How to replace an Alternator’s Nut/Stud Bolt?

[Josh]

I have a 1997 3.8L 3800 Buick Lesabre Custom with 96,000 miles that I can not seem to locate a replacement alternator mounting stud/nut bolt. Here’s how I arrived at this problem: I replaced the one plastic coolant elbow on the tensioner bracket. As I was putting everything back together the alternator’s mounting stud/nut bolt that secures the alternator to the tensioner bracket, engine block and also serves as a mounting point for a short steel brace that runs from the alternator to the underside of the ignition coil module fell out of my hand and likely fell into the front end spash guard under the radiator. I do not have the tools to get under my low profie car to remove the splash guard to search there. I have tried the universal bolts from auto parts stores like Autozone with little success at fitting the aternator housing, belt tensioner bracket, and the engine block. I did NOT try to force the “universal” bolt in for fear of damaging the threads in the engine block, alternator or tensioner bracket. Would GM beable to help me here? I am at a complete loss as to what I can do here. I would not mind taking the car to mechanic to have them see if it is indeed stuck in the splash guard. However, I would need some “band-aid fix” to get my car to them to look for it seeing as how its unlikely the car would run without the serpentine belt hehe :). I am considering looking into junk yards to find a replacement but that could take awhile in some cases. So I was wondering if someone had any more immediate “temporary” solution. Oh! Something I Should note, I have all the other bolts in their proper places in the engine so would it be possible to perhaps make sure those are all torqued down and leave that one bolt out till I can get the issue resolved? Any help you could offer would be greatly appreciated.

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[Richard Kirshy]

Have you tried using the vehicle jack to raise the car and support it.
Or perhaps run one tire up on a curb to get under the car.

[Josh]

Thank you for your advice and responding to my question. As to your idea of finding a way to jack up the car and remove the splash guard that way, I say this.. the only jack I have on hand is a scissor jack and after a lot of research, first hand experience, as well as knowing scissor jacks don’t tolerate being used as a “working” jack well-might not be the best idea to put myself under a vehicle on such a flimsy jack.

This effort would only be exacerbated by the fact of how considerably HEAVY these model year GM/Buick front ends typically are. As for using a curb, the short answer is the car isn’t drive-able at the moment as the alternator is part of my engine’s accessory drive system. In which this system includes the Power Steering Pump, Alternator, A/C Compressor, Crankcase, Water Pump, and Idler Pulley and Belt Tensioner Assembly. The vehicle is parked in the center of my driveway with no curb in sight even if the essential components ran without the alternator.

UPDATE: I contacted my local Gm dealer today and had an experience with their parts department that I’ll call “two-fold”. First, the bad news: they told me the Alternator’s Mounting Stud/Nut Bolt is no longer being manufactured because GM decided to discontinue it :(. Now the good news: Even though the part was discontinued he was able to pull the spec sheet for the bolt to give me the details on threads, bolt size, and length. So that’s at least a starting point, right? YAY Parts Guy!

For anyone who may need them in the future or if you are just curious here is the full specs:
hfh 10mm-1.5 x 55mm w/49 thd, 10mm-1.5 x 20mm w/18 thd 84tl 20.8 od

Or, written another way in terms the average person could understand, what I read that as is:
Bolt is a combo bolt.

The side that tightens the Alternator to the Belt Tensioner Bracket is a 10-1.5 x 55

The side of the bolt used to hang the Alternator Brace that connects the brace from the Alternator to the stud under the Ignition Coil Pack Module is a 10-1.5 x 20 (if it were separated into two separate bolts.)

UPDATE: I was amazingly able to find a bolt that fits today at Lowe’s with a length of 50mm of the 55mm all because of that information thanks to the parts guy at Buick! So, I am on my way to getting back up and running!

Thank you all again!

[Author]

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