i broke the rear shock bolts! what to do??
08-23-2010, 01:54 PM
#22
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You will have to strip it to bare metal, have someone weld it, and then put a bolt in and spray/under coat around the new piece. It is not really that hard if you have the tools. If you can get it fixed just enough, a competent fab shop could easily do it.
08-24-2010, 02:57 PM
#26
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I remember now (It was about fifteen years ago, btw.) that we installed them with a friend's homemade tool similar to this one on page 3271:
His version included a thrust bearing that made operation very easy. He also had a deep-well socket with an Allen wrench insert to hold the head of the bolt and upper part of the jacking assembly while turning the larger part.
The rivet nut installation at least as strong as any nut, bolt, and washer of the same size would be. Keep in mind the nut part is on the opposite side of the sheet metal from the shock mount. It looks to me like there is plenty of room in the structure for it, and the access from below is pretty good when the shock is out of the way, which it will be while you're installing the rivet nut.
His version included a thrust bearing that made operation very easy. He also had a deep-well socket with an Allen wrench insert to hold the head of the bolt and upper part of the jacking assembly while turning the larger part.
The rivet nut installation at least as strong as any nut, bolt, and washer of the same size would be. Keep in mind the nut part is on the opposite side of the sheet metal from the shock mount. It looks to me like there is plenty of room in the structure for it, and the access from below is pretty good when the shock is out of the way, which it will be while you're installing the rivet nut.
Last edited by winchman; 08-24-2010 at 03:02 PM.
08-24-2010, 04:48 PM
#28
Regardless of how tight you may be able to get the joint between the rivnut and the chassis, it's still going to be two separate pieces, which will lead to ultimate failure. That joint is continually under either tension or compression whenever there is a dynamic load on the suspension, and that joint will gradually and progressively become looser and looser. It's your car, but consider that every failed attempt at repair will likely make the proper repair, i.e a welded joint, that much more difficult. No chance I'd ever be able to drive that car without always thinking that joint would fail if it wasn't properly welded.
08-24-2010, 05:07 PM
#30
Well, not much more I can say, if you can't understand how a loose joint under such high loads is prone to fail. Just by your own example, what will you do if the nut spins when you're trying to install remove the shocks? Cut up the chassis and butcher it even more? I don't get it. What's wrong with fixing it the right way the first time, and just be done with it?
08-24-2010, 11:24 PM
#31
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How about posting a picture of the broken stud? I'd like to see how it's installed. It's probably installed through a hole with the flange spot-welded on the other side so only the bolts sticks through. This installation is most likely for a stressed part such as this.
A welded replacement stud cannot match the original, since you don't have access to the far side of the joint. It'll depend solely the welder's ability to make an overhead weld on sheet metal that's been galvanized and painted. Grinding will remove the paint and zinc and some metal. It'll also remove any protective coating on the other side, which you'll never be able to replace. You'll also have the thickness of the flange and some weld to upset the fit of the shock mount against the sheet metal.
The rivet nut will hold the sheet metal against the shock mount just as tightly as the original stud did. You'll only lose the corrosion protection on the drilled out edge of the sheet metal, which can be touched up easily with zinc-rich primer during installation. The primer that gets around the inside will tend to hold the folded-over part of the rivet nut from turning, if you ever have to remove it.
The rivet nut is much closer to the strength and durability of the original than the welded replacement would be, and avoids the problems associated with welding.
A welded replacement stud cannot match the original, since you don't have access to the far side of the joint. It'll depend solely the welder's ability to make an overhead weld on sheet metal that's been galvanized and painted. Grinding will remove the paint and zinc and some metal. It'll also remove any protective coating on the other side, which you'll never be able to replace. You'll also have the thickness of the flange and some weld to upset the fit of the shock mount against the sheet metal.
The rivet nut will hold the sheet metal against the shock mount just as tightly as the original stud did. You'll only lose the corrosion protection on the drilled out edge of the sheet metal, which can be touched up easily with zinc-rich primer during installation. The primer that gets around the inside will tend to hold the folded-over part of the rivet nut from turning, if you ever have to remove it.
The rivet nut is much closer to the strength and durability of the original than the welded replacement would be, and avoids the problems associated with welding.
Last edited by winchman; 08-24-2010 at 11:27 PM.
08-25-2010, 07:31 AM
#34
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^ enlighten us then....
LOL, the dude is posting in a forum.......looking for a quick fix....
peeps here are doing a good job in trying to come up with a way to fix it....
its his car, he has to decide.....some people are just scared sheit of welding and want nothing to do with it....others dont...etc...
He posted no pic to show exactly hows its damaged.....etc..etc..seems to me everyone is "trying" and its ultimately up to the OP...
I thought about going home and digging in my car yesterday to get a better "Grasp" of whats all going on after commenting, but im a busy person and didn't get a chance too...
in the end, even Nissan themselves would turn him away and a body shop hack getting paid hourly would weld on some quick fix...........paint, galvanized metal, blah, blah....its gonna be a "repair" either way in the end, something hes gonna have to end up monitoring....
-J (Stress Analysis Engr)
LOL, the dude is posting in a forum.......looking for a quick fix....
peeps here are doing a good job in trying to come up with a way to fix it....
its his car, he has to decide.....some people are just scared sheit of welding and want nothing to do with it....others dont...etc...
He posted no pic to show exactly hows its damaged.....etc..etc..seems to me everyone is "trying" and its ultimately up to the OP...
I thought about going home and digging in my car yesterday to get a better "Grasp" of whats all going on after commenting, but im a busy person and didn't get a chance too...
in the end, even Nissan themselves would turn him away and a body shop hack getting paid hourly would weld on some quick fix...........paint, galvanized metal, blah, blah....its gonna be a "repair" either way in the end, something hes gonna have to end up monitoring....
-J (Stress Analysis Engr)
Last edited by JasonZ-YA; 08-25-2010 at 07:50 AM.
08-25-2010, 08:05 AM
#35
The studs will never experience a compression load because those loads go through the mount into the chassis. Its very rare (and a poor deisgn) if compression loads in a fastened joint are passed through the fastener and not the joint itself.
The studs do experience a tension load from the corner unsprung weight at full droop. That's what... 100 lbs worst case? Two M8 class 10.9 studs can handle that just fine.
The studs do experience a tension load from the corner unsprung weight at full droop. That's what... 100 lbs worst case? Two M8 class 10.9 studs can handle that just fine.
08-25-2010, 08:59 AM
#36
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ya, its not a question on loads at all... its a question on how to fix it...properly yes of course, but will it really??? well see??
Look back at my post #3.......the use of such small bolts breaks how???? they break not by design but by reality.......(ie. OP and his install procedures, how else does a teenie weenie M8 bolt break in this application???).....
My gripe with them is they are small, and not the daily driving loads that screw them up but installs that break, bend, strip threads, etc.....
I've never screwed one up, but I knew it would happen...
I agree completely with your post #2 by the way.....as you can see in my post 4.
-J
Look back at my post #3.......the use of such small bolts breaks how???? they break not by design but by reality.......(ie. OP and his install procedures, how else does a teenie weenie M8 bolt break in this application???).....
My gripe with them is they are small, and not the daily driving loads that screw them up but installs that break, bend, strip threads, etc.....
I've never screwed one up, but I knew it would happen...
I agree completely with your post #2 by the way.....as you can see in my post 4.
-J
08-25-2010, 12:06 PM
#37
im at work and cant get to the car. but i will post better picture once i get home. here's a picture from mdracer76 (hope he doesnt mind).
thats how it look like down there. this is a picture on the right, my problem is on the left side. the stud the broke is the one facing the driver seat. it snapped clean on the shocks upper mounts. hopefully that gives a better picture of whats going on.
thats how it look like down there. this is a picture on the right, my problem is on the left side. the stud the broke is the one facing the driver seat. it snapped clean on the shocks upper mounts. hopefully that gives a better picture of whats going on.
08-25-2010, 02:04 PM
#38
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I feel at least a little qualified to talk about loads, since I spent five years designing equipment for field testing of helicopter turbine engines and another twenty years doing engineering work on sub-launched missiles and support equipment for handling, assembling, and testing them.
I feel I've also got a pretty good understanding of design, welding, machining, and fabrication, too. You can see a sampling of my work here:
http://smg.photobucket.com/home/winchman/allalbums
I feel I've also got a pretty good understanding of design, welding, machining, and fabrication, too. You can see a sampling of my work here:
http://smg.photobucket.com/home/winchman/allalbums
Last edited by winchman; 08-25-2010 at 07:08 PM.
08-25-2010, 08:20 PM
#40
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Can you take a picture with the shock mount pulled down and away from the studs?
What sort of paint scheme is that? Looks like urban camo or something in post 37.
What sort of paint scheme is that? Looks like urban camo or something in post 37.
