Rear Caliper Screw F-ed Up
#1
Rear Caliper Screw F-ed Up
I changed my pads today and one of the bolts on the rear caliper mis-threaded. I didn't know what to do so I just tightened as much as i chould but there is like 1/3 cm space bewteen the caliper and the bolt. Any idea's or comments.
#3
Originally Posted by rynberg
The rear caliper mounting hole tends to get chewed up over time....if the caliper's that worn, probably best to just get a new one.
As such, purchasing another rear caliper will not solve the problem of a messed up thread.
I tried re-tapping the threads on both the BOLT and hole's thread but it won't hold the minimum torque value.
As such I purchased a NEW bolt (from Mazda Motorsports), and installed a "spark-plug" thread Heli-Coil.
Just go to your local Advance, Autozone, PepBoys, and purchase a Heli-coil 5334 "Sav-A-Thread" for under $30:
http://www.sjdiscounttools.com/hel5334-14.html
Be sure to use some oil and newspapers to catch the fall-out while you're tapping; clean it out VERY well with brake-cleaner, mineral spirits, or acetone.
The instruction say to use an RTV sealant, but due to the higher torque than a spark-plug, I used liquid metal. Also, use the LONGEST insert (you can purchase additional inserts as well).
READ the ENTIRE instructions TWICE before installing and let the liquid-metal cure for 24-hrs MINIMUM (dont' ask me how I know!).
I've been happy with this repair for the last 6-months, and I remove my calipers at least twice every quarter due to track-specific pads & rotors.
:-) neil
#5
Originally Posted by rynberg
The rear caliper and "mounting bracket" are one integrated piece. Yes, you could fill in and re-tap, but I figured if he could do that, we wouldn't have posted the thread.
you are correct, the caliper does have the mounting thread. I was thinking about the bracket that holds the caliper to the hub.
However, my fix is not a "fill-in" and tap, but tapping the stripped-hole to a larger size, in order to install an insert (made by Heli-coil) similar to a Timesert, but not a "Heli-coil" which is more akin to hardened wire.
:-) neil
Last edited by M104-AMG; 04-30-07 at 03:54 PM.
#7
BTW: here are pics of a helicoil vs. a Time-sert:
Note: the "Sav-A-Thread" spark-plug product is produced/made by Helicoil but is NOT a "heli-coil" in the traditional sense since it IS a solid-bushing insert:
Helicoil:
Time-sert:
taken from timesert.com:
TIME-SERT® is a solid bushing insert. This guarantees easy installation and allows for full load use of tapped hole, ensuring protection against stress and vibration.
TIME-SERT® is thin walled due to synchronized internal
external threads. Thin cross sectional area allows for installation in areas of limited space and clearance material.
TIME-SERT® is self-positioning. Having a flange on the top of the insert will insure that the insert will have positive placement and cannot wind down into the newly repaired hole.
TIME-SERT® is self locking. On installation the bottom internal threads of the insert are cold rolled to expand the mating external threads into the base material locking the insert in place.
Note: the "Sav-A-Thread" spark-plug product is produced/made by Helicoil but is NOT a "heli-coil" in the traditional sense since it IS a solid-bushing insert:
Helicoil:
Time-sert:
taken from timesert.com:
TIME-SERT® is a solid bushing insert. This guarantees easy installation and allows for full load use of tapped hole, ensuring protection against stress and vibration.
TIME-SERT® is thin walled due to synchronized internal
external threads. Thin cross sectional area allows for installation in areas of limited space and clearance material.
TIME-SERT® is self-positioning. Having a flange on the top of the insert will insure that the insert will have positive placement and cannot wind down into the newly repaired hole.
TIME-SERT® is self locking. On installation the bottom internal threads of the insert are cold rolled to expand the mating external threads into the base material locking the insert in place.
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#10
Originally Posted by binary89
Ok, also does it make a difference which bolt goes one top and which goes on the bottom. One had a H ( I beleave so ) and another had a T.
If you look at either the bracket or the caliper (I forget which), the corresponding letter is stamped to match the bolt. You can also just like at your other caliper.
:-) neil
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