Allis-Chalmers M 100C Grader engine oil pressure sending unit

[Legdoc]

Happy holidays to all and howdy from South Texas. I have a A-C diesel maintainer with 24 volt starter. The engine oil pressure sending unit functions but has a steady oil drip. A-C being long out of business the OEM part is not available.
The unit is single wire. I don't know if it is 12 or 24 volt. It needs replacement but I'm not sure how to proceed. Any help would be appreciated.

 

[Tones]

If you can't get any satisfaction to you question then fit a mechanical sensor and gauge. They should be available at any good auto parts store.

 

[OzDozer]

Hi Legdoc - If the starting system is 24V, the engine oil pressure sender would be 24V. I understand the M100C is actually a Fiat-Allis machine, produced after the Fiat-Allis Chalmer merger that occurred on Jan. 1st, 1974.
I believe this machine still uses the Allis Chalmers 10,000 series engine. I'm fairly sure Allis Chalmers always used Stewart-Warner instruments, which means all gauges, senders and sensors were made by Stewart-Warner - and as Stewart-Warner are still in business, and components for Stewart-Warner are still readily available, sourcing a new sender unit should be no problem.
If you do a Google search using "Stewart Warner oil pressure sender" and then click on "images", this will often provide a photo of any available sender that is identical to your unit.
Or you can either take your sender out, and take it to local parts supply house that supplies electrical and gauge components, and they should be able to provide a replacement.
eBay sellers can also be a likely source of a replacement sender.

 

[8V71]

Don’t know if they have the part you’re looking for or not or if you’ve already solved your issue, but I use to have a lot of success getting Fiat and AC parts from Minn-Par. I haven’t worked on them in several years don’t know what they have now but you may check for any other parts you might need for that machine.

 

[Delmer]

If the pressure sender has one wire, then it operates by varying the resistance to ground of the wire from the gauge, so it might not matter if it's 12 or 24V. Take it off, clean it up to find numbers, see if you can find anything with those numbers, or go by looks will probably work too.

 

[56wrench]

StewartWarner makes the Hobbs pressure sender which can be had in 1,2,or three terminals. Go online to their site and see if you can find one

 

[Legdoc]

I appreciate the advice from all. I have been tied up on other year end issues that have come up and have not had the luxury of any time to proceed with this project. I will update the progress ASAP.
Thank you all!