AT THE HEART OF THE ROAD TRANSPORT INDUSTRY.

Call our Sales Team on 0208 912 2120

road and workshop

5th February 1971
Page 65
Page 65, 5th February 1971 — road and workshop
Close
Noticed an error?
If you've noticed an error in this article please click here to report it so we can fix it.

Which of the following most accurately describes the problem?

by Handyman

B enchwise: repair risks (6)

IT IS in the 'later stages of servicing and repair that things are most likely to be rushed and critical features overlooked or their significance missed. One of the jobs that seems to get this neglected attention all to frequently is the replacing of pipes, wiring, etc, under the cab platform or catwalk on artics.

The actual job could well be a clutch plate, flywheel-ring change or replacement gearbox and this may well be carried out satisfactorily in every detail. However, today we have to deal with an ever-increasing number of gadgets, pipes and wires—for example several other uses are found for the speedo drive, one of which is automatic lubrication. More items have to be reset tidily and safely after the main job is done, and before the catwalk or platform is bolted down.

Considerable care is needed where the items which have to be moved to remove a gearbox are steel pipes for air-brake supply. Very often these items are in lengths or positions that do not allow easy or complete removal, and the tendency is to spring them aside, rather than remove them completely. Sometimes a stiff steel air pipe is bent and its nose and union nut well out of line to its mated connection on assembly, and the force needed to bring things into line is quite often enough to start fractures, or cause leakage.

The rush and bustle called for to deal with the final trimming quite often produces a lot more work either now or later, and the operator who says "Come on lads, you have got the box in, let's have the other stuff slapped together," is quite often instrumental in laying up a lot more trouble ahead. Similarly, the supposedly simple task of dropping the catwalk platform back in place is often left to a junior, semi-skilled helper or driver, and while they are quite capable of bolting the platform down securely, it is possible that things are not left as safe as they should be and it can be some little time before this is discovered.

One of the regular examples of this feature can come in the form of later air-loss from one of the flexible brake hoses between unit and trailer, brought about by trapping or squeezing the hose at or below the platform. Quite often the person fitting the platform just tucks the pipes loosely below, clamps the platform down, and because the brakes work is quite satisfied that all is well. But a pipe down below may be squeezed and kinked, and at that point of a smaller bore size than called for—as a result it Will give a lower braking effort.

Flexible pipes

Equally damaging is the fact that like all flexible pipes under pressure, it will try to straighten out at each brake application, and must be quite free to sort this force out for itself. If it is trapped in any way, it will apply effort and movement at that point, and even wire-wrapped hoses can be worn or chafed through to the inside layer. An example of this is shown by the accompanying photo, where you are looking down past the side of a catwalk at a flexible brake hose, which had been allowed to go below when the platform was fitted. It will be seen that this hose is being squeezed on the *3 /16in.-wide edge of an angle bracket, 'and that the corrugations of the hose are astride this edge. The result is that this hose will be on the 'move at this very point each time the air pressure varies inside the pipe,, and early failure at this point is certain.

Tags


comments powered by Disqus