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Old 10-29-2010, 07:48 AM
mbboy mbboy is offline
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Join Date: Jun 2008
Posts: 473
More Subframe Mount Questions

I've been reviewing some threads on replacing the subframe mounts on a 107, as I'm getting ready to replace the mounts on my 380sl. Based on what I've read, it seems to me that the easiest way to do this is the one RandyA reported in the following thread:

107 subframe mount replacement

According to his post, after supporting the car on jack stands, the subframe can be supported by a jack and lowered simply by loosening the 4 subframe mounting bolts without disconnecting anything else. Then, one bolt at a time can be removed and the corresponding mount replaced.

However, other threads state that the brake lines, calipers, sway bar, shocks, engine shocks, and/or motor mounts have to be disconnected or removed to lower the subframe enough to replace the subframe mounts.

For instance, the following thread, which has a fairly good description and pictures of the process, suggests that the brake lines, shocks, sway bar and tie rods have to be removed to replace the subframe mounts.

http://www.benzworld.org/forums/r-c107-sl-slc-class/1461717-front-subframe-bush-change-pics.html

Having thought about these different methods, it seems to me that it should be possible to drop the subframe enough to remove the mounts without disconnecting the calipers or brake lines, which would eliminate the need to bleed the brakes afterwards, and that the tie rod and shock absorber should just move with the control arm.

However, if I'm not mistaken, since the motor mounts are bolted to the subframe, and the engine is bolted to the motor mounts, wouldn't it be necessary to remove or at least loosen the motor mount bolts before the subframe can drop?

Also, in another post, someone stated that you can drop one side of the the subframe at a time simply by loosening the bolts on that side without loosening the bolts on the other side, and that neither the motor mounts, or engine shocks have to be disconnected.

It seems to me, however, that since the subframe is one piece, the bolts on one side would prevent the other side from dropping -- or that dropping one side at a time would have to abnormally compress the mounts on the other side?

In addition, I was wondering if dropping one side of the subframe at a time with or without disconnecting the motor mounts and or engine shocks could possibly cause the engine to tilt in a way that could bend or throw the drive shaft, linkage, or something else out of line, given how finicky these things are?

Since a number of people here have already replaced these mounts and or their subframes, I was wondering if one or more of you could clarify these things for me.

Thanks very much in advance.
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