I was installing new seat covers in my SATURN VUE. To install the rear seat covers, I had to remove the rear seat. What did I find? The seat is secured by a total of 8 bolts: the 6 in the rear were english (5/8" head size)-no problem. the front two-were “TORX” head bolts-I had to drop everything, drive to the auto parts store, and buy a set of sockets for this one job!!
Why the h*ll can’t GM use the SAME style bolts in one car model?? Is it asking too much that you be able to work on a car with ONE set of tools? Oh, and I forgot-the bolts in the engine compartment are ALL metric-so we have 3 styles of bolt in the car! What kind of idiot dreamed this up?
Welcome to the mechanical world, where there is and never will be any rhyme or reason for the choice of certain types of hardware fasteners and their sizes.
I’ve worked on equipment where one needs the full chest of advanced mechanincal tools to take the thing apart. Torx, metric, standard, hex, hex with a key, torx with a key, etc.
It gets frustrating at first, but after you’ve aquired all the necessary tools then you can laugh in the face of the engineer who designed it while taking it apart effortlessly.
Typical. I’ve found that even the older model cars (resto work) have the same issue. You need at least 2, sometimes three, different sets of tools just to work on one component.
I’ve always wondered how they manage to design every single bolt so that you have to unscrew it left-handed.
And then there was my old Omni: metric engine in US Standard car. Sigh.
Not at all, as long as your one set of tools has english, metric, torx, hex, and everything else you might need. C’mon man, go out and get some proper tools!
Speaking about interrupting a job to get tools, if you ever use threadlocker on bolts make sure you have the right set of easy-outs close by. You don’t want to have to drive to the shop to get them, giving the threadlocker time to set up on the broken bolt. Trust me on this.
And pick up a torque wrench as long as you’re there so you won’t be breaking off bolts.
It’s a conspirisy I tell you a big fat frigging conspirisy of designers, manufacturers, the product safety commission, EPA, big business, gov’t. etc. to screw you out of your insanity or into it as the case may be. Valid logic reasons, if any, are few and far between.
Settle down. Cheer up. Have a cup of coffee.
Now I’m missing a new metric box-open end wrench with special ratcheting feature and some miscreant stole it or hid it to keep me out of sorts. Also hid a 5/8 wrench over 60 years old and irreplaceable! Sob…
I guess i don’t understand-couldn’t GM realize some major savings by standardizing? I don’t understand why GM could not use ONE standard metric for bolts and screws-make the whole car metric (or english). Remeber too, that this extends to the production line-they have to stock 3X the parts because of this. It would benefit everybody, if they had some standardization.
Did you consider that maybe making it really, really difficult (or at least inconvenient) to perform your own maintenance is beneficial to GM repair facilities?
Not that I think that’s a good idea, but that would be my WAG.
GM probably already realizes major savings by subcontracting out various components to other companies, and trying to enforce uniformity on all of them is likely damn-near impossible. Margins being pretty thin, if they demand that Subcontracter X retool for metric/English, Subcontractor X is just as likely to reply “Sure, if you don’t mind us charging an extra 175% per unit to pay for the retool and waiting a month for us to reconfigure our assembly line.”
Are there any cars that are completely assembled at one factory?
No, but I would think seats are installed within the confines of a single structure.
I gotta disagree. The Japanese are insanely strict about what they’ll accept, rejecting parts that have minor cosmetic flaws in areas that only the installer will see. I presently work for a company that makes nuts for various companies, including automotive and aircraft manufacturers and I can tell you that the car companies are nearly as picky as the aircraft companies are. They can do it, they just don’t want to be bothered to think about such things.
Seems to me, that there was a car which was supposed to be built using only a few stanard sized fasteners. Hmm, I wonder who that could be and what happened to that company?
They don’t, as I learned the hard way when I twisted off some lug bolts on a late '70s model 1-ton Chevy. The driver side rear wheel on duallys had left hand thread back then. Maybe they still do, I don’t know.
It used to be ('60s - '70s) that Chevy’s popularity among hot-rodders was partly due to the inter-changeablility of their parts, and the corresponding supply of after-market parts. The parts makers could get interested in selling parts that would fit many makes and models. I’ve always suspected that GM got away from common parts because ACDelco and other GM children wanted their piece of the profit from replacement and performance parts.
Not necessarily true. On Subarus, for instance, virtually every fastener (aside from Phillips head screws) are hex head cap screws (“hex bolts” in the vernacular of the unwashed masses) in three standard SI sizes (10mm, 14mm, and 17mm, IIRC.) The same is, or at least was, true of Toyota, Nissan, and Honda. American car manufacturers, unfortunately, use a plethora of different types and sizes of fasteners, and in my experience GM is the worst of all.
Commonizing on fasteners is a cost savings from both a service and assembly standpoint. I once spent six weeks going though a family of telescopic material handlers and reducing the ~120 different fasteners (different lengths in 16th" increments from 1/8" through 7/8", cap screws, socket heads, et cetera) they were using into 17 by commonizing on four standard sizes. This worked out to be a cost savings of approximately $1,400 per machine (from reduced labor and stocking) or roughly $300k annually. They were so greatful that I was RIF’d two weeks later. Most ag equipment has a similar stupendous and gratuitously unnecessary profusion of fasteners.
The same is true in areaspace, but at least there’s usually some justification for it, though when I see someone using aluminum bolts on a stainless steel pipe fitting (???) I have to question whether they’ve really thought that through. Not my rocket, though, so it’s not my problem.
Stranger
I used to work with an ex-Navy chief, who was a terrific man to work with. When some recent college-boy (his words) engineers use a different size allen head bolt on 1 of a set of four screws “because we want the maintainers to remove this screw last”, he wasted no time on telling them what kind of ****** idiots they were and tell them how many times they qould get cussed in the coming years when when the maintainers had to make an extra trip back to the toolbox for the extra hex wrench.
Besides cussing them, he wrote a formal problem report and got it changed. I miss old Harry sometimes.
I’m surprised that they didn’t just drill it out and replace it with the same as the other three.
There are sometimes (I won’t say often) very good reasons for the seemingly stupid design choices made in mechanisms, like being forced to remove one bolt last. I’ve been cursed at on a few occasions by assemblers who wanted to know why we couldn’t do x…and then I let them do x and they see how that impacts y later.
But many choices are made either because “that’s what we’ve always done” or because the engineer wasn’t really paying attention to consistancy. Don’t even get me started on spiral lock washers. Most useless invention ever.
Stranger
And for a long time Chrysler Corp cars had left-hand threads on the lug bolts on the driver’s side of the car. Lots of potential for error there…
But what I really meant (and failed to express properly) was that I always, always end up having to use my left hand to reach the bolt I’m working on. I can usually just barely touch it with the tips of my fingers, while lying upside down under the dash, with my feet draped over the back of the seat, my neck bent 90 degrees to one side, and dislodged bits of crud dropping into my eyes.
And I’m still not quite sure how the trouble light manages to shine directly into my eyes while simultaneously burning my ear. But they don’t call them “trouble” lights for nothing.
It was still a protoype, he got the production drawings changed so the change went into production. We need more people like him with the guts to fight for issues like that. That’s why I miss him.
Elaborate a little on this, please. I’ve been putting these things on vibrating stuff at home and on the farm and I thought I was doing a good thing.
I call them drop lights, or more accurately, one-drop lights because you drop the damned things one time and the filament breaks in the bulb.
The idea behind spiral lock washers is, depending on who you talk to, is either that it adds to/normalizes the preload of the bolt, thus making it more secure, or alternatively that the pointy ends of the washer dig into the bolt and flat washer should it start to come loose, preventing it from backing all the way out. The problem with these explainations is that they’re both completely wrong. Spiral lock washers add nothing to the preload–which is determined entirely by the torque you apply to the bolt and the friction between the threads–and do nothing to the joint once they’re flattened out. The amount of load necessary to flatten a spiral washer is tiny, anyway, with respect to correct preload for the corresponding size screw. As for the second explaination, anything beyond a Gr. 2 bolt is going to have a surface hardness of such that the point isn’t going to dig in or grab it, and if the bolt is backed out enough that the washer isn’t flattened then whatever resistance it puts up is too little, too late. And you’ve have to remember to put the spiral facing opposite of rotation, which isn’t obvious to most people, even if it worked.
There are washers that verify preload, but they do so by deforming (torque washer) or compressing (belleville washer or disc spring). The former are generally used with bolts that are too large to accurately measure torque (large steel structures like bridges and skyscrapers), and the latter with smaller fasteners that require very low and very precise torque requirements.
In general, a properly torqued bolt on a nut with dry threads will not back out (the nut is designed to give slightly) under any load that won’t fatigue the bolt, or you can use a locking nut to assure sufficient friction. Another option, if you have sufficient free thread length is to use a jam nut to stretch the bolt between the jam nut and regular nut. Note that the jam nut should be to the joint side of the regular nut, not the other way around as is too-frequently seen. (It seems “intiuitively logical” to put the jam nut on second, as it is an ancillery nut, but it should actually go on first, so as to be wedged between the joint and the main nut, thus forcing the main nut to take the ultimate load.)
Screws that are inserted into a blind threaded hole are often more problematical; if they require high torque you generally insert a threaded insert (especially if the material is cast iron or aluminum) and friction locking can’t be assured (and you don’t really want direct steel to aluminum contact, anyway) so you either use threadlocker (either liquid or preapplied on a patch of the bolt), or you mechanically lock the bolt in place with a cotter pin. In critical joint design, lockwire (a wire that is threaded through a hole in the bolthead) is used to either lock two bolts together or lock the bolt to adjoining structure after it has been inserted, but this is costly and time-consuming.
Whenever I get a kit with spiral lock washers, I just throw 'em away. At best, they do nothing, and at worst they degrade the quality of the joint. If you want to keep a screw from walking out, clean the threads with solvent and threadlock the screw in place, or if it’s a through bolt, jam nut it together.
Stranger