Slow Running Control

[SV_Minor]

Can someone give me a good description on how the rod is attached to the pedal controls under the floorboard? A photo or two would be great, too. Thanks.

[Ian Grace]

Hi Jonathan,

I don't have a picture handy but I'll try to describe.

On the throttle cross-shaft, you should find a bronze fitting with a Whitworth female thread. The slow running control rod simply screws through it and pushes on another bronze fitting that is attached to the cross-shaft, so screwing in the rod pushes on this and opens the throttle. You'll be able to check mine at the next Fountain meeting on the 15th.

[Ian Grace]

Correction. The female thread is in the driver's side (obviously!) cross shaft bronze support and the rod impinges on a steel flat which forms part of the throttle pedal lever. I'll post the best photo I have in a mo ...

[Ian Grace]

Not really useful, but you can see the bronze mount and the black steel pedal lever.

[SV_Minor]

Thanks Ian, I've just come across a photo I've taken previously, so the parts in question are not the focus of the shot, and you can see the mechanism I have fitted. Does it look right or wrong? The female thread is actually mullered, so it's currently useless. I had the full mechanism connected up, and working, when I first had the car. The issue I had was the rod was/is in two parts and the lower part was bent somewhat. That has clearly damaged the thread over time. My old-school mechanic friend can't figure out how the rod is meant to actuate the throttle when there doesn't appear to be any means of it (the rod) moving in relation to the fixing point at the knob on the underside of the dashboard.

[Ian Grace]

So in your photo, the original arrangement can be seen at top left. You can see the threaded hole in the cross shaft attachment. The rod should screw right through this hole and push on the flat bit which is part of the throttle pedal.

When you screw the rod down (to open the throttle), the rod obviously shortens at the instrument panel end. This is compensated for by a clever spring under the mounting fitting which impinges on serrations on the underside to hold the rod in place (i.e. stop it rotating with vibration. This spring is clamped onto the rod with a nut and screw.

I hope that makes sense!

[SV_Minor]

Thanks again, Ian, for your detailed explanation. I have studied a drawing in a Morris parts booklet and the rod and associated fittings is all present and correct. That's good. With it all fitted in place I guess there should be a gap on the rod between the knob and the mounting fixture, so as you turn the knob and it moves along the thread in the tab on the cross-shaft the gap is taken up until the knob contacts the mounting and stops you engaging it any further. If so, then I haven't had enough length in the rod to allow that. The knob has always been up against the mounting.

[Ian Grace]

Ah, that's the problem then. I don't know the history of your car, but I know that when rebuilding the ash frames, it is not always easy to get the position of the instrument board spot on compared to the pedals. If you are running our of length, I'd suggest you have a slightly longer rod made.

[SV_Minor]

I've just come back in from spending 20 mins in the garage. My assumption that there should be a gap between the knob and the mounting plate is clearly wrong. I've tried it and the serrated 'friction' plate won't work in that set-up. I hadn't considered the location of the dashboard having an impact on the mechanism if it's not positioned exactly as it was from Cowley. Well, as I mentioned a few posts back, my main issue is the condition of the thread in the cross-shaft. I'm going to have to re-tap it before I can move forward. Thanks for your help, Ian.