Threaded inserts

So I've got this idea/plan for the front brake problem. The caliper sits too far inboard and the backing plate for the pad rubs on the bolt that holds the rotor to the hat and the actual pad rubs on the hat. It's machining itself currently but when pad wear becomes too much, the backing plate will hit full on with the hat. Not to mention the chance of causing one of the bolts to fail. The caliper needs spaced outward about 1-2 mm or so. The options I see are two.
A) Design a radial mount to use a different caliper. Benefit is larger diameter rotor and off the shelf rotor. Disadvantage is the extra pair of calipers and rotors I currently have.
Option Find a way to make what I have work. The way I see to get these to work is to move the caliper outward somehow.

I've decided for now to proceed with option b.
Some background. The current hats on upright was tapped with a 7/16-20 tap to hold the caliper on. I did not drill either the upright or the caliper and tap M12X1.5.

My rear caliper bracket has a pressed in, what appears to be knurl style 7/16-20 insert. So my idea is to bore the upright like in the diagram so that the lower part of the threaded insert is at the bottom of the existing hole. Depending upon the thickness of the insert, this will result in moving the caliper outboard from center and hopefully fix the rubbing problem.

Anyhow, anyone know of any good sources for press in threaded inserts? McMaster doesn't have up to 7/16-20 and everything else I seem to find is all Time Serts or the like.
Thanks
Grant

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Grant Hughes

No, but if you can't find, then I would consider filing/grinding the holes outward, welding up the inner edge and re-tapping. The force on bolts/tapped holes should be all tangential, and thus not really stress the welded area. (Even a braze fill should be strong enough. ) Is this cast iron or machined steel?

Regards,
Mark B.

I don't know of any non-custom press in inserts that go past 1/2" because all of the standard machines for inserting them max at 12K lbs of force. When I need something bigger I generally trade over to something from these folks:

http://www.on-b.com/doc/onb-nut.htm

They're meant to be projection spot welded but you can just zap them on with a quick mig weld on the flange.

Tim

These guys:

http://www.timesert.com/

make oversized threaded inserts.

Generally used to rescue a block that you've pulled the heli-coil out on a head stud.

Cheers, Ted

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Pure mathematics is the enemy of every truly creative man -- Sir Alec

You could turn the OD or the rotor down by 1-2mm.
I thing you may have not done your enlarging of the original 7/16th hole out to 12. whatever exactly on center.

It should take just a few minutes on a brake lathe or a conventional lathe.

As for the backing plate near the bolts, take an angle griner and a 60 grit disc and kiss away the steel backing.

Why are these things so hard?

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John Vanlandingham
Sleezattle, WA, USA

Vive le Prole-le-ralliat

www.rallyrace.net/jvab
CALL +1 206 431-9696
Remember! Pacific Standard Time
is 3 hours behind Eastern Standard Time.

I didn't enlarge any holes. I tapped it 7/16-20 so I couldn't have been slightly off center.

I could turn the rotor down a millimeter and grind the pad down a millimeter, or I can take these spare uprights I have here that I plan to put new bearings in and the new M14 studs I have in the hubs of and put in the threaded inserts that will place the caliper in the correct place. Then attach the new tie rod ends and new adjustable TCA to the new uprights and put them all on the car at the same time. Do the same with the uprights that come off the car at my leisure so I have spare uprights.

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Grant Hughes

NoCoast Wrote:
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> I didn't enlarge any holes. I tapped it 7/16-20
> so I couldn't have been slightly off center.

Huh?

Maybe here's where we're having problems, I opened the calipers out to 12,7mm for a 12mm bolt.
>
> I could turn the rotor down a millimeter and grind
> the pad down a millimeter, or I can take these
> spare uprights I have here that I plan to put new
> bearings in and the new M14 studs I have in the
> hubs of and put in the threaded inserts that will
> place the caliper in the correct place.
Or do the threads to 12mm, offset plunge the caliper ears on a mill.

Then
> attach the new tie rod ends and new adjustable TCA
> to the new uprights and put them all on the car at
> the same time. Do the same with the uprights that
> come off the car at my leisure so I have spare
> uprights.
>
> Grant Hughes
> www.nocoastmotorsports.net
> Denver, CO

---

John Vanlandingham
Sleezattle, WA, USA

Vive le Prole-le-ralliat

www.rallyrace.net/jvab
CALL +1 206 431-9696
Remember! Pacific Standard Time
is 3 hours behind Eastern Standard Time.