[Volcomjerk]

After the usual check up i noticed an amound of play between the pivot bold and the bushings.

I thought the 1/2"DP bush was worn out, after replacing these there still was an amount of play.
Looking further i saw the play is between the Sunday's main pivot bold(at the right on the pic.) and the iron bush(in the middle on the pic.)
If you look at the pic. you 'll get what i mean.

I noticed that the middle tube is not rotating in the 1/2"DP bush. and that the main pivot bold is rotating inside the tube, so it all got worn out.

My question is: Am i the only one with these problems or is it an known problem, and has anybody got an id before i start making a new main pivot bold.

Cheers,

Roy

Hope you guys get what i mean


http://www.pinkbike.com/photo/1538642/

 

[Udi]

That shouldn't happen, I'm guessing you didn't do up the bolts tightly enough which allowed the shaft to rotate inside the shock reducer.

Basically the way it works is, the screw that goes into the left of the shaft (in that diagram) tightens the shaft against the reducer, sandwiching the reducer between itself (on one side) and the frame/pivot (on the other side).

The screw that goes into the right of the shaft, expands two wedges in the shaft against the large aluminium pivot nut (on the non-drive side) which stops it from rotating/moving etc.

Anyway I've found those bolts do have a tendency to come loose, so I'd suggest 262 loctite (you can still undo them without much hassle when you want to) and torquing them down fairly hard. Do the drive side first (to preload the setup), then the non drive (to lock it in place).

If there's play now though, you'll probably need a new shaft... but for next time.

 

[Volcomjerk]

Thanx Udi

That's some information wich is usefull.

Strange thing is that i have tightened all the bolts with a Torque wrench to the specifeid torque's.

Anyway now i know what to do.

Cheers,
Roy

 

[pelo]

I had the same problem on my 07 sunday. On the uppermount too.
I think because of the 10mm hardware, the iron bush gets so thin it wears in to the linkageplates and that reduces pressure on the ironbush from the linkageplates. When that happens the bolt rotates inside the ironbush, but it´s the ironbush that´s supposed to rotate in the dp-bush as you say, but it can´t cause it´s worn in to the linkage-plate...
I will try to use a 8mm thrubolt on my next bike for the uppermount. That will hopfully put more pressure on a slightly wider iron pin/iron bush from the linkage-plates.

 

[davep]

My 07 had the exact same issue. The problems was a fit issue between the oversized head allen bolt and the thru shaft. The bolt simply would not thread into the shaft far enough to pinch everything together.

Looking closer, it seemed the problem was the bevel on the inside of the shaft did not match the bolt head, and thus the bolt would bind against the shaft before it was tight against the link.

Simple solution: get a 1/2" or 12 mm drill bit and cut a more correct bevel in the shaft, allowing the bolt more room to tighten.

 

[Udi]

Davep - I'm guessing you're talking about the non-drive side bolt? So was the bolt head binding against the inside of the alloy non-drive pivot nut? I can't see how it couldn't make the shaft's wedges expand otherwise, even if the bevel was wrong it should still force it to expand as you tighten the bolt?

Pelo makes an interesting point too...
I guess the only solution there is regularly checking the bolts to make sure they're tight, because as long as the reducer is clamped tight it can't rotate around the shaft.

I've kept an eye on mine and so far so good, I actually wore out the top DU bushing a little fast, must be because it cops so much rotation (compared to the lower one especially). I'm running 35-36% sag so it's got plenty of movement to deal with. Wonder if dw has anything to say about that?

I'm not too fussed, the things are cheap enough... but I can't help but wonder if a bearing setup ala specialized demo would be a smart idea there. Guess I wouldn't want the extra weight though.

 

[davep]

Drive side upper shock mount...the non-expanding side. That allen is a custom bolt with an extra large flat head. The bevel on the underside of the head was such that the bolt would bind against the end of the shaft before the shaft was tight against the inner surface of the drive side upper link.

I cut an inside bevel on that end of the shaft (without actually shortening the shaft), that allowed the bolt to tighten another turn or so, pulling everything tight against the link.

 

[Udi]

Oh the upper one, yep makes sense now.

 

[S.K.C.]

Udi is pretty much right on with this - been away for the weekend. Well done Udi.