The means of adjusting and holding the tension on the track assemblies of all Allis-Chalmers, Caterpillar, and International Harvester Tractors, was until 1951 accomplished by turning an adjusting screw out of an internally threaded retainer. The retainer is in most cases fixed through a recoil spring to the track frame, and the screw is connected to the front idler wheel of the tractor. As the screw is turned the idler is pushed forward which results in a tightening of the track chain.

This mechanical procedure of adjusting tracks requires an average time of approximately one and one half hours. The job of adjusting tracks is always difficult and in most cases requires the use of a large wrench and lever bar, and the time of two or more men. Track adjustment is required as a result of track and roller wear and is also required when the condition of the soil in which the tractor is working changes with the result that the track tightens or loosens.

When the tracks are extremely loose they climb the sprocket teeth or idler rim which frequently results in a thrown track, requiring several hours to replace. As a result of the work and time required to adjust the tracks they are frequently allowed to run without proper adjustment which results in excessive wear on the tractor rollers, idlers, sprockets and track links. The tractor manufacturers estimate that improper track adjustment accounts for 25 to 30% of the wear on track parts.

Since the track system represents one fifth of the cost of the machine, it is therefore very essential that proper care be taken at all times, especially to the track adjustment.

In 1951 a hydraulic means of adjusting and holding the tension on the tracks of crawler tractors was invented and patented by Mr. Bill Henderson of Pittsburg, Texas, which eliminates all of the work with the large wrench and lever bar. With this device it is possible to adjust the tracks on any size tractor in two or three minutes. This device, called a HYDRA-JUSTER, enables the operator to both tighten and loosen the track chain as required without effort.

The tracks can be adjusted simply by using a hand grease gun. Track tension is released by opening a
bleeder valve located at the base of the cylinder. An adjusting force of approximately 10,000 PSI can be obtained with the hand grease gun. This multiplied by the area of the piston gives an adjusting force in excess of 30,000 lbs. even on the small HYDRA-JUSTER.

As stated above, adjustment is achieved by adding grease to the cylinder chamber which in turn forces the idler forward. This grease remains trapped in the cylinder until the track adjustment requires changing. During tractor operation the pressure on the piston may exceed one hundred tons as a result of idler recoil. However, no grease is lost due to the design of the special grease holding seal. As grease is a semi-solid and cannot be compressed, track adjust­ment always remains the same.

The allowable track adjustment when HYDRA-JUSTERS are installed is equal to or greater than that possible with the original mechanical adjusting screw.

HYDRA-JUSTERS have been so widely accepted that most tractor manufacturers have been forced to approve of the hydraulic method of track adjustment. Hydraulic track adjusters are now being provided on a few of the new tractors as standard equipment. However, to convert an existing tractor to hydraulic adjustment HYDRA-JUSTERS usually costs less than half the amount charged for the tractor manufacturer’s hydraulic conversion. In some cases HYDRA-JUSTERS cost less than one-third the price asked for the manufacturer’s hydraulic conversion.

Since 1951 we have manufactured and sold more than 1,230,000 sets of HYDRA-JUSTERS which, as you can see, proves that the HYDRA-JUSTER is a time-tested and field proven product.

As HYDRA-JUSTERS are tailor made to fit all popu­lar models of Allis-Chalmers, Caterpillars, and In­ternational Harvester Tractors, the installation must of necessity vary according to the particular tractor. Complete instructions regarding installation and proper operation accompany all shipments.