Austin 1275cc (A-Series) Mini Air Conditioning Problem and advice needed

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B. - 01 Jul 2004 00:03 GMT

Hi,

I have just got around to removing the air conditioning from my donor
1275cc A-Series MG Metro. It has the same engine as the Mini and the
air conditioning is a "Unipart" (Austin's accessory supplier)
aftermaket unit so it is quite universal. It is about 20 years old and
the guy I bought the car from said it needed regassing as it doesn't
chill.

I'll say straight away that I'm no expert in A/C but I very carefully
removed the system and have it ready for installation except for a fly
in the ointment.

On the dash there is a screw on control unit with 2 rotary controls,
one for fan blower speed, the other for temperature (you hear it click
when it turns through the position of the current ambient
temperature). My first problem occured when I unscrewed this and
lifted it slightly from the dash - at that point I heard a really
faint hiss (for about 2 seconds). When I lifted the unit further I
noticed it had a small diameter pipe (probably copper, around 1/8"
section) which was crushed at the point where it goes into the rotary
control - unfortunately it has subsequently severed. The other end of
the pipe goes into the main centre console ac fan unit with no unions
anywhere and is about 4 foot long.

When I unscrewed the main rubber plumbing pipes from the engine to the
interior ac fan unit, there was no hissing at all so I assume there
was no gas present.

If you're still with me, I have the following questions based on this:

- Is it possible to fix the controller (it really has severed flush
with the temp control unit with not much to play with)?

- Can I get a universal replacement which would join onto the end of
the pipe?

- Is this pipe's system continuous with the main refrigerant system -
ie if I re-gas the system, will it leak out from this point or is it
indepandant and just for temperature control

- Can the a/c operate without the temperature control if I solder up
the pipe (ie. just continuous output)

- In general, what's involved in regassing the system afterwards (and
does anyone know of a service centre that they would recommend around
SW London)

Any help in these areas (or general advice) would be most appreciated,

Cheers,
E.

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B. - 01 Jul 2004 11:42 GMT

I've just noticed that the capilary tube can be pulled out from the
main fan unit (other end of rotart temp control unit) - it's like a
sealed probe. Now that I look at it, this assembly is basically a
fridge thermostat - long sealed capillary tube with a rotory control
at the end which switches the 2 electrical sensors based on
temperature recorded.

The rotary control unit says 110v 240v on it so I assume Unipart have
just found a cheap generic household fridge unit and put it in a fancy
palstic shroud.

If anyone knows anything about this unit (eg. what sort of refrigerant
to use, whether or not the cheap kits on ebay for not much money are
any good).

Generally, has anyone tried to regas?

E.

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Kelley Mascher - 01 Jul 2004 18:00 GMT

I believe what you have is called a Bourdon tube. It's a thin tube
with a bulb on the end usually filled with ether or something like
that. They can be used as a pressure switch. Cooling the bulb lowers
the pressure of the gas in the tube and throws the switch.

This is a very common way to provide temperature control in air
conditioning systems. They are fairly delicate so it's helpful to get
a replacement that's the right length so you don't have to worry about
what to do with the excess tubing.

You are probably correct that the tube and switch are generic.

Cheers,

Kelley

>I've just noticed that the capilary tube can be pulled out from the
>main fan unit (other end of rotart temp control unit) - it's like a
[quoted text clipped - 14 lines]
>
>E.

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