csizzle84 Posted January 21, 2018 Share Posted January 21, 2018 hey guys... quick q... how much fore and aft play is acceptable in the entire rear brake assembly? meaning, if you were to grab on to the stout piece of metal that connects the rear caliper to the swingarm, can you move yours a tiny bit forward and backwards? another biker friend hit me the other day and the only visible damage was to the rear fender... I'm just examining everything to be really sure nothing is off. thanks! Link to comment Share on other sites More sharing options...
mossrider Posted January 21, 2018 Share Posted January 21, 2018 It's common for that to rattle around a bit until you touch the rear brake, then it should feel rock solid. Link to comment Share on other sites More sharing options...
r1limited Posted January 21, 2018 Share Posted January 21, 2018 My foreplay usually consist of closing my eyes and fantasizing the brake is from a YZR-M1 Motogp back brake and then a Ducati GP18 touches my left had and ... Oh wait sorry, What @mossrider said Damn I embarrass myself “Laws that forbid the carrying of arms disarm only those who are neither inclined nor determined to commit crimes.” --Thomas Jefferson quoting Cesare Beccaria Link to comment Share on other sites More sharing options...
csizzle84 Posted January 21, 2018 Author Share Posted January 21, 2018 right on... thanks for the help Link to comment Share on other sites More sharing options...
markstertt Posted January 22, 2018 Share Posted January 22, 2018 12 hours ago, csizzle84 said: hey guys... quick q... how much fore and aft play is acceptable in the entire rear brake assembly? meaning, if you were to grab on to the stout piece of metal that connects the rear caliper to the swingarm, can you move yours a tiny bit forward and backwards? another biker friend hit me the other day and the only visible damage was to the rear fender... I'm just examining everything to be really sure nothing is off. thanks! Absolutely none...you can wiggle the caliper on it's pins but the 'stout piece of metal' or caliper bracket is fixed solid once you torque your axle nut down...if it's moving then something is loose that shouldn't be. Of course, I don't know if you are actually grabbing the caliper vs. the mounting bracket when you feel the wiggle but I will assume you know the difference from what you wrote so something is up...Mark Ok, that answer was to brief and I started to worry...I don't know where or how hard your bike was hit but if that mount is loose then most likely so is your rear axle and you may even have a damaged swing arm, bent axle, bent/damaged wheel or all the above just to name a few. I would recommend not riding this bike until you've got it up on a rear paddock stand and checked it out, if you don't know what you're looking for then please get an experienced person or mechanic to take a look at it for you. A lot of things to consider really so if the axle nut has lost torque and allowing that movement then you need to figure out why. Be safe, not sorry...M Link to comment Share on other sites More sharing options...
csizzle84 Posted January 22, 2018 Author Share Posted January 22, 2018 @markstertt Hey man...I appreciate your help. Here's what I should have done from the beginning: Let me know what you think. Thanks! Link to comment Share on other sites More sharing options...
rick Posted January 22, 2018 Share Posted January 22, 2018 W/o having my hands on mine, I'd say that really should not move. Looks like part #10 here is rotating https://www.yamahapartsnation.com/oemparts/a/yam/53a99b08f8700220a4415848/rear-brake-caliper I would think - like markstertt well described - once the axle has been torqued, that shouldn't move - even a bit. If you grab the wheel at 3 and 9 o'clock, and give it a tug back and forth, will the wheel move? With that bracket so loose, I'd guess yes. If that's the case, do not ride until the axle nut is properly torqued. Link to comment Share on other sites More sharing options...
markstertt Posted January 22, 2018 Share Posted January 22, 2018 That assy. should not move if your axle nut is torqued properly, do you know if it was torqued to Yamaha specs before the hit? If you know that it was, then I would suggest more investigation and not just torqueing the nut and moving on. At the least check and see if the wheel is still in alignment, quick and dirty check is to see if the alignment hash marks are roughly the same, left and right, if you knew where they were before the hit and aren't in the same place now, then we've got a clue. Do as Rick suggested with the bike on a rear stand and check for wheel movement grabbing not only the wheel (top and bottom) but also the sprocket carrier and see if you get movement there. My concern is that if the axle was originally torqued correctly and after the hit it's now lost torque, I'd want to know what happened mechanically to allow this loss. Let us know what you knew of the bikes condition before the hit and any recent maintenance that you've done on the rear. No need to speculate to much, right? Link to comment Share on other sites More sharing options...
rick Posted January 22, 2018 Share Posted January 22, 2018 Almost afraid to ask, but have you had the rear tire replaced recently? If so, it was never torqued properly and the hit is just making you now look at stuff. And if that's truly the case, you oddly owe yer friend a drink for causing you to check things before something bad really happened. . Link to comment Share on other sites More sharing options...
csizzle84 Posted January 22, 2018 Author Share Posted January 22, 2018 hey... so the bike probably has around 900 miles now and i got it about 5 months ago... i assume it was torqued to spec from the factory and everything was good. i did check earlier and the hash marks on both sides are aligned. the chain slack seems to be dead on from when i cleaned/checked it a few hundred miles ago, too. I'm going to get it up on the stand and see if there's any play in the wheel itself... but I've already decided I'm going to tear it down and inspect everything...it's nagging at me now. the strike came from the right rear at around 10-15 mph...i don't know exactly where it hit and i want to spend a little more time searching for clues... i have some theories about what's going on and they're dependent on what got hit. I'll keep you guys posted. thanks! Link to comment Share on other sites More sharing options...
rick Posted January 22, 2018 Share Posted January 22, 2018 Just riding the bike tends to pull the axle forward - against the adjusters, So it's possible the wheel could have been loose and the chain would stay in adjustment. Would think the wheel would make some clunking noises though. You'll know 2 secs after you put a wrench on the axle nut. Link to comment Share on other sites More sharing options...
rick Posted January 22, 2018 Share Posted January 22, 2018 So, just got home and put hands on mine - Tight as a drum! From what I can see, that brake mount plate gets squeezed between the right side wheel spacer and the swinger. There's no way it can rotate like that - unless the axle is not tight. I'm guessing the hit from the side just caused you to look and it's been this way for a long while. If that's the case, kudos to the shop that prepped the bike for you. Link to comment Share on other sites More sharing options...
csizzle84 Posted January 22, 2018 Author Share Posted January 22, 2018 @rick Dude, that's awesome -- big thanks for checking yours and letting me know. Sadly, I bet you're right about it being this way all along... I'll keep the updates going as I know more... Link to comment Share on other sites More sharing options...
Premium Member blackout Posted January 22, 2018 Premium Member Share Posted January 22, 2018 25 minutes ago, csizzle84 said: @rick Dude, that's awesome -- big thanks for checking yours and letting me know. Sadly, I bet you're right about it being this way all along... I'll keep the updates going as I know more... If you try to loosen or tighten the axle nut, spray WD-40 on the axle threads that are showing past the nut to clean any debris off the threads and metal locking mechanism. These nuts are know to seize when dirt gets between the threads and metal locking piece that is at the end of the nut. Craig Mapstone Upstate New York Link to comment Share on other sites More sharing options...
csizzle84 Posted January 22, 2018 Author Share Posted January 22, 2018 @blackout Hey...thanks for the advice...will do. Link to comment Share on other sites More sharing options...
markstertt Posted January 22, 2018 Share Posted January 22, 2018 1 hour ago, rick said: So, just got home and put hands on mine - Tight as a drum! From what I can see, that brake mount plate gets squeezed between the right side wheel spacer and the swinger. There's no way it can rotate like that - unless the axle is not tight. I'm guessing the hit from the side just caused you to look and it's been this way for a long while. If that's the case, kudos to the shop that prepped the bike for you. Exactly Rick...that assy. is a stack up of parts that are 'as one' once the axle is torqued up...from one side of swing arm thru the wheel bearings/spacers, sprocket carrier and thru to opposite side of swing arm...no play. I'm thinking this is the most likely scenario....also. Link to comment Share on other sites More sharing options...
mossrider Posted January 23, 2018 Share Posted January 23, 2018 I hate to be bearer of truth here but every single one of your bike's has that 'play' in the brake stay depicted in the video. Just because you cannot feel it with the limited torque your fingers are capable of exerting does not mean it isn't there because it still is. If you doubt this put the rear on a paddock stand, lock the rear brake via lever pressure, grab the wheel and give it a healthy rotational forward/backward twist. There it is. By design. This bIke has a non floating rear brake. There are many pros to this type of system. It is cheap, simple and reliable system used on many models for many years, both drum and disc setups. One of the downsides of this type of system however is brake hop or 'clatter'. Many of you have experienced this during hard braking over washboard or pot holed surfaces. It manifests itself as the loud metallic "CLACK, CLACK, CLACK" heard during a panic stop or wheel skid over very rough ground or when the rear wheel looses/regains traction. That sound is caused by the exact motion he is demonstrating in that video clip and no matter how much you over tighten the axle nut you can't stop it from happening since the forces acting on the system simply overpower the frictional forces on the 'axle stack' as others have mentioned. In actuality there is nothing affixed to the axle, everything just slides over it. If you doubt this pull the axle out of the bike and take a picture of every thing that remained attached to it. All those spacers, bearings, blah, blah will move on it. Bottom line: All of our bikes have that play. It is harmless (assuming nothing is broken, missing or installed wrong) I've attached an old diagram that kind of depicts what is going on. Ours is obviously a variation since our brake stay is a fork that straddles a lug on the back side of the swingarm but the function is the same. The forces are transmitted through the rear suspension, not directly into the chassis. Link to comment Share on other sites More sharing options...
Premium Member blackout Posted January 23, 2018 Premium Member Share Posted January 23, 2018 54 minutes ago, mossrider said: I hate to be bearer of truth here but every single one of your bike's has that 'play' in the brake stay depicted in the video. Just because you cannot feel it with the limited torque your fingers are capable of exerting does not mean it isn't there because it still is. If you doubt this put the rear on a paddock stand, lock the rear brake via lever pressure, grab the wheel and give it a healthy rotational forward/backward twist. There it is. By design. This bIke has a non floating rear brake. There are many pros to this type of system. It is cheap, simple and reliable system used on many models for many years, both drum and disc setups. One of the downsides of this type of system however is brake hop or 'clatter'. Many of you have experienced this during hard braking over washboard or pot holed surfaces. It manifests itself as the loud metallic "CLACK, CLACK, CLACK" heard during a panic stop or wheel skid over very rough ground or when the rear wheel looses/regains traction. That sound is caused by the exact motion he is demonstrating in that video clip and no matter how much you over tighten the axle nut you can't stop it from happening since the forces acting on the system simply overpower the frictional forces on the 'axle stack' as others have mentioned. In actuality there is nothing affixed to the axle, everything just slides over it. If you doubt this pull the axle out of the bike and take a picture of every thing that remained attached to it. All those spacers, bearings, blah, blah will move on it. Bottom line: All of our bikes have that play. It is harmless (assuming nothing is broken, missing or installed wrong) I've attached an old diagram that kind of depicts what is going on. Ours is obviously a variation since our brake stay is a fork that straddles a lug on the back side of the swingarm but the function is the same. The forces are transmitted through the rear suspension, not directly into the chassis. Be that as it may, his axle is most likely not torqued to spec allowing the play to be easily felt. A proper clamping force on the axle nut should snug the caliper bracket such that it can not move under typical braking forces. Otherwise, there would be excessive wear over time on the bracket and, or swingarm. Craig Mapstone Upstate New York Link to comment Share on other sites More sharing options...
mossrider Posted January 23, 2018 Share Posted January 23, 2018 Well then he should by all means put a proper snug on it then. 😆 Point being even if he can't move it with his fingers no matter how tight the nut is braking forces will move the parts as needed and they will never wear out. Link to comment Share on other sites More sharing options...
markstertt Posted January 23, 2018 Share Posted January 23, 2018 If it wasn't for the fact that we need to move our wheel back and forth for chain adjustment, we could just through drill that brake stay on the swing arm and the caliper bracket and install a bolt and there would be no slop in the brake assy. and if production tolerances were such that the stay on the swing arm and the corresponding groove in the caliper bracket were a snug fit, then there would also be no relative movement which would be ideal. Any movement in that caliper mount bracket is a design consideration that is acceptable in a mass produced bike with production line tolerances. It's the way it's done, I know, is it a big deal...no...but in csizzle84's case, he can move it by hand and that is the issue here...right? Rick may be right, csizzle84's torque may have been light from the start (set up) and has been getting worse the more the parts have moved causing wear between the swing arm and caliper bracket, bracket and spacer etc. and I think this might be evident by how much slop the video shows as csizzle rotates the bracket about the axle...this may have resulted in some hammering damage to the caliper brackets groove considering the bracket is aluminum and the swing arm lug is steel. Chafing wear on the other components may also be evident. Just something to check as I'm not one to just torque it down without looking. This would be a good time to pull that axle and look at all the components, with only 900 miles there just may be some warranty considerations...maybe he had the 600 mile check done and that's when it was left loose? Just thinking out loud here...food for thought. mossrider, a fully floating rear brake would be ideal but like you said, what we have is a cheap production compromise that works and 99% of bike owners probably don't know the difference any way. Now you may have started something, I have some extra Brembo rear calipers and might just convert mine to a full floater...that darn fat tire and Yoshi can leave me little room if any for the brake stay but will look at it any way. ok, so I just went out and undid my rear axle nut to see what kind of slop my bike actually has with no torque, I can move the caliper mount the same as in csizzle84's video but mine doesn't appear to be as much...subjective I know but at least I looked and of course once torqued I can't move anything. I would still want to pull my axle and check the components if I were csizzle84, the loose torque would allow the bearing inner races to possibly spin on the axle grooving it...not acceptable in my book, esp. on a new bike. Csizzle84, I don't know your situation but if the dealer has been the only one to do maintenance on your bike then you may consider taking it back before doing anything and ask him to check it out now that you know that indeed your axle nut torque is off and you should now have an idea what damage or wear possibly could occur. The only fly in the ointment is the fact that your buddy crashed into the back of your bike...good luck...Mark Link to comment Share on other sites More sharing options...
markstertt Posted January 23, 2018 Share Posted January 23, 2018 Csizzle84, there is one thing I forgot to mention last night when I released torque on my axle nut to check for the free play as in your video. I released torque in increments until the bracket would 'just' move easily, at this point there was still some torque on the nut and with the bike held upright in a front wheel chock, I could not move the wheel by hand by grabbing at the rear and jerking it side to side. So one could surmise that, although loose, your axle nut torque may not have been loose enough to have noticed except by accident as you did. I would still want to look at the axle etc. but that's just me being cautious and curious and having the available stands to do this inspection easily. Easiest scenario is to do as mossrider suggested, torque it up and carry on but I would add to check chain tension and alignment and use a torque wrench to set torque on the axle nut. 76 ft. lbs.. per Yamaha. Link to comment Share on other sites More sharing options...
csizzle84 Posted January 23, 2018 Author Share Posted January 23, 2018 @markstertt Hey Mark...thanks for that...can't convey how much I appreciate it. I think we're thinking the same way here -- I want to set my torque wrench low and step it up incrementally as I try and tighten the axle nut. My goal is to figure out what it's currently torqued to without tightening it any further. From there, I'll tear it all down and inspect... I did do a little snooping around last night and the strike point seems to be on the tire only. There's a big smudge in the shape of another tire on my rear tire...so I'd say it was mostly tire-to-tire contact. My rear fender took some of it, too. It wasn't hard enough to loosen its mount under the tail, but it cracked a lot of the cheaper/weaker plastic around the license plate... Of course that necessitated ordering that fender tidy up kit that I wanted -- and a bunch of additional shet for the bike I had told myself would came later in the year, too... oh darn. ;-P It might be a few days before I get it tore down, but it'll happen ASAP. I'll keep the updates coming. Thanks everyone! Link to comment Share on other sites More sharing options...
rick Posted January 23, 2018 Share Posted January 23, 2018 Clearly, there's more friction on the adjusters than on the round flange of that caliper mounting plate. Gonna agree with pulling it apart to have a look at everything - including a reach in to the wheel bearings to feel for smoothness. It'll probably be just fine, but the thing's already on the stand and the tools are out, so may as well have a look. Link to comment Share on other sites More sharing options...
rick Posted January 23, 2018 Share Posted January 23, 2018 2 hours ago, csizzle84 said: @markstertt I want to set my torque wrench low and step it up incrementally as I try and tighten the axle nut. My goal is to figure out what it's currently torqued to without tightening it any further. From there, I'll tear it all down and inspect... It's really hard to use a torque wrench to determine how much has been applied to a fastener. Static friction is always gonna make it look like there's more torque than what's really been applied as you'll have to overcome that friction before the nut starts to get tighter - or looser for that matter - something that's not advisable to try with a torque wrench. We're thinking it's gonna be way loose. What the actual number is, well, . Link to comment Share on other sites More sharing options...
markstertt Posted January 24, 2018 Share Posted January 24, 2018 7 hours ago, csizzle84 said: @markstertt Hey Mark...thanks for that...can't convey how much I appreciate it. I think we're thinking the same way here -- I want to set my torque wrench low and step it up incrementally as I try and tighten the axle nut. My goal is to figure out what it's currently torqued to without tightening it any further. From there, I'll tear it all down and inspect... I did do a little snooping around last night and the strike point seems to be on the tire only. There's a big smudge in the shape of another tire on my rear tire...so I'd say it was mostly tire-to-tire contact. My rear fender took some of it, too. It wasn't hard enough to loosen its mount under the tail, but it cracked a lot of the cheaper/weaker plastic around the license plate... Of course that necessitated ordering that fender tidy up kit that I wanted -- and a bunch of additional shet for the bike I had told myself would came later in the year, too... oh darn. ;-P It might be a few days before I get it tore down, but it'll happen ASAP. I'll keep the updates coming. Thanks everyone! Sounds good, you should find the torque to be quite a bit less then optimal...yeh, good excuse to buy stuff but to bad it had to happen at all. Hope your buddy is giving you a hand if nothing else. Link to comment Share on other sites More sharing options...
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