Author Topic: OZ rear shock upper bushing frame wear (Read 5293 times)

IMO · « **on:** January 07, 2009, 10:13:35 am »

Hi all

My bike has developed a tiny clunk , which is more annoying than anything else. It would appear there is some slight wear on the frame plate holes that the stepped bushes fit into on the rear shock mounts.

Its probably no more than .5mm at most, and is almost even around the bushings. I was expecting to see a dink in the load area , but there wasn't one.

Do you think it would be OK to Araldtite / Epoxy the bushes into place, Or should i be searching for new bushings first ? I have no idea where to source them from, maybe RDS/TFT?
They show no sign of wear themselves, although they must be clocking up the miles well into the thousands by now.

I don't want the holes to get to big , and in my experience, leaving just a tiny bit of play will excellerate the wear.

Thanks for your help. Rob

jeffhop · « **Reply #1 on:** January 08, 2009, 07:46:17 am »

go to your lbs and get some disc brake calliper shims, they come in a load of thicknesses so a combination of them should take up any wear in your fame and theyre a hell of a lot cheaper than new bushes but a bit trickier to fit but not impossible. i paid £30 from tftuned for the mount kit (bushes) i had on my oz.

shovelon · « **Reply #2 on:** January 08, 2009, 08:28:42 am »

It would be a bummer if the carbon itself is wearing. I would take up that gap as soon as possible. Maybe a combination of shims like Jeff has suggested and the Epoxy.

I have also seen that some people have removed the plates alltogether and replaced with alum plates.

Good luck on that.

IMO · « **Reply #3 on:** January 08, 2009, 09:05:50 am »

I am almost certain that the carbon is wearing . I base this on the fact there is normally some black dust that appears when I drop the shock for any maintenance. Its a little like the soot they get on the F1 cars when they pull a wheel off. There is also some scuffing in the hole and a slight tapering , rather than a square shoulder to the hole itself.
Think I am going to Aradtite the bush into the hole tomorrow afternoon as I am out at Swinley on Saturday.

I cant see how disk spacers would help, all they do is move the caliper away from the frame to allow centering on the disc .The play is not lateral. I have taken that up with2 penny washers, 1 each side of the bolt that holds the shock in place. Its vertically, so would actually require more of an insert to take the slightly larger hole.

Will post up a report into my bodgtastic repair at a later date..

Cheers Rob

Colin · « **Reply #4 on:** January 08, 2009, 09:46:02 am »

I think you need to check a few things, unless I'm misunderstanding you? (quite possible! <GRIN>)

The upper shock bolt should pass through a fixed metal washer on the RHS plate (viewed from above and facing forward) and then screw into a fixed metal Nut on the LHS plate.
When tightened up this should fix the shock bushes firmly into place and the shock should then pivot on the bushes, so that any rotational movement and wear is between the bushes and the shock.
If this doesn't happen without distorting the plates, then the outside faces of the bushes need packing with washers (sounds like you may have already done this?)
Quite often the bushes seize in the shock causing creaking/cracking noises and transferring the rotational force onto the side plates, I think that this may be what is happeneing with yours.
I think you need to strip the rear shock out and make sure that the bushes are removeable and that the shock rotates freely on them, (at both ends while you're at it.)
I had this issue on my 4000se and once I'd done this the problems dissappeared.

Col.

IMO · « **Reply #5 on:** January 09, 2009, 09:03:07 am »

OK, Thanks Colin.

There are no metal things attatched to the carbon plates. Neither a washer or a nut. It might be the OZ is different to the 4000. It also might be that the shaft needed to fill the eye on a Manitou swinger is bigger than the OE shock. This might then require the fixed plate/ washer and nut to have been removed. The top mount on mine is a longish bolt with a nyloc nut on one end , obviuosly its mostly shoulder and the shock mounts on the smooth shoulder.

So my bike goes Bolt , carbon frame, inset frame bushing, penny washer, shock eye bushing, shock eye bushing, washer, inset frame bush , carbon mount plate, Nyloc nut.

Going to Epozy in the inset frame bushes to see if that cures the 'chicker'

Rob

Old Proflexer · « **Reply #6 on:** January 10, 2009, 06:34:18 am »

on the carbon frame side plates, there should be at least one permanently attached 'bushing' on the left side.
this left side piece has a rounded threaded nut that the cross bolt screws into. on the right side should be a flat
bushing that is permantly attached that simply allows the cross bolt to slide thru. these bushings do not appear
on the carbon spec sheet for the oz that i can see.

http://idriders.com/proflex/resources/carbon_tech_sheet.pdf

if these bushings have loosend or worked themselves loose, they need to reaffixed permanently or you'll have what
you describe and it'll get much worse even if the crossbolt is firmly tightend down to prevent movement in the area.

the upper right side of this pic shows the insert crossbolt head:

and this the left (sorry but no closeups in my gallery) it should be just a small rounded button that's threaded internally:

OP

and we've seen some of the side plates removed and replaced here, people have put bolts thru the rivet holes and permanently attached new plates.
try to keep it as original as possible - i should imaging that filling the gaps between the bushing inserts and carbon with an epoxy would work just fine -
that's what i'd be inclined to do.

Colin · « **Reply #7 on:** January 11, 2009, 08:36:43 am »

Quote from: IMO on January 09, 2009, 09:03:07 am

OK, Thanks Colin.

There are no metal things attatched to the carbon plates. Neither a washer or a nut. It might be the OZ is different to the 4000. It also might be that the shaft needed to fill the eye on a Manitou swinger is bigger than the OE shock. This might then require the fixed plate/ washer and nut to have been removed. The top mount on mine is a longish bolt with a nyloc nut on one end , obviuosly its mostly shoulder and the shock mounts on the smooth shoulder.

So my bike goes Bolt , carbon frame, inset frame bushing, penny washer, shock eye bushing, shock eye bushing, washer, inset frame bush , carbon mount plate, Nyloc nut.

Going to Epozy in the inset frame bushes to see if that cures the 'chicker'

Rob

I was describing an Oz, the 4000se issue was the siezed shock bushes.

You should definately have the fixed nut and washer as original, if not then yes, they have been removed.

you say..."It also might be that the shaft needed to fill the eye on a Manitou swinger is bigger than the OE shock. This might then require the fixed plate/ washer and nut to have been removed."

That sounds to me like a bodge, whatever shock you buy, you then need to buy the right bushes to match the gap between the mounting plates on the bike and with an internal diameter to suit the original bolt.

If both of the fixed pieces are missing then you could use a loose washer under the screw head and a loose nut and washer on the other side, but you need to get the right bushes.

Col.

rapiddescent · « **Reply #8 on:** January 13, 2009, 04:55:28 am »

we don't have bushings in at the moment but will do soon; I'm getting made for another project.

Old Proflexer · « **Reply #9 on:** January 14, 2009, 09:29:05 am »

Posting these for IMO - please review and comment -

http://img.photobucket.com/albums/v297/Southpaw1/PICT02341.jpg

http://img.photobucket.com/albums/v297/Southpaw1/PICT0235.jpg

http://img.photobucket.com/albums/v297/Southpaw1/PICT0236.jpg

http://img.photobucket.com/albums/v297/Southpaw1/PICT0237.jpg

http://img.photobucket.com/albums/v297/Southpaw1/PICT0238.jpg

http://img.photobucket.com/albums/v297/Southpaw1/PICT0239.jpg

OP

shovelon · « **Reply #10 on:** January 14, 2009, 09:39:59 am »

Hmmm, those are not the type bushings I have. Good idea to bond them in.

Colin · « **Reply #11 on:** January 14, 2009, 11:36:55 am »

OP,
Those aren't original, are they?

I guess the same thing as IMO is seeing, someone (you?) has removed the original fixed nut and washer and drilled out for a pair of replacement bushes?

Looks like it would work fine, have you got a photo with the shock fitted? Do you use a Screw and a Nyloc Nut or similar?

Col.

IMO · « **Reply #12 on:** January 14, 2009, 12:01:34 pm »

OP kindly hosted and posted the pictures of my frame.

You can just make out the gap between the frame and bushing. The shock is mounted on a 10mm bolt , with a nyloc.

Having now epoxy'd those bushings into the frame ( hence the glue on the plates) and did a quick trial bolt up there is still some play. I think its the bolt, but needs more investigation

Rob

Colin · « **Reply #13 on:** January 14, 2009, 12:14:51 pm »

Aaaaah I see, it is your one, great to see some pictures.
That Swinger looks cool on it, maybe have to post a piccie of the other end to see it's fitting, That's what I want to put onto my Oz rebuild.

Anyway, here's some piccies of it:
Standard Right hand fixed Thro' washer/stud

Standard Left hand fixed Nut

Standard Shock Bolt

Standard NR-5 Shock Bushes ( a bit rusty! )

You can see from this last photo that when the bolt is done up it compresses the side plates onto the bushes, locking them in place and then the shock body can pivot on the central bush surface. If the right hand thro' hole was a bit big then you could potentially get a bit of movement there, but not on the LHS threaded nut.

Obviously not a lot you can do now, but I would have thought that if those bushes of yours are now bonded into the shock plates then when the bolt is done up it would compress onto the bushes fitted onto the shock itself and hold everything steady, of course, if the bolt is slightly under M10 (which it probably is) then there may still be a slight lift and drop "knock" but if this does cause any wear then it should just be on the bushes.
Try doing that, lift the back of the bike and see if it drops a bit and "clonks"?

Have you checked that the shock revolves freely on the two bushes that are fitted to it? If it doesn't then the slight rotational movement as the shock compresses will need to be transferred somewhere and so what was probably previously happening was the two retrofit bushes were rotating in the plates and causing a bit of wear. If they are now glued solidly in place then the shock will have to rotate on its own shock bushes as is normal, but if that is jammed then something will have to give..............

Col.

Old Proflexer · « **Reply #14 on:** January 14, 2009, 07:31:55 pm »

where there's a will, there's a way.

you'll want to run some epoxy into those gaps between the bushings and the carbon to keep them in place.

That bolt shold have little to no movement in the bushings or the top eye of the shock -
should be the exact same sort of setup as the the bottom mount on the swingarm.

wonder what happened to the original bushings?

OP

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Author Topic: OZ rear shock upper bushing frame wear (Read 5293 times)