16 replies to this topic

[ryecowley]

Just thought i would share this as its not something ive come across before and the bolts that failed are not something you would normally touch

 

My mighty mini is fitted with copy front brake calipers, during qualifying on saturday at silverstone, I came down the wellington straight flat out in 4th, tried to brake for brooklands only for the pedal to drop to the floor, on investigation in the paddock it turns out that the bolts holding the 2 caliper halfs together had worked loose on the drivers side, allowing the seal to blow out, the passenger side was not far away from the same fate, there was no evidence of thread lock on the bolts and no spring washers fitted to stop these bolts from working loose

 

I was on a nice wide track surrounded by other drivers who are alert and half expecting the car in front to spin at any given moment so i was able to jump back on the power and drag it round the corner sideays without too much drama, but had i been on the road, coming up to traffic lights, it might have been nasty

 

So if you have these copy calipers, get some threadlock on the bolts holding the 2 halfs together

 

Ryan

[mini danny]

Thsnks for the info glad you managed to stop with out any accident

[Ethel]

I wonder if it could be an issue with the extra heat you're likely to get with competition pads in race conditions?

 

Mini 8.4" calipers?

[ryecowley]

could have played a part in it although we arent particularly hard on brakes in mightys really, particularly at silverstone, you only need them twice per lap, and ive not got a particularly hard pad in there, im on ebc yellows at the moment

[ryecowley]

and yes 8.4 calipers, although i would hazard a guess that the copy 7.5's are coming out the same factory

[Old Bob]

Sorry, unsure what you mean by 'copy' callipers.   Are they your own rebuilt or after-market ones from somewhere?

 

Bob

[cal844]

i believe they are after market copies or re built calipers.

 

cheers

Edited by cal844, 15 May 2013 - 02:17 PM.

[ryecowley]

no not rebuilt ones, if i had done them they would have been done properly! aftermarket -  minispares part number gbc138 and gbc141 although i want to make it clear im not pointing the finger at minispares here as mine came from another supplier although it matters little who supplied them as its a manafacturing problem really

 

Ryan

[Badboytunes]

I guess you get what you pay for.

 

 

glad you stopped, incident free.

[fastcarl]

Locktight is one   answer but surely the correct torque applied and the bolts would not come loose, i have dissasembles  a few old ford  2 piece calls in the past and never seenany signs of threadlock.

 

 

 

carl

Edited by fastcarl, 15 May 2013 - 11:02 PM.

[ryecowley]

yep, if they had been torqued up from the factory they would have probably been fine, however as they were brand new out of the box calipers it never even occured to me to check em! which is why i just wanted to warn others, the loctite was an emergency measure as i was trying to get the car ready for the race and didnt have the torque figures to hand, besides, cant be a bad thing having some on there

[Dan]

  They are supposed to be a special thread with a self locking profile, Loctite would be redundant and frankly they should lock even if not quite properly torqued.  I suspect the wrong bolts are being used, do you have any photos of them?  You should make Mini Spares and any other stockists you know of aware of this.

[GraemeC]

Are they not normally a nyloc version of a set screw with a small nylon 'slug' set into the thread?

Edited by GraemeC, 19 May 2013 - 07:03 PM.

[Dan]

  I have to say I've never taken one out, but they are listed as self locking screws.  It must be something like that, or a serrated or oversized and cut thread that works something like a philidias nut.  It should not be a plain thread though.

[Captain Mainwaring]

I wonder if it could be an issue with the extra heat you're likely to get with competition pads in race conditions?

 

Mini 8.4" calipers?

Uhm, I personally wouldn't accept that as an excuse.