MF65 Brakes

I am in the process of changing the brakes on my MF-65 right now. The brakes were locking up as soon as you touched the peddal. I thought I would find the pads and actuators worn to the bone, but what I found when I opened it up was that the oil seals on the outboard planetary gears had let oil seep into the axle housing, contaminating the brake pads. The pads and the actuators were full of sticky gunk. I cleaned out the housing, replaced the inboard and outboard seals, all four brake disks, and the 5 actuator balls and 3 springs on each side. Total cost in parts: about $200.00 from jackssmallengines.com. Good luck.

- Doug

I changed the brakes on a 175, which has a similar setup with the dry inboard brakes. I also suspected that the actuator was worn. What I found was that the springs on the actuator had lost their tension from heat. The pads had worn down to little more than nubs. When we cleaned everything up, and reassembled with the new pads and springs, we had lots of brake. The biggest help I had was from Big Dean on this site. I got his CD ROM and used it to figure out what I needed to do. He also helped with personal advice. I went to a Massey dealer, who found aftermarket parts that were inexpensive, especially compared to Massey. My local dealer wanted over $400 per axle for seals, pads, springs, etc. I went to another dealer, about 15 miles further, got all the same parts for $58 per axle. Go figure. Toughest part of the job was the screw that holds the brake cover on. Needed serious oxyacetalene heat for that, as well as grinding a BIG screwdriver to match the slot exactly. Get it touch w/ Big Dean, if he is feeling better... I know he went thru some rough time recently.

My actuators look pretty new, or at least not worn. The donut-shaped outer wear surface of the actuators is about level with the unmachined part which holds the armature pins. There are pretty good pictures in the repair manual and a really good drawing in the parts manual. I strongly suggest picking up both manuals if you plan to do much work on the old girl yourself. Good luck.

- Doug

I measured my actuators and there is about 0.050" between the machined surface of the actuator plate and the top of the hook on the retainer springs. The lined brake discs look new. When I stack both lined discs and the actuator(consisting of 2 actuator plates and 5 balls)in the end of the axle tube and set the carrier plate on, I measure approx. 0.050" to 0.060" clearance between the inboard lined disk and the carrier plate through the pull rod port. That means if each actuator plate were more than 0.025" to 0.030" thicker I wouldn't have any assembly clearance. Are the tolerances tigher than I realize? Do you know how much gap I should have? Originally, I had a problem with a brake hanging up and it's been suggested the actuators are worn out and the balls are coming up out of the pockets in the actuators and locking the brakes on. With these clearances I'm having a hard time seeing that, thus my interest in the dimensions of new parts.
Ken