John Deere F935 isolator replacement questions

[canucklehead]

Here is a similar thread someone posted that I found through a search: http://www.tractorbynet.com/forums/...6432-yanmar-f935-rubber-coupler-isolator.html

I posted there, but no replies. I'm wondering if no replies because of the section where the original topic was posted, so I'm asking here hoping to find good info.

After mounting isolator on driveshaft, I went to slide it onto crank pulley. I noticed one of the 3 mounting spots was snug, and the other 2 spots were at least 1/8-3/16" short of touching the pulley. I read about the motor mounts wearing and sagging at the rear. I tried wiggling motor with prybar and it moves but only with the motor mount stretching. It's not sloppy or knocking like worn out car motor mounts that I've replaced. Not to say these aren't worn, I don't know how else to compare it.

So I shimmed a flat washer between the pulley and the isolator, then tightened all 3 bolts. It still looked a bit cocked, almost exactly the same as the pics from the above link I posted. I removed the shims and it is still cocked, maybe worse.

This is the 3rd or 4th isolator replacement (I just bought this F935 from a friend, and he did previous isolator replacements). So is a bit of a wave/wiggle appearance in the isolator normal?

For torque, closest thing i could find was JD general specs indicating M8 10.9 bolt should be 30 ft lbs. I think "10.9" is a grade 8 bolt. the bolt does have that marked on it. so I torqued all 6 of these to 30 ft lbs, and also used blue loctite. Is that correct..? too tight maybe cuz of the rubber?

the driveshaft looks pretty straight but it's hard to tell how perfect it is. when islator goes, driveshaft whips around and takes out rad, and it is expensive. i'd like to make sure this is done right.

THANKS! :thumbsup:

 

[jwinner]

I shimmed the two rear engine mounts, and left the isolator alone. Maybe 3/8" steel or thererabouts, drilled a hole in it to use the same mounting hardware, and you could just get the nut back on most of the way. Now there is almost no visible warpage of the isolator and it runs smoother at idle.

 

[canucklehead]

haha!! I never updated my post, but i think I pretty much did the exact same thing. Can't recall, but i thought I shimmed all 4 corners...maybe it was only rears. I used 2 flat washers per corner, and it barely left me enough thread to put the nut on. In fact, I worry i don't have enough nut threaded onto the bolt. I should have put one shim/washer above and one shim below on the mount.

anyways, it lines up way better, and no twist on the isolator. I've put a few hours on it and it seems good so far.