Mailing List lml@lancaironline.net Message #70142
From: John Cooper <snopercod@comporium.net>
Sender: <marv@lancaironline.net>
Subject: [LNC2] MLG tires hitting upper wing skin
Date: Sat, 07 Jun 2014 11:15:54 -0400
To: <lml@lancaironline.net>
After replacing the original Rosenhan brake calipers that came with my L-235 with new Matco B5-4 units, the tire now contacts the underside of the upper wing skin just before the gear is fully retracted. As you all know, the brake mounting plates fit between the aluminum gear casting and the axle. The old Rosenhan die-cast brake plates were .210 thick. The new Matco brake plates are only .125 thick, so I had to add shims between the casting and axle to keep the brake disc properly "centered" between the brake pads. On my latest installation, the distance between the gear casting and the axle is now .310, which extends the wheel and tire out  .100 more than before. The gear door is probably only .060 away from closing when the tire hits the underside of the upper wing skin, so the addition of the shims seems to have caused the problem.

I originally had 70 PSI in my Cheng Shen MLG tires and bled them down to 60 PSI but that didn't help.

Today I will attempt to reduce the thickness of the shims, but I fear that's not going to work because the new Matco brake pads are thicker than the old Rosenhan pads and need more clearance to allow for wear.

So the only options I can think of at this point would be to 1. carve out a crescent of the upper wing skin core where the tire it hitting, 2. grind down the ridge on the tire where the tread meets the sidewall, 3. Reform the middle gear door, or 4. fly with the aft edge of the middle gear door about 1/16" away from being flush.

Has anyone run into this problem? Any suggestions?

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