Looking for some help to remove a rusted nut on my 96 Bonneville SE (3.8L non turbo) to allow me to change the serpentine belt. I have read the forum for hours for the proper procedure to change the belt without success. I know that the star ended stud must be removed to allow the engine mount spacer to drop out and allow the belt to go around the engine mount leg. It is the "18mm hex nut" on the end of the stud that I think needs to be removed prior to loosening and removing the stud bolt. According to the information I found, the procedure is as follows:
1. Remove engine mount bracket nut.
2. Remove engine mount stud with the E-10 end.
3. Remove engine mount spacer, which can be tough to get back in.
I was wondering if this nut is welded to the engine mount bracket or is the nut left hand threaded? I have tried several treatments of rust penetrator (PCB?) from Advanced Auto prior to trying to loosening the nut counterclockwise using extensions and a 15 inch breaker bar. I have even tried my impact wrench at almost full power using counterclockwise rotation without any movement. I am worried that if I ring off the nut and stud, a significant repair will likely result due it'* location. I need to replace the belt due to a tensioner pulley failure that damaged the belt. I was looking for suggestions on how to remove the rusted nut or if I am using the wrong procedures for the belt replacement.
Thanks in advance, Steve
1996 Bonneville SE 3.8L (non turbo)

Just did this the other week. The nut IS NOT welded or reverse-threaded.

18mm for the nut. The name of the bit to take out the sutd evades me at the moment. Reverse-Torx. Your gonna have to put some a$$ into it Soak her down with some lube first though and get your self a beer while it soaks.

Good Luck

Do you have a torch you could heat it up with?
Its definitely not reverse threaded or welded on.

As mentioned, it'* a normal threading. Sounds like yours is a bit corroded. In the case of my car the nut and stud came out together and I'm fine with that.

One or the other needs to break free.

Same-o same-o. Use PB blaster. Wear gloves. Don't breathe it.

Why are you taking the nut off? I did this just this morning, took ten minutes with a 3/8" drive socket wrench and a torx E10 for the stud. Should come right out - if not, soak it with WD40, let it sit a few hours or overnight, and try again. Also, for some reason or another, there may be some weight on that bracket - try evening out the weight with a floor jack and a 2x4.

Thanks for the suggestions on removing the frozen nut. Last weekend I finally tried to remove the 18mm nut again. This time, it was one week since I spayed it with Blaster rust stuff. Using a large breaker bar, I was finally able to losen the bolt on the engine stud bolt with CCW torque. The nut came off, then I was able to remove the star ended stud with a significant amount of CCW torque. I was surprised that the nut and stud were both without much rust after I removed them. However, the engine spacer had to be removed downward since there was a small nut on the engine which would not allow upward movement of the spacer for removal. Removal of the spacer was allot easier than putting the spacer back in. Even though the spacer slide up and down almost the full diameter of the spacer when trying to remove it, it still had to be pulled down very hard to get it pass the engine bracket leg that finally gave a little to get it out. Thanks again for all the help, and my bonneville is finally back on the road with 187,000 miles. Steve

Steve, what is CCW?

I'm guessing something funny

I'm goin with counter-clockwise...

Just to clarify, we're talking about pulling out this red bolt and dropping down that spacer in the middle?