Blackburn Transport Leyland Atlantean VBV 18Y
 

Hello all,


In November last year i purchased a Blackburn Atlantean, it is one of two Blackburn Atlanteans in preservation so quite rare. It has an East Lancs body and was registered in September 1982.

Just wondered has anyone got an Unloader valve for an Atlantean as mine is playing up and it won't let the air system build up to 120psi

Thanks :D

http://www.partline.co.uk/Automotive...TYPE=Air+Brake

Part no: FBU7110
Description: Valve - Unloader

Repair kit:-

Part no: BBU1761
Description: Kit - Unloader Valve

Although your vehicle is a Leyland, the parts would be from Clayton Dewandre or Bendix Westinghouse and common with parts fitted by other vehicle manufacturers.

Is the fault with the unloader valve or the compressor?
The unloader valve signals the compressor delivery valve to 'unload'.

Although the following video is US-orientated, the description of the governor/unloader valve (from 5:45 on) should explain how it works:-

http://www.youtube.com/watch?v=2U_R46CZnUM

I cannot see how a faulty unloader/governor valve would result in inadequate system pressure - unless the spring-setting has been tampered with.
More likely that the system pressure would rise too high as the unloader valve failed to signal the unload.

You could check whether the compressor is working adequately by temporarily disconnecting the unloader valve from the compressor (probably a small diameter plastic signal pipe unless the valve is fastened directly onto the compressor cylinder head) when the system pressure should rise above the governed pressure until the safety valve blows off.

Check for leaks that might be preventing the system from reaching governed pressure - or the compressor might be faulty . . .


.

Compressor diagnostics:- http://www.youtube.com/watch?v=JZM2NFExZsA

Governor/unloader valve:- http://www.youtube.com/watch?v=JqZLrx5mm_0

Consider a repair kit if the original valve is leaking air.

Most motor factors dealing with trucks should be able to supply these.

.

A kit for a Bendix (not necessarily the same as yours - yours might be Clayton Dewandre and might be a single cylinder rather than a twin cylinder - with other Atlantean owners around you should be able to identify what make) compressor (scroll down for a list of parts):-

http://www.ebay.co.uk/itm/Bendix-Air...item3f2e7b943d


If you need parts try:- http://www.partline.co.uk/Automotive...TYPE=Air+Brake

or any commercial motor factor - once you know what you need