front caliper torx/star bolt

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Richard Price
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Presumably there is a bracket to which the caliper is bolted and that bracket is fixed to the upright?

I've noticed that the latest cars have a different upright with bosses to accommodate radial calipers.

There also seems to be a couple of different factory fit options with both two and four pot radial options.

griffchris
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Yes, I spoke to parts today and they confirmed these are a new upright/caliper configuration.  They didn't know what the bolts were either Wobble  - but are going to get back to me.

Last night I managed to coax the bolts out of one caliper using the E12 Torx socket, but on the other side (the side I tried 1st), the bolt heads are too rounded off to get a purchase.  Doing a bit more research, I am fairly certain that these are External Torx Plus bolts (M10 x 70), which have their own specific socket range, denoted EPxx, I found comments such that using a standard Torx socket on a Torx Plus bolt is likely to lead to damaged bolt and socket Banghead 

I have ordered a Torx Plus socket set, in the hope that these will still get purchase on the damaged bolts, I have also ordered a bolt extractor kit as a back up.....

 

Jonathan Kay
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Look forward to seeing if the next ones fit. And my money is on them doing just that.

If there's enough head left there might be ways of getting the bolt out before you resort to extractors. Experts often recommend welding something onto it that gives you some leverage. I try cutting a slot with a Dremel.

Jonathan

PS: And your experience might have saved someone else's bolts! :-)

Wrightpayne
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could you switch to a more readily available bolt type once out - cap head perhaps?

griffchris
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Yes, you read my mind, I've just been looking at M10 x 70 cap heads.  The External Torx bolts are grade 10.9, but I can only find the cap heads in 12.9 (i.e.higher grade - I've looked at Namrick, Westfield and a few other websites) - would this be a problem (?impact on torque values etc)?

Wrightpayne
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I'm no expert but I'd use a 12.9 instead of a 10.8. Its all to do with tensile strength - higher the number the stronger the bolt.

Ian

ScottR400D
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A 12.9 is higher tensile strength than 10.9, of course, but unless what you are bolting them into is strong enough to allow you to increase the applied torque there's no point changing.

Further, the higher tensile bolt is also more brittle and more susceptible to failure cause by cyclic loads such as seen with repeated heating and cooling.

I'd stick with what's specified. 

 

 

 

 

elie boone
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griffchris
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Good thought, but the head diameter (22.3mm) is too wide to fit into the recess in the caliper body - hence why cap head (16mm head diameter - same as the external torx head flange) seems a better bet.

Richard Price
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If buying alternative bolts, you also need to be sure what pitch to buy.

It's more common for M10 fixings to be 1.5mm pitch rather than the 1.25 that JK links to.

Like for like repacement would be a more sensible option.