My local (and highly untrusted Sprinter) MB service shop charges $173 to "...retighten rear axle U-bolts...". Everytime I ask for a quote they give me different prices.I just bolted in a driveshaft using torque+angle and monitored the actual torque, which was a lot higher than the simple torque spec of 52 ft-lb for the driveshaft attaching bolts. I used the Mercedes spec of 15 Nm (11 ft-lb) + 70 degrees, and the torque wrench showed about 75 ft-lb (around 100 Nm). But it's naturally not that simple. The original M10 bolts on the Dodge chassis were Mercedes p/n N000000003435, which had an E14 head. The current N000000007445 grade 10.9 bolts have an E16 head, resulting in significantly more surface area between the bolt head and driveshaft flange. Does this affect the torque value? And in which direction? 75 ft-lb is way above the torque chart values for M10 10.9 bolts. So are my bolts torqued more correctly that they would have been using Dodge's 52 ft-lb spec, or are they way over-tightened? Darned if I know!
I have a nice 1/2 inch Craftsman digital torque wrench and the proper sockets and would DYI but all this "torque plus angle" talk has me thoroughly confused.
Can wanyone make it simple for me?
2013 3500 bought used, doubt previous owner ever had service performed...no service records. Ciurrently 43000 miles.