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Posted: 10/5/2012 10:16:23 PM EDT
So I'm posting this in GD so I can hopefully get an answer before I need to use my car.
I just replaced my brakes, all four wheels, and forgot to order the single use bolts I was supposed to use on the brake calipers. Each caliper has two bolts. They come with thread locker on them already. Should it be a problem if I just cleaned the bolts, put some new thread locker on, and drove it like that until the replacements arrive? |
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Brakes are pretty important. Yeah, which is why I'm trying to find the answer before driving on them. |
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Quoted: Quoted: Brakes are pretty important. Yeah, which is why I'm trying to find the answer before driving on them. I would get new ones. It would really suck if a caliper fell off while driving on the freeway. |
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I am curious, what vehicle and what was torque value required and applied?
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If they are torque to yield bolts, replacing them is very important. (I doubt they are these though) Most chassis bolts that require replacement for locktite only can be reused, just add a drop of it on each one. Manufactures specify replacement for liability purpose, because these bolts are critical.
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They're not torque to yield bolts, they don't need to be replaced. Manufacturers recommend you get new bolts because they come with thread locker and only for that reason. They are not going to assume you know how to clean and reapply your own thread locker, so they tell you to buy new ones with thread locker already applied.
OP, clean the old stuff off and apply new thread locker. |
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So I'm posting this in GD so I can hopefully get an answer before I need to use my car. I just replaced my brakes, all four wheels, and forgot to order the single use bolts I was supposed to use on the brake calipers. Each caliper has two bolts. They come with thread locker on them already. Should it be a problem if I just cleaned the bolts, put some new thread locker on, and drove it like that until the replacements arrive? No. Between the heat, the threads getting stretched, and then being torqued and retorqued, you're magnifying the probability that the bolts will loosen or break under load. I'd hold off on driving it until you've replaced the bolts. . . . |
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What kind of POS car has single use bolts? A lot of things have single use bolts. And they're not single use because they want to sell you new thread locker. . . . They're pretty common in areas that see a lot of heat, corrosive conditions, or in this case, both. |
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He should probably be replacing wheel studs every time he gets the tired rotated too then huh.
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So I'm posting this in GD so I can hopefully get an answer before I need to use my car. I just replaced my brakes, all four wheels, and forgot to order the single use bolts I was supposed to use on the brake calipers. Each caliper has two bolts. They come with thread locker on them already. Should it be a problem if I just cleaned the bolts, put some new thread locker on, and drove it like that until the replacements arrive? No. Between the heat, the threads getting stretched, and then being torqued and retorqued, you're magnifying the probability that the bolts will loosen or break under load. I'd hold off on driving it until you've replaced the bolts. . . . |
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They specified torque to 100N/m and this was on a 2000 Volvo V70R.
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Yeah. If there is no corrosion , and unless you abuse and change brake pads like they do at a NASCAR short track, a drop of blue lock tite on each one, and you will be good to go.
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]He should probably be replacing wheel studs every time he gets the tired rotated too then huh. Yes, because thats completely the same application as what the op said. . . . . Those don't get as hot, due to distance, more cooling, and are going to be larger than the bolts in the OP's question - so the effects of heat and corrosion will be less extreme. |
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googled it and found this:
http://volvospeed.com/vs_forum/topic/50562-re-use-of-15mm-caliper-bolts/ i lol'd at: I reused one bolt one time and my entire house fell over, the sky turned red and meteors fell from the sky creating large holes in the ground letting out hot MAGMA that burned me very, very badly!!! ……But my car was fine!!
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]He should probably be replacing wheel studs every time he gets the tired rotated too then huh. Those don't get as hot, due to distance, more cooling, and are going to be larger than the bolts in the OP's question - so the effects of heat and corrosion will be less extreme. Barely larger. There was no corrosion on the thread surfaces. |
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What kind of POS car has single use bolts? Honda, Toyota, VW, BMW, Mercedes, Nissan, Ford, Chevrolet, Chrysler........etc. |
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Most brake caliper retaining bolts receive very little heat due to the fact that brake pads do not transfer heat well, especially in normal day to day driving. I should also add. Since some bolts are also allow the caliper to float, you should also inspect them for wear.
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YES, especially if you are replacing your brakes once a week. Some interesting info: http://www.youtube.com/watch?v=6-XXVk_vwKw Wow. Thanks for posting that. |
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What kind of POS car has single use bolts? Honda, Toyota, VW, BMW, Mercedes, Nissan, Ford, Chevrolet, Chrysler........etc. John Deere, Komatsu, Caterpillar. . . . |
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What kind of POS car has single use bolts? Honda, Toyota, VW, BMW, Mercedes, Nissan, Ford, Chevrolet, Chrysler........etc. John Deere, Komatsu, Caterpillar. . . . Cessna, Boeing, Lockheed.... This is fun! |
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I just replaced the 2.8l engine in my 85 s15 with a scrap yard 3.4l out of a 93 firebird.
Same block, just bigger bore and stroke. Same heads, only different head gaskets. The fel pro head bolt p/n was same for BOTH engines. The fel pro torque data book showed a straight 65-75 ft-lbs of torque for the 85 block where as the data for the 93 block showed 41 ft-lbs plus 90 degrees. Your guess is as good as mine with the only difference possibly being is that the head gaskets may have been different materials in 85 and 93, but today, they are the same material. So to sum it up, I will call it simply the "brother in law" effect. |
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What kind of POS car has single use bolts? Honda, Toyota, VW, BMW, Mercedes, Nissan, Ford, Chevrolet, Chrysler........etc. Iv always had gm, never seen one... |
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This is fun! Its less fun when you watch a $125k engine get turned into scrap because a $0.40 bolt got reused one time too many. |
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I'm thinking he should drill and safety wire these bolts after replacing them with new ones, and adding extra high heat locktite. For liability reasons, I must say I'm kidding.
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Most brake caliper retaining bolts receive very little heat due to the fact that brake pads do not transfer heat well, especially in normal day to day driving. I should also add. Since some bolts are also allow the caliper to float, you should also inspect them for wear. True for carbon/ceramic pads but not so much for sintered metal pads. My calipers get very hot when the car is pushed hard. But, that's the point: to pull heat out of the rotor. -J |
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I'm thinking he should drill and safety wire these bolts after replacing them with new ones, and adding extra high heat locktite. For liability reasons, I must say I'm kidding. Fuck that noise. Drilling causes the metallurgy to change, which could cause the bolt's UTS to be reduced, causing it to relax or fail. The only logical course of action is to replace them with Inconel bolts, with a H7/u6 interference fit, and ultrasonically weld the bastard in place. You know, just to be sure. . . . . |
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What kind of POS car has single use bolts? Honda, Toyota, VW, BMW, Mercedes, Nissan, Ford, Chevrolet, Chrysler........etc. Iv always had gm, never seen one... Honestly, every car I've had previous to this hasn't had them. But they seem to be pretty common on Eurotarded cars. |
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Most brake caliper retaining bolts receive very little heat due to the fact that brake pads do not transfer heat well, especially in normal day to day driving. I should also add. Since some bolts are also allow the caliper to float, you should also inspect them for wear. True for carbon/ceramic pads but not so much for sintered metal pads. My calipers get very hot when the car is pushed hard. But, that's the point: to pull heat out of the rotor. I did say "most brake pads " and "normal day to day driving". Edit - I didn't say most brake pads. But I did say the second part. |
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Most brake caliper retaining bolts receive very little heat due to the fact that brake pads do not transfer heat well, especially in normal day to day driving. I should also add. Since some bolts are also allow the caliper to float, you should also inspect them for wear. True for carbon/ceramic pads but not so much for sintered metal pads. My calipers get very hot when the car is pushed hard. But, that's the point: to pull heat out of the rotor. -J I did say "most brake pads " and "normal day to day driving". HPS Semi metallic, lots of mountain driving! I'm going to replace them anyways with full knowledge that it's probably a fools errand, just because it will bug me otherwise. |
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Nice! This does sound like the solution.
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I'm thinking he should drill and safety wire these bolts after replacing them with new ones, and adding extra high heat locktite. For liability reasons, I must say I'm kidding. Fuck that noise. Drilling causes the metallurgy to change, which could cause the bolt's UTS to be reduced, causing it to relax or fail. The only logical course of action is to replace them with Inconel bolts, with a H7/u6 interference fit, and ultrasonically weld the bastard in place. You know, just to be sure. . . . . |
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Brakes are pretty important. Yeah, which is why I'm trying to find the answer before driving on them. I would get new ones. It would really suck if a caliper fell off while driving on the freeway. Actually they don't fall off - when the first bolt fails the caliper rotates until it hits the inside of the wheel, then it cuts a nice groove in it while you're trying to stop. |
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Nice! This does sound like the solution. Yes. Now I just need $15k to make up a set of bolts and get the work done for the OP. . . . . |
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What kind of POS car has single use bolts? Usually the head bolt are single use stretch bolts, never heard of them being used on calipers |
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No, you don't need to replace the bolts. You should definitely should use plenty of lock-tite though. I actually did have one work it's way out on the highway because I didn't. It's hard to believe they can do that, but they are subject to alot of vibration.
You can use red thread lock. It will still come out easily when you need to change them nexy. |
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Holy crap, I must be screwed!
Not only did I not replace any of the nuts and bolts when I did my brakes, but I didn't use any thread locker either either! Hell, I actually used C-5A copper grease so I could get them apart in the future! I must be SCREWED! OP...I'm pretty damn sure you can re use them at least once. If yours came with thread locker on them (Mine doesn't appear to have ever had any), then clean them up real good and use a dab of locktite on reassembly. Change the bolts next time if it bothers you that much. |
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Those are just grade 12.8 socket head screws, right? I don't see how they could age or fail due to heat if they are. (Or at least I don't see how a responsible engineer would expose them to those conditions). The thread locker is probably the reason.
Though it's possible that the spec'd torque is in the yield region for that fastener in which case they should be replaced. That would be very odd; yield fasteners are generally spec'd as "torque to xyz then a further 120 degrees'" or the like since torque gets weird when the bolt is yielding. |
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I had no idea they were single use bolts. me neither, just did my brakes on my 01 ram 2500 about 2 weeks ago, 5th brake job on the front and 2nd on the rear and used the same caliper bolts each time. J- |
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I have reused caliper bolts without any loctite many times and have never had a problem.
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Quoted: I have reused caliper bolts without any loctite many times and have never had a problem. This... but you can do what you want. Only place I have seen use once only bolts were in the motor. |
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I've never heard of torque to yield bolts being used on a brake system.
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Most thread lockers will fail at brake temp heat ranges. I used "Jet" nuts on road race brakes in the past to prevent failure. Some bolts are better off tossing. My dad would pick up bolts off of the floor in my trash pile to re-use ! WTH really they're in the trash pile for a reason
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