Under Torqued Flywheel Bolts

I just buttoned up my 2002 Golf ALH 5speed Sachs clutch install with Single Mass Flywheel and I under torqued my fly wheel bolts. Bolts were new but I miss read the torque and only torqued to 44 and not 44 plus 90 degrees. I’m I pulling it back apart or is that enough torque (not right but enough)? My thought was to run it but if it vibrates I know what the problem is and i’m tearing into it anyways. Any thoughts?

you could run it and you might get away with it but those bolts are liable to back out on you at probably the worst time.

I'd say if it loosened up enough to vibrate it would have damaged the flywheel and crank before you'd detected it.

Using a torque angle wrench, the ftlbs reading at the 90 over is something like 150ftlbs. I'd pull it back apart and fix it. Could possibly damage the crank when it fails.

I guess if the bolts haven’t been torqued to spec then I don’t need to replace them, and I haven’t run the car yet... going to be fun dropping that tranny again. Any tricks getting that thing in and out I struggled with it... no lift just in the garage?

I wouldn't be afraid to reuse them. Technically, I wouldn't unbolt them at all. Just make sure they're still torqued to 44, then just go the 90 over.


I've done 4 of these clutches, and all I've ever done is had the front end on jack stands, with the rear end on the ground. I won't say it's an easy project, but what I've done that makes it a tad easier is to take out the three bolts for the lower ball joint mount on the driver's side. That way the wheel can be pulled over and move the CV shaft out of the way. You'll still need to take off the trans mount for clearance though. Good luck!

sorry, this sounds like no fun : (

The bolts definitely need to be tightened properly.
Each of them should be loosened a little bit and tightened to the torque value.
Then each should be marked with paint or scribe, something and also mark a reference point to judge against.
finally, go around and turn them all the required angle.
imo, you cannot 'check' that something has been torqued because static friction is different, maybe always higher. that said, the most likely result is that if you set your torque wrench to 44 and turn them most likely they will all turn a bit before the wrench clicks due to embedding.

http://www.boltscience.com/pages/tighten.htm

Yeah that's not a little undertorqued, it's a lot and they are likely to back out.

Which, if it happens, will be very, very bad.

Thanks for the help I was just hoping someone would say (or a few would say) oh your good go for it. I figured I was pulling it out again... bummer. I only double check after I was almost done because I thought it was to soft in the back of my mind. Should have check twice and did it once!

Personally, I think it would be stupid NOT to reapply blue locktite to each bolt.

Prairieview said:

Personally, I think it would be stupid NOT to reapply blue locktite to each bolt.

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I've always put it on my flywheel bolts, but that's because I've had crank bolts back out before.

Maybe double-check that your torque wrench is calibrated correctly as well. I discovered that my torque wrench was reading too low after I calibrated it.

Just did this the other weekend. Driveway job. Came out very easy, I got a 10” or so box that had styrofoam in it. Pulled tranny off and kind of landed it on the box. Worked well.
Back in, I just pushed it up into place and had my wife throw a jack underneath it. Again, worked well but was a pretty good push. Alternatively, you could have a buddy lift from the top with a rope or whatever to help a bit. Getting the thing on a Standard 3 ton jack to slide in would just be too easy

Nero Morg said:

I've always put it on my flywheel bolts, but that's because I've had crank bolts back out before.

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The flywheel bolts I've always received (granted, sample size of three) have had green loc-tite on them.