Tooth brush and white lithium grease.
Use a tooth brush to clean the elevation threads. (Do the bevel while you're at it.) Then use the tooth brush to apply white lithium grease. This should solve the problem.
If it doesn't, look for the stop bolt. It probably needs a 1/2 turn.
Use a tooth brush to clean the elevation threads. (Do the bevel while you're at it.) Then use the tooth brush to apply white lithium grease. This should solve the problem.
If it doesn't, look for the stop bolt. It probably needs a 1/2 turn.