Just tried fitting my rear subframe.
The horizontal trunnion bolts fit nicely (subframe toward rear seat).
The vertical trunnion bolts are slightly missaligned as shown in pictures below.
The trunnion on each side needs to move toward the front and the middle to align properly.
This is a replacement subframe with new bushes.
What are my options?
A) different (thinner) bushes
B) tighten nuts to compress bushes.
C) enlarge hole in boot (and use washer)
D) other
Lastly, I assume the rear trunnion bolt is inserted from inside the boot (pointed downward).
Rear Subframe Alignment
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rogerotto66s
- 998 Cooper
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Rear Subframe Alignment
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Roger Williams
1966 Austin Cooper S - LHD - Wet - Personal Export
1966 Austin Cooper S - LHD - Wet - Personal Export
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Exminiman
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Re: Rear Subframe Alignment
My first priority would be to make sure all is straight on the car and on the subframe.
Are both sets of vertical trunnion bolts misaligned by the same amount ?
Presume its not a new subframe or subframe mounting panel not been worked on ?
Are both sets of vertical trunnion bolts misaligned by the same amount ?
Presume its not a new subframe or subframe mounting panel not been worked on ?
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Peter Laidler
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Re: Rear Subframe Alignment
Take heart Roger, that's EXACTLY how mine was, even with a replacement Unipart/BMC/BL rear sub frame and boot floor of car after being rebuilt using the datum marks/alignment as shown in the workshop manual. (I rebuilt mine using the datum marks accurately marked on two 6 foot tables)
Personally, I loosened all of the other retaining bolts off, PLUS the rubber bush nuts which made the sub frame slightly more jig-about-able or flexible. From there, with the 6 other bolts and all 4 nuts IN PLACE- but loose, I got the rear right hand bolts in. Then tightened it all up.
I feel that as well as acting as flexible mountings, the rubber bushes will easily be able to accept the very slight variation. It has done. I stripped it to replace the rubber bushes a couple of summers ago and they were perfect - so I put them back!!
Personally, I loosened all of the other retaining bolts off, PLUS the rubber bush nuts which made the sub frame slightly more jig-about-able or flexible. From there, with the 6 other bolts and all 4 nuts IN PLACE- but loose, I got the rear right hand bolts in. Then tightened it all up.
I feel that as well as acting as flexible mountings, the rubber bushes will easily be able to accept the very slight variation. It has done. I stripped it to replace the rubber bushes a couple of summers ago and they were perfect - so I put them back!!
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Andrew1967
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Re: Rear Subframe Alignment
Sometimes you do need a Phillips screwdriver or similar in one hole to just pull the trunnion into line.
That’s certainly not the worst I’ve seen.
That’s certainly not the worst I’ve seen.
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AndyPen
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Re: Rear Subframe Alignment
I have just done mine and had similar alignments. The rubber does give a bit and the set of posi screwdrivers were invaluable.
Something you don't hear about much is that in the factory they trimmed down some of the rubber bushes slightly. I only saw them doing it on the inside when I visited the production line, and was surprised enough to ask why?
The answer was, with tolerances of plus or minus 1/4 inch, it means there can be half an inch difference sometimes.
The reality of mini building!!!
Something you don't hear about much is that in the factory they trimmed down some of the rubber bushes slightly. I only saw them doing it on the inside when I visited the production line, and was surprised enough to ask why?
The answer was, with tolerances of plus or minus 1/4 inch, it means there can be half an inch difference sometimes.
The reality of mini building!!!
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111Robin
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Re: Rear Subframe Alignment
One word, podger, your alignment tool of choice, the longer the better to give good leverage against the rubbers.
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rogerotto66s
- 998 Cooper
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Re: Rear Subframe Alignment
Thanks all.
I guess “misery loves company” applies to some degree!
It is a replacement subframe and the mounting panel has not been worked on.
Both trunnions do appear to be misaligned by the same amount, both front/back and left/right.
Left/right both trunnions need to go toward the middle.
I will try to align using the screwdriver and then if need be compress/trim the trunnions slightly.
Front/back both trunnions need to go front.
If the left/right adjustments also solve this front/back alignment I am done (hopefully).
Else I will elongate the boot hole slightly and use a washer in the boot.
If all goes well ... I may have the “S” back on the road by end of summer!
This would be the first time I will have driven the “S” since I purchased it in 1993 ...
... and the first time it would be back on the road since 1980 ... if all goes well!
... one small step for man ... one giant leap for me (not really a techie car guy)!
I guess “misery loves company” applies to some degree!
It is a replacement subframe and the mounting panel has not been worked on.
Both trunnions do appear to be misaligned by the same amount, both front/back and left/right.
Left/right both trunnions need to go toward the middle.
I will try to align using the screwdriver and then if need be compress/trim the trunnions slightly.
Front/back both trunnions need to go front.
If the left/right adjustments also solve this front/back alignment I am done (hopefully).
Else I will elongate the boot hole slightly and use a washer in the boot.
If all goes well ... I may have the “S” back on the road by end of summer!
This would be the first time I will have driven the “S” since I purchased it in 1993 ...
... and the first time it would be back on the road since 1980 ... if all goes well!
... one small step for man ... one giant leap for me (not really a techie car guy)!
Roger Williams
1966 Austin Cooper S - LHD - Wet - Personal Export
1966 Austin Cooper S - LHD - Wet - Personal Export
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AndyPen
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Re: Rear Subframe Alignment
I do recall having the trunnion shoulders machined back at the heel board end on one car, my wife's - as they bottomed out in the subframe and stopped us compressing the rubber any more. That was way back in the early 90s mind you, so they've only lasted nearly years 
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rogerotto66s
- 998 Cooper
- Posts: 603
- Joined: Mon Sep 10, 2018 8:29 am
- Location: Collegeville,PA USA
Re: Rear Subframe Alignment
Subframe is in!!
On my first attempt I inserted the front bolts but had problems with aligning the boot trunnion.
On the successful attempt I started with the boot bolts and then inserted the front bolts.
Not sure what the difference was.
Not sure but possibly I had the boot trunnions on the wrong way.
... onto the front subframe.
On my first attempt I inserted the front bolts but had problems with aligning the boot trunnion.
On the successful attempt I started with the boot bolts and then inserted the front bolts.
Not sure what the difference was.
Not sure but possibly I had the boot trunnions on the wrong way.
... onto the front subframe.
Roger Williams
1966 Austin Cooper S - LHD - Wet - Personal Export
1966 Austin Cooper S - LHD - Wet - Personal Export
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rogerotto66s
- 998 Cooper
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- Joined: Mon Sep 10, 2018 8:29 am
- Location: Collegeville,PA USA
Re: Rear Subframe Alignment
Had to drop the subframe to re-route the battery cable properly.
All looks good now.
All looks good now.
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Roger Williams
1966 Austin Cooper S - LHD - Wet - Personal Export
1966 Austin Cooper S - LHD - Wet - Personal Export
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TECH396
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Re: Rear Subframe Alignment
Don't forget to put the hydro line insulating sleeves on.rogerotto66s wrote: ↑Fri Jun 04, 2021 8:49 pm Had to drop the subframe to re-route the battery cable properly.
All looks good now.
46888FB1-D8F0-44ED-B1C6-23435CC6E0FB.jpeg
Paul H.