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I think this is common practice to crank the nuts on with an impact wrench. First reason it's fast and less time for the mechanic and two it's reducing liability for obvious reasons. The only places that use a torque wrench are usually the very expensive boutique shops that are already overcharging you for the extra time.
My concern is changing a flat, if I cant get them off with the standard emergency tool kit i'd be in a world of trouble. Aside from carrying an electric impact wrench! Haven't heard back from the dealership so ill keep everyone posted.
When I brought in my car to have the flywheel replaced they had noted that the previous mechanic I took it too over tightened the gearbox housing bolts with an air gun.
I had to get a specialist to remove the bolts and check the threads. Based on that you'd assume they wouldn't do up my bolts with a air wrench!
At the price I paid i'd expect the right torque to be used.
The dealer should take care of it with no excuses. You can bring a tire iron and demo to them how you or their mechanic can't loosen the bolts.
I use discount tires and they use impact wrench with a torque limiting stick, then followed by hand tightening with a torque wrench. Costco is even more impressive. They tighten each wheel in 3 stages. First while the wheel is in the air free rotating, following by a wheel choking the tire suspended in thr air, then final torqing with a torque wrench after they lower the car fully to ground.
I have never had this problem with the 996 as the only two times I have taken it to a local shop or dealer they specialized in Porsche and use the proper procedure so when I take off the wheels for suspension/brake work..no problem removing. I only use the impact wrench to remove the wheels....torque wrench only for installing.
For what it's worth I have encountered this on other project cars (over tightened) frequently. I use an I-R impact wrench rated at 550 ft-lbs with 5 adjustable settings. My home compressor delivers 7 scfm @ the normal tool air supply of 90 psig w/ a 30-gallon receiver and it will still dance around for a while to get stuck bolts off. I upgraded the air hose to 3/4-inch. Even the 1/2-inch hose was limiting the wrench noticeably. As mentioned above, air delivery is important to get the rated tool performance. Also, use impact sockets (hardened) if you have them. Regular sockets may slightly dampen the transmitted torque with flexure.
You may want to consider replacing the over tightened studs/bolts as they and the threads may have been torqued beyond yield.
Good luck with this. At least you're finding out about it at home and not on the road.
I was using a kinchrome wheel 19mm impact torque bit so that was all good.
Not too sure about the compressor it's not the greatest but it wasn't as cheap as the gun!
I might upgrade to the 500Nm air wrench. Bought a brand new kinchrome 1/2 torque wrench too but didn't get to use it!
This actually happened to my grandfather, he got a flat and the one bolt was on so tight a shop had to destroy the rim to get it off the car! Can't trust a rattle gun in anyone's hands. . .
Dealership noted there were no notes on the rear wheels being removed from the last service.
Last time I was at the dealership I had some minor body work done in the rear wheel wells by a place they recommended it might have been them that over tightened them.
The dealer should take care of it with no excuses. You can bring a tire iron and demo to them how you or their mechanic can't loosen the bolts.
I did exactly that! As mentioned earlier I asked the guy behind the counter to make a note NOT to over torque the lug nuts (getting new tires). After they finished I took my 20" breaker bar from the trunk (larger than the lug wrench that comes with the car) and they wouldn't budge. I handed the breaker bar to the guy behind the counter and said: "You try it". He couldn't get it them either. I asked him how am I supposed to get this off on the side of the road when I get a flat? He saw that I was upset.
Stick a pipe over the end of the breaker bar. Something will have to move with the additional leverage. Like others have said, check the lugs carefully. If you can't easily spin the nuts on and off by hand the lugs have been stretched and should be replaced.
Thanks for the advice everyone. Dropped at the dealership this morning for them to re-torque and replace my 997 rims with original 996s with pirelli P0 rosso all round.
I'll be replacing the P0s soon with pilot sport 2s but as per everyone's advice ill be taking them 2 at a time loose!
If it ever happens again, take a cheap socket that fits over the lugs (I believe its a 19mm) and hit the socket with a hammer. Shocks them for lack of a better phrase . Then crack them loose by hand or impact gun, whatever tickles your fancy.
11-06-2016, 09:07 PM
