1850D Tachometer Drive

I've got an 1850 w/o functioning tachourmeter. So far the cable is bad, but, I can't figure out what the other part is.

- Below the injection pump there is a right angle gear drive that slips over a gear that is protruding, and then the tach cable screws onto that. What is that right angle part? It spins freely when removed, but, the gear drive doesn't engage it. Teeth on the gear that is poking out are fine and spin when the engine is running; I'm assuming the teeth on the internal right angle thing are not so good and I need that part. I'm having trouble identifying it in the parts book.

Some googling indicates that this is a common fail with that internal drive being stripped out..and they are either hard to get or expensive or both. Can someone enlighten me?

Thanks,

J

Is there any other fix? I assume the cable was damaged or something caused the drive not to spin and it chewed it all up..

I looked at my 2-105, also with the Perkins. Same CAV pump and the same housing as the 1850, however, instead of there being a worm gear parallel to the block at the front with a 90deg drive, the tach on the 105 goes straight into the backside of the housing, facing the cab.

Is there another option to get a tach going that people have done; the gear inside the 90deg looks like it's had it's last... How do you properly get those caps off that 90deg? I knocked one out with a punch, but, it chipped off the lip (figured no big deal since the drive isn't sealed; I can fix that).

J

I had asked before about changing to the same drive that the 2-105 has. Somebody said I'd have to change that shaft that drives it.

any chance someone has the correct p/n for the diesel tach cable? I can find: 121695 or 122466 here on YT. I think the longer one, however, is the drive-side different on the Perkins tractors?

Further digging reveals the part Jack indicated; it's actually a complete unit; the cover + gear + 90 adapter: 158761AV. Make sure you are sitting down.

I figured that out, finally.. Went to local agco, discontinued and they can't get it. I found an auto one that is 81 long, I'm going to try that and see.

What is the block under the CAV pump that the tack plate and gear bolts to? I'm wanting to figure out an exploded diagram to see just what may be necessary to change this over to how the 2-105 is driven, given that the right angle drive is unobtanium. Mine appears to work now, but, I don't hold out long term hope :).

J

Comparing to my 2-105, the aux-drive block appears different. At this point I think I have the right-angle adapter filed to where it will work. An 80 speedo cable is proper length, but, the driven end is the wrong configuration for whatever was meant to engage in the right-angle. Looking at it though, I'm positive I can fab something up that will allow it to engage. I don't know how long it might work given the poor shape that drive is in. When I stopped at the local agco they could find the cable core, but, it was no longer available.

The Aux drive on my 1850, as with others I've seen, has a large shaft with a key protruding from the back side--the side pointed at the operating position, exactly where there is some sort of drive for my 105. I suppose I could leave the original gauge in for show, but, stash a modern tach somewhere else just so I have it as this tractor will be doing work! I've been scouring the internet looking to see if any other perkins 6.354 used the same arrangement as the 1850 for tach drive; i don't think so. The closest thing I can find is this:

Link

There are more annoying things to do next; previous owner appears to have panted the tractor, only with something other than Meadow Green, and, none of the dash and light components were painted white. That's driving me nuts!

J