NCSprinter30 Posted January 10, 2014 Report Share Posted January 10, 2014 I've stripped my brake calipers, all of the bolts holding the calipers together were pretty seized. When reassembling them is it wise to copperslip the bolts? Also should I lube the whole piston with red rubber grease or just the seal once it's seated in the caliper? Link to comment Share on other sites More sharing options...
Alex_H Posted January 10, 2014 Report Share Posted January 10, 2014 I've never been a massive fan of copper slip on caliper bolts myself, its the one set of bolts on the bike I dont want coming out easily. And I just use red rubber grease on the seals, should be fine as long as the piston is in good order. Link to comment Share on other sites More sharing options...
owene Posted January 10, 2014 Report Share Posted January 10, 2014 Why would using copper slip cause the bolts to come out?? Lubricated bolted joints work better than dry ones, since more of the applied torque goes into stretching the bolt, rather than overcoming friction on the thread. Link to comment Share on other sites More sharing options...
BudgetBoy Posted January 10, 2014 Report Share Posted January 10, 2014 No to copper slip Red grease on seals Job jobbed. Link to comment Share on other sites More sharing options...
Gusset Posted January 10, 2014 Report Share Posted January 10, 2014 I usually copper slip the bolts because I hate seizures; but I always thought the important place was on the back of the pads to stop them squeaking. Link to comment Share on other sites More sharing options...
Superdunc Posted January 10, 2014 Report Share Posted January 10, 2014 I always soak the new seals in brake fluid for a few hours, or ideally a day, before installing them, which makes assembly much easier. This was recommended to me buy a brake manufacturer. If you use rubber grease, you only need the lightest smear on the sides of the piston. Link to comment Share on other sites More sharing options...
NCSprinter30 Posted January 10, 2014 Author Report Share Posted January 10, 2014 Thanks very much for the advice, is scotchbrite OK to clean the pistons up with? It won't damage the finish will it? Link to comment Share on other sites More sharing options...
owene Posted January 10, 2014 Report Share Posted January 10, 2014 I used Scotchbrite to do just that, and it worked a treat. Easiest way is to lay the Schotchbrite pad on the table, and rub the piston across it. Link to comment Share on other sites More sharing options...
Alex_H Posted January 10, 2014 Report Share Posted January 10, 2014 Why would using copper slip cause the bolts to come out?? Lubricated bolted joints work better than dry ones, since more of the applied torque goes into stretching the bolt, rather than overcoming friction on the thread. When torquing such bolts does your manual give you a torque for a dry thread or a lubricated one? Because it wouldn't be the same value. Link to comment Share on other sites More sharing options...
owene Posted January 11, 2014 Report Share Posted January 11, 2014 Fair enough, and good point about the torque values. I've used copper slip on caliper mounting bolts and not had any problems, but that's not a big sample I guess. Link to comment Share on other sites More sharing options...
bignige Posted January 11, 2014 Report Share Posted January 11, 2014 And also allows the fastener to come undone easier. There are plenty of documented instances of the wrong fastener finish being used (BZP being in place of natural for example) and having been responsible for the failure of the joint, let alone the use of a lubricating medium. As I've mentioned before, I helped an engineering company that was consulting for Kent Constabulary when they investigated the death of a bike engined kit car driver at Brands Hatch. The builder, who was also the driver, had used copperslip liberally on every fastener when building the car and this had resulted in the sprocket carrier bolts coming undone and the drivetrain locked up. Could they have come undone by not being tightened correctly in the first place? Or was the use of copperslip directly responsible for it? Link to comment Share on other sites More sharing options...
Recommended Posts
Archived
This topic is now archived and is closed to further replies.