Belarus 520 PTO Adjustment

Usual Disclaimer:  Information here is not necessarily the "Truth", but it's the best information I have.  If in doubt about any step, verify with some other source. If anyone sees something wrong, please let me know.  rawham (at)

Important:  In the instructions, please note - "rear" refers to the rear of the tractor.  "Front" is towards the front of tractor.  "Right" and "left" are in reference to  the right and left of the tractor.  You will be making the adjustments from the rear, well above the  PTO shaft end. The start/run band adjustment will  be the front one, (farthest away from you.)   I have added some labels  to
figure 38 from Tractor Manual for reference.

If you have a friend with long, thin, strong, flexible fingers ask him/her for help.  To access the adjustment screws/shafts, you must remove a small rectangular plate about three by four inches.  The plate is raised in the center.  There is a small  bolt at each corner and and an additional larger bolt at the rear of the plate.   The access plate is horizontal, above the PTO shaft, between the raised portion of the gas tank and under the rear portion of the main lift cylinder.  Photo of plate taken from left - rear .  Bolts have been touched up for better detail.  It's not easy to get into the  area to do the work!   Lower the rear hitch, and remove the pin that attaches the rear portion of  the  main lift cylinder. Prop up/tie up  the cylinder rear end to get it out of the way as much as possible.  Next is the hard part: (See above advice about long flexible fingers.)  Remove the bolts and remove the plate.  You will see the top of two adjustment screws/shafts sticking up.  See Figure 38.   The front one (the one farthest away from you)  is the one  that controls the start/run bands.

Below is the method of adjustment as printed in the Tractor Manual (except for my additions in italics).  In my opinion, this appears to be suitable if the system has been completely rebuilt or taken apart, and this describes the first time adjustment.  If your PTO is slipping under load, I would only adjust the start/run band as necessary.

To begin, (See Step 1. below.) the PTO shaft control lever must be placed in the middle slot of the quadrant (item 7, figure 38).  The hole ( 31, figure 38) must be lined up with a hole in  the housing and a bolt placed to hold it in this "neutral" position during the adjustment.  Find a bolt that is snug, but it does not need to be threaded in, only placed in far enough to prevent forward/backward motion of the lever.  See Step 1. below.

Before Step 2. you must lower the  hitch and get the cylinder out of the way as described above.  After you have removed the access plate, then what I have done,  is to turn the front screw (the one away from you) in (clockwise) one turn.  Then remove  the bolt holding the control lever in center position.  Move the lever forward to engage the PTO run position.  It should be firm and snap in the  foreword position.  If it goes into the forward lock position without  much pressure, then reinsert the bolt, and turn the forward adjust screw in another one half turn. Test again.  Keep advancing until it takes considerable pressure to lock forward in running position.  If unable to advance all the way forward, then back the adjustment screw off slightly, until able to properly lock forward in  running position.  After final adjustment, replace everything into original condition.  Don't forget to remove lever stabilization bolt.

Adjustment of Rear Power Take-Off Control System
Copied from Belarus Manual

"Brakes" as used below refers to the PTO bands.

Start of Copy:

The rear power take-off control system (see Fig. 38) needs adjustment of the reduction gear brakes and control linkage rod which is effected in the following manner:  
Link to pdf file of Figure 38 from Tractor Manual - Print for reference

1. Bring the hole in the shaft lever to register with the threaded hole in the rear axle housing and fix the lever in this position by screwing the bolt M10X60 mm in.

2. Remove the cover from the adjusting port and turn in the adjusting screws as far as they go: turn the screws one by one, applying a torque of 0.8—1 kgf-m. Then back every screw out by three turns.

3. Remove the PTO cap if it was not removed beforehand, and check the PTO shaft for easy rotation by turning its tail end by hand. If rotation proves to be tight, back the screws out by another half a turn.

4. Make sure that the control lever is in neutral position (in the middle slot of the quadrant) with the shaft lever in the fixed position. If necessary, change the length of the linkage rod to obtain this condition. Having done this, turn the bolt out and reinstall all the parts removed.

In service the factory adjustment gets disturbed because of the wear of the brake band linings. As a result, the brakes fail "to hold", i. e. they start to slip. Never go on working with the brakes slipping.

If any signs of slipping are noted, remove the cover and turn each adjusting screw in by half a turn.

End of section.