So, having acquired the amusingly named warning light bulbs, I tried them out, on and off all perfect.
Today I decider to accuraty time how long for them to go out and compare with the book figures.
From cold and discharged white light and flag up on 1min 25 secs. Red light still on after 8 mins, though gears engage.
Switch problem? I have spare compressor I thought about fitting when I did the brake pump but as there's never been air / gearbox issue I didn't bother.....
Ps I know the information will be somewher in one of the dozens of magazines and books I've got but what is size/part no. for compressor /brake pump drive belts?

My bus number (if any): 1842

Ian

I had Gates 6476EXL AVX 13 x 1150 fitted, but I think the 13 x 1125 size can be used. It was quite easy to slip the belts over the pulleys, perhaps the larger size is better in that respect.

While some electrical problems can be traced with a light bulb, it is so much easier to have a multimeter available. Likewise hydraulic and pneumatic problems can be resolved more easily with gauges. Remove the drain bung complete from the air tank and the hose that leads to the gearbox ep valve and take them to a good commercial motor factor. They should be able to supply the necessary fittings etc so that you can connect an air pressure gauge 0 - 150psi.

You probably need a 1/2"bsp male adapter and an iso test point, a length of hose fitted with iso test connectors and either an air gauge or means of connecting to a tyre pressure gauge. You will also need a hose tail to suit (your 1/2"?) hose and the means of connecting that to an iso test point. I use a hose tail screwed into a male "C" coupling connected to a female "C" coupling with an iso test point screwed onto the back of it and a jubilee clip. There may be a simpler way, but I have these to hand anyway.

With that connected you will then know what is going on. You will be able to know what pressure is in the air tank and what pressure is being delivered to the gearbox. You will also be able to see at what pressure the warning light operates. With the technical data in the manual you have got and an aerosol can of Rothenburger plumber's leak detection spray the job becomes easier.

Top advice, Roy.
Time to actually know what's going on rather than making assumptions and guessing....
Thanks

My bus number (if any): 1842

I made up a testing rig for the brake pressures



more details on ROOF

http://www.rmoof.co.uk/Gear%20box%20Air%20Pressures.htm

Cheers

My bus number (if any): RMs 238, 471. 2213 & GS 7

Thanks Chris, I've just found your step by step guide which I'm looking forward to following...

My bus number (if any): 1842