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Belleville washers: wet or dry?
I watched Vic Syracuse?s excellent webinar on RV maintenance this evening and learned a lot! Thanks, Vic!
I would like to see what others think about Belleville washer installation. On page 40A-07 the note on Step 2 says: ?NOTE: Belleville washers are slightly cupped and in order to function properly the outside perimeter of both washers must be in contact with each other when installed. See Figure 2. Install the washers dry.? In his presentation, Vic recommends greasing the washers to prevent corrosion and other threads in this forum favor grease as well. I have tremendous respect for Van?s and Vic and, as a first time builder, would normally not question advice from either but it seems as though they can?t both be right. So here?s the question to my fellow builders... Which is correct in this case, and why? |
According to the following two websites, Belleville washers should be lubricated.
https://www.machinedesign.com/techno...es-put-squeeze http://www.bellevillesprings.com/dis...nstalling.html However, Van's might know something about their application that the washer manufactures do not. |
Here is a tiebreaker for you !
Call Craig Catto. He sells the washers and has skin in the game. I anxiously await your finding because I have two setts of washers on order.
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The plans don't say to lubricate them. I inadvertently greased them very well when I greased the nose tube. When they were greased I couldn't get the nose wheel breakaway force to stay set. I cleaned off all the grease, reassembled, tightened, and have had great wheel performance for 80 hours.
Mine are thus lightly lubricated as I didn't super clean them, just gave them a good drying with a blue towel. But I won't be greasing them again. |
Orientation
Belleville washers are really springs. Be sure to install them as specified by the designer. I’m not familiar with how many are used on the RV-10 landing gear, but I know first hand what can happen when Belleville washers are stacked as “washers.”
The orientation of multiple Belleville “washers” can have a drastic effect on the spring constant of the stack. Clarification: For multiple Belleville “washers,” orientation refers to the arrangement of the cup sided face to the adjacent “washer.” They can be face-to-face, back-to-back,or face-to-back with the addition of each “washer.” Yes, it does make a difference. Don’t treat them as just “washers.” If there ever were a misnomer, this is one. We traced a problem of 55-inch carbon electrodes in a phosphorus furnace slipping in their holders due to Tennessee good ole boys stacking assemblies of 12 Belleville washers any old way. |
Hmmm. Perhaps Scott wants to weigh in here, but I've always greased them and have had no problem setting the breakout force. They don't stick, and they don't rust this way.
I've had people call me with steering problems and I have told them how to clean them and put it all back together with grease, and they have called back and told me how much the steering improved. Vic |
In lieu of safety wire
I have used on brake caliper bolts vs safety wire without issue, greaseless. Grease is about environment, not about purpose...right?
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They will get lubricated even if you install them dry, since grease/oil will creep from the bronze bushing onto them.
I would not install them dry. While we're on the topic of these washers, it's also a good idea to increase the bearing surfaces somewhat (they are basically a sharp edge) as shown here, by using some emery on a flat surface or equivalent. I've not had to adjust mine in 18 years/1700 hours. The sharp edges, if not removed, can carve into the bronze bushing, which will reduce the breakaway torque. |
The Grumman Tiger/Cheetah OH manual calls out the their Bellville washers to be lubricated every annual.
Essentially it's the same design as Vans... :) |
Quote:
I lube my washers because they will get greasy on their own. Lubing at install keeps breakout constant. Did it dry at construction but that was 850 hrs ago. Lots learned since then. |
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