Rear Bumper engine adjuster

[The General]

Finally got some time in the shed today. Recently had a broken Bolt (with broken ezi-out inside) repaired, that belonged to the bottom rear chassis perimeter frame on my 93 FJ. I`ve heard they are often broken without owners knowing. Got to think`n why?

Apparently only break on drive side so guess chassis flexing does it. But while in tha area and pondering I wondered what the role of that rear bumper engine adjuster is. ...If I tightened it up hard I reckon it would compromise those majic rubber engine mounts...so did a bit of a forum search and found this same question.....also seemed unanswered,
http://www.fjowners.com/index.php?topic=523.msg12593#msg12593.

Just interested to know.  Cheers

(Yep, finally making the effort to get her back on the road!)

[ribbert]

...so did a bit of a forum search and found this same question.....also seemed unanswered,
http://www.fjowners.com/index.php?topic=523.msg12593#msg12593.

Doug I just read that, I think it was answered perfectly, it mentions beer, more beer, tequila and pizza. Sounds like a solution to me.

Noel

[The General]

...so did a bit of a forum search and found this same question.....also seemed unanswered,
http://www.fjowners.com/index.php?topic=523.msg12593#msg12593.

Doug I just read that, I think it was answered perfectly, it mentions beer, more beer, tequila and pizza. Sounds like a solution to me.

Noel

Nahhh....that was the suggestion to fix the front engine mounts....Oh, that works BTW...Also tried to figure out the bumper adjuster function with same ingredients...might`ve worked, just can`t remember tha answer!

[The General]

Finally got some time in the shed today. Recently had a broken Bolt (with broken ezi-out inside) repaired, that belonged to the bottom rear chassis perimeter frame on my 93 FJ. I`ve heard they are often broken without owners knowing. Got to think`n why?

Apparently only break on drive side so guess chassis flexing does it. But while in tha area and pondering I wondered what the role of that rear bumper engine adjuster is. ...If I tightened it up hard I reckon it would compromise those majic rubber engine mounts...so did a bit of a forum search and found this same question.....also seemed unanswered,
http://www.fjowners.com/index.php?topic=523.msg12593#msg12593.

Just interested to know.  Cheers

(Yep, finally making the effort to get her back on the road!)

\
Anyone?  Three questions in my waffle. 1. Why does the perimeter chassis bolt break?  2. Role of rear Bumper adjuster? 3. Doesn`t it compromise Rubber engine mount function? 

[ribbert]

Anyone?  Three questions in my waffle. 1. Why does the perimeter chassis bolt break?  2. Role of rear Bumper adjuster? 3. Doesn`t it compromise Rubber engine mount function? 

Doug, I have the answers, from a mechanics perspective.

1. It just does. Put a high tensile bolt in there and forget about it.

2. Dunno. Looked at it for 5 minutes once, couldn't figure it out, can't be important, next.....

3. See above.

Seriously, I did stare at it once for at least 10 mins thinking everything through and could see no purpose for it. Someone might know, but I don't and as I can't see any purpose for it, I no longer need to know.

Noel

[ribbert]

Anyone?  Three questions in my waffle. 1. Why does the perimeter chassis bolt break?  2. Role of rear Bumper adjuster? 3. Doesn`t it compromise Rubber engine mount function? 

Doug, I have the answers, from a mechanics perspective.

1. It just does. Put a high tensile bolt in there and forget about it.

2. Dunno. Looked at it for 5 minutes once, couldn't figure it out, can't be important, next.....

3. See above.

Seriously, I did stare at it once for at least 10 mins thinking everything through and could see no purpose for it. Someone might know, but I don't and as I can't see any purpose for it, I no longer need to know.

Noel

Now that I think about it, I did come up with a few theories about limiting engine twisting under extreme torque to relieve some of the load on the rubber mounts and so on but when I thought it all through they didn't make sense. It does seem odd though that it's at the same corner as the bolt that breaks.

Maybe with the front mounts not rigid and the back mounts almost in line with the output shaft, it needs some triangulated bracing to stop it twisting after all.

Someone will know or have a theory.

Noel

[The General]

Thanks for your thoughts Mate. I did end up replacing 8mm bolt with a 10 mm grade 8. Was advised by a pretty cluey mate not to go higher in tensile as they tend to be brittle and actually break more often in a suspect flexing situation. (but no, he couldn`t figure out the function of the adjuster bumper either.)
I did momentarily suspect the centrestand loaded stop might have an affect on that bolt, but nahh, I don`t reckon that`s what causes the bolt ta break.
Interesting ay. 

[Arnie]

If you're talking about the bolts that hold the lower frame rails to the main frame behind the footrest plates....
I don't know why they break (or loosen) either.  When I found mine broken I wondered why they had a 10mm hole and only an 8mm bolt.  I replace the bolt with a 10mm and re-tapped the threaded receiver.
Haven't had any problems since (about 10-12 yrs now).

Arnie

[X-Ray]

Mmmm, my rear adjuster bolt (bumper/damper) just spins in the threads, so doesn't do anything. Couldn't be bothered trying to fix it as along with Noel, I really don't think it serves much purpose.