I have not had to replace the solinoid (bendix).
If its having trouble turning the car, chances are you have a bad battery or more likely a bad connection some where.
Clean all your connections first especially the earth strap.
Make sure it has a good battery & give it a try.
Jumper leads have never worked for me.
You would be better with a change over starter if the solinoid is bad, the rest of the starter will be on the way out.

Good luck

__________________
Grumpy Old Diesel Owners Club group

I no longer question authority, I annoy authority. More effect, less effort....

1967 230-6 auto parts car. rust bucket.
1980 300D now parts car 800k miles
1984 300D 500k miles
1987 250td 160k miles English import
2001 jeep turbo diesel 130k miles
1998 jeep tdi ~ followed me home. Needs a turbo.
1968 Ford F750 truck. 6-354 diesel conversion.
Other toys ~J.D.,Cat & GM ~ mainly earth moving