Ok,

This may be much ado about nothing or something to be expected.

I'm doing pads and rotors on the 95 SC2 I recently reacquired. I've done the front . At the same time with the wheels off the vehicle, I cleaned them thoroughly including the center area that goes over the axle nut and the scuzz accumulated at the face of the holes where the studs pass through the wheel.

Thes car has tapered lug nuts which conically center themselves as you put them on and tighten them in a crosswise pattern. I am wondering if the exact place on the stud where the lug was sitting created a weak spot sing still for 3 and 1/2 years with the same static stress on it, and now that the lug nut is grasping a different overlap of the threads, that the lug nut is simply twisting off because it is weak.

For the record I actually broke the wheel stud during final tightening with my torque wrench it was very strange because it felt like the one that broke got about two more rotations on it than the rest which is when I started to realize something was wrong. I had actually already backed everything off once and started over I arrived at the same situation. The torque wrench was purchased calibrated, has never been dropped, and clicks properly at the torque for some of the other lug nuts on the car . It also clicks when I lower it's work value setting meaning it clicks on all four logs on a wheel so I do not think the wrenches at fault.

My concern is that if one has a weak spot, and there are others that were behaving this way when I began to approach what should be final torque, if I am not just safer replacing all of the studs and lug nuts.

Or do I just need to chase the threads with a tap and die respectively? These lug nuts have always gone on and off like butter, and the one that twisted off was more than happy to keep going. However at some point it either got hung up on the stud threads or the metal was weak. What do you all think aside from the fact that I find a way to take a simple subject question and turn into a 33 line Post?

 

If you're going to replace one, I'd replace them all, derf. My opinion is that they all wear at the same rate. Hell, I'd replace both sides on the front if it were mine. They don't cost that much and you'll feel much safer knowing that neither front wheel is going to fall off. I wouldn't worry about the rear wheels. But that's just my frugality kicking in.

 

Studs stretch over time especially when abused by the local tire shop. Have you ever noticed that they tighten them with a gun then verify the torque after the fact with a torque wrench? I never see them finally tighten them with the torque wrench, I mean visibly turn the nut further to torque. It is always click and move on so the torque is at a minimum of what the torque wrench is set at. That is why some nuts seem loose and others destroy your star wrench trying to get them off.

That being said, I would replace them all on your car. I am very particular on my vehicles and all that I work on. We even use the green plastic pointers on our lug nuts so all you have to do is look and see that all the lug nuts are there and that none have backed off.

 

Thank you, sir. My wife thought I was being a spaz but with other ones feeling as though they are about to go I sensed replacing all was certainly the safer bet.

The only other variable in all of this is that this is the first time I have used my brand new dewalt cordless impact gun. I had to set it on the middle setting of three for it to loosen the nuts it took about 10 hits each and I know the lug nuts were torqued properly because I'm the last one that did it with a torque wrench. The only other thing I am wondering is whether the hammering motion of that particular tool is in some way putting an uneven stress on the stud while it's hammering away on the bolt. I of course always try my best to keep level when I use any tool to remove or attach anything.

I might do the back brakes tonight. Maybe I will take one of y'all off with a compressor and one wheel off with the tool and see what twists off.

Cuz I am in a retentive about keeping my car absolutely stuck for when it is repainted and entered in local classic car shows, I ordered GM studs and lug nuts for this vehicle. That was at the end of September. They are special order. They claim they were available but they are not even in house yet.

 

I use OEM studs and nuts if available. The local tire shop comes to us sometimes for parts. They know I am a pack rat especially on parts for my fleet. The Ford dealer calls sometimes also since I stock F550 parts they have to order.

 

Another funny story is that I don’t carry a spare tire for my shop truck. When I travel out of town like now I tow a trailer with parts for the generator and two spare tires. Neither spare is for my truck because my truck has 235/85r16 tires. I can get those anywhere, I carry a trailer spare that fits most trailers company wide and a 10 hole 19.5 wheel and tire that fits our popular F550s and our 5500 Dodge trucks. I used the 19.5 on the second day here in California. I had the only spare tire in 75 miles. 😃

 

Just called The parts House. If the parts don't ship today they ship Tuesday then arrive Thursday which blows another week. I guess I will do the rear brakes and put the tires back on not super tighty.

Needs a fuel filter change as well. Haven't touched white car all week.

Not changing the thermostat back on the black car until I pressure test the system so that I can address any leaks the first time not after I refill the system. What is the proper way to test fuel injectors for being clogged? Disconnecting power to them has an effect. I actually put in reman injectors that I bought off RockAuto like 10 years ago while trying to track down the vibration issue on the white car. I may take this downtime to swap three of the mounts from the black car to the white car because I know they're good. It should be amount issue but it's not. But I have to check.

I got the pressure tester cap for the expansion tank but I am waiting on the adjustable pressure manifold with the gauge on it. I will also have to get some line and a t e e to test the cap. Or shall I say the cap and the seal.

 

Examining the wheel stud that twisted off, I cannot by hand remove the lug nut. So what happened is the lug nut suddenly bit into some part of the threads it could not travel through and literally just twisted off the stud.

This may sound ridiculous, but I truly did clean both the plate on the hub and the inside of the wheel both front and back while I had it off. I think it exposed threads in the stud further in that had never been reached by the lug nut. Basically they were full of solid crud and the lug couldn't follow the threads so it crossed threaded. Very smoothly I might add.

I've replaced the front eight studs. Pretty much no work. I always thought it was more difficult. It isn't, at least on an S car. The quality control is annoyingly bad. Of the first 10 pulled from the bag, I could not thread a lug nut all the way onto two of them. They have what I expect is a green rust inhibitor on them which is clogging up the threads. Had to chase them with a die . Lame.

So front brakes done, two wheels studs done wheels back on, totqued to spec, all well is well on that front. Fuel filter replaced.

Need to get the damaged boats off of the caliper brackets on both sides in the rear in order to do the brakes and replace the wheel studs and lugs.

Frame looks incredibly good for 25 years old. I'm yet to get under the black car.

Dash is rebulbed. Found whole scraped in flex pipe. I know I could buy just the flex pipe but I can't weld anyway and it's easier to just attach the correct shaped pipe as a downpipe with a flex in it. The rest of the exhaust is rusty but it is not soft.

Cam cover gasket, purge valve solenoid, lines to it, and spraying underside of intake manifold for vacuum leaks which for some reason never dawned on me to do.

​​​​​​I have a bolt extractor and now I have pinless swivel sockets to get square on the fastener. Hopefully they are not too rounded and I can get a grip on them then use the impact on a very low setting and work my way up. Do not want to twist these off. Already torched them trying to loosen them up to no avail. Maybe I am just not getting it hot enough
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Fuel Filter (OEM) changed. Fun.

Evap hose torn leading from canister . Purge valve has been sucking air whenever it opened.
No idea how long. Changed purge solenoid out even though when I got it off the back of the block and blew through it, it seemed pretty firmly closed.
Had replaced the canister. Figured new canister, new purge valve, gotta have new evap line. Put it all together, started it up and -- wait for it -- 0 effect on anything. Which was no surprise after testing the orig valve and learning hands on that it's not open enough of the time to cause my type of issue. You all already said that.

So why did I do it? Partly because the parts were available -- which sounds stupid until you go back to look for something and no one has it. Forever. Small investment in learning more hands on stuff on cars. I am so far behind in that area. But my confidence is slowly building as I am doing a whole bunch of stuff I've not done to my cars before. And that's worth the $$ to me right now b c I will go insane without something to sink my mind in.
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Got my swivel sockets. Went with Astro Pneumatic after reading that quite a few of their tools double as private label tool truck tools. They are at the edge of what I can afford as I slowly replace my worn out stuff.
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Caliper Bracket Bolts: Derf 2, head twisted off 1, partially rounded still on car 1.
I soaked the crap out of these for a week each side. I torched them.
Got the bottom ones out easy with an impact. I had to try the extractor on the rounded one as the next size down sae or metric was too small.

Twisted off
There is barely a nub so I don't think a stud extractor will grip. Plus it's solidly rusted in place.
Do I drill a pilot hole for an easy out, then let it bite while installing?
Or do I just drill the damn thing out and not f up the threads, then break it up when close to the threads?
The caliper mounting bracket and the hub are both threaded -- yay. I have the tap and die to clean up afterwards and replacement bolts to boot

Rounded off still on car
Do I try to file down to the next largest impact socket then put the swivel in it and hope for the best? Or leave it for someone who deals with this regularly (other people's rounded off rusty fasteners. Never twisted anything off in my life. Two and running. MIGHT be able to get a Dremel sander in there to get flats and a smaller head......

How is this supposed to go (besides not twisting off stuff)?

All input appreciated.

ORRRRR

Do I try to break up the rust by trying to rotate the caliper bracket around the stuck bolt?

 

If there's room to rotate the bracket, that's what I'd try next, derf. If that doesn't work, you need a torch that will heat that sucker to cherry red in order to bust the rust loose. Our hand held propane torches just don't have that ability with all of the other metal attached.