll buy some from them and from McMaster-Carr, the fiber washer from Abingdon, and then try them all to see what actually works. It may take awhile, but will report back after a little trial and error.

Cheers!

Jim






Jim Rice

Jim,

I called Abingdon a few weeks ago and they don't have any of those plus in stock. I too, could use one whilst I repair my thermo bulb.

Still have no solution to the repair. One of the problems is finding a small quantity of ether. However, I have bough a defective TF gauge for expermentation, and hope to have it resolved by the time the snow is gone. (Maple) sap is running, so it shouldn't be too long!

Gord Clark
Rockburn, Qué.
Gord Clark

Gord:

I'll advise tomorrow on what items I will likely try to purchase. Besides the reference part number that Declan provided earlier from McMaster-Carr, this is the other place that sells British threaded fittings, etc.

https://www.britishmetrics.com/Category/Index/520?webdesc=NKBR

Jim
Jim Rice

If you are unsure go for the taper plug. The taper plug will always seal on the parallel thread but not the other way around. The parallel thread will not seal in a taper thread. BSP threads require a seal. The copper/fibre washer or even an O-ring on the BSPP and PTFE tape on the BSPT.

Regards
Declan
Declan Burns

Hi Gord, you will need diethyle ether to get the correct calibration. "Quick Start" for diesel engines is the correct type of ether according to the product label. Put the spray can in the deep freeze overnight and you will find that the ether comes out as a liquid and not a spay. At 100deg C. this ether has a vapour pressure on very nearly 100psi.
Hugh Pite
H.D. Pite

Many thanks, Hugh. I have lots of, that 'quick-start' stuff around here. That seems to resolve a major issue.

Also, I presume, I should use the little red plastic capillary that comes with it. I've located a 1mm drill for my Dremel. Getting ready to do my first try on the damaged unit. From the att curve, it looks like Vapour Pressure is about 5 bar at room temp (20°C) for dimethyl ether. But I will still take your advice, and put the can in my freezer overnight. Much easier to work with when its not a gas and less volatile, too.

I'll, post the results.

Gord Clark
Rockburn, Qué.



Gord Clark

Hi Gord, there is no way to get the ether directly from the spray can into the bulb. The method described in the link below works very well and is pretty straightforward once you have the ether and a can of some sort of very cold spray. I think this spray is used in the manufacturing of circuit boards and I can tell you it is VERY cold.
https://forums.g503.com/view topic.php?t=232995 .
I think this is correct however there may not be a space between the "view topic" in the link.
Cheers, Hugh
H.D. Pite

Gord, here is the corrected link.
https://forums.g503.com/viewtopic.php?t=232995 .
H.D. Pite

just to repeat what I said earlier, the BSP plug is for the heater supply on later TF's. The thermostat tapping is NOT BSF I think it is American Pipe.
I just checked my spare and neither pitch nor core diameter are the same.
Ray TF 2884
Ray Lee

Gord, last couple of times that I did the temperature gauge surgery my source for the ether was the bulb from a new gauge. I chilled it and cut its tubing and spliced it onto the T-car's tubing with a copper sleeve soldered over the joint. Bud
Bud Krueger

Me thinks that Ray (in his last post above) may very likely be correct. I did some searching on the interweb yesterday, and in a couple other forums (mgexp and britishcarforum), this topic on water temp thread size was discussed several years ago. Some of the members here were also in those discussions. There was also some input from Mr. Dave Dubois. The consensus there was the thread for the temp gauge fitting is U.S. 5/8-18. A plug you can get at most US auto parts houses and likely at McMaster-Carr.

It's an odd set-up. As best I can tell, that temp bulb fitting that screws into the housing is a 16MM wrench head size. If all true, I'll never understand why MG used a metric fitting on one end and a U.S pipe thread on the other. If so, a 3/8 BSPP or BSPT would not work. I have several BSP type plugs headed my way, so I'll advise if those work or not.

Jim
Jim Rice

I'm pretty sure the thread and fitting under discussion is 3/8 SAE 45° flare (Tubing - 5/8x12 thread)
I just bought a couple from Amazon...


J Stone

MG just liked messing us about.
MAD METRIC
BSF
UNF
BA
Standard Brass
British Cycle possibly
BSP
American pipe
Whatever the kingpins are ?
1 BSW bolt on dynamo stay

Ray
Ray Lee

It gets interesting. Image1 is the contents a SunPro donor kit. Image2 is the closeup of the ether cylinder and the assortment of hardware offered to install the cylinder in the car. Bud





Bud Krueger

J Stone:

If you plan to install one of those, can you advise if it fits OK? I'm going to be tackling the temp bulb removal and not confident the BSP type plugs I have coming are going to work.

Thanks,

Jim
Jim Rice

Getting a 'doner kit' doesn't seem to resolve the issue. I can't see any difference between cutting off a new bulb, to cutting off an old bulb.

Bottom line is, that I don't have the skills to weld/solder/fuse two tiny capillary tubes together. And I don't a copper sleeve of the connect dimension, to cover them.

The fitting size doesn't enter into the equation because I returning the original to the original hole.

I have everything I need to do the job. I will cool both the bulb and capillary line, and also the bottle of ether (in this case, 'Quick Start'). With a solder-sucker close to the drill point, using my Dremmel, I will proceed to drill a 1 mm hole in the end of the bulb. Using the little red plastic snout, I will inject enough ether to fill the chilled bulb. With that done, I will immediately solder the hole (with a soldering iron).

I'll report on my result.

Gord Clark
Rockburn, Qué.
Gord Clark

Whoa, Gord, the precept is that somewhere in your original tubing there is a hole that the original ether leaked out of. Unless you can find it, and close it, via a sleeve, you are going to lose this new ether. The 'donor' system replaces the tubing, the bulb, and the ether. Your end result should be like this image. You can do it. The soldering that you do is away from the cut ends. Bud





Bud Krueger

Ray,

For the sake of completeness.

Kingpins ACME

John
J Scragg

Gord, at the risk of repeating myself you will not be able to: 1. get the ether into the bulb directly from the spray can and 2. if you do succeed then you will not be able to solder this hole shut with the ether in it. How do I know? I have tried this method and after numerous tries had absolutely no success.
Cutting the line and splicing in a sleeve will work but you end up with a section of the capillary that will not bend. This is probably not an issue in most cases. I have used this method and was really not satisfied with the result.
After trying several different methods I found that the one mentioned in the link I sent in a previous post worked extremely well and is pretty easy to do. In addition I had a look at a repaired temp. gauge done by one of the professional companies and it was pretty obvious that this was how they did it.
Hugh Pite

H.D. Pite

Email sent to:
Jim Rice
San Francisco
CA
bmd29te@yahoo.com
best,
J Stone
J Stone

This thread was discussed between 11/02/2022 and 17/03/2022

MG TD TF 1500 index

This thread is from the archive. The Live MG TD TF 1500 BBS is active now.