Joe, On my nose strut, I could not tighten the AN4 bolts enough to squeeze the firewall bracket tight on the strut. There was always a little tiny wiggle. With weight on the nose wheel there was no detectable wiggle. Weight on wheels to weight off wheels cycles plus rough ground taxi will generate the wiggles. The shock load, as the strut hits one end or the other of its play, will impose large impulse shocks at the firewall. These shocks would be in the vertical direction. There's not much loading laterally due to the swivel of the nose wheel. The shock loads could also fatigue the epoxy joints in this area.
In my case with Dan Diehl's concurrence I drilled the ¼-inch holes out to 5/16-inch and used close tolerance bolts. The strut feels like it is welded to the bracket now. On the firewall you have to keep the bolts tight clamping the wood. Wimpy individual 3/16 fender washers on the back of the firewall won't do here. Make a backup plate the same size or larger as the bracket on the front. Drill the holes to ¼-inch and put in AN4 bolts for some clamping muscle on this high stress area. Just like prop bolts, don't crush the lumber. Going to AN4 bolts will also help fix your elongated holes in the firewall. Sid Wood Tri-gear KR-2 N6242 Mechanicsville, MD USA >Thanks for the heads up Joe. I will check mine as that is one area I have not >thought about. Mark Jones (N886MJ) Wales, WI Visit my web site: www.flykr2s.com E-mail: flyk...@wi.rr.com ----- Original Message ----- From: "Joseph H Horton" <joe.kr2s.buil...@juno.com> To: <kr...@mylist.net> Sent: Tuesday, March 20, 2007 5:56 PM Subject: KR> Safety check item > > Guys, > For the guys with nose gear I found a item that I need to check > on more often. The 4 an-3 bolts that go thru the Deihl nose gear bracket > where it attaches to the firewall on mine have loosened up and slightly > elongated the holes in the wood. This can not be identified with the > weight on the nose gear. It has to have the nose raised and all the > weight taken off to be able to detect the movement at the firewall. In > all fairness I had an occasional front wheel shimmy and I found this > defect while working on the shimmy problem. The hole elongation is > vertical only not laterally. > Joe Horton > joe.kr2s.buil...@juno.com >
