Steering on MF165

I have my father's MF 165 Diesel. Great tractor that has been used hard and actually well maintained. My issue is that there is a full 90 degress of slop/play in the steering wheel. Front axle and tierods replaced 5-6 years ago. I would appreciate any advice as to how to diagnose the problem.

Check the complete steering system starting with the gearbox, and repair any loose parts. The only play allowed is at the cylinder actuating valve on the power assist system. High hour tractors may need the steering shaft verticle bushings replaced and reamed to size also, not a fun job..

Hi, you have not mentioned whether the tractor has power assisted steering. Dieseltech has given you the basics. In a little more detail; place the steering in the straight ahead position. Take hold of the rear of the drag link that runs along the engine. Can you move it inwards and outwards? If so there is an adjustment on the opposite side of the steering box behind the fuel filter mounting brackets.It consists of a slotted screw and 1/2-nut. Take most of the weight off the front wheels with a jack. Slacken the nut and tighten the screw 1/4 turn at a time. Work the steering back and forth until you feel the 'high spot'. Adjust until it just passes the high spot without any tightness. If you cannot make this adjustment then there is likely to be significant wear in the steering box.
Check the ball joints on the drag link for wear. Look for sideways movement in the vertical shaft in the axle casting. The bushes are prone to wear quite often through the operator not being aware that there is a grease nipple in the casting. Replacement of the bushes is straight forward but they will need to be reamed to the correct size. The shaft may need to be replaced as well. There is a steering arm on the bottom of this shaft. Over a period of time the splined clamp will wear and become loose. This can add to your free travel. Finally check the outer track-rod joints. These will wear quicker than the inner due to greater movement. It is worth packing new joints with grease when fitting. Although not directly connected with the steering play it is worth checking the king-pin bushes and bottom thrust bearings especially if the tractor may have had a loader fitted at any time.
Nearly all parts will be readily available from non-genuine parts suppliers. Let us know what you find.
DavidP, South Wales