Does anyone know how to restore the kick-down gear changing facility to a routemaster. I have looked at lots of manuals but cannot find any reference to the kick-down which disappeared many years ago. RM1001 is totally original on the electrcal and mechanical side except for an uprated DY52 alternator. It is fitted with an SGC gearchange panel.

My bus number (if any): RM1001

I don't Mike but I know a man who might. I think the removal of this gear change facility as you say was a very early alteration and was a campaign change done on overhaul and major rotas and the remedy may have been such as to make it impossible to restore. Its a long time ago but did it coincide with the "cannot start in third gear" modification?

My bus number (if any): RTL 960, RML 2667, RM 1585, RMC 1458 and 14 RTs

Hi again Mike

As far as my contact can remember it was a wiring change to the control panel, so perhaps it can be restored. Maybe if you can lay your hands on an original RM wiring diagram and a later one perhaps the difference in the wiring might give you the answer to how to restore it.

My bus number (if any): RTL 960, RML 2667, RM 1585, RMC 1458 and 14 RTs

Mike

There is little reference in the LT Maintenance Bulletin 47, it does however refer to Part 3 having details of Fully Automatic Control. Moreover the Walker Manual has diagrams of both CAV&SCG panels, along with a description of the Accelerator Switch and the 3 functions Light-Normal&Kickdown. It seems the functions are achieved using + voltage from the switch to sensing relays used in both the CAV&SCG panels. With this in mind if you can obtain the services of a decent commercial auto electrician, and reference to the diagram you may be able to reinstate the kickdown function. It may be that with reference to the Walker Manual, the reason the kickdown and 3 position switch was modified is because of problems in operation. I would leave the throttle switch as it is, as the benefit of a kickdown facility on the RM is not going to be very useful, even though it may have been an original feature. The same effect is being produced by the gear control unit at a given road speed, instead of the driver at what may be the wrong speed in any case.

Ed

My bus number (if any): RML 2335

The problem with re-instating kickdown & light throttle range lies in the mods carried out to the switchbox (SCG) and the illimination of the switchbox in lieu of a coast switch under the throttle pedal on CAV fitted buses.

On SCG control panels many have been modified and have had two of the seven pots removed. To re-fit kickdown and light throttle you need, as a starting point, a panel with the full complement of components. There were two versions of the SCG chassis mounted switchbox. One had three switches for the three throttle ranges, the later one, fitted after approx 1964 only had one. The earlier boxes were modified to the new condition by the removal of two of the microswitches and the simplification of the wiring loom from the junction box mounted on the offside front diaphram two one pair of wires. The loom into the junction box from the tree in the cab was also modified.

You will need to re-fit two switches in the chassis mounted box and modify the wiring loom back to the original specification. For that you will need a pre-1964 copy of the wiring diagram. I have both types. The directions for setting up the various mechanical and electrical paramiters are contained in the genuine LT manuals.

As far as I am aware CAV switch boxes were removed because of constant problems caused by water ingress and wear to the switch tips and were replaced with a 'coast' switch under the throttle pedal. The only CAV switchbox I know of still fitted to a bus is on RM 1. Good Luck.

My bus number (if any): RM 912 & RML 2455

Hi all

The kick-down facility was removed because the actions of ‘heavy footed’, aggressive and over eager drivers to turn the buses into racing cars to try and gain or regain lost time produced a situation for passengers and the conductor which caused a sharp rise in ‘on-bus’ accidents and complaints, especially from conductors.

This is much the same as the type of ride that some of today’s bus drivers achieve with harsh acceleration and braking.

Claire

My bus number (if any): RML2330 etc.