First time in 30 years of riding...
Threads on both attachment points on the rear bracket are completely gone and transferred onto the bolt threads!!
Best mate thinks winter riding and salt could cause this...
Has anyone seen this before?
The only time I have seen something similar was caused by over tightening the bolts into the cast alloy mounting
Yes, someone overtightened them
Corrosion wouldn't do that. A hamfisted mechanic would, though.
Yes I had that happen on my GTR to one of the fixing points. I had to have it helicoiled.
A not too common fault but a fault that does occur, over tightening is the usual cause. Easily enough to repair with a helicoil, once repaired use a small amount of light oil or grease on the bolt threads and torque them up properly rather than risk over tightening again.
That's what I thought but did use torque wrench and locking compound to avoid this and never had a problem before... Going to check my torque wrench is working properly!!!
I have ordered bolts and spare bracket to double check the cast metal not faulty.
Have also helicoil kit so will do this while waiting for new bracket.
Thanks for confirming what I thought... never seen salt doing this...
The problem with coppasliping [ made up word ] threads is that it changes the friction and makes it very easy to overtighten things even with a torque wrench
There are numerous different thread locks and lubricants from makers like Loctite for different metals and applications.
Is the use of locking compound recommended for this application ?
You have steel bolts and cast alloy mounting,
From the manual
Rear Caliper Mounting Bolts 25Nm, 2.5 Kgf-m 18 ft/lb
So not a lot, and no mention of lubricant or thread lock
Most bolts have a "Factory" coating that acts as a lubricant during initial assembly, once undone again a couple of drops of oil on the threads gives the ability to apply the correct torque. It's not in manuals but every factory trained technician is taught about the use of oil as a lubricant for assembly. The use of Loctite on Aluminium parts is discouraged due to the risk of pulling threads during dis assembly.
Thank you all for the very useful information provided.
Have taken everything on board and will double check all bolts and fixings that might have been affected by applying mild strength thread lock compound and by previous jobs.