It seems that eventually everybody is concerned about their levelling jacks crack and pop, especially in the middle of the night. Some people even feel a slight jar.
So, what causes this?
Usually, this is caused by contraction of the hydraulic fluid when the temperature drops during the night. Although nothing is damaged, the sound a jolt can be disconcerting. If you want to minimize this, use levelling blocks or something under your jacks so that they do not have to extend as far.
At the winter 2000 Freightliner rally in Las Vegas, it was recommended that the hydraulic fluid be changed every two years, even though the owners manual states that this is only needed every three years. Changing the fluid is a pretty easy job, but you will need a funnel and about three feet of hose to replace the hydraulic fluid in the cylinder. Be sure that you have your jack retracted when you do this.
Also, it is a good idea to periodically fully extend the jacks and spray the cylinder with WD-40 or a silicone grease. Again, in Las Vegas they recommended spraying the cylinders every week with WD-40.
The DISCOVERY OWNERS ASSOCIATION, INC, was formed to promote the sharing of information and the camaraderie of fellow Discovery motorhome owners. Membership in the club is limited to owners of Fleetwood Discovery motorhomes.