when to replace motor mounts?

[einreb]

Ok, I'm installing some bilstien sports on the rear of my '88 911 and I notice that when I jack up the car via the engine (with a recently purchased AC Hydraulics jack from p.p.) that there is some 'play'. I.E. the engine jacks up a bit prior to lifting the car.

Question... how much 'play' is normal? How tough is it to replace them on my car? Easy to do the fronts too? I read something about the mounts with the G50 being different.

I searched... but didn't see a 'when to replace' thread (feel free to point it out).

Thanks!

Bernie

[buttjoint]

The rubber is usually cracked when thir gone.

[einreb]

ok, the top side isnt cracked... i can feel the bottom side... doesn't seem cracked. Should there be 'play' as the engine is lifted? can something be tightened? I see the one big bolt and two small bolts to either side.