Dear Ole Mechanic;
Some time back you helped me identify my Ford tractor; it turned out to be 9N engine and serial number and a much later 8N transmission and rear axle.
My problem now is that I have NO BRAKES! The brake pedals only go down about half way and there is no noticeable slowing of the tractor, no matter how hard I push on them. I blocked up the tractor and after removing the rear wheels and brake drums, I found the problem--the brake shoes are completely soaked with thick oil. I purchased new brake shoes, but they are not any thicker than the old ones, so the old ones have little or no wear. There are fresh scratches and it looks like someone has worked in this area recently. They may have been installing new brake shoes. I don’t want these expensive new shoes that I bought getting soaked like the old ones.
What should I look for? Is there something else I should do?
It Won’t Stop
Dear Won’t Stop;
The first thing you should do is check the transmission/rear axle/hydraulic gear-oil dipstick. That is the dipstick just behind the driver's right foot on the side of the tractor. All to0 often the three-point lift gets a little sluggish and some people think that a little extra hydraulic oil couldn’t hurt. Then they overfill it with hydraulic oil. This does not help; in fact, it makes the situation worse in several ways. First, it raises the oil level in the rear axle, so that oil runs out to the either end of the axle housing where the rear axle grease seals are located. Since the seals are not intender to be submerged in oil, they leak oil right onto the brakes. Now you have no brakes and ruined brake shoes. The second problem caused by excessive oil is that the Ford hydraulics are designed to work with “all-mineral oil SAE 90 weight transmission lube oil”. The thinner hydraulic oil makes the hydraulic three-point lift even more sluggish. Also, the thinner hydraulic oil does not do as good a job of lubricating the hydraulic pump. Last, but not least, the thinner oil does not do as good a job of lubricating the transmission and rear axle gears. My suggestion would be to drain the transmission/rear axle/hydraulic oil. There is one drain located underneath the tractor just behind the dipstick. It will take about five gallons of all mineral SAE 90 transmission gear lube, available from any tractor of auto parts supplier in 2 ½ gallon containers. Do not overfill the system! The fill point is right next to the gear shift lever.
Now for the brake problem. Yes, there is more to do before you install the new brake shoes. Since you have the brake drums off, you are almost to the rear axle seals which should be replaced. You will need to remove the wheel hub. That is held on by the single large (two-inch) nut on the very outside of the axle. There is a retaining clip that must be removed before you can remove the nut. If you don’t remove the clip, you will mess up the threads that are part of the axle! With the hub off, there are eight bolts that come out of six holes. This sounds confusing, but as long as you unscrew all of the bolts and nuts, you will soon understand. At the top and bottom there are two bolts that go into both ends of one threaded hole. With all of the bolts out, a good yank should leave you holding a bunch of parts. They are, in order, the grease seal retainer, the brake shoe holding plate, the bearing retainer, the shims and the brake backing-plate. As long as you keep things in order and not lose any shims, you will not have any trouble. What you will need to replace is the grease seal and they usually can be ordered from most auto-parts stores. You will need a good gasket sealer because all of the parts that came out will need to be sealed as they go back in after you have installed the new grease seal, so grease can’t get on the brake shoes.
That big two-inch nut? That gets tightened to 400 foot-pounds of torque. It sounds like a lot, but it is only a 200 pound person putting their weight on a two-foot long cheater pipe on a wrench or a socket and breaker-bar.
While all of this may sound involved, it won’t take that long. The last time I did it, it only took me two days at a retired pace. That's about two hours in the AM and three hours in the PM on both days.
Herr Professor Nuzanbolts