New capillary tube for temperature instrument

[Berggreen]

Dear All

I am going to renovate the temperature instrument, and I have a very good instrument mechanic, who knows how it is done. He has renovated a similar temperature instrument for my Volvo 1800S from 1969 before, and he did a great job with new capillary tube and new ether and calibration of the instrument.

However, just as when he did the instrument for the Volvo, I am tasked with sourcing new capillary tube!

I have measured the outer diameter of the tubing at around 1.4 mm, but I have not chance of measuring the inner diameter.

So two questions:

1) Does anyone know the inner diameter of the tube?

2) Do you know a good place to buy new capillary tube in the dimension that fits the temperature instrument?

Looking forward to hear back from you.

Cheers,

Christian

[scoot]

This is quite odd.  From my past experience, you need    a)  the gauge    b)  the sender    c) the length that the new capillary tube needs to be.  The shop should replace it entirely.   Note that this is almost impossible to have done now in California, as the only shop that would do it in the past is really hesitant to do it now.  It's kind of dangerous.   They should not need you to supply the tube, and I wouldn't have your mechanic do this --- send it out to a professional who does this exact work.

[Berggreen]

This is quite odd.  From my past experience, you need    a)  the gauge    b)  the sender    c) the length that the new capillary tube needs to be.  The shop should replace it entirely.   Note that this is almost impossible to have done now in California, as the only shop that would do it in the past is really hesitant to do it now.  It's kind of dangerous.   They should not need you to supply the tube, and I wouldn't have your mechanic do this --- send it out to a professional who does this exact work.

Hi Scott

I am located in Denmark in Europe, and there are companies here who can do it as well, but it is costly!

My friend is actually not an amateur, as he is a retired aircraft instrument mechanic, and does a lot of classic car instrument repairs now, as a hobby business in his otium.

This also includes repairing capillary tube temperature instruments. But he does tell me that he needs to go out and have some fresh air sometimes, working with ether in tiny small capillary tubes in his shop! But no worries, he gets the job done. Old school guy!

But what he is not good at is sourcing around the internet for materials. So I have to help him with that, and that includes sourcing the correct tubing. I already have the sender unit / probe from the old instrument and this will be reused.

So I need to find some tubing, and if you know where to get it and what dimension, it would be great info.

Cheers,

Christian

[Pawel66]

I looked through the EPC for that, but got a bit confused. There is part available for early M130, but not for a later one. As there are differences apparently, I am afraid to recommend anything...

[Berggreen]

I looked through the EPC for that, but got a bit confused. There is part available for early M130, but not for a later one. As there are differences apparently, I am afraid to recommend anything...

Hi Pawel

Thanks for looking into this!

Sounds odd that there should be a difference. Because I have never seen this, when looking for replacement units. SLS is selling some pattern replacement temperature instruments with a small VDB written on the front plate of the instrument, which is not very attractive. But as you see, SLS does not sell different versions: https://www.sls-hh-shop.de/main/de/mercedes-230-280sl-w113/54-elektrische-ausstattung-karosserie/54-a-cockpit-instrumente/fernthermometer-r113-celsius-hinweise-p-5469

Which part numbers did you find in EPC?

Thanks,

Christian

[Pawel66]

Christian, sorry, something is wrong with me recently apparently... I was looking at the oil pressure tube... getting old.

As for the temperature gauge, the only way I saw them was as a set - gauge with the tube and sender. I bought mine from Niemoeller for late M130, works just fine.

[Leester]

It looks like capillary tubes can be found on the internet but your question was the ID of yours.  I don't have either a gauge or capillary tube to look at (its installed) but it seems like the capillary tube may be attached over (or soldered to?) a hollow post at the temperature gauge. If so, would it not be possible to grind off (or un-solder) the capillary tube where it attaches to the the gauge, then measure the OD of the male post. Or possibly use a dremel and cut what you have cleanly - then measure the ID?  Just possibilities.  Lee

[lpeterssen]

Dear Friends

I ended with that problem installing on the same place the pagoda has the capillary principle temp gauge, and electric unit from a MERCEDES truck.  Just remove your old dial from your pagoda and screw it to the new electric unit and solved. It’s now electric.  You have to change the resistance that is on the back of the unit itself for one that doubles the size since this was intended for a 24V system and your car runs on 12V.

https://www.ebay.com/itm/Mercedes-Unimog-Truck-Bus-Temperature-Gauge-003-542-33-05-0035423305-/303884474435?mkcid=16&mkevt=1&_trksid=p2349624.m46890.l49286&mkrid=705-154756-20017-0

Best regards
Lp

[Berggreen]

It looks like capillary tubes can be found on the internet but your question was the ID of yours.  I don't have either a gauge or capillary tube to look at (its installed) but it seems like the capillary tube may be attached over (or soldered to?) a hollow post at the temperature gauge. If so, would it not be possible to grind off (or un-solder) the capillary tube where it attaches to the the gauge, then measure the OD of the male post. Or possibly use a dremel and cut what you have cleanly - then measure the ID?  Just possibilities.  Lee

Thanx Lee! Very good input and ideas. I will give it a shot!

[Berggreen]

Dear Friends

I ended with that problem installing on the same place the pagoda has the capillary principle temp gauge, and electric unit from a MERCEDES truck.  Just remove your old dial from your pagoda and screw it to the new electric unit and solved. It’s now electric.  You have to change the resistance that is on the back of the unit itself for one that doubles the size since this was intended for a 24V system and your car runs on 12V.

https://www.ebay.com/itm/Mercedes-Unimog-Truck-Bus-Temperature-Gauge-003-542-33-05-0035423305-/303884474435?mkcid=16&mkevt=1&_trksid=p2349624.m46890.l49286&mkrid=705-154756-20017-0

Best regards
Lp

Thanx, good alternative. But I am more of a traditionalist and would like to stay with the original type instrument.

[Berggreen]

Christian, sorry, something is wrong with me recently apparently... I was looking at the oil pressure tube... getting old.

As for the temperature gauge, the only way I saw them was as a set - gauge with the tube and sender. I bought mine from Niemoeller for late M130, works just fine.

Pawel, you were right about the oil line. Because today I helped a friend take out the instruments in his 250SL, and the fitting going into the oil pressure instrument is much longer on the 250SL than in my late 280SLs.

Cheers,

Christian

[Kevkeller]

I used to get a good restoration magazine called Skinned Knuckles.  A great magazine.

Years ago I did read an article about fixing temperature gauges that used capillary tubes and replacing the gas/liquid. It’s not that difficult from the looks.

[Mike Hughes]

Skinned Knuckles is still going strong - it has even been featured in an episode of Jay Leno's Garage.  Back issues are available from the publisher and on E-bay.  Type "Skinned Knuckles Magazine" in your search engine . . .

[Berggreen]

Thanks all for good input.

An update is that I have now handed over the temperature instrument to my instrument mechanic, and after looking at the old tubes, he has decided to use new tubing with an internal diameter of 0.2 mm, which is also used for similar capillary tube temperature instruments in MGs.

Let's see how it turns out.

Cheers,

Christian