The Fordson Tractor Pages Forum

Hi,

I am fault finding a 1962 super major lift cover that following installation will not lift. It has been sitting on my work bench for about 5 years before recently installing. After inspecting the check valve, pressure relief valve, I have decided to remove the lift cover and inspect the control valve which moves freely and the unloading valve.
My problem is that I cant find a suitable bolt with the correct thread to fit the unloading valve plug. I have tried a 3/8" UNF, 3/8" BSF but both bind on attempting to screw into the plug. I can see that it is a relatively fine thread.
Can someone please confirm what the correct size and thread type I should be using for the plug. I am now thinking of trying a 5/16" UNF ? I have tried to force the 3/8" UNF thinking maybe the thread is dirty, but this will do damage to the thread, so am fairly convinced it is not the correct size or thread.

Many thanks,

Michael.

Hi,

Don't think you can find the answer in unc and unf. Is it a tapered or a parralel thread? I would suggest to check for BSPP or BSPT first.

https://en.wikipedia.org/wiki/British_Standard_Pipe

Good luck!

and please post some pictures on what you're doing or intend to do.

hydraulics can be life threathening when openings where valves are fitted are blocked by solid plugs. I don't realy undertand what you're going to do,.............

Hi Emiel,

The plug I am referring to is on the lift cylinder next to the main control valve and has a threaded hole which I need to insert a bolt with suitable packing such that when I screw it in, I can jack the plug out. The plug needs to be removed to access the unloading valve. I believe it is a cylindrical thread.

Regards,

Michael.

Hi,

Read it all carefully again. Then read through the manual. There is spoken about a special tool to remove to plug, but the thread is not stated.

For the threads of the plugs on the auxiliary service control housing is stated some of them are tapped No. 6-32NC. But that is far smaller then the 5/16 you assume. You might have luck at a old ford tractor dealership.

You're lifts symptoms can be a sticking unload valve, I think you're looking in the right direction.

rgds
Emiel

can't you just turn a machine tap 3/8 unf in? then your bolt wil fit afterwards,..............worst case result is that you have to machine a new plug on the lathe.

I just replaced the seal on the unloader valve and the threaded hole on the plug is 3/8 NF. I did a bit of sleuthing until I discovered that. Just thought I would put my two bits worth in.
George