How can I test oil pressure on John Deere 425?

Rob50056 · Jun 18, 2017

I replaced cam gear with metal and had to replace oil pump gear also.The oil pump gear had stripped out also.
The oil pump gear is driven by cam gear and so is governor along with water pump.
The oil light stays on and I checked oil sending unit by removing it,reconnecting to wire then used compressed air to test it and light goes out.
Whether using air is a reliable test I do not know so Im looking for another way to test oil pressure.
The oil pump is all metal parts if I remember correctly so I can't see it failing unless gear some how stripped out again.
Is there a way to test oil pressure using outlet where oil pressure switch screws in?
I'd think an oil pressure gauge of some type might work????

Rob50056 · Jun 18, 2017

Rob50056 said:
I replaced cam gear with metal and had to replace oil pump gear also.The oil pump gear had stripped out also.
The oil pump gear is driven by cam gear and so is governor along with water pump.
The oil light stays on and I checked oil sending unit by removing it,reconnecting to wire then used compressed air to test it and light goes out.
Whether using air is a reliable test I do not know so Im looking for another way to test oil pressure.
The oil pump is all metal parts if I remember correctly so I can't see it failing unless gear some how stripped out again.
Is there a way to test oil pressure using outlet where oil pressure switch screws in?
I'd think an oil pressure gauge of some type might work????

I discovered the problem.
When changing the oil pump gear there is a spring that can fall out very easy and sits on top of check ball.
I double checked my work space and behold they was the spring.
I must thank this link which has a full repair manual for John Deere 425 available to download.If I hadn't seen pictures I may have missed it.
http://www.mytractorforum.com/334-john-deere/142324-john-deere-425-445-455-technical-manual.html

crazyal · Jun 19, 2017

Glad you solved it. Usually I find that it's a simple mistake or something missed when a new problem arises after doing work. From the sounds of it you should get a lot more life out of your engine before needing to do a full rebuild.

Richard001 · Jun 19, 2017

Rob50056 said:
I discovered the problem.
When changing the oil pump gear there is a spring that can fall out very easy and sits on top of check ball.
I double checked my work space and behold they was the spring.
I must thank this link which has a full repair manual for John Deere 425 available to download.If I hadn't seen pictures I may have missed it.
http://www.mytractorforum.com/334-john-deere/142324-john-deere-425-445-455-technical-manual.html