Flywheel stuck to crank

[belize1334]

I can't seem to get this Fidanza Aluminum Flywheel to come away from the crank on the '90 TSI I'm parting out. The bolts have all been removed but the thing is seized on either the ring or the dowel or both. I tried just rocking it back and forth by hand and even some gentle prying which has served me well before on OEM FWs but this thing is really stuck. Does anybody have any tips for getting this thing to come apart? Or, alternatively, since I'm gonna be stripping downt he motor anyway is it possible that I can leave it and pull the crank with the FW still attached and then separate it later when I can get the whole thing in a brace or some kind?

 

[Barnes]

Well, since it is aluminum hitting it with some heat should do the trick. The thermal coefficient of expansion for aluminum is great than steel. So if it is stuck on the dowel, or the circumference of the crank face, it should get it off.

 

[belize1334]

Hm. It is about 20*F in the garage so that could explain why it's stuck on there in the first place. Worst case I guess I could just try again on a warmer day. /ubbthreads/images/graemlins/smile.gif
Is there any reason to think that taking a torch to it would make it structurally unreliable?

 

[Barnes]

Unless you get it *really* hot, like... 500 degrees or something. Hell, 50-100 degress would probably be plenty. Just hit with a bit of heat for 10-15 secs, try it. If it doesn't go, give it a bit more.

Wear some gloves though! Aluminum is an excellent conductor of heat. The periphery of the flywheel might get hot enough to burn you. Although I think it'll come off before that point. Just being careful. /ubbthreads/images/graemlins/smile.gif

And yes, the 20 degrees could explain it.

 

[Muskrat]

And remember, aluminum doesn't tell you when it's hot.

I learned that lesson the hard way!

 

[Rausch]

Little PB around where it sits on the crank- soak, rinse, repeat. Couple taps with a rubber/plastic mallet ought to free her up then.

 

[toybreaker]

Bolt an old junk pressure plate to the flywheel.

Take a slide hammer with a hook tool, and place the edge of the hook under the pressure plate case.

Give the slide hammer a few good hard whacks, straight back, alternating sides.

...Profit...





(or maybe not, if you get your little baby fingers inbetween the slide and the hammer... then you'll have to feed the swear jar. /ubbthreads/images/graemlins/wink.gif )

 

[GVR-4]

Aluminum and steel can become electrochemically "welded", especially when they are forced together like that. I'd try the lube, then slide hammer, then heat in that order.

 

[belize1334]

Well I got it off. I didn't have immediate access to a torch and the slide hammer that I could have rented nearby wasn't set up to attach easily so here's what I did. I found a few pieces of steel that I had around and bolted them to the outside of the FW. I was then able to strike these lightly with my hammer from the back side and slowly work the flywheel away from the crank. It appears to me that the PO didn't quite clean the mating surfaces which caused the FW to bind on the circumference of the crank when it was torqued down. It doesn't appear any the worse for wears so I'm pleased that I was able to remove it.



A note on using this method. Remember that these bolts are rated at 12 ft-lb in the FSM so you can't torque the steel pieces down too much or you risk stripping the FW. This means that you also can't hit them very hard in working it away or you again risk damage to the threads. Also, anytime you are hitting something off-center like this you will cause it to bind on the circumference and you want to minimize this if possible. It's a good idea to turn the flywheel by hand after every strike and keep an eye on the gap between the back of the FW and the rear-main-seal housing. This will let you gauge how crooked the surfaces are and help you decide where to hit next to make sure that it comes off evenly.