Applying Chassis Lubricant
Description and Application:
The proper application of chassis lubricating grease follows the same pattern no matter what equipment is being serviced.A grease gun,either hand or mechanically actuated,is employed with a coupler on the end of the extension pipe of the gun.the following steps are reqquired for this operation:
(1)Wipe fitting clean before applying gun.
(2)Apply coupler to the fitting in a straight line.
(3)Squeeze trigger or pump gun slowly.
When old lubricant shows up at the end of the bearing or shackle,move gun slidewise or up-and-down to break the connection.Hight pressure application is essential for spring shackles and bolts.It is important that the lubricating grease reach all part of threaded bolt shackles and threaded “U” shackles.When these parts are lubricated infrequently,there is often difficulty in forcing fresh lubricant through the shackles.Somtimes prying against the hanger with a pinch-bar or bouncing the car while applying gun pressure,will help to force the fresh chassis lubricant through the bearing.Rubber-bushed shachles do not require periodic lubrication and are never serviced with lubricating grease.
In the application of chassis lubrication it should be kept in mind that many lubricating point require low pressure for greasing.for this reson it is important that lubricating charts be consulted and their recommendation followed.Anti-friction bearing and any points which have seals should not be subjected to high pressures.
Frequently a special gun is provided for lubricating with low pressure.Also adaptors are available which fit on the end of the pipe of a grease gun and assure that the lubricant is delivered at a low pressure.In addition, unloader valves which vent at 650 to750 psi can be where there is a possibility of damaging seals.
The terms hight pressure and low pressure are relative and may not mean the same to all people.Suppliers of lubricating equipment consider 700 psi as low pressure.Since most hight pressure pumps have ratios of at least 40 to 1 and since service station generally to the gun at least 125 psi of air,a lubricating grease may be delivered to the gun at 5000 psi. Of course still highter pressure,somtimes up to 20,000 psi are developed and used in some cases.