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At times, when landing, the front wheel on my 2003 DA 40 vibrates or shimmies. It’s like when driving I cross over the rumples at the side of the road. Any ideas or concerns?

Take the wheel pant off and tighten the nut that holds the wheel and caster assembly to the nose wheel strut. I had a 2003 DA40 and mine did the same thing.

It would seem that the friction damping is too loose. It is easily remedied. There is a procedure in the AMM for setting it properly. But that nut is a locknut that should have been getting removed numerous times by now due to the nose-gear pivot AD and it may warrant replacement so it stays put.

I just bought a 2007 XL last month and I had this problem as well. Nothing was mentioned in the pre-buy.

I took it to my mechanic and he had me push on the tail so he could check the nose and when he came back, he was shaking his head. He said that it's a very common problem that he has seen.....basically, the bearing in the nosewheel are coated with Teflon and they should *not* be greased, but many mechanics don't read the Diamond service manual and grease it anyway. This causes the shimmy and, eventually, breaks down the nickel plating on the strut. A few days later, he took off the nosewheel and showed me the excessive grease and then the notching in the nickel. Looks like it's going to cost me a new strut at the next annual.

Anyway, he put on new bearing and cleaned off the grease. No shimmy at all now.

Hello,

My mechanics greased all the bearing of my main and nose gear.
So I just looked in the AMM and I have found this. Finally, has the bearing to be lubrificated or not?

Thank you.

Arnaud.

Arnaud brings up an interesting point about lubrication. I believe what his screen shots are referring to may be the wheel bearings rather than the fork pivot. But earlier in that same section is this:
Note the lack of inclusion of the pivot. I can find nothing in the AMM that clearly address lubrication (or not) of the pivot.

I have lubricated the pivot every time the fork has been removed for the dye penetrant inspection (every 200 hours). I don't recall that the pivot socket on the fork has teflon on it, just bronze bearing inserts. A couple of the large indexed washers do have a teflon coating. No wear is apparent, and my pivot preload remains stable between lubrications.

Having said that, I seem to recall that the fork pivot socket had a design change sometime after my model year (2001), so others may be different.

Steve wrote: ↑Tue May 04, 2021 4:25 pm Having said that, I seem to recall that the fork pivot socket had a design change sometime after my model year (2001), so others may be different.

The bushings changed pretty early to a pair of these:
One mounted from the top, the other from the bottom. They just look like common bronze bushings. They replace the old straight bushings and indexed washers. We've re-greased every time we've done the nose gear AD.