ASK ARB – Old
vs New

Dear ARB,

I have one of your air compressors which I purchased about ten years ago. It’s mounted under the bonnet of my 4×4, and is regularly used to inflate the tyres on my vehicle, plus invariably it gets used to pump up all my mates’ tyres as well. It’s taken a real hiding over the years, but has never let me down. However, I noticed in previous editions of your magazine that you now have a new unit available which is twice as fast as mine. 

Furthermore, I’ve just been reading the December issue of 4×4 Australia magazine and saw that your new compressor comfortably beat everything else on the market. I think it’s awesome that a genuine Aussie designed and built product can beat all the imported brands, and despite the fact there’s nothing wrong with my old compressor, I’m keen to upgrade to the new model. My question is, does the new compressor share the same mounting footprint as the old model, and are changes necessary to the wiring loom?

Regards,

Jeff McMahon

Hi Jeff,

The mounting holes and the power connections of the new CKMA12 air compressor are all identical to those used on the previous RDCKA model.

This suggests that a CKMA12 model can be installed or retrofitted by simply bolting the new compressor in where the RDCKA was, and plugging it into the existing wiring connections. This is an acceptable practice, and the new compressor was intentionally designed to be able to be used as an RDCKA replacement should one be required.

Please note however, that the loom which is supplied with the new CKMA12 model was redesigned to include:

• Heavier gauge wiring to reduce the resistance between the battery and the compressor motor
• A higher rated more durable fuse socket capable of heavier loads and hard usage
• Two control circuit diodes to protect against current leakage on newer model vehicles
• A second ground wire in the circuit which was designed to support 24V as well as 12V installations

For a replacement compressor the supply voltage should not be an issue. However, to gain the full benefits of the high flow output that is specified for the new CKMA12 models, the old loom needs to be replaced with the one that comes with the new compressor (i.e. for the lowered supply resistance).

If you are doing this then please note that only the power supply portion of the loom needs to be replaced. The short section of loom from the switches to the firewall plug does not need to be changed to gain full performance in an existing installation.

If you book your vehicle into one of our stores, this work can generally be undertaken in two to three hours, depending on the vehicle.

Daniel Bongard
(Engineering Supervisor)