So, completed the R/R of the sub frame mounts on my 66 230 sl this Sunday. After reading several posts and the link to the 108 instructions, I must admit I was hesitant. So, it is a big job, but since the motor and transmission were out of my car it really was not that big of a deal. So, If you have the motor out now is the time to R/R the sub frame and motor mounts.
Below is some feedback.
My sub frame mounts were stuck to the sub frame on both sides. So, to save time, before lowering either side of the sub frame, remove the 4 chassis bolts and the cover, then put the 4 chassis bolts back in. That way when the sub frame is lowered, with the large bolt removed the mount will pop out of the sub frame. From there one can remove the 4 bolts and then the mount is free to be removed,
I tried to follow the 108 instructions, and undid one side of the sub frame only, and of course did not have enough clearance to get the mount out. So, rather than force the free side down, I ended up removing the 4 bolts on the other side, which allowed the whole sub frame to drop and the mount was easily removed. I did this on both sides.
The first time I tightened the large sub frame mount bolt the mount twisted so the 4 chassis bolts did not line up.
Once the new mount is in place, before securing anything, hand screw the large bolt, then raise the sub frame not quite all the way and hand tighten the 4 chassis bolts without the cover, letting the bolts pull the mount to the chassis. This will allow for one finish to raising the sub frame, then tighten the large bolt and keep the whole mount straight when tightening the center bolt.
As far as aligning the longitudinal springs, before I unscrewed any of the spring bolts I took a metal brush and cleaned the metal all around the springs. Then took a permanent marker and outlined the location of the springs. Honestly, it appeared that they bolted back up in place. I will have the alignment checked once I get the car back on the road.
When nearing completion, I hand tightened all bolts, then re installed the shocks, brake lines, tires etc, shook the front of the car, lowered the car onto the wheels, shook the whole car, then torque the large sub frame bolt, the 4 chassis bolts, then the centering rod, then; if they line up; the spring bolts.
As an after thought, since I removed all of the 4 chassis bolts on both sides to gain clearance to get the mounts in and out, I wonder if I had purchased 4 long bolts, maybe 3 inches long, and put them in the opposite side of the sub frame one is trying to replace. That way once could loosen the opposite side up to say 2.5 inches without having the sub frame completely loose. Then once the mount is in, all one would have to do is tighten the bolts up and the frame should be mostly lined up. I think the trick would be to find such long bolts.
I also wonder if by removing the chassis bolts from both sides of the sub frame If I could have skipped unbolting the springs. The springs did not really move much when I dropped the sub frame. There are 2 bolts holding the spring on. A front and rear. I noticed the front of the spring did not drop at all, the rear did drop but never actually cleared the bolt. I could have left the nuts on, but loosened.
My old mounts were about ¼ of an inch shorter than the new mounts. Otherwise they looked ok. The whole job took me about 5 hours. If the motor is out I would rate this job a 5 out of 10 on the difficulty scale.
Matt
Austin Tx
66 230 sl - "white"
78 300 D - Blue
98 C230
