Eric Walker’s stripped caliper mounting bolt

Just hit the Honda Swing button: I'm upset with myself, changed tires and decided to replace the brake pads. Putting the back caliper managed to strip the top mounting bolt. Oh my. What next spread 'lock tight' on it... Go ahead kick me. What next?

You could Google methods of dealing with stripped threads. There are some ingenious solutions out there. Locking wire would work but it's a bit unsightly.

Failing that, you can re-tap the threads and use an oversized bolt.

Eric.

Your post has been moved to a more appropriate topic and sub forum.

Hey, it would be nice if you graced us with an introduction in the, um, Introduction section.

If it happened to me I would investigate Loosemarbles last suggestion and re-tap to a larger size. For about 9 bucks you can get a M10x1.25 drill and tap set at Home Depot. Push the drill bit into the stripped section. If it will freely pass through you have removed an unknown amount of metal and it probably would not be safe to re-tap to 10 mm. If the drill bit will not freely pass through there is a good chance that it can be drilled to the proper size and tapped properly. There is not a lot of leeway in drilling and tapping because you want good strength. The entry hole would have to be drilled slightly larger than the 10 mm bolt the same way that it was drilled larger than the 8mm bolt originally. Ask the clerk for a clearance bit to enlarge the entry hole for a 10mm bolt.

All this would apply if the original bolt was 8mm. I am not certain that we are thinking about the same bolt. I would replace the caliper if a 10mm won't work. Could this be another case of an impact wrench being used on a bike? Get help if this is not clear to you. Do what you have to do but do it wisely.

" Putting the back caliper managed to strip the top mounting bolt "  

Not sure if you mean the upper caliper sliding pin or the bracket bolt, in either case you don't have a lot of material to drill out/thread for a Heli coil and they are both sandcast aluminum rather weak and soft.
I would not recommend any drilling as a fix.

If it is the "Upper/Aft" 12mm head bolt, easy fix, 1. Get a longer same metric thread bolt, approx.3 in(75-80mm), it must have twice the threaded section or an all-thread bolt, 2. a 5/16in.(8mm) inside dia. bushing (or washers), about 3/8 in.(10mm) long/thick. 3. A locking nut for bolt (or regular nut with Loctite).

Run same size tap thru threads if required, install longer bolt, install bushings/washers (you will have to grind one side flat to fit casting rib), install/tighten nut while holding bolt head, etc. snug or 15-18 ft/lbs is sufficient here, IMO

I believe that zrx12's suggestion will be easy and it will not be necessary to sacrifice 2mm of metal from the caliper and the mounting plate. 2mm is not much but every bit counts.

Those caliper bolts only torque to 22lb/ft. It doesn't sound like much but it does the job.

Loosemarbles wrote:

Those caliper bolts only torque to 22lb/ft. It doesn't sound like much but it does the job.

Well IMO it is too much, probably why they strip/fail, that's an area where the Honda Service Manual is wrong/flawed, all the torque values are too high IMO/IME for bolts going into aluminum, the 22lb/ft for 8mm is usually for a steel fastener installed in steel threads, when you install a steel fastener in aluminum or softer cast aluminum, using those values could be a bad thing   , you could/should reduce torque 20-25% on any steel fastener going into aluminum listed in the service manual, without any issues., I do.  

For example, my ZRX1100 specified 18lb/ft on 10mm caliper mounting bolts, not 22lb/ft on 8mm , since I'm on a roll, how about the BS of one time use on front caliper bolts, only because they are ALOC "locking compound already applied". but you can reapply loctite to rear caliper bolts

Yes, my fix is simple/safe and will get you back on the road. I could easily live with it vs paying $50 plus for a new bracket or while I sourced a used one on ebay, etc.

IAC you can see on this pic, that there's not a lot of material to drill/tap for Heli-coil, etc. Plus, it needs to be fairly straight/square any side load could crack bracket when torqued

As an old wore out mech/machinist I agree with zrx212's solution. Good job zrx212!

DavidinDunnellon wrote:

As an old wore out mech/machinist I agree with zrx212's solution. Good job zrx212!

Well, Thank You, I always look for ways to solve mechanical problems by the simplest and DIY ways, IAC, Knowledge not shared ...

Just wondering what happened to the OP

It seems that OEM parts no-longer exist. Partzilla, dealers and to secondary market ebay, craigs, Facebook etc? Obviously supply and demand at work. Comments please.

Accident front, dash/box surround, side, silver muffler cover and foot rest. (It is a 2013 - 10,000 miles. Went over on right side) Insurance company says it is a write-off/beyond repair because of parts and labor cost to value but really not that bad it's just plastic panels. Comments please.

Parts appear on EBay at times. I would suggest a search for motorcycle salvage yards. Some of those inventories are surprisingly huge and most of the parts that they keep from salvaged bikes are in good condition.

Maybe a bit more clarity would help ?
I find it unlikely the high tensile bolt has stripped it's thread, so I'm going to assume Eric means the thread in the aluminium caliper hanger, to which there a several repair options.
A helicoil is the first thing to mind, or if there is enough meat to insert a Ribnut, not sure if those names are used state side.

Be safe, be seen!

JohnyC wrote:

Maybe a bit more clarity would help ?
I find it unlikely the high tensile bolt has stripped it's thread, so I'm going to assume Eric means the thread in the aluminium caliper hanger, to which there a several repair options.
A helicoil is the first thing to mind, or if there is enough meat to insert a Ribnut, not sure if those names are used state side.

Be safe, be seen!

My responses/suggestions "Back" in July/2022, were educated guesses, based on O/P's vague description of issue, but since the O/P never came back to comment, clarify and/or report outcome. Kinda left me and other responders, wondering ,

6 months later we still don't know, exactly what part was stripped, the caliper pins or mounting bracket threads, a picture or p/n might help.

BTW, try your luck with Ron Ayers for parts (USA), https://www.ronayers.com/, call or email p/n's,
I got lots of parts for my SW600 at great prices and free shipping, as most orders passed $129 minimum.

Eric, we need more clarity on the stripped thread issue. It can be fixed in one way or another but are we talking about the thread inside the bolt hole or the bolt itself?

As for repairing/replacing tupperware, it would useful to know exactly where the damage is and how severe. Some forum members have made some excellent repairs. Others just replace the parts. There are plenty of second-hand parts out there.

If the insurance company has written the bike off then it's down to economics and /or time and effort. I, for one, would like to hear how you get on with it all.