Heli-coil for brake caliper banjo bolt (Page 2/2)
pmbrunelle FEB 22, 02:45 AM
I opened the jaws of my slide caliper to the major diameter of the M10x1.0 STI tap.

Then, I then placed the jaws on the ridged bearing area of a Fiero caliper for reference:

Not an excessive loss of washer bearing area. I also checked my GM Metric calipers, off-camera. The result was similar to that of the Fiero caliper.


Looks like the pic of the caliper above.

I think the idea is workable.

A Heli-coil repair job for the larger pitches (1.25 mm, 1.5 mm) might be less good, as the STI tap increases in major diameter as the pitch increases.
Notorio FEB 22, 11:06 AM
It looks like you will lose 1-2 'rings' in the crush area. That will leave how many? Maybe you should inspect the remaining ones with some magnification to confirm that they are all good and not damaged from a PO.
Dennis LaGrua FEB 23, 05:55 AM

quote
Originally posted by Will:


Had a duh moment... was talking about helicoiling the banjo hole so that he could change the thread pitch from 10x1.5 to 10x1.25 or 10x1.0 in order to be able to use the combo banjo bolt & bleeder screw he linked in his first post: https://www.pegasusautoraci...tails.asp?RecID=5036

That's an unusual reason for a helicoil installation, but doable, I guess.




Basically agree but if I understand the correct strength of Helicoils, they are stronger than the original threads, so the high pressure argument made by you know who doesn't hold. Stripping out the caliper banjo mounting holes on 30 yr old calipers doesn't take much more than to exceed the torque spec by just a few pounds. You can't keep rebuilding these calipers forever so either welding and re-threading and or using threadserts or Helicoils may be the solution.

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Tony Kania FEB 23, 10:05 AM
Try it. Inspect for weeping. If it fails, weld and tap.
Will FEB 23, 01:43 PM

quote
Originally posted by Dennis LaGrua:

Basically agree but if I understand the correct strength of Helicoils, they are stronger than the original threads, so the high pressure argument made by you know who doesn't hold. Stripping out the caliper banjo mounting holes on 30 yr old calipers doesn't take much more than to exceed the torque spec by just a few pounds. You can't keep rebuilding these calipers forever so either welding and re-threading and or using threadserts or Helicoils may be the solution.




Whether helicoils are stronger or not depends on a lot of factors like the length of the thread, the parent material, how tightly toleranced the installation is, how many load/unload cycles they see...