Ok , i just had the seed rate go down during the day earlier this year ,wasn’t sure what the problem was, after a few tweaks here and there this cured problem. The metering wheel ran smooth just slipping a little !!
Thanks for replies. I bought a used machine this year intending to put low disturbance tines on in future but with it breaking back all the time I can’t see how it wouldn’t disturb the top, but maybe if they pull through easier they may be ok. Do the springs weaken with age?