mf35 rear wheel seal

How difficult is it to replace the rear wheel seals? We have an MF50 & MF35 and both right real seals have leaked to the point on no brakes.
I am 64 and was a mechanic on printing presses for years but have never done anything this heavy. Fall in Texas is a good time to get this done as right now the temp is over 100.

These were from one I did lately, hardest part is if the brake drum doesn't want to come off.

The inner seal is pretty easy to get to. The brake drum retaining screws can be hard to get off because just a slotted head. The inner seal is what keeps the oil from getting through. If it fails it will allow the transmission oil to wash through the bearing grease and on to the brakes. You may get away with just replacing the inner seal. However, the sure thing is to replace both seals and you might as well do the bearings while you are there. The outer seal really just keeps the bearing grease from leaking on to the brakes. The outer seals however can be a real pain because it requires removing the axle collar and bearings. The axle collar needs to be drilled and chiseled off. Then the bearings need to be pulled off the shaft. I went to heavy truck garage and it took them 3 hours with a large shop press and a torch to get the bearings off. (bearings destroyed in process) The outer seal was then easy to remove and replace. Replacing the bearing requires heating it in oil to get it to slip on. The axle collar needs to be red hot to slip (or pound) it on. It is important that the bearing and collar are properly seated because the axle end plate should be kept between .002" and .008". You will need to have an assortment of shims on hand and a good dial indicator to measure the end play. I would not call it an easy project, but if you have oil leaking on the brakes then you really should do both seals and the bearings.

Having removed many 35 and 135 axles in my 40 years of MF experience I can add that it is possible (usually) to remove the hub bearing from the axle shaft by bringing it down under its own weight squarely onto an anvil or something similar. This will take a lot of effort to do so it should not be attempted unless you are fit enough. Generally the bearing can be refitted by using a suitable piece of tube to drive the centre ring of the bearing on. However there is no escaping the need to heat the locking collar to cherry redness. You will normally only get one chance so it has to be hot enough the first time. If it goes on OK then leave it until it grips the shaft. If you have to heat it again you will heat the shaft as well.

When setting the axle shaft end-float arrange your jacking so that one side is a little lower than the other. The shaft in the lower side will try to 'fall out' allowing you to check the end float on the higher side knowing that you will get a true reading. If you do not have a DTI the adjustment can be made by removing the thinnest shims until you feel a little tightness with at least 4 bolts fitted when turning the shaft aagainst the other one. Add shims slowly until you can just hear a 'knock' when pulling and pushing on the shaft. If it's a 'bang' there are too many shims in. Refit the remaining bolts and check the end float again. There MUST be no tightness.
DavidP, South Wales