Can some one please explain what the difference between both is?
I once had an “old school” drum brake workshop in my area that told me guys who machine and re-line car drums will not do this correct to our drums as these are different jobs.
Unfortunately they don’t exist any more.
Thanks.

As far as I know there is no difference between the lining material, however someone used to working on cars may struggle with the different brakes on bikes.

The relining process is the same.
Radiusing the shoes is different for mechanical brakes or hydraulic brakes.
The linings are very different.
Mechanical brakes generally have a lot softer and higher friction material than hydraulic brakes.
Usually if we have to fit car linings we go for a racing lining which down here is bright green.

email (option): bsansw1@tpg.com.au

Somebody recently wrote here that even the softest car linings are to hard for our bikes.
And that could very well be true.