880 Selectamatic safety starter switch

[DRM]

I noticed the remnants of the safety starter switch on my 880A this afternoon (operated directly by the clutch pedal, not the later ones in the top of the gearbox). Looking at the parts list, there should also be a lever, pull rod, spring etc between the switch and the clutch pedal. All of this is missing on my tractor.

Does anyone know if these starter safety switches are still available? Is there another switch (e.g. brake light switch) that can be modified to do the same job?

I would also be grateful if anyone has any photos of either the original arrangement or a rework using modern parts.

Many thanks,

David

[rid54]

My 880 has a safety switch, it is a single unit mounted on the side of the clutch housing and operated by a protrusion on the pivot end of the clutch pedal arm. It is a simple "push to close" kind of switch, no visible mechanics. I'd guess it can be replaced by any kind of similar switch that can be adjusted into a suitable position vs the clutch arm. It is mounted on a machined surface with two screws, it doesn't look like anything home-made.

[DRM]

Great - many thanks for your reply. Would it be possible to take a photo or two showing the arrangement, when you get chance?

Thanks,

David

[philedge]

If you look here https://sites.google.com/site/deerebrow ... wn-info-ii towards the bottom of the list theres a selectamatic service manual that includes a list of technical service bulletins. Have look in the micellaneous section and youll find details of the interlock switch.

If you use a different switch just check that the replacement switch will carry the current, as starter solenoids pull a fair current- way more than a set of brake lights!!

[DRM]

Thanks for that. Similar switches are available so assuming there's somewhere to mount such a switch then that could be an option. I'll give it some thought.

[DRM]

Have been doing some research. According to:

https://drive.google.com/file/d/1knZlQm ... IjHSm/view

the original starter switch was Lucas type 76701. These are still available.

The question is - how were they mounted and what was the connection to the clutch pedal like?

David

[tomryall]

The switch pictured is not and isolation switch, it is a starter switch from a cropmaster it is mounted on the lower left front side of the fuel tank support and connected to a pull knob under the dash.

[rid54]

Check the area around the clutch pivot shaft. There should be an extension in the casting in the clutch housing where a switch or switch mounting bracket could be mounted with 2 screws. In the clutch pedal arm, near the pivot point, there should be a kind of "cam lobe" that can act on a switch push-rod, if it is mounted in the correct position. No other mechanical components are involved, at least not on my 1971 Selectamatic.

[philedge]

Thanks for that. Similar switches are available so assuming there's somewhere to mount such a switch then that could be an option. I'll give it some thought.

Have a trawl through the technical service bulletins I linked to as they detail the later type of switch too. The TSBs almost always give a tractor serial number from which they apply and youll be able to work out which set up originally applied to your tractor. It may have been modified at sometime but at least youll know what should have been there originally.

[DRM]

I found the service bulletin showing the change to the later type of plunger switch fitted on the side of the clutch housing (Technical Service Bulletin TSB13). Have you found a TSB showing the original arrangement (pre-68?)? If so, I'll go back and dig a bit more.

Mine definately had the switch mounted to the left hand tank support as there are still parts of it screwed to the tank support with the original screws. This is also confirmed by the dates and tractor numbers in the TSB. The switch and anything fastened to the clutch pedal is missing though. There are a couple of photos on the forum showing the lever/spring arrangement fastened to the clutch pedal (search for "880A Selectamatic information request"). The problem there was that the switch was missing. I wonder if that user (Selectamatic 880) got it sorted?

Below is an extract from the Lucas/CAV/Simms/Butlers information sheet I provided a link to earlier showing the two types of switch. Looks pretty similar to the photo I posted?

Thanks again for all your responses.

David

[philedge]

Ive seen 2 TSBs for the starter interlock. Ones in the miscellaneous section but I cant remember which section the other one was.
If I remember correctly the first version had a pull switch where a spring assembly connected to the clutch pedal and pulled the switch to allow starting. The second version had a push switch where a cam on the clutch pedal pushed a switch to allow starting. Double check the TSBs but I think that's how things evolved

[philedge]

TSB 20 in the miscellaneous section details the earlier set up which is what seems to be showing in the pictures/topic you referred to above. TSB 13 in the electrical section details the later version

[DRM]

Great - thanks. I'll have a look.

David

[DRM]

TSB 20 in the miscellaneous section details the earlier set up which is what seems to be showing in the pictures/topic you referred to above. TSB 13 in the electrical section details the later version

Thanks for pointing me to that. Pretty much everything I need to know is there in the bulletin. I reckon I could make the linkage between the pedal and the switch (see photo below). Unfortunately, the switch shown in the TSB doesn't look much like the switch in the photo above. It looks more like a brake light switch. I'd be most grateful if anyone has a photo or description of the switch used.

Using the later plunger type switch is going to be difficult as my clutch pedal doesn't have the cam profile on it and there is no where to mount the switch on the clutch housing.

Just need to find a suitable switch.

[cobbadog]

I really don't think that the switch in post 340 is not the one for your tractor and as you have described an alternative as being like a brake light switch may be the one you need.
Those water marks through the pics a re a nuisance aren't they.