CJ's MJ Posted May 28, 2015 Share Posted May 28, 2015 Hey guys I was wondering if anyone would know what causes the metal around the back glass to crack. I noticed that I have what you would call stress cracks in all 4 corners. I never noticed it before but recently discovered it. It's been there for a while because of the rust build up. It explains why the guy I bought it from painted the truck. He was trying to hide the problems. Lol. There is also a roll bar so it also blocked view of the cracks. I can't seem to post any pictures with my phone or I would put some up. The lower passenger side looks to be the worst it has a significant amount of rust build up. I originally thought the rust was from the back glass leaking through the sliding window. But after discovering the cracks I don't believe it's what's causing the rusting. I know it isn't helping it but not the original cause. Link to comment Share on other sites More sharing options...
Pete M Posted May 28, 2015 Share Posted May 28, 2015 stress fractures. :( comes with having a unibody rig. can happen to any MJ, but usually appears on rigs that are worked hard (either flexing or loaded up). Link to comment Share on other sites More sharing options...
CJ's MJ Posted May 28, 2015 Author Share Posted May 28, 2015 That's the bad thing about buying an older vehicle. You just don't know what the previous owner(s) have done to it. When I bought my MJ I had no clue as to what may be wrong with it. At times I think I should have passed on it lol. Don't get me wrong I really like my truck it's just getting it back in good condition is costly. Lol. By the time I get it to where I want it more than likely I will have invested several $1000s in it. Unfortunately being on Guam everything I need I have to have shipped. Back there I could run to the JY and save a lot. I am starting to understand why so many people list them on craigslist for $20k lol. That being said what's my best options to reinforce it? One day I would like to be able to take it out and do some wheeling. Lol Link to comment Share on other sites More sharing options...
shelbyluvv Posted May 28, 2015 Share Posted May 28, 2015 I posted this same subject about 2 years ago. I found cracks at all four corners on my 86. I still have not fixed it. It has been sitting torn apart for years now. Once I finish my 89 I'll get back on it. My plan was to stop drill the crack and weld them up. I was also going to fish plate the corners to keep it from happening again. Link to comment Share on other sites More sharing options...
Minuit Posted May 28, 2015 Share Posted May 28, 2015 Just went down to the garage and checked my cab. No cracks but now I'm worried. Is this an issue that frame stiffeners would prevent? Link to comment Share on other sites More sharing options...
Eagle Posted May 28, 2015 Share Posted May 28, 2015 I think you answered your own question -- Roll Bar. People don't put roll bars in vehicles they drive to the Quik Mart three times a week. The previous owner probably wheeled the truck hard and the roll bar wasn't stiff enough to prevent the body from flexing. You need to get the cracks drilled at the ends and then TIG welded to prevent propagation. Link to comment Share on other sites More sharing options...
CJ's MJ Posted May 28, 2015 Author Share Posted May 28, 2015 I posted this same subject about 2 years ago. I found cracks at all four corners on my 86. I still have not fixed it. It has been sitting torn apart for years now. Once I finish my 89 I'll get back on it. My plan was to stop drill the crack and weld them up. I was also going to fish plate the corners to keep it from happening again. Fish plate? Link to comment Share on other sites More sharing options...
HOrnbrod Posted May 28, 2015 Share Posted May 28, 2015 That's the bad thing about buying an older vehicle. You just don't know what the previous owner(s) have done to it. When I bought my MJ I had no clue as to what may be wrong with it. At times I think I should have passed on it lol. Don't get me wrong I really like my truck it's just getting it back in good condition is costly. Lol. By the time I get it to where I want it more than likely I will have invested several $1000s in it. Unfortunately being on Guam everything I need I have to have shipped. Back there I could run to the JY and save a lot. I am starting to understand why so many people list them on craigslist for $20k lol. That being said what's my best options to reinforce it? One day I would like to be able to take it out and do some wheeling. Lol Did you ever run a Carfax or similar on your truck? It would be interesting to see where it originally came from and how long it's been on Guam. I sold a Chevy Celebrity I had to a local when I left there to move to the Marshall Islands in the early 90s. A few years later I was on my way to Japan via Continental Air and took an overnight on Guam. The taxi that I used from the airport to the hotel turned out to be the same Celebrity I had sold years before. Found out it had been sold several times since I left and was still chugging around earning $$ as a taxi. :yes: Link to comment Share on other sites More sharing options...
Megadan Posted May 28, 2015 Share Posted May 28, 2015 I posted this same subject about 2 years ago. I found cracks at all four corners on my 86. I still have not fixed it. It has been sitting torn apart for years now. Once I finish my 89 I'll get back on it. My plan was to stop drill the crack and weld them up. I was also going to fish plate the corners to keep it from happening again. Fish plate? In simple terms, a fish plate is a method of reinforcement where a "plate" of steel overlaps the joint being welded, and does so in such a way to break the weld line of the original joint and disperse the stress load over a wider area. If you google search it, you will find a lot of results on it. Link to comment Share on other sites More sharing options...
CJ's MJ Posted May 28, 2015 Author Share Posted May 28, 2015 That's the bad thing about buying an older vehicle. You just don't know what the previous owner(s) have done to it. When I bought my MJ I had no clue as to what may be wrong with it. At times I think I should have passed on it lol. Don't get me wrong I really like my truck it's just getting it back in good condition is costly. Lol. By the time I get it to where I want it more than likely I will have invested several $1000s in it. Unfortunately being on Guam everything I need I have to have shipped. Back there I could run to the JY and save a lot. I am starting to understand why so many people list them on craigslist for $20k lol. That being said what's my best options to reinforce it? One day I would like to be able to take it out and do some wheeling. Lol Did you ever run a Carfax or similar on your truck? It would be interesting to see where it originally came from and how long it's been on Guam. I sold a Chevy Celebrity I had to a local when I left there to move to the Marshall Islands in the early 90s. A few years later I was on my way to Japan via Continental Air and took an overnight on Guam. The taxi that I used from the airport to the hotel turned out to be the same Celebrity I had sold years before. Found out it had been sold several times since I left and was still chugging around earning $$ as a taxi. :yes: No I haven't done that yet. I will check it out later today after work. You are right would be interesting to find out where it came from. Link to comment Share on other sites More sharing options...
CJ's MJ Posted May 28, 2015 Author Share Posted May 28, 2015 I posted this same subject about 2 years ago. I found cracks at all four corners on my 86. I still have not fixed it. It has been sitting torn apart for years now. Once I finish my 89 I'll get back on it. My plan was to stop drill the crack and weld them up. I was also going to fish plate the corners to keep it from happening again.Fish plate? In simple terms, a fish plate is a method of reinforcement where a "plate" of steel overlaps the joint being welded, and does so in such a way to break the weld line of the original joint and disperse the stress load over a wider area. If you google search it, you will find a lot of results on it. Awesome idea. I will definitely implement it in when it is getting repaired. Thanks a lot. :-) Link to comment Share on other sites More sharing options...
Incommando Posted May 28, 2015 Share Posted May 28, 2015 I posted this same subject about 2 years ago. I found cracks at all four corners on my 86. I still have not fixed it. It has been sitting torn apart for years now. Once I finish my 89 I'll get back on it. My plan was to stop drill the crack and weld them up. I was also going to fish plate the corners to keep it from happening again.Fish plate? In VERY simple terms think of it as running a large washer under a bolt head to distribute the load. It is a plate placed over a repaired area or one subject to exta stress to spread the load Link to comment Share on other sites More sharing options...
jimoshel Posted May 28, 2015 Share Posted May 28, 2015 I think you answered your own question -- Roll Bar.People don't put roll bars in vehicles they drive to the Quik Mart three times a week. The provious owner probably wheeled the truck hard and the roll bar wasn't stiff enough to prevent the body from flexing.You need to get the cracks drilled at the ends and then TIG welded to prevent propagation.Eagle Sorry Eagle. Gotta disagree with you this time. Many peeps mount roll bars just for looks. Their truck will never leave the pavement. Link to comment Share on other sites More sharing options...
HOrnbrod Posted May 28, 2015 Share Posted May 28, 2015 True Jim. That's why they call them "sport" bars. Purely for cosmetics. Link to comment Share on other sites More sharing options...
jimoshel Posted May 28, 2015 Share Posted May 28, 2015 I once mounted a "Sports bar" on a '62 AH3000 I had. After about the tenth time I banged my head on it I removed it. :fs1: Link to comment Share on other sites More sharing options...
glundblad Posted May 28, 2015 Share Posted May 28, 2015 That's the bad thing about buying an older vehicle. You just don't know what the previous owner(s) have done to it. When I bought my MJ I had no clue as to what may be wrong with it. At times I think I should have passed on it lol. Don't get me wrong I really like my truck it's just getting it back in good condition is costly. Lol. By the time I get it to where I want it more than likely I will have invested several $1000s in it. Unfortunately being on Guam everything I need I have to have shipped. Back there I could run to the JY and save a lot. I am starting to understand why so many people list them on craigslist for $20k lol. That being said what's my best options to reinforce it? One day I would like to be able to take it out and do some wheeling. Lol Did you ever run a Carfax or similar on your truck? It would be interesting to see where it originally came from and how long it's been on Guam. I sold a Chevy Celebrity I had to a local when I left there to move to the Marshall Islands in the early 90s. A few years later I was on my way to Japan via Continental Air and took an overnight on Guam. The taxi that I used from the airport to the hotel turned out to be the same Celebrity I had sold years before. Found out it had been sold several times since I left and was still chugging around earning $$ as a taxi. :yes: Dang, what are the chances? Link to comment Share on other sites More sharing options...
HOrnbrod Posted May 29, 2015 Share Posted May 29, 2015 Damn near slim and none. :rotfl2: I actually saw a turkey turd tan Celebrity in the taxi line; and thought no, it can't be. But it was. It still had the aftermarket dual chrome outlet muffler I put on it years before. Link to comment Share on other sites More sharing options...
CJ's MJ Posted May 29, 2015 Author Share Posted May 29, 2015 One thing about Guam is people will use a car until it falls apart. The locals call them Guam bombs lol. Seen several that actually look as if it's held together by duct tape. A few years back I saw a camery that had no doors, no hood or trunk, had plastic bag taped to the back covering where there should have been glass. It had vice grips for a steering wheel and it is still on the road today. Lol. Link to comment Share on other sites More sharing options...
Pete M Posted May 29, 2015 Share Posted May 29, 2015 I guess the good news is that I've got no memory of anyone having more then the initial hairline cracks, meaning it doesn't seem to propagate into serious structural damage. but rain leakage is an issue. Link to comment Share on other sites More sharing options...
Eagle Posted May 29, 2015 Share Posted May 29, 2015 I think you answered your own question -- Roll Bar. People don't put roll bars in vehicles they drive to the Quik Mart three times a week. The provious owner probably wheeled the truck hard and the roll bar wasn't stiff enough to prevent the body from flexing. You need to get the cracks drilled at the ends and then TIG welded to prevent propagation. Eagle Sorry Eagle. Gotta disagree with you this time. Many peeps mount roll bars just for looks. Their truck will never leave the pavement. Well, we may be talking about different things. I suspect you are talking about those bars that the factory offered that fit in the bed, against the back of the cab. Those aren't roll bars, those are show bars. When the OP said the previous owner had installed a roll bar, I assumed (perhaps incorrectly) that he had put a structural roll bar inside the cab for protection and stiffening when doing severe off-roading. Link to comment Share on other sites More sharing options...
64 Cheyenne Posted May 29, 2015 Share Posted May 29, 2015 I've had cracks around my back glass as long as I've owned the truck (Chief). Top corners only, don't seem to be growing. And in the situation, I'd rather have a proper mounted "show bar", VS a NO Bar. FWIW, my Chief did have a factory bar at one time, but no longer there. Maybe it actually helped cause the cracks because of the stiffness it added, but being in the wrong plane to offer the correct total structural reinforcement. Link to comment Share on other sites More sharing options...
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