Nick, no need to compress the engine mounts before installation if that's even possible. When replacing the engine mounts in two of our 124 cars I removed the engine mounting bracket and engine mount on each side as an assembly. Bolted the new engine mount to the engine mounting bracket and torqued it properly before reinstalling each assembly.

After reading some recent posts, and considering my experience with the driver's side engine mount, it's probably easier to leave the engine mounting bracket in place and use a stubby 17mm open end wrench to remove the bolt attaching the engine mount to the engine mounting bracket. Then tighten the bolt as much as possible after installing the new engine mount since there is no space to use a torque wrench.

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Fred Hoelzle