O ring seal help

[robin]

I need a 0 ring for a 1962 forson super major that fits on the end of the oil feed pipe from the pump to the lift cover, it is a rare size. Help

[JC]

Hi Robin,
Welcome to the BB.
I just looked on the New Holland web site and it lists that o-ring as 5/8" I.D. x .103 (3/32") thick. I found several companies on the internet that sell that size o-ring. Just search for "o-rings" on your favorite search engine and you should be able to find one near you.

[robin]

Thanks for that, Looking in the manual page 9 section 6 feed & exhaust pipes assembly, it looks like it is showing 2 0 rings, 1 on top & 1 in a recess/groove? can you tel me if it as one or two

[Brian]

Two, but the one in the recess in the casting is only a low pressure one on the exhaust oil so can usually be used again.

[robin]

Hi again Brian, I have made some progress! Taken off the auxiliary unit & put a blank plat on the top, removed the bung out of the side & put a pressure gauge in & we are at 3000 psi, brill, I seem to have oil going through and down the auxiliary valve but not coming back up, or what is coming back up is of low pressure and not much volume, so it must be exhausting around the check valve area as it is not returning back up to the auxiliary vale so the oil can be distributed ether to lift arms, or tipping pipe. When this is happening the tractor engine has no stress, so the flow of oil must be easy, not like having to push open a relief valve, I thought I would see what you think before going further.

[Brian]

Its not the check valve Robin. That only hold the oil in the cylinder. Its as I told you first off. Its the unload valve.

[robin]

ok will get in to it monday but be carefull ya.

[robin]

Hi Brian` just got the unloading valve out but all I think is ok, I am not sure how or what operates it, but it runs smooth. I have no o rings or seals on any of these valve is that normal, apart from the one on the end of the unloader valve. Did find some rubber in the end of the control valve spring cover? What do you think.

[Grani]

The unloadingvalve is working better without the o-ring. It´s a very low oilpressure that operates it.

[robin]

Well it works, all ok you was right unloader valve give it a clean out,
thanks for your help Brian, your a must have tractor mate. going to the sale tomorrow at Holton le moor squire Gibons.

[Brian]

Glad you got it sorted Robin. As Grani says the unload valve will work without the "O" ring and this was one of Ford's fixes in the early days of the Super Major. Later tractors had a piston ring type seal.

Water or lack of use will cause sticking on the valve stem and these should be polished with Brasso or another brand of metal polish to clean them up. Wet and Dry or emery is a big No-No.

The exhaust filter and valve must also be in good condition, in the early Supers, this was supported by a bracket welded onto the main pressure pipe. This broke and dropped the exhaust filter into the gears. The first indication you got was a sticking unload valve. Later tractors have the filter supported by a bracket from the pump pedestal.

The exhaust oil system is held at 12 psi to allow the unload valve to work.

[robin]

Yes I think your right, my oil is new but due to the fork lift main ram seal a little damage it sent the oil milky, this sounds like the problem, oil is so costly over £50 for 5 gallon what type would you replace it with.