Changing Brakes on Farmall Super M

I have a Farmall Super M. Which I bought last summer. When I got it, one brake held, the other did not work at all. I took apart the bad one and replaced the disks, cleaned everything up, and put in new balls and springs. I also found a lot of slop in the linkage piece that attaches to the pedal, so I had a friend weld the elongated hole to make it round again. I was very careful to be sure everything was sone right.

Now, the brakes on that side lock up. I still do not feel they are the greatest brake, they seem to be either all ON or all OFF, not much in between. On a hill, I still have to put every ounce of effort I have to hold the tractor in place. But that replaced brake locks up tight, so I have to keep backing up to release it almsot everytime I use the pedal firmly. I've taken it apart several times again, reversed that center piece (from side to side), and tried other adjustments. No matter what I do, it locks up and is still a poor brake until it totally locks.

The side I did not work on is also a poor brake, but does not lock up.

Either way, I am not happy with these brakes. Before this tractor I had a Farmall H with band brakes. Even with worn shoes, that tractor stopped much better.

I know the standard M tractors have band brakes. If I replace the housing, can I change this Super M to the band type brakes? I've spent a fortune on these disk brakes and all they do is irritate me. If I cant change it, I will likely sell the tractor and get a standard M. These brakes are dangerous, and I've run out of ideas how to fix them.

Thanks

Gary

Gary, when the disk brakes are working properly, they really are much more effective than the band brakes.

Not cheap, but OEM tractor parts offers a service where they take your old brake mechanism, recondition it, and send it back to you good as new. I suspect that yours are worn.

Converting back to band brakes, if it's even possible, is going to be a LOT of work. The transmission cover needs to come off.

Gary,Disc brakes are good breaks,but you cant cut corners.Replace all of the parts,perrty expensive compared tp band brakes

jimmy

Did you thoroughly clean & take all the rust out of the brake casting[housing]? Are the splines on the brake shaft free of rust/dirt? Is there any binding when you pull the actuating bolt? These brakes are usually good if they are clean. I assume the surfaces where the fiber discs contact are smooth.

Based on that one brake not releasing I'd say you're problem may be rooted in something to do with the actuator discs. One thought is that one or both of them have worn in some way that's left a depression in one or more of the ramps deep enough to bind one of the balls and keeping it from returning. In that case, you might want to look into having yours machined/refurbished by OEM as mkirsch described. I don't know if their setup is a core swap or if you get your own back, but it might be worth considering.

It could also be some excessive wear on the spline of your bull pinion that's causing one or more of the actuators or friction disks to bind. Having to back up to get it to release makes that real possibility, too.

In that same vein, do you have it adjusted just plain too tight? Whether bands or discs, the recommended method for setting up and matching brakes on the letter series was first to set up the pedals for both brakes for an equal throw. Then jack up both sides of the rear to get the tires off the ground, start the tractor, get the wheels spinning in third or fourth, then apply the brakes (pedals latched together). Adjustment was to SLACK OFF the one that stopped FIRST.

One other thought, and I'm goin' out on a limb a little here, is a question. I'll assume you cleaned everything up the various times you've had it open. Did you lube it when you put it back together? you really don't want much of anything more than a light coat of graphite in there. Anything more than the lightest coating of oil or grease (yo don't really want much of anything called a lubrcant near your brakes anyway) will draw dust and clump up and interfere with correct operation.

Presuming the metal friction surfaces are smooth (ie. not rusty or pitted), disc brake locking up is the result of excessive distance (wear) between the inner and outer non-moving friction surfaces. However it can also be caused excessive actuator plate ball ramp wear, slightly undersized actuating balls or wear (notching) of the brake shaft splines.

What’s happens is as the balls roll to the ends of the ramps they become wedged when the brake begins to take hold. Further movement causes the brake to "cam" and lock up. Backing the tractor unwedges the balls and releases the brake.

The ideal repair is new parts (inner housing, cover, actuating disc assembly). However you can probably accomplish the same thing by milling perhaps 0.10” off the cover mounting face - effectively decreasing the distance between the inner/outer friction surfaces.

Alternatively OEM Tractor Parts can rebuild Super series disc brakes - I don’t recall the cost however.

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Incidentally from my personal experience the Farmall Super series disc brakes - with all internal parts within tolerance, clean (no oil!), and properly adjusted - work great…..better than the earlier band brakes IMHO.

oem does them for 142.00 each side, they machine the drums and expanders, new disc pads, actuator balls and boots. they require a core exchange