Freightliner FLD N2 injector reinstallation

This week we returned to our Freightliner FLD and began reassembly. We replaced the O-rings on all the injectors we removed (3 per injector) before returning them to their bores. We cleaned out all bolt holes of oil to ensure we would not damage the engine when we torqued the bolts down. Then we reinstalled the rocker arm assemblies and the Jake brakes and torqued them down. We did not finish the full torquing procedure before the end of class, so we marked on our service information what we still had left to do.

Preparing to change O-rings on injectors. There are 3 for each injector.

Jake brakes have been reinstalled and are ready to be to be torqued.

Looking up our specs for torquing the Jake brakes.

Some thoughts on what I learned this week:

Torque, torque, torque. Especially with internal engine components, it is important to torque bolts to the values specified by the manufacturer. Whether on gasoline or diesel engines, failing to do so can lead to problems, premature failures, or damage to engine components. The torquing procedure for the Jake brakes calls for 40 ft-lbs on all bolts starting at the intake side. It then requires you to re-torque them to 100 ft-lbs on all bolts repeating the sequence.

Sometimes the torquing procedure may ask you to torque to a certain value, then back the bolt off a certain amount. You will also encounter procedures that call for torque angle (such as when torquing the head).

Properly torquing the bolts to manufacturer specification is just good practice that can save time and money avoiding possible problems and customer comebacks.