question, is there a forward to back orientation for the M5 flex disk?
There are arrows that point to the flanges but it seems like it could go either way
There are arrows that point to the flanges but it seems like it could go either way
is there a forward to back orientation for the M5 flex disk?
- Thread starter mark99
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Honolulu
Well-Known Member
Yes, there is only one correct orientation. You have to carefully read the instructions that should have come with the part. Once you understand those, it's pretty clear, but 'cuz I'm old, and it has been some months, I forget zackly how it's oriented. RTFM! or go online, youtube has videos that show the process, and some of them detail the direction to install.
I agree the arrows make it appear the part could be installed in either direction, and I've never had a failure (except for donuts that are many many years old).
I agree the arrows make it appear the part could be installed in either direction, and I've never had a failure (except for donuts that are many many years old).
thanks, I thought I read there was a front and back but I can not find anything about that
I don't remember seeing instructions with it, I did get a BMW part
Honolulu
Well-Known Member
Let me see if I get this right (it's been a while).... If you have the donut in your hand, imagine the torque from the trans flange on one side and the resistance to the dshaft plus wheels plus weight of the car working against it. Three bolts on one, three on the other. Do you want the donut working in tension or in compression? I'm not sure I remember the rubber webs between bolts are thicker between three "pairs" of bolt holes.
Youtube will tell you but you have to pay close attention.
Youtube will tell you but you have to pay close attention.
well I looked at all the videos and manual, no front to rear orientation, but arrows to the flanges
You just need to remember that the gearbox `pushes` the prop-shaft via the 3 pairs of boltholes. The arrows are assuming the gearbox flange bolts are fitted from the rear, and the prop-shaft bolts are fitted from the front....if fitted wrong it won`t last long....
As long as the arrows point towards the flanges, you should be good if the disc has one arrow for every bolt.
Look at the picture and imagine you turn it 180 degrees, the arrows will still point the same way, and the thicker part of the flex disc will still be at the same place.
The one in the picture is the one I used, a FEBI M5 disc.
And remember that the nuts goes on the flange side, not against the disc. Then you need keep the bolt still, while tightening only the nut.
Oh, and before you tighten the nuts, leave a little bit of play (like 5mm) between the gearbox flange and the disc then rotate the driveshaft and look if the gap is consistent all the way around when you spin it, if not, adjust the driveshaft center bearing and/or the gearbox mounts until it is consistent.
If it isn't consistent all the way around, it will eventually destroy your flex disc and/or give you vibrations.
Look at the picture and imagine you turn it 180 degrees, the arrows will still point the same way, and the thicker part of the flex disc will still be at the same place.
The one in the picture is the one I used, a FEBI M5 disc.
And remember that the nuts goes on the flange side, not against the disc. Then you need keep the bolt still, while tightening only the nut.
Oh, and before you tighten the nuts, leave a little bit of play (like 5mm) between the gearbox flange and the disc then rotate the driveshaft and look if the gap is consistent all the way around when you spin it, if not, adjust the driveshaft center bearing and/or the gearbox mounts until it is consistent.
If it isn't consistent all the way around, it will eventually destroy your flex disc and/or give you vibrations.
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What he said. I own an 88 M5.