I originally sent this to joe_padavano as a PM for clarification but thought this might be good for the forum to know if this has happened to anyone else.


I have a 1972 Cutlass Supreme 2 door hard top coupe. When I took the body off, the pictures I took showed that the top cross member over the rear axle has the none bolted bushing pads (as it should be). this would be position 5 I believe. My pictures also showed position 4 the next set in front of the rear axle cross member also had the same none bolted bushing pads.


My question is, did the assembly plant (Fairmont Cal.) make a mistake. When I got my new bushing set it shows that position 4 should be bolted for a 2 door hard top. Only if it is a convertible it should be a none bolted bushing pad. Has this been noted before as a mistake by any other members


I have the nut plate in the body to bolt it and my assembly manual says it should be bolted. Does it really matter if it is bolted or not?
I got my bushings from Supercars Unlimited and referring to there bushing placement guide.

 

So what did Joe say?

 

Did not get a response back yet.

 

 

"As far as the 70-72 Cutlass Holiday coupe, there are 6 bolts: two at the cowl, and 4 behind the rear axel. All others are the ones with non-holes"


The bushings that are under the driver and passenger seats do have holes but are different they are countersunk to allow the tail of the nut plate in the body to fall in and is threaded. But I am pretty sure I ended up with 8 bolts that came out instead of 6. I'll have to go out and do another count of the parts that came out.


If it is just 6 bolts that means that the cab/passenger compartment rides free, must be for a reason.


This is turning into a good discussion and maybe an eye opener. But the assembly manual still calls for bolts in these two locations, or am I reading into it wrong?

 

I can not speak for anything other than 1970 as I am looking at it right now.


Position 2 calls for bolts on all models.
Position 3 calls for no bolt on (body codes 57, 77, 87)
Position 4 calls for no bolt (unless it is a station wagon)
Position 5 calls for no bolt for all models.
Position 6 requires a bolt.
Position 7 requires a bolt.

 

Ok back to my previous question


If it is just 6 bolts that means that the cab/passenger compartment rides free, must be for a reason.


"BREAKER BREAKER Joe you got your ears on"


oops I'm dating myself.........

 

 

Good move putting it out to G-Pop. I've PM'ed Joe in the past and have gotten no response either but asked question in general section and he was usually within the top 3 to respond. My guess is he doesn't do PM.

 

Let me preface this by saying I work for a different car company, but I may be able to help a little.

Bushing theory is like this. You must locate the body to the frame. One bushing is a tight fit for the bolt. This is the datum. It locates the body in the X and Y dimensions. The next bushing is a slot for the bolt. It fits tight one way, loose in the other. You point the slot at the datum, this way the tolerances can be off for the distance between the datum bolt and this one. The tight direction locates the body in the Z rotation axis around the datum (ie it stops it from rotating around the datum.) This is called the sub datum.

Next thing you have to do is hold it down, in the Z direction. All bushings to hold it down have oversized holes, because they don't care about X or Y travel or Z rotation. They just want Z travel, as in DOWN on the frame.

Now, problem is that the body has tolerances. Too many bolts holding it down will bind it to the frame, since it will not naturally bottom out on all of them. This is why hard tops are held down in 4 spots or 4 different areas (some have two bolts in the general area). More bolts could bind it. Plus, the frame is supposed to flex a little, and it could make popping noises if you had extra things bolted down when it does.

Convertible bodies are going to flex anyway, and probably won't bind since there's no roof, so that's why they have the extra bolts.

All that being said, an extra bolt, provided the body doesn't normally float over that bushing when at rest, probably won't matter. I would follow the assembly manual.

 

My 1970 Fremont built 442 (12B date) is exactly as described above.

And I removed the original body bushings, so they were factory installed.

Of note is that locations 3-4-5 had floating nut plates, so you could use a bolt there.

 

Here is the assembly manual showing all for 72's. I do stand corrected for position 4 it should be a none bolted cushion. Position 3 is the one that is showing it bolted. So I presume that the requirement to bolt it changed from 1970????

 

Is that the only page?

 

Here are the relevant pages from my copy of the 70 Assembly manual. There are differences when the car has the W30/W31 options.

MainBodyMount.pdf

MainBodyMount2.pdf

 

Yes this is the only page.

 

Jeff,
That second page was deleted from the 1970 PIM.
See attached.

 

The W cars received a firmer durometer mount than the 442 cars did.

 

IMHO I say no, it does not.

I've worked with design engineering for years too, and while that is true in theory and likely practiced at your car company in much later cars designed on the tube it was not practiced as stated at Oldsmobile assembly in the early 70s.


Oldsmobile bolted the main hardtop and sedan bodies to the frames in positions 3 & 4 for years before they omitted them. When I restored my '65 I even put bolts in position 5 because the cages were there. I have never experienced binding that I could tell, certainly never popping and I sure love the way the car drives. My guess is that they omitted the bolts because of ride, cost and ease of assembly reasons.



.

 

I may well have overestimated their engineering, so you may be right.

 

Last night I went home and did a inventory of what came out when I took the body off. Bolted positions where 1,3,6 & 7. My assembly manual matches this so I'll be following the manual (see previous post attachment) with the torques. However the kit I received only had 6 bolts. Glad to see the responses and the knowledge this forum has to help see the changes that where made over the years for the different models. Sounds like position 3 is the only one that has the (should be/not be) bolted question over the years 1970 to 1972............Interesting

 

I believe position 1 is the Core Support, did you mean 2,3,6 and 7?

 

I believe the core support is its own identification?? and 1 is for convertibles only.


But yes 2,3,6,7

 

That was a good post offering some behind the curtain knowledge for those who understood it : )


Position one is right next to #2 as seen on the earlier models:

 

Same for 1970, I had it wrong in my earlier post.