Had one of the TM155's reported that its Air con had packed up, first thought was the 4 wire switch on the high pressure tube near the compressor, they don't seem to last for ever but it was a surprise to find that ok and power getting to the right places except the last bit from the pressure switch to the clutch. Testing proved the switch was ok so time to chuck the gauges on. Ah! no gas!
Didn't take long to track the cause down, one of the bonnet brace bars had rubbed on an 8mm steel tube that along with some rubber hose makes the pipe assembly from the condenser to the filter dryer. Seeing as the damage was well away from the hose section it was ideal for a small solder repair. Took the offending item off, plugged the open system connections. Then cleaned up the injury area and applied some water based flux and then made a small "patch" to fit the rubbed area- I cut an angled section of a small splitpin to fit the grove and support the silver solder to make a good repair, then it was a bit of brazing with the propane torch followed by a good clean up and a spray of zinc paint.
Before refitting the tube assembly was connected to the flushing kit and flushed both ways, then new orings applied before refitting along with a new filter dryer and about 1/2floz of pag oil to replace what would be in the old filter dryer and would of lined the the now flushed tube assembly. Next a quick vacuum test confirms a leak free system which is followed by pressure testing with nitrogen for 30 min at 10 bar and then a 30min vacuum to get out any moisture. Having lost all the gas meant recharging it with 1.4kg of fresh gas before giving it a performance test.
Made a nice little job for once.