Just experienced this recently as reported here:
http://www.irv2.com/forums/f278/wind...rm-339447.html
The newer design wiper arms (from '14 and later) have a wedge tightening device with an allen head cap screw in it. The allen head bolt is under the little plastic pop-off cover on the wiper arm shroud. It is hidden by the washer hose. That bolt needs to be tightened sufficiently to jam the wedge in hard enough to form the male splines on the drive shaft into the aluminum of the wiper arm. That is what retains and drives the wiper arm, not the nut.
This design came loose on many people as described due to lack of proper installation of the jamming wedge bolt at the Entegra factory.
The design was changed again and a retaining nut was added to the end of the splined shaft to keep the arm from falling off if/when the wedge system failed.
That nut is just a band aid to keep the shaft from falling off. It does not deliberately drive the wiper arm. If the splines in the aluminum arm are not formed correctly at the original install then they will strip and the arm will not move with the shaft. It won't fall off due to the retaining nut. But it can stall the blade on the windshield as described just when you need it most.
There was a major retrofit done on many coaches that had the wedge design arm but did not have the retaining nut. Some were retrofitted at the factory and others by "request" when wipers failed.
There is indeed a complete "kit" to update a '13 or previous coach to the splined drive shafts that are manufactured with the retaining nut. You need the kit if you need to replace an arm on a '13 or older coach as the older clamp style arms are not serviced and all that is available is the new arms with the wedge coupler.......which was proven to be inadequate in MANY cases thus the addition of the retaining nut to keep the arm from falling off.
This whole situation is indeed dangerous and has been very poorly documented and communicated to techs and customers. I had to talk to several Entegra techs and several AM Equipment reps before I finally found the guy that lived thru the changeover in wiper arm designs with Entegra. I pieced together the story from their input. It is not even clear to me when the design to the wedge came in. Our '13 has the older clamp style connections but it is an early build '13. I suspect the change happened at the change over from '13 to '14 model years but this is a guess as no one I talked to seemed to know for sure. I'm sure it happened when the assembly line ran out of the old parts......LOL. There are probably late '13's with the wedge design without the retaining nut on the splined shaft as well as early '14's that were built that way and not retrofitted before they left the factory.
The kit includes new splined wiper drive shafts, two new wiper arms and other hardware to retrofit an older coach. The box is labeled 13V-330E, Jayco recall, and AME# AMP102-1109. Clearly printed on the label is "Jayco recall".
AM Equipment sent me one of the kits after many many calls and much conversations. It was actually shipped by Entegra as it turns out.
If an arm with the wedge shaped clamping method has slipped on the shaft then it is likely ruined with the splines stripped (at least partially). The arm should be replaced. Period.
Tightening the nut under the little plastic pop-out cover just keeps the arm from falling off. A mediocre to poor band aid in my opinion. It might tend to help the arm move from friction but it is NOT the main drive mechanism. The splines are the drive connection and if the arm has slipped the splines are damaged and a new wiper arm is required.
Tightening the allen head bolt under the pop-out cover is what jams the wedge into the splines to lock the arm to the shaft which is the correct drive connection. If this is done correctly the nut is superfluous. If you do anything, take the pop-out cover off, move the washer hose to one side and tighten the allen head bolt hidden underneath the hose. THAT is what is making the joint.
This whole issue is very frustrating as the only way to service an arm on a '13 or older coach is to get the kit. Enough service techs have changed jobs and/or are "new" at Entegra and AM Equipment that most do not even know about the kit, the failures and/or the mass replacement and recall. Only getting a fix like this if you happen to attend a rally is a poor way to do business. Not having this info in red letters on a "wiper trouble shooting check list" for the factory techs is inexplicable. I talked to a lot of people and looked at a lot of other Entegras over the period of 3 weeks to come to this conclusion.
BTW....the oldest arms have a split clevis at the splined shaft with a recessed allen head bolt tighting the clamp. The old arms do not have a little pop-out cover on the arm plastic shroud. The allen head bolt is visible if you pivot the wiper arms out. The bolt is perpendicular to the splined shaft. The new arms have the pop-off cover and a hex nut on the end the splined drive shaft. The allen head bolt that tightens the wedge is parrallel to the splined shaft.
Hopefully this info will help someone in the future avoid a wiper failure.