Pins & Bushes grease filled type
■ The internal pin and bush wear on greased and sealed chains is measured by the chain stretch. This is done by measuring the pin centres over 4-5 links and comparing to new chain specs.
WORN PIN END
■Besides the obvious factor of hillside operation and uneven ground, this type of wear is caused by incorrect chain tension and roller wear
■If chain elongation has not reached the limit, then adjust chain tension and rotate some rollers
■ If this pattern of wear starts immediately after installing a new undercarriage, then check position of the track guards is not too close to the chain
LOOSE PINS
If there is no obvious fault such as incorrect assembly or disassembly, then this can be caused by bending stresses during heavy operation of the machine
To eliminate this, replace any worn shoes, check bolt tension and/or fit narrower shoes
EXTERNAL BUSHINGS
■ Wear is caused at the point of contact between the bushing and the sprocket tooth. To measure this wear, use a small outside calliper
CRACKING OR BREAKING OF SURFACES IN CONTACT WITH SPROCKET
■Due to excessive wear either externally or internally, will allow the bush to break
■It could also be caused by to heavy working conditions or packing sprockets. To reduce this effect, check and adjust chain tension and use track shoes with mud holes in.
PIN BREAKAGES
■Main cause of this failure is extreme shock or high static loads which occur when the machine works on rocky ground and/or when material packs in the sprocket causing extreme tension on the track chain
■Protect the track chain and sprocket from material packing under the shoes by using shoes with mud holes in
EN
