Our mailman, Mike Jones, recently purchased a 1989 Belarus 500 2wd diesel tractor. Showing 1200 hrs, it came equipped with a cab and the price was right. It had a wiring issue which he fixed in a breeze but when he ran the tractor for a bit another issue cropped up; antifreeze was leaching out of the head gasket. This led to an upper engine tear down and the replacement of the head gasket. All the work was done at Mike’s shop.
First up was the acquisition of a manual and the replacement parts. Once the tin was removed the engine was stripped of components that impede the job, the antifreeze was drained off into a container and the head nuts were backed off in torque sequence. Torque sequence is the sequence that the nuts/bolts are loosened or tightened, and to what PSI. The manual will show this information which is important to follow to prevent over stressing the head which could result in cracking it, turning a basic job into an expensive one real fast.
With the head removed and set aside, the block was cleaned with a scraper and solvent and examined for any cracks. The engine was rotated to examine the cylinders for any potential concerns such as scores that would have to be addressed. As none were present we continued on. By dragging a standard roofing square crisscross over the block Mike checked for warpage and thankfully none was present, however, when the head was checked he decided that it would have to go to a machine shop for dressing.
Dressing is conducted by placing the head on a large band sander which lightly sands it to a smooth true surface necessary for the proper sealing of the head gasket preventing leakage of antifreeze and compression.
Once the head was returned from the shop a new head gasket was installed and we lifted the head back into position. A note here —
these diesel engines are quite robust and the components are heavy so lifting equipment such as an engine hoist is recommended. The head nuts/bolts should be cleaned and assembled with no lubrication, as it can cause an over torque which can also lead to overstressing the head and possibly cracking. With all the nuts hand tight a torque wrench was used. Following the torque sequence outlined in the manual the process of torque the nuts began. This procedure differs from manufacturer to manufacturer, some requiring a partial torque to all with a wait time and then a final. Others require an over torque then backing off and re-torque. Some require just a straight one time torque for all of them. You have to consult the manufacturer for the proper procedure. In Mike’s case the manufacturer also recommends that after 100 hrs you re-torque the nuts again.
Old tractors offer simplicity of maintenance, they are straight forward and require no special tools or analyzers. They are almost a joy to work on and should not discounted if and when you are in the market for a tractor. My first was a 1953 8N Ford, over 60 years old, yet parts are still readily available. With three deflated tires, no paint, no wiring and totally seized, it was purchased for $120. As most are, the engine is intergraded as part of the chassis and after I removed the head and oil pan, I was now armed with an aftermarket manual to stay on track and ready to start the rebuild process. Most of the rebuild I did myself with some specialty work sent to a machine shop. After reassembly, I converted it to 12 volts, stripped and cleaned the carburetor and fired it up with no issues.
Here are some points to consider if you are looking to purchase old iron:
--most important: look at the castings (engine block, transmission, rear axles and front axle). If they’re in good shape the rest, as a rule, can be rebuilt or replaced
--the tin (body parts) are hard to find but can be replicated if you really have to have a grill or tool box that’s original looking.
--if you are thinking of buying a particular tractor you want to be there when the owner starts it up for the first time of the day. If spray ether is used you may be in for some internal work right up front as for the most part these old engines weren’t designed to be started with ether.
--when it fires up is there a puff of black smoke? If there is, how long does it take for it to dissipate? If it is a short duration (a couple of minutes) the piston rings are leaking but are tightening up after they warm so it isn’t a huge issue.
---as it’s warming up, carefully remove the radiator cap and look inside for bubbling, a sure sign that the head gasket is leaking, which is also confirmed with “milky oil” on the dipstick.
--turn the steering wheel from side to side, if it’s turning significantly and the wheels aren’t that’s what your driving will look like. Look at the tie rod ends for a sloppy movement, if none, look at the king pins for the same movement. If all are tight your problem will be in the steering box. Most have an adjustment screw, the rest use shims, which mean tearing the box apart for a rebuild.
--overall, look at the grease fittings and the presence or lack of grease. No grease means overall neglect. Also look for oil leakage at all seams; a certain amount is quite allowable and presents no issues. If it’s pooling on the frame or around components you have some work to do and possible gaskets to replace.
--all of these issues should be factored into the final purchase price.
Mike’s Belarus 500 was successfully fired up with no leaking antifreeze. Good work Mike!
- Dan Kerr
Mike begins removing the tin.
With the tin off it is easier to work on the engine
When components such as the injector lines are removed, the open orifices are covered to prevent foreign material contamination
A cardboard holder is made to keep the removed pushrods in proper sequence for re-installation
The head is perched on top of the bolts before removal.
Mike checks the head with a rafter square for warpage.
Once the head was returned from the machine shop it was time to re-assemble with the new gaskets. Note the cleanliness of the mating surfaces
