I've noticed on some of my later model GM beater trucks the bolts on things like the rearend cover on one, and the bumper bracket to frame bolts on another, the heads have literally rotted and started to crumble. What is it about these bolts that they do this, yet I can go dig some more HAMB-friendly car out of the mud where it's sat for 40 years and while the bolts are rusty, 95% of the time I can at least get a socket on enough to bust them if they don't want to turn? Is it that the metal is cheaper, that it's been recycled too many times, or is it just the prolonged exposure to road salt and so forth? And it varies from vehicle to vehicle and even bolt to bolt, just what ones you can put a socket on no problem and what ones won't take one. We're talking like 85-95 model years here, some of that stuff should still have been American made. This stems from me wanting to put a hitch on the van I picked up so I can haul oldies with it. The wieght-distributing hitch for the later Chev vans actually replaces the lower bumper bracket, using the bolts for it plus adding one more on each side. I pulled a used one in a junkyard that was in decent shape, and of the 8 bolts that held it on, 5 of them just snapped off, including two of the bumper bracket bolts. Those are the only ones you need to re-use, so I saved the two that spun out for me to use when I go buy new ones. The junker is the same year as mine and seems to have been junked because of a rotty frame rail (won't pass a NYS inspection that way), yet I was able to get sockets on all the bolts. Frame rails on these are basically a deep U-channel welded to the floorpan at the top. On mine, the same bolts look like they're going to just crumble around the edges until they're two or three sizes smaller. Which is what had happened on the rearend cover on one of my Suburbans. That one I was able to get apart by using a cutoff wheel to put enough of an edge on the rotted heads to get a secure hold with vise-grips and start them that way. It ruined the cover in the process, but I'd already gotten a replacement. With the van I may have to drill the things out if the bolts crumble, because unlike the rearend cover, where they are is up in between the bracket and the spring hanger - I may be able to grind them enough to get a grip on, but there's no room for visegrips - or if I can get a set on there it won't matter, the other one I needed the 1/2" breaker bar to get enough leverage to start them. I am thinking I'll open up the floorpan over the frame rail, vaccum out any loose rust, and hit them from the top with PB Blaster before I do much else. I suppose if I have to I can drill them out and just put regular ones through from the top, I'm just not looking forward to trying to drill out more bolts laying on my back going upwards (just had to do manifold bolts on that Suburban to put a Y-pipe on it). They're too long to try to go through from the top and the rail is too deep to grind them off from that side. If needed to visualize, I could come back and post a pic of the diagram from the shop manual -
I used to play around with pulling bolts off using the longest pipe I could find. Then I bought a torch set. Heat those bastards up. It works. You can sometimes get away with using MAP gas for smaller stuff. You'll have to soak them for a year before PB will do anything.
There's a lot of different salt that is now in use. I don't know much chemistry, but this stuff ain't table salt any more. Calcium- potassium- magnesium- chloride. Salt used to be sodium cloride. Are these other chemicals more harmful to metal? And how do they react when you travel and run into a combination of them in different areas?
I figure I may as well learn how to pull them without heat, because when I go to the junkyard, I'm not allowed to bring a torch with me. And with my luck on these particular bolts, working 6 inches from the gas tank, I'll blow myself up with one. Otherwise I would try heating them up and melt some wax on them.
When I lived back east I learned that whenever possible, it was better to tighten and snap them off then to try to loosen them. Especially bumper bolts. I would work like hell with or without heat and then 1/2 way off, the head would spin in the square hole and I was screwed cause you can't grab or hold it. So I learned you put a good socket or visegrip on that nut with a big bar or pipe and go right instead of left!
There are "easy-outs" for nuts & bolt heads. They are sockets with LH spiral cutting edges inside. Just keep going smaller till one bites in and holds. They work.
I've come across a few on my project similiar to what you describe. I was able to loosen them with a few whacks of a cold chisel, then twist em out (or twist off the heads) with vise grips. Couple more whacks, you can sheer the head right off. Works fine if - as you mention - you're just trying to get the piece they're attached to and don't care about the condition of the original fastener. Grabits and tap-outs *do* work, chisel has been faster and somehow more satisfying.
Of course the problem with this latest set of fractured heads is it would be nice to unscrew whatever's left of it so I can use the holes. I have some sockets made for grabbing bolts, but I never could get them to work. Uisually what happens is they ride up and off because not only do the edges of the head fracture, they come off leaving an angle behind. I wonder if I could buy a couple nuts to fit the loose bolts I saved off the donor van, open up the floorpan from the top, spin the nuts on, and snap them off from that side. Then it would both be easier to drill, and I stand a chance of catching the bolt and maybe spinning it out. If I end up destroying the threads I'm going to have to open it there anyways, so I can use regular bolts instead. I already know the actual floor metal is pretty thin - and it wouldn't hurt to get a look in there to check for rot anyways.
Heat is the number one best wrench there is but if you can't use one then a chisel and a BFH usually works . If the nut is there but rusted fast the a good socket with a breaker bar usually work but bring along a piece of pipe just in case you need some more power . Easy outs work good when the heads get rounded out . A good battery powered impact gun works very good too . A small generator with electric impact works good too . these are a few things I take to the salvage yard on a wagon ! RetroJim
If you can't get a heat wrench in there take along about 4 sharp chisels and a good size hammer. I'd just cut the nut's in two, then knock the rusty bolt's out. If they won't spin breaking them off by tighting them would be first, because their probally as rusty on the inside as outside of the frame rail.
There is no nut on there now, they're bolts that thread into the bottom of the frame rail. The problem here is from the top I get about a 2"x4" hole to work from, length I can adjust some, width I can't. From the bottom where the heads are, one side I get just about the same width space to work from. I think they'll come loose with enough leverage, the clunker I took apart came loose or broke easy enough, the problem is the heads are fractured and cracked and probably not going to take a socket. I need the holes so I can put the hitch on with them. The bolts are expendable - but they gotta come out. I could screw around upside down trying to weld a nut on them and go that way, but there's a good chance the heads will twist off anyways. I think my best option now that I've given it some thought is to try to bust the top end off where it's threaded into the frame using some new nuts, and just drill the bastards out from that side. Going from the top I can put the leverage into the drill and I should be able to go right through without it being a major hassle.
Obviously as usual half the guys reading this completely missed the part where you mention that it's BOLTs you're trying to remove not nuts and there is no access to the nuts without cutting a hole, not to mention the nuts are welded to the frame.... How can people make any educated suggestions when they never READ the fuckin question ? A few good hard smacks with a BFH and then pounding on a 6 point socket that's smaller than the original size works sometimes. I always thought this was what metric sockets were for ? I've worked in salvage yards half my life and on those Chevy van bumper bolts the good news is that the threads are somewhat protected up inside the frame. If you can get the bolts to turn they will often come right out without breaking. Good luck with it. And my opinion is that not only is the hardware not nearly as good but the stuff they're using on the roads to melt the snow is very hard on metal. At the used car dealership where I work now we just got in a 2001 Rodeo and the frame is so rotted it's about broken in half. On the other hand the 57 Bel Air I'm working on at home has a really good frame...
Hey at least we tryed, maybe the fact we don't mess with 70's thru 80's vans means we are not experts like you junkyardman, but we tryed. Geeez get a "grip" pun intended, Mr. selfrightousness...
Read somewhere recently that the chemicals used nowadays on roads have changed, especially that stuff they put on BEFORE the expected snow storm arrives. That's the stuff that retards the ice and snow from accumulating to start with. Suspicions are that this stuff may have been a contributing factor to the collapse of that bridge in MSP, MN. Back in the '50s when I was a teenager and getting interested in cars to the point of obsession, nothern cars were sought after in the South to the point that in Atlanta there was a used car dealer named "Northern Car Co.". Roads in the South were often rough and bumpy and many were still dirt outside the cities and off the main highways. Cars traveling these roads took a real beating, and since the North was not yet using all that salt and stuff on the roads, used cars from up North were usually in better shape at an equivalent age. Nowadays, if you're buying a late model used car, it pays to do a little research on it's past and avoid it if it's from up North. Dave
I agree with breaking them by tightening or with a chisel or splitting the nut. Besides, if they are bad enough to have to use any of these methods, you can't reuse them.
Center punch the head, use a good sharp 1/4" bit for a pilot hole, enlarge as needed. Cordless drills and impacts are great things to prevent assorted busted knuckles, etc.
After you have tried all the above, and if you break the bolt head off, try to center punch the remaining shank, the drill with LH (LEFT HAND) drill sold by snap-on and other tool dist. It heats as it drills and most of the time it (THE LH DRILL) will catch and unthread the shank. Roger
To be fair, some of the replies (e.g. "split the nut with a chisel") don't seem to have any practical application to this particular problem. I wouldn't take it personal. I wasn't so much concerned with a way to get them apart as if anyone has a good explanation of why these bolts corrode like this. I don't want to use stuff like that on my Chevy to put that back together. The manifold studs I get, they see a lot of heating/cooling cycles and if the donuts aren't tight they get exposed to the exhaust gasses. But these other bolts like I said there's just no rhyme or reason to which ones just plain won't take a socket anymore and which ones are still okay. Normally I'd agree, trying a smaller socket and hammering it on can do the job. But I know from the truck I tore the hitch off from, these damned things are torqued down tight, the heads aren't that tall, and it's liable to be an excercise in frustration trying that trick on them. That's why I went out and bought some bolts that will fit the threads so I can go at them from the top instead. I just haven't gotten off my ass to do it yet, there's no real hurry to install the hitch, so I put the tilt column in it instead.
I`ve had good luck mig welding a good bolt onto whats left of the bad one,the heat from welding lets them come out easily. If the bolt is broken flush,weld a pile of bead about 1/4 inch high on it and then weld the bolt on the pile. Works good once you master the welding.
My guess... just plain old cost cutting by the fastener suppliers, downgraded plating specs, bad batches of bolts that missed some treatment in the process, etc.. the car companies started screwing suppliers for cost real bad in the 80's. The first off samples would be perfect and meet all testing requirements but once in production...who cares!! save a dollar where you can, no one is going to find out for at least 20 years and how long was the warranty on yer new car??
Back in the '50s when I was a teenager and getting interested in cars to the point of obsession, nothern cars were sought after in the South to the point that in Atlanta there was a used car dealer named "Northern Car Co.". Roads in the South were often rough and bumpy and many were still dirt outside the cities and off the main highways. Cars traveling these roads took a real beating, and since the North was not yet using all that salt and stuff on the roads, used cars from up North were usually in better shape at an equivalent age. HUH? if a car/truck resides north of lexington, ky - most people south wouldn't have it
Maybe you need to sharpen your reading skills! I clearly said "back in the 50's". That's before they started using so much salt and before many roads in the South were even paved at all. Were you even around then? Dave
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