Sorry guys, my signal comes & goes here & I'm all in a rush & probably not making perfect sence, I'm not worried about the clutch, that seemed to bleed up ok, its just that I spilt the clutch fluid & it has swelled up a rubber boot that looks to have sealed the throttle piston but It's too swollen to stay in place now & air is just hissing up around it, what I want to know, before I do any dismantling & cocking something else up is, was this seal the only thing holding the throttle air in or should the air get that far? Does that question make sence? I've taken apart clutch cylinders & there's a bung on the piston, or like a syringe, do these air throttles have something similar, should the air be getting up past the throttle piston & out at the swollen rubber boot or should it not be getting that far anyway & the rubber is just like a bush,... God I'm hoping I'm making more sence now, the brake & throttle tanks will not fill up & the air is definitely coming out from the throttle pedal mechanism.. thanks guys, Kate

I have absolutely no experience of air-operated throttles.

There should be a 'protection valve' that should limit the loss of air. It shouldn't be possible to lose all your air with a single failure.

I'm not familiar with Leyland 'light' truck systems so I might be mistaken of course.

The air throttle control is called a treadle valve, it is 30 years since I worked with these but it is a plunger operated valve similar to a foot brake valve. It works on vehicle air pressure. You could take it apart as it will consist of O rings (take pictures as you strip it) it may be an easy fix. Google the make of valve and you may find a replacement or repair kit. Good luck, remember to keep us posted on your progress.
Update, have a look here as explains how valve works and safe removal of valve.
http://www.oshkoshmanuals.com/litera...ies/625-3A.pdf

I knew that there would be someone along with the knowledge!