Kirby height adjustment...
Hello Joseph.
When that happens with the height adjustment on a Kirby, it is the front axle shaft assembly 'teeth' or the ratchet lock assembly 'teeth' being worn. Or, a combination of both.
If you have further questions about this or other Kirby questions, shoot me an email & I will provide you all of my contact info.
Cheers & hagn/d all,
Bill
