Aircon and Heating ...

14 January 2018


The R107 500SL donor car had an aircon and I wanted one for the pickup as I'm a bit sensitive to the heat. However, original W115 aircon parts are basically unavailable. So what to do?

One idea was to use components of a Smart; but this would have been a tight fit, as the original heater box is already huge. There's not so much space behind the dashboard.

W115 heater box

So after a lot of researching, I found a company in the US, which offers "restomod" aircons, i. e. very compact units of heating and aircon for classic cars.

This unit is actually smaller than the original heater box, but includes an aircon. So after some phone calls with the manufacturer, I ordered it in the US for a hilarious price ... the shipping was nearly as much as the unit itself.

The unit is electronically controlled and includes the expansion valve as well. So all we still need are the heater and aricon hoses and a condensator.

The photo shows the unit in the car, two holders were manufactured to install it with the original screws.

Bantam II - heater and aircon

What's quite special with that unit is the possibility to adapt your original control Levers to it. So I ordered two linear potentiometers (for mode and temperature) and a radial one for the vent.

I designed an adapter for the "new" radial potentiometer, that fits exactly into the original position. So the vent can be operated with the original knob.

Furthermore I completely modified the original levers to operate the new linear potentiometers. So in the future two out of four linear controls will operate the aircon unit, whereas two are void. Nothing can be seen from the inside of the car.

Modified heater/vent control unit
Original W115 heater/vent control unit
3D-design of the vent potentiometer adapter

Another challenge was to get air from the outside to this new aricon/heater unit. I designed an adapter for the original fan opening with an exit to the right. A flexible hose will connect this to the aricon unit, which was also equipped with an Adapter (all 3D-printed).

At the moment I'm designing all the adapters for the dashboard vents, i. e. defrost, left, right and centre. Nearly finished, but I'll report that at a later point.

Adapter for outside air with hose
Adapter for outside air to the aircon unit
Adapter for outside air at the aircon unit

And the best thing at the end: The new controls, the vents and the unit perfectly fit behind the dash board!

All provisionally fitted

Aircon and Heating continued ...

19 May 2018


Well before my holiday we "configured" the aircon hoses by using an old garden hose for the length and attaching the fittings with tape to the end ;-) They were delivered and - surprise - fitted all. Five hoses for 550 Euros, it's an expensive extra, this aircon.

A lot of work (and money) to fiddle all this, just too tight everywhere ... but we're getting there!

Two aircon and heater hoses each ...
Dryer with a self-made holder ...
... the whole unit from the inside with the new hoses ... my 3D-printed-adapter for the outside-air is shown here too ...

Control Light Aircon ...

14 January 2018


Even now, I still get ideas how to improve things. I noticed that I don't have a control light, if the aircon (i. e. compressor) is on or not. Thought long about where to put a control light ... cluster is full, centre console too ... but the lever in the middle vent is not needed anymore, so there's a gap.

Designed a little plastic part for a 3mm green LED, glued it in nicely, sprayed everything black and put the LED in. Some proper "Mercedes plug" connected to it ... works! Just have to add another two cables to the harness...

Original position ...
Printed part fits ...
Design ...
Glued in, ground and painted ...