How To: Clear Sunroof Drain Pipes
I had a blocked drain pipe on my sunroof and couldn't clear it - using wire/coax etc. didn't help and I couldn't see the exit under the car clearly enough to tackle the problem from the opposite end.
However I worked out a neat solution that worked for me and cleared the blockage - a compressed air line would make short work of the task but if you don't have access to one (like me) and have discovered that the air machines on the forecourt of a garage are useless because of the valve mechanism read on...
1. Buy a bottle of drink/water with a sports cap and fill it with water.
2. Pull the drainage hose off the sunroof and feed it over the sports cap of the bottle.
3. Use one hand to hold the rubber drain pipe on to the cap of the bottle firmly
4. With your free arm, trap the bottle between your hand and the edge of the door and push hard, building pressure in the bottle that subsequently applies force down the drain pipe.
I had to squeeze really hard but eventually the blockage gave way and hey presto - a free draining pipe!