What causes a bolt to loose its preload?
There are two basic mechanisms for loss of preload – spontaneous loosening and slackening. Spontaneous loosening, or rotational self-loosening, is essentially when a bolt rotates loose due to shock, vibration or dynamic loads. Even a slight rotation can be enough for a bolted joint to lose all its preload.
Who is the inventor of self loosening bolts?
Research into the causes of bolt self-loosening has been ongoing for nearly 60 years, however, it is still the pioneering work of German engineer Gerhard Junker in the 1960s that forms the basis of modern methods and theories behind self-loosening prevention.
What causes a bolt to lose its clamp force?
These repeated movements work against the friction between the bolt and joint threads that is holding the joint together. Eventually, vibration will cause the bolt to “unwind” from the mating threads and the joint to lose its clamp force.
What causes a bolt to loosen on a car?
Even a slight rotation can be enough for a bolted joint to lose all its preload. This is the most common cause of bolt loosening. Slackening is caused by three mechanisms: settlement, creep and relaxation. “Settlement is critical when it happens due to dynamic loads.
How do you remove the camshaft timing pulley?
Last night I got stuck trying to remove the camshaft timing pulley, and wanted to share how we eventually did it in case it might help anybody else. The engine repair manual casually says “Hold the hexagonal wrench portion of the camshaft with a wrench, and remove the camshaft timing pulley bolt.”
How to remove timing pulley on Hilux 4×4?
The engine repair manual casually says “Hold the hexagonal wrench portion of the camshaft with a wrench, and remove the camshaft timing pulley bolt.” YEAH RIGHT. That bolt is as tight as anything. Firstly, it became apparent relatively quickly that trying to hold the camshaft steady with your hand (using a wrench of course) was not going to work.
What’s the best way to loosen a pulley bolt?
If hook does not reach your desired spot, turn the crankshaft clockwise to give yourself some more room. See first pic. – Using the ratcheting wrench and the socket, turn the crankshaft pulley bolt counterclockwise (loosening) as far as you can go.
How do you tighten the pulley on a Nissan?
Nissan has a tool that locks the flywheel in place. It’s shown in the directions to change the timing chains. Using that would get the desired results and get an accurate torque when done. Bumping the engine works providing someone lets go very fast, but tightening you need a positive stop to torque.