Thread: LOF Clutches Front EXTREMEspec Big Brake Kit 330mm

Originally Posted by twr7cx

SUTTON M14 X 1.5 Carbon Hand Tap - Bottom M2061407 | Total Tools

After a quick look I’m not sure how much there is to gain there. Looks like the thread stops 2 or 3mm before the bottom of the hole. I think bottoming taps chamfer is one and a half threads so even after running a bottoming tap through the effective, usable thread will stop 2.25mm before the bottom of the hole (1.5 x 1.5mm thread pitch = 2.25mm).
I’ll measure it up properly tomorrow and see what’s what for potential gains.

Personally I wouldn’t touch that part. I’d shorten the bolt on a lathe to suit.

Originally Posted by Slunnie

Personally I wouldn’t touch that part. I’d shorten the bolt on a lathe to suit.

That's probably the reason for the two lock washers - they didn't have the correct sized bolt.

Originally Posted by Discosux

That's probably the reason for the two lock washers - they didn't have the correct sized bolt.

By far their easiest, fastest and cheapest option when they need a bolt which is between standard lengths.

Originally Posted by Slunnie

Personally I wouldn’t touch that part. I’d shorten the bolt on a lathe to suit.

Agreed as the bolts are much easier to source and replace than the mounting brackets.

There also seems to be a large number of places that can provide custom bolts:
Custom Bolts | WA Fasteners
Custom Fasteners - United Fasteners - United Fasteners
Custom Metal Bolts | Hot Forging & Custom Fasteners | E J Hadaway
Special Custom Made to Order Fasteners - Bolts, Nuts, Washers, Screws and More Exafast | Fasteners, Components and Kits
Custom Bolts and Fasteners | National Bolt & Nut Corp
https://www.kdfasteners.com/custom-bolts.html
including one locally - https://www.carsonscustomfasteners.com
which would assist in having both the correct length an selecting an ideal head type for the bolt.

Originally Posted by twr7cx

Agreed as the bolts are much easier to source and replace than the mounting brackets.

There also seems to be a large number of places that can provide custom bolts:
Custom Bolts | WA Fasteners
Custom Fasteners - United Fasteners - United Fasteners
Custom Metal Bolts | Hot Forging & Custom Fasteners | E J Hadaway
Special Custom Made to Order Fasteners - Bolts, Nuts, Washers, Screws and More Exafast | Fasteners, Components and Kits
Custom Bolts and Fasteners | National Bolt & Nut Corp
https://www.kdfasteners.com/custom-bolts.html
including one locally - https://www.carsonscustomfasteners.com
which would assist in having both the correct length an selecting an ideal head type for the bolt.

I’m sure that last company would be very helpful to you!

Some measurements of the fastening setup:

Caliper thickness at mounting points 66.4mm

Bolt M14 x 1.5 x 80mm
Bolt hex head diameter 26mm
Bolt head thickness 9.5mm
Bolt thread length 79.4mm

Adapter hole depth 14.4mm
Bolt thread engagement in adapter 10.3mm
Adapter hole unthreaded 4.1mm

Nordlock washer thickness 3.6mm


So 79.4 - 66.4 - 10.3 = 2.7mm - their setup needed a washer of at least 2.7mm thickness to not reach the limit of the threads in the adapters hole. The Nordlocks provided this for them with a 0.7 - 0.9mm extra margin.

To do away with the washer I'd need to shorten the bolts by at least 3.3mm (80 - 66.4 - 10.3 = 3.3mm) + probably 1mm as a safety margin.
The issue here is then that it's the bolt head directly on the brake caliper - no washer in-between - reducing load distribution? I do not that bolts used on brakes usually don't have washers under the heads but they are usually more of a flange head style.
And if the Nordlocks are removed should Loctite be considered on the threads as a Justin...

These measurements are not with things at the torque specified though - not sure what sort of compression could be expected by the parts or stretch of the bolt at 165 Nm.

Originally Posted by twr7cx

Agreed as the bolts are much easier to source and replace than the mounting brackets.

There also seems to be a large number of places that can provide custom bolts:
Custom Bolts | WA Fasteners
Custom Fasteners - United Fasteners - United Fasteners
Custom Metal Bolts | Hot Forging & Custom Fasteners | E J Hadaway
Special Custom Made to Order Fasteners - Bolts, Nuts, Washers, Screws and More Exafast | Fasteners, Components and Kits
Custom Bolts and Fasteners | National Bolt & Nut Corp
https://www.kdfasteners.com/custom-bolts.html
including one locally - https://www.carsonscustomfasteners.com
which would assist in having both the correct length an selecting an ideal head type for the bolt.

Don't mention it's for Automotive use, they may shy away.

Like Slunnie said, I'd just shorten the bolt and get rid of the washers. Just make sure there's enough clearance to the bottom of the hole. Don't do a dead stop.

It's been a while since an update.

Pricing for custom bolts came back at $120.00 a bolt... And even with this option I'm not entirely sure I had all the angles right to achieve the clearance gap.

Tapping the thread all the way to the bottom of the hole in the bracket achieve 13.3mm of thread engagement now - increase of 3mm from the original.

Using standard flat washers, grinding off the top corners of the bolts (reduces the hex for the socket to grip on from 9mm to 6mm) improves clearance a bit:



With the flat of the hex pointing towards the wheel barrel there is close to 3mm of clearance:



But with the hex points pointing towards the wheel barrel it reduces down to only 1mm of clearance:



One option is to torque the bolts close to spec, then rotate a bit further for ideal bolt head position to achieve the clearance.

Another option is no washer used:

I've been examining the Ford Australia FPV vehicles fitted with Brembo brake callipers and they use a cap screw with a 10mm internal hex. The diameter for the bolt (m12 vs M14) and it's head size is much smaller than this setup. There is also no washer used.


BA_BF_FG_Brembo_Swap_11_10_5_2015.jpg

BA_BF_FG_Brembo_Swap_02_10_5_2015.jpg

BA_BF_FG_Brembo_Swap_12_10_5_2015.jpg

A trial fit using no washers results is 3mm + of clearance gap even when the points of the hex are pointing towards the wheel barrel:



Using no washers I probably cannot use the full length 80mm bolts as there is only 0.4mm of unused thread in the brackets which is likely starting to cut it too fine when torquing up (comparatively the standard setup had 0.7mm of unused thread in the bracket).
If using the 75mm bolts then thread engagement into the bracket would be reduced by 1.4mm which isn't ideal either.
Option C is to remove 0.3mm off the bottom of the 80mm bolts to bring back to the original spec...