DJT Posted January 2, 2011 Share Posted January 2, 2011 Guys,Does anyone have a Stag brake caliper in bits? I am trying to obtain some new bolts which secure the two halves together. These are not listed in the online supplier catalogues, despite the fact that the seals between the two halves are available.As I am offshore I cannot measure the ones at home, so if anyone has some lying around they could measure I would appreciate it.Thanks,Dave Link to comment Share on other sites More sharing options...
thescrapman Posted January 2, 2011 Share Posted January 2, 2011 No-one sells the bolts as the calipers are not supposed to be split. They wouldn't want to leave themselves open to problems.I suspect they may be stretch bolts, they are done up to a very high torque.Correct ones if you source them will possibly be expensive for that reason.Fit new seals whatever.CheersColin Link to comment Share on other sites More sharing options...
Make mine a V8 Posted January 2, 2011 Share Posted January 2, 2011 Hi Dave,that is a fair number of posts on here. Do you double post or are you switching over for your on-line stag fix?Graham - grahamb on SOC Link to comment Share on other sites More sharing options...
Deleted User Posted January 2, 2011 Share Posted January 2, 2011 Same post on soc forum,switching is activated Link to comment Share on other sites More sharing options...
DJT Posted January 2, 2011 Author Share Posted January 2, 2011 2803 wrote:Hi Dave,that is a fair number of posts on here. Do you double post or are you switching over for your on-line stag fix?Graham - grahamb on SOCHi Graham,I've been visiting this forum for a few years. I did join CT but found that there was nothing to be gained as no local activities and the area coordinator couldn't be bothered to answer my contact emails. Didn't bother to renew my membership.I also use, and have done for many years, the triumphstag.net forum. But the SOC forum does everything I want and it will remain my first port-of-call for my online Stag-fix.Regards, Dave Link to comment Share on other sites More sharing options...
Deleted User Posted January 2, 2011 Share Posted January 2, 2011 Oh dear,The soc ;D ;D Link to comment Share on other sites More sharing options...
Make mine a V8 Posted January 2, 2011 Share Posted January 2, 2011 2740 wrote:Oh dear,The soc ;D ;D? Link to comment Share on other sites More sharing options...
stag_ste Posted January 6, 2011 Share Posted January 6, 2011 I also don't think these bolts are available anymore as a service part. It's not just the size and threads that are important, the material, hardening, tempering etc will also be very important. You shouldn't just use any bolt that will fit the hole.Why do you want / need to replace them?All bolts stretch when torqued up, during which they work harden which means that they will not stretch as much next time you torque them, and hence need a slightly lower setting torque to get the same clamping force.In reality, I would just re-use the old ones and tighten them very tight, but use new seals. I really can't see a major problem with re-use even if they are yielding bolts. Link to comment Share on other sites More sharing options...
DJT Posted January 6, 2011 Author Share Posted January 6, 2011 stag_ste wrote:I also don't think these bolts are available anymore as a service part. It's not just the size and threads that are important, the material, hardening, tempering etc will also be very important. You shouldn't just use any bolt that will fit the hole.Why do you want / need to replace them?All bolts stretch when torqued up, during which they work harden which means that they will not stretch as much next time you torque them, and hence need a slightly lower setting torque to get the same clamping force.In reality, I would just re-use the old ones and tighten them very tight, but use new seals. I really can't see a major problem with re-use even if they are yielding bolts. The bolts are high tensile S grade and I am getting some from a brake parts supplier through LDpart. The reason I am changing them is that the heads on a couple have corroded and won't hold the correct socket for torquing them up. Dave Link to comment Share on other sites More sharing options...
Deleted User Posted January 6, 2011 Share Posted January 6, 2011 I have a complete set of these brand new with new calipers in my loft. Must be worth a fortune now if you cant get them. Link to comment Share on other sites More sharing options...
stag_ste Posted January 7, 2011 Share Posted January 7, 2011 The old 'S' Grade is equivalent to about 780MPa ultimate tensile strength. I don't know the yield stress though. So, I would say that a modern 8.8 grade would be sufficient (ie 800MPa ultimate tensile strength with 0.8 x ulitmate tensile strength as the yield strength).From the thread you could work out the tightening torque, unless you have it listed somewhere.This is a reasonable calculator to make it easier - http://www.efunda.com/designstandards/screws/calc_bolt_torque.cfmBUT IT IS IN AMERICAN UNITS, Grade S is about equivalent to SAE Grade 5 or 5.2. Link to comment Share on other sites More sharing options...
DJT Posted January 8, 2011 Author Share Posted January 8, 2011 stag_ste wrote:The old 'S' Grade is equivalent to about 780MPa ultimate tensile strength. I don't know the yield stress though. So, I would say that a modern 8.8 grade would be sufficient (ie 800MPa ultimate tensile strength with 0.8 x ulitmate tensile strength as the yield strength).From the thread you could work out the tightening torque, unless you have it listed somewhere.This is a reasonable calculator to make it easier - http://www.efunda.com/designstandards/screws/calc_bolt_torque.cfmBUT IT IS IN AMERICAN UNITS, Grade S is about equivalent to SAE Grade 5 or 5.2.I have been advised by the supplier/brake manufacturer that the correct torque is 60lb/ft, which I believe is around 80 of those new-fangled newton thingies...........Dave Link to comment Share on other sites More sharing options...
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