defective shock mount on carbon arm

[Scott]

Just got this off eBay-the threaded side of the mount is missing and the alloy mounting plate hole is ovalized-any suggestions as to a fix?  The arm is new otherwise. Had the pics been better I'd have passed on the auction!  Is the steel threaded plate insert a seperate part from K2-they look to be replacable like shock bushings?

[Simon]

Do mean the the threaded insert is missing from the plate or the plate is missing, any chance of a pic if its just the steel threaded insert,how about drilling the hole centrally to accept a suitable rivnut with an M6 thread.  
Simon

[Scott]

It's the non threaded steel insert that's missing and the bracket is drilled improperly to reieive a replacement-what s drilled is ovalized:O(  I will try to post a pic here though I'm not always successful!

[shovelon]

Scott,

I think I can help you with your problem. First I want to rule out that the bonding rivets are not ovaled out where the mount is glued to the swingarm.

If the screw holes are the problem, you say that the threads are gone and the hole is ovaled? Was there a steel insert pressed into the thread side? I will check my swingarm for that configuration.

If that is the case than the hole will have to be opened up to accept a sleeve, threaded or nonthreaded, whichever is better. Possibily a flanged sleeve that can be llightly pressed into place.

Lookover your mount and get back to me and I will work with you on the fix. Let's save that puppy!

Terry

[Scott]

It's the steel, non-threaded shock bolt bushing which is missing.  Looking at the mount you'll see there are  steel inserts on either side of the triangular mount to accept the steel bolt.  The alloy mount's drilled to accept them and in my case the bit looks to have spun off somehow and opened up an ovalized hole. I should have a pic. tomorrow!

[Old Proflexer]

i sounds like the attachment nut bonded to the side of the plate came off and the shock was loose on the mount for a while - causing an ovalized hole to occur (where the crossbolt was banging against it)

check with simon first but what i'd do is fill the hole with some jb weld - perhaps with a lubed bolt in the hole then remove leaving just the hole, then refinish the area (maybe an epoxy will work) -

put a nut on the end of the crossbolt and crank down the lower shock mount to specs or better (i think it's a 125 or 175 inch pounds - check the specs)

the nut popping off happens at the seat mount for carbon frames on occasion and one can just use a loose bolt or reepoxy the original or something different.

OP

[Scott]

The arm was never installed-they slipped when drilling the alloy for the steel  non threaded side insert and that was that-into the bin!  Until I found it on eBay and thought it was only missing the insert-certainly nobody would sell something with an ovalized/gouged up mount on it that wasn't clearly shown in the pics??  

[tmaybee]

Hi Scott.  Sorry for your luck...  I was so excited that I found what I thought was such a good deal  

Did you contact the seller about a refund?

Cheers,
Trevor   [smiley=groucho.gif]

[Simon]

Hi Scott,are you stuck for a s/arm or is this one a spare
If you are stuck and you can't get a refund but it looks repairable (need to see a pic)I may be able to help out,
I have a brand new unused carbon arm I'd be willing to P/X for yours to get you back on the trails (this is only if your stuck) and provided postage etc is paid (I'm in the UK).
Simon.  

[shovelon]

Hi Scott, I looked at my swingarm and think that yours is salvageable. The holes are shot on both sides, right? Are they still in line?

What I would do for the threaded side is find a steel rivnut close in size thread to your bolt. Then make the hole more round and sized to the rivet nut using a jeweler's round file.

Rivnut can be installed using washers between the flanges and with a nut outside the other side of the bracket. Turn the bolt while holding the nut and the rivet nut flares and seats into the hole.

The rivet nut can be found at www.McMaster.com. Search under threaded inserts.

The bushing will have to be faced slightly to clear the lip on the rivet nut but that can be done with a flat file easily if you are handy with them.

The other side if is still in line, could be filled with epoxy as OP suggests. Worth a try. If you need sleeves or bushings modified, send them to me with a sketch and I will turn them for you as a buddy fix. Just give me a week or so.

Terry

[Scott]

First off-a THANK YOU to all the offers for help here.  Simon,  I'm all set for arms and had purchased this as a spare in case the original became knackered or worse,  Terry, the hole is so outsized there isn't a fix to be had so I have  spare dropouts only with this arm.  Trevor, no worries, I settled up with the seller who proved to be a stand up guy.

[Simon]

Scott,Thats a shame but now you've established that the mount is not salvagable maybe as a future project you could look into making a new mount (as the old one is removable) you could look into making it a bit simpler by having the end plates further out eg having a flat piece of aluminium or other material of your choice and bending them to make the up rights,you can then cut the uprights to give the shape required,even better you may even find the correct size u channel instead,all you need then is suitable spacers for the shock and a long enough nut and bolt,maybe even going to an M8 bolt.
Also there is the added advantage of extra shock clearance making it easier to mount some of these newer shocks that are available,you could also go as far as adding in multiple pivot points so you can try different compression ratio's,or even have a slotted hole with location indents and mount the shock with a QR so you can adjust on the trail,
I know I'm getting carried away but these are things I've mulled over in the past.
Simon.