wherearewe
Rub on Ya Titties
Just like the title says, should I use loctite on the retaining bolts for my disc to the hub (in addition to the locking tabs). Blue or Red?
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Brake Disc Retaining Bolts - Loctite ?
- Thread starter wherearewe
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- brakes maintenance
Just like the title says, should I use loctite on the retaining bolts for my disc to the hub (in addition to the locking tabs). Blue or Red?
I use a little "Never-seize" on the threads, and regular lock washers. Torque to 14 ft-lbs.
You could use blue locktite if you want to..................don't use red.
osteoderm
out of the box
The locking tabs, properly applied, should do as their name suggests; I'm with retiredgent, and suggest the neverseize, as you have steel fasteners going into aluminium, which can cause issues down the road.
Having said that, I've used round allen button-heads for my rotors, making the standard locking tabs useless, and gone with loctite, and had zero issues. Blue loctite only, modestly applied to scrupulously clean/degreased threads.
Having said that, I've used round allen button-heads for my rotors, making the standard locking tabs useless, and gone with loctite, and had zero issues. Blue loctite only, modestly applied to scrupulously clean/degreased threads.
wherearewe
Rub on Ya Titties
Thanks guys. My gut told me a little blue loctite was prob the one.
Chiming in here
Stainless steel socket head bolts.
if you look close you can see they are drilled and safety wired, no fluids used.
Stainless steel socket head bolts.
if you look close you can see they are drilled and safety wired, no fluids used.
jd750ace
Front Toward Enemy
A drilled head cap screw is not your typical hardware store bolt, at least not at my hardware store. They are more than likely a higher specification.
Check out this place when it comes to specialty hardware for your bike.
http://www.metricmcc.com/
Check out this place when it comes to specialty hardware for your bike.
http://www.metricmcc.com/
Well yes there are some variations with stainless yield strength. But most stainless bolts of reputable manufacture will have properties approximating grade 5 bolts. I don't recall a grade marking on the original bolts? IE they are not high grade? The 6 bolt Yamaha disk attachment is somewhat over engineered compared to modern brake attachment methods. I am not worried. I might also suggest the aluminum hub threads would be the weak point. It is probably best to use a bolt with a full size unthreaded shank. I think more modern hubs also have an unthreaded bore to accept the bolt shank before the threads start, that allows a much shorter arm between the rotor and hub and a larger cross section of bolt shank to take torque loads absorbed at the interface. Newer Yamaha brake bolts are designed that way but the hub would have to be drilled out to accept those bolt shanks. It would also reduce the amount of threads in the aluminum. Somewhat of a trade off. I did spend a bit of time reading standards before using the stainless bolts on my own bike. Not sure if I chose wisely or rationalized what I chose.... I probably should use blue lock-tite and torque them but I did neither on this bike. I did find an "expert" who claimed anti seize calls for a 30 to 40% reduction in torque when using anti seize compared to lock-tite or light oil. What's the Yamaha torque spec for these bolts?
A BMW guy bolt discourse.
A BMW guy bolt discourse.
PS I'm guilty of safety drilling my own bolts. Did em all on one sharpening of the drill bit!
I buy my bolts at Fastenal They are probably a bit tighter about spec and quality than F&F and Menards!
I buy my bolts at Fastenal They are probably a bit tighter about spec and quality than F&F and Menards!
Gary, I like your front brake set-up. I'm sure the safety wiring will get the job done, without locktite on the threads.
I find the Anti-seize works fine, and I use 14 ft-lb torque, which is normal spec for 8 mm bolts. I've had my disks on and off 3 times over the years, and when I remove the bolts, they are always just as tight as when they are installed. I also use the split type lock washers.
If you work in the aircraft or nuclear industry, then calibrated torque wrenches, and exacting bolt material specs are very important. However, these are just motorcycles, and I don't feel the need to be that precise. I just occasionally check the bolts on the bike, and if they haven't backed off, then all is well.
I find the Anti-seize works fine, and I use 14 ft-lb torque, which is normal spec for 8 mm bolts. I've had my disks on and off 3 times over the years, and when I remove the bolts, they are always just as tight as when they are installed. I also use the split type lock washers.
If you work in the aircraft or nuclear industry, then calibrated torque wrenches, and exacting bolt material specs are very important. However, these are just motorcycles, and I don't feel the need to be that precise. I just occasionally check the bolts on the bike, and if they haven't backed off, then all is well.
wherearewe
Rub on Ya Titties
So no one here uses Loctite - Just good old anti-seize and split washer or the lock tab. Ok cool - looks like i was gonna over cook it! The SS cap screws look sharp I must say. The specs for the replacement bolt are M8 25mm into a mag?
jd750ace
Front Toward Enemy
In high heat applications, or in the case of dissimilar metals, dip your fasteners in milk of magnesia. Heat does not adversely affect the residure, and it prevents galvanic corrosion in the threads. The manganese acts as a sacrificial layer, and if either material reacts with it, the oxides formed do not attack the other material. We used Zinc Chromate primer for that in the old days. If you do it that way now, it's Zinc Phosphate (if you can still get THAT where you live) but the old WWII era field answer is milk of magnesia. Still used to this day to install igniters in tens of thousands of Williams-Rolls turbine engines. Great for exhaust bolts.
Also, if you are into shade tree engineering (no skin on the wall here kids!) take the chart in Gary's post. 12 fasteners, 8 MM in diameter and a 5 MM thick disc is 40 square millimeters of bearing area per bolt times 12 bolts is 480 square MM of bearing area, or .744 square inches. Multiply that by the yield strength in the chart and it would take 42,408 Pounds of pressure to yield all 12 bolts. The minimum bearing yield value for a common wheel casting alloy, A356 in the T6 artifically age hardened condition, is 44,000 PSI, so the grade 2 bolt will support more load than the wheel over that area, with an edge marging of 1.5 diameters. Since that's not the case, the bearing yield value of the aluminum is 52000 PSI, which when multiplied by the .744 inches of bearing area, the aluminum stii fails before the grade 2 bolt. Of course that's shit house math, and MANY factors are not taken into account, and that's not how simple it really is, but done correctly, given the shade tree math produces a margin of nearly 20% in favor of the fastener, I'd say even a grade 2 would work just fine in that application. As I said, I'm not an engineer, but I have built and maintained aircraft successfully for over 25 years in spite of them!
PS, a good safety wire job looks trick!
Also, if you are into shade tree engineering (no skin on the wall here kids!) take the chart in Gary's post. 12 fasteners, 8 MM in diameter and a 5 MM thick disc is 40 square millimeters of bearing area per bolt times 12 bolts is 480 square MM of bearing area, or .744 square inches. Multiply that by the yield strength in the chart and it would take 42,408 Pounds of pressure to yield all 12 bolts. The minimum bearing yield value for a common wheel casting alloy, A356 in the T6 artifically age hardened condition, is 44,000 PSI, so the grade 2 bolt will support more load than the wheel over that area, with an edge marging of 1.5 diameters. Since that's not the case, the bearing yield value of the aluminum is 52000 PSI, which when multiplied by the .744 inches of bearing area, the aluminum stii fails before the grade 2 bolt. Of course that's shit house math, and MANY factors are not taken into account, and that's not how simple it really is, but done correctly, given the shade tree math produces a margin of nearly 20% in favor of the fastener, I'd say even a grade 2 would work just fine in that application. As I said, I'm not an engineer, but I have built and maintained aircraft successfully for over 25 years in spite of them!
PS, a good safety wire job looks trick!
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This was one article I found on stainless bolts. I've got stainless bolts all over my bike and I'm pretty sure they are up to the task but probably not much stronger than any other common bolt...but no rust.
http://reviews.ebay.com/Stainless-Bolts-Usually-very-weak?ugid=10000000001623345
http://reviews.ebay.com/Stainless-Bolts-Usually-very-weak?ugid=10000000001623345
jd750ace
Front Toward Enemy
Stainless is like any other material. It's properties are modified by alloy and heat treating. It's possible for incredible strength to be extracted from stainless today. Many high tension bolts on aircraft are stainless now because you can equal or exceed design strength of a joint easily, and the stainless is not prone to hydrogen embrittlement, corrosion, and stress corrosion fracturing as many carbon steels are. It's not ideal in all applications, but it's utility is far above what it was 30 years ago.
osteoderm
out of the box
I'll try to stay out of the metallurgy debate, but I will say this: dissimilar metals should always be isolated somehow. Stainless bolts can and will "weld" themselves to aluminium. I see examples of this every day in my work troubleshooting and repairing marine systems. With stainless on stainless, I see endless evidence of galling as well.
Just a little appropriate lubrication goes a long ways in these cases. I default to Tef-Gel for pretty much any/all threaded parts, especially in cases of dissimilar materials. Duralac isolates just as well, and adds some threadlocking. Some of the Loctite products go further in that regard (and for those who don't already know, Loctite has a few bajillion compounds besides just "red" and "blue").
Anti-seize compounds and that great milk of magnesia trick are helpful to both lubricate and isolate. Use whatever goop you prefer, but at very least threads should be clean and very lightly oiled; dirty/dry threads can be difficult to properly install and torque.
Oh and gggGary, have you seen one of these? It's on my wishlist.
Just a little appropriate lubrication goes a long ways in these cases. I default to Tef-Gel for pretty much any/all threaded parts, especially in cases of dissimilar materials. Duralac isolates just as well, and adds some threadlocking. Some of the Loctite products go further in that regard (and for those who don't already know, Loctite has a few bajillion compounds besides just "red" and "blue").
Anti-seize compounds and that great milk of magnesia trick are helpful to both lubricate and isolate. Use whatever goop you prefer, but at very least threads should be clean and very lightly oiled; dirty/dry threads can be difficult to properly install and torque.
Oh and gggGary, have you seen one of these? It's on my wishlist.
Marvelicious
Naturally Aggravated
My reading indicates that he is full of it when it comes to the strength issue. A2 (which are fairly common in my experience) fasteners come in 70 and 80 grade which equate to 70,000 and 80,000 psi tensile strength: in between grade 5.8 and 8.8. I wouldn't just buy whatever from the bin at the hardware store without seeing the box, but if it says A2 on it, it's pretty strong.
Galling is definitely an issue with stainless on stainless.
I dig that drill guide, and I'm definitely a fan of safety wire.
jd750ace
Front Toward Enemy
Here's the hot setup for do-it-all drill guides.
http://www.ntxtools.com/network-tool-warehouse/OTC-4794.html?gclid=COGKiebX5LQCFUid4AodCVsARA
I don't do commercial grade bolts in general, just aerospace, but there are some parallels. If it's not inside the cases or holding them, or the suspension on, odds are your hardware store stuff will be just fine. Not a big market for shitty bolts and screws.
Agree- Stainless on stainless is prone to galling.
http://www.ntxtools.com/network-tool-warehouse/OTC-4794.html?gclid=COGKiebX5LQCFUid4AodCVsARA
I don't do commercial grade bolts in general, just aerospace, but there are some parallels. If it's not inside the cases or holding them, or the suspension on, odds are your hardware store stuff will be just fine. Not a big market for shitty bolts and screws.
Agree- Stainless on stainless is prone to galling.
