M20C, 1966, very squirrely & eratic on landing roll.

[Cfidave]

On landing roll out my M20C starts to swerve wildly after touch down. It almost took me off the runway ( to the left). At first

I though it was me accidentally hitting the brake. I made a conscious effort to make sure that was not the case today.

Takeoff doesn't seem to do it as badly, but there is some instability as speed picks up. I have thought about maybe a brake pad

dragging on the disk, but the brakes seem fine. Any ideas what maybe causing this? thanks much.

[MikeOH]

The Eight Second Ride:

https://web.archive.org/web/20190207032823/http://donmaxwell.com/the-eight-second-ride-sb-m20-202/

[midlifeflyer]

Nice find, @MikeOH

But I had to laugh at 

"if it darts, usually to the left, it's not right."

[Ragsf15e]

1 hour ago, Cfidave said:

On landing roll out my M20C starts to swerve wildly after touch down. It almost took me off the runway ( to the left). At first

I though it was me accidentally hitting the brake. I made a conscious effort to make sure that was not the case today.

Takeoff doesn't seem to do it as badly, but there is some instability as speed picks up. I have thought about maybe a brake pad

dragging on the disk, but the brakes seem fine. Any ideas what maybe causing this? thanks much.

The 8 second ride thing is real if the nosewheel isn’t set up correctly.  You can also get lots of slop in the steering over time.  This made the steering on my F feel “loose” or maybe it “wandered” a bit but it didn’t “dart”.  Sloppiness is usually worn bolts/bushings and you can see where with it up on jacks.  Lie under the nosewheel and turn it slowly back and forth see where.

If it’s really darting, check the link @MikeOH posted.  I would do that pronto as people have gone off the runway with that one.

[varlajo]

So you are not depressing the brake, but what about the rudder? If you are approaching with rudder input to correct for crosswind, but fail to neutralize rudder input prior to the nose wheel touching down, the plane will inevitably depart the centerline, possibly with noticeable enthusiasm. 

[Cfidave]

4 hours ago, varlajo said:

So you are not depressing the brake, but what about the rudder? If you are approaching with rudder input to correct for crosswind, but fail to neutralize rudder input prior to the nose wheel touching down, the plane will inevitably depart the centerline, possibly with noticeable enthusiasm. 

That is possible but today the wind was dead calm, no crosswind. I think Don Maxwells article is exactly what I am experiencing. 

[Cfidave]

4 hours ago, Ragsf15e said:

The 8 second ride thing is real if the nosewheel isn’t set up correctly.  You can also get lots of slop in the steering over time.  This made the steering on my F feel “loose” or maybe it “wandered” a bit but it didn’t “dart”.  Sloppiness is usually worn bolts/bushings and you can see where with it up on jacks.  Lie under the nosewheel and turn it slowly back and forth see where.

If it’s really darting, check the link @MikeOH posted.  I would do that pronto as people have gone off the runway with that one.

Yes, and I very much thank MikeOh for the article. I have already ordered the shim from lasar. This is my 3ard Mooney, had an F and an E, never experienced

anything like this  on either previous airplanes. I am going to have the shop check the entire nosewheel when it goes in. 

[Bartman]

I didn't have the 8-second ride, but it was more like the nose gear was wobbling like a bad shopping cart wheel.  About 10 years ago, we sent my nose gear to LASAR for rebuilding and the installation of new shock discs.  We also installed the new steering horn, and basically everything is like new.  

[65MooneyPilot]

When you get it up on jacks, try to move the nose gear up and down vertically and see if there is a lot of play. Mine was going up and down at least an inch. Totally wore out. I sent mine into LASAR also and had it rebuilt. Just like new again.