Fuel jumper & bolt breakages.
There have been a few cases of loco failures due to breakages of fuel jumper, T Jumper bolts & benzo bolts.
Total No. of incidences = 13.
It is advised to incorporate following practices in scheduled maintenance.
Fuel Jumper-
Fuel jumper must be checked for dimensional accuracy & alignment in a fixture. Flatness and perpendicularity of the surface is very critical to avoid unequal torquing/ over tightening of T Jumper/ Benzo bolts. Faces of hole of the fuel pump inlet (fuel T-jumper) provided for fitting the banjo bolt with cu washer should also be absolutely parallel. Parallelism and perpendicularity of machined surface should be within 0.010”.
Fuel jumper must be DP tested & carefully examined for groove depth and eye hole condition. Fuel jumpers having excessive groove depth should be rejected.
Use only bolts of approved make, weed out all unmarked bolts. All new & old bolts should be carefully examined especially in vulnerable area. Vulnerable area is first three threads from shank. Cut mark or tool mark should not be permitted in that area.
Bolts must be having rolled thread and not machine cut thread. Careful examination of thread in old bolts will yield valuable clue about thread condition of block thread & bend/misalignment of T jumper.
During major schedule when T jumpers are fitted, it should be ensured that no T jumper bolt is forcibly fitted. All bolts must go inside freely & should be hand tightened initially.
It is a good idea to check torque value at the time of fitment for loosening each bolt & it must be same as tightening torque value. If higher torque is required to open a particular bolt then T jumper of that location should be examined for dimensional accuracy & alignment. Such T jumpers should be summarily replaced.
T jumper bolt & engine block should be carefully cleaned, degreased & fitted with thread locking compound. After tightening with torque wrench, one permanent mark should be made on head of bolt & T jumper. Any shifting of mark will be a sign of loosening. Use of thread locking compound will eliminate need of periodical tightening of fuel jumper bolts.
Vibration must be measured in every trip schedule & any excessive vibration (more than 10% from last reading or adjacent reading) is a sign of concern & cause of vibration should be identified & arrested.
It should be ensured that uniform gap is always available between fuel jumper bottom face and fuel header face.
Groove depth of flexitaullic gasket should be maintained within 0.108”-0.115” to ensure required compression of flexitaullic gasket. Copper washer should not be reused, whenever Fuel jumper is replaced/removed/fitted
Use of variable mixture of copper washers to maintain gap should not be resorted in major schedule, it is better to replace worn-out T jumpers in such cases.
There have been a few cases of loco failures due to breakages of fuel jumper, T Jumper bolts & benzo bolts.
Total No. of incidences = 13.
It is advised to incorporate following practices in scheduled maintenance.
Fuel Jumper-
Fuel jumper must be checked for dimensional accuracy & alignment in a fixture. Flatness and perpendicularity of the surface is very critical to avoid unequal torquing/ over tightening of T Jumper/ Benzo bolts. Faces of hole of the fuel pump inlet (fuel T-jumper) provided for fitting the banjo bolt with cu washer should also be absolutely parallel. Parallelism and perpendicularity of machined surface should be within 0.010”.
Fuel jumper must be DP tested & carefully examined for groove depth and eye hole condition. Fuel jumpers having excessive groove depth should be rejected.
Use only bolts of approved make, weed out all unmarked bolts. All new & old bolts should be carefully examined especially in vulnerable area. Vulnerable area is first three threads from shank. Cut mark or tool mark should not be permitted in that area.
Bolts must be having rolled thread and not machine cut thread. Careful examination of thread in old bolts will yield valuable clue about thread condition of block thread & bend/misalignment of T jumper.
During major schedule when T jumpers are fitted, it should be ensured that no T jumper bolt is forcibly fitted. All bolts must go inside freely & should be hand tightened initially.
It is a good idea to check torque value at the time of fitment for loosening each bolt & it must be same as tightening torque value. If higher torque is required to open a particular bolt then T jumper of that location should be examined for dimensional accuracy & alignment. Such T jumpers should be summarily replaced.
T jumper bolt & engine block should be carefully cleaned, degreased & fitted with thread locking compound. After tightening with torque wrench, one permanent mark should be made on head of bolt & T jumper. Any shifting of mark will be a sign of loosening. Use of thread locking compound will eliminate need of periodical tightening of fuel jumper bolts.
Vibration must be measured in every trip schedule & any excessive vibration (more than 10% from last reading or adjacent reading) is a sign of concern & cause of vibration should be identified & arrested.
It should be ensured that uniform gap is always available between fuel jumper bottom face and fuel header face.
Groove depth of flexitaullic gasket should be maintained within 0.108”-0.115” to ensure required compression of flexitaullic gasket. Copper washer should not be reused, whenever Fuel jumper is replaced/removed/fitted
Use of variable mixture of copper washers to maintain gap should not be resorted in major schedule, it is better to replace worn-out T jumpers in such cases.
No comments:
Post a Comment