Henrietta's lift has been dropping under load for some years. Recently however it has got very bad and will not hold the plough up long enough for me to change gear, so the time has come for me to check out the problem.

Unlike the Super Major and the Dexta, the Major hydraulics are fairly simple and easy to work on. The only time you have to have the top off and involve yourself in heavy lifting is if a fault occurs in the hydraulic pump. As Henrietta has a dropping problem, the fault will most likely be in the valve chest or piston seal.

Before attempting to remove the chest, make sure the lift arms are fully down or things will get rather messy.

The trailer pipe is off and a little oil leaks out of the port. Most of the bolts are out including the hidden ones under the valve chest itself.

With all the bolts removed the valve chest can be eased away from the lift housing and with it (usually) comes the ram cylinder and the pressure pipe. The connecting rod stays in place and when the cylinder is refitted, falls into place without any special requirements.

The cylinder itself just pushes onto the valve chest and is located into the housing by the ring around the top. It is then held in position by the bolts which hold the chest on. There is an "O" ring around the inside that will need replacing as this can cause a leak down. The outer part of the cylinder is very rusty, this is normal and caused by over 50 years of condensation. It will get lightly cleaned before it gets put back together.

The main pressure pipe has an "O" ring at either end. These will need replacing. I buy "O" rings in kits from my local hydraulics shop. For around £12.00 you get a large box of assorted rings. They won't always do everything you want but they can be very useful.

The piston seal is held on the piston by a metal plate. This plate also has a lock tab for the retaining bolt. The plate itself is no longer supplied so the tab has to be carefully moved to allow the plate to be used again.

Once the plate has been removed the seal comes off easily. Now we can see why Henrietta's lift was dropping. Wonder if it is still under warranty!

I knew there was no chance of getting a new seal from CNH so I went to a local company who specialises in seals for all applications. They are called "Allseals" in Norwich but I am sure you will have companies local to you who do similar services. however,not all things are as easy as getting a seal off the shelf, the dimensions of the seal are specific to Fordson Majors but the company is quite happy to make me a special out of material that will last for another 50 years. Don't think I shall worry to much about replacing it next time it fails! Total cost of the new seal? £11.00, and it is ready in two days.

New seal and "O" rings fitted and a small drop of gasket sealer around the ring to hold it in place. The gasket on the valve chest is broken so I have cleaned it off and will used instant gasket to replace it. Now she is all bolted back together its time to get some more ploughing done.