How do you remove elastomers from 855?

[singletrackmac]

So, i got some new elastomers for my 855. I got the new elastomers on the vector 2 fork easily, but cannot for the life of me figure out how to take the rear elastomers off the rear shock.

I found the instructions on how to replace the oil on the ODS shock in the "how to" section, but is does not help me get the shock apart.

My problem is that i cannot get the shaft the elastomers slide on off, or the black cone shaped piece off the end of the shaft. You can see in the pic the black cone shaped thing I am talking about.

So, how do you get these elastomers off?

Thanks of any help.

[Colin]

Hi,
I'm not very familiar with the 855 Friction shock (which you have) as I've never had one.

If that bit on the end is the split collet, it should come off as it's just a slide fit, but also it looks like it might be on the wrong way round....? Maybe I'm wrong on that. Does that piece on the shock fit into a recess on the strut?

Callum used to have an instruction sheet (MCU855instructions.pdf) on his RDS site on how to replace the MCU's bought from him, but it's not there any more:
http://www.rapiddescentscotland.co.uk
Does anyone have a copy?

Col.

[fyrstormer]

The bottom end of that shock does not look right. At least, it's not what I expect it to look like. The end piece should pull off, exposing a cylindrical shaft, and then the elastomers slide off the end of that shaft. Unless they're so old they glued themselves in place, of course.

[Colin]

Agreed, that shock piston shaft looks wrong and I've just noticed the screw extractor that's been used on the fixing bolt, that sort of force implies something done badly wrong in the past......?
Is that "cone" end we're seeing actually the piston shaft flared out due to excessive tightening force of the fixing bolt? I'd have imagined the thread would strip before that.............and anyway the shaft wouldn't be black, so maybe it's something jammed on the end.

As the existing MCU's are junk, why not cut down the side of them and peel them off? (don't scratch the piston shaft).

Then we can really see what's going on...............

Col.

[orange]

Try this link for the instructions:

http://web.archive.org/web/20120417192043/http://www.rapiddescentscotland.co.uk/index.php?module=documents&JAS_DocumentManager_op=viewDocument&JAS_Document_id=3

[Colin]

As I said, the instructions themselves are not downloadable, i.e. not archived, so does anyone have a local copy?

[singletrackmac]

Alright, here is an update. But, first of all, I appreciate you guys looking into this for me. Thanks!

So, I was unable to find any info online on how to disassemble this specific shock. So I decided to just try and pull it apart, gently  And i discovered that there is a bolt inside the main shock body that releases the shaft for the elastomers. To get to the bolt you need remove the top-cap piece the connects the top of the shock to the frame.

Since I could not find any info online I figured I would posts a pic of the shock disassembled. Also are some pics of the black (painted) tapered cone piece that goes on the end of the elastomer shaft that connects to the seat stay (strut). That piece does not come off, trust me, I tried. You can see the marks form my trying. One thing I can say is this is well built and very tough.

As for the speed out, the bolt that connects the strut to the shock was ceased up. I ended up stripping it trying to get it out. So, speed out to the rescue again.  Any suggestion on where to get a replacement bolt?

I am excited to get the 855 back up and running as close to original spec as I can. This bike was 1995 Dual Suspension Bike of the Year in Mountain Biking mags dually shootout. I used to drool over this bike. Still have the magazine.

[singletrackmac]

And the tapered cone piece.

[singletrackmac]

And the Pro-Flex 855 1995 Dual Suspension Bike of the Year article from Mountain Biking Mag

[BigO]

Im glad you got the elastomers out, I was going to recommend trying to heat them up for removal but it seems you got it figured out. That is awesome that you have a copy of the old mag with 855, such a sexy beast of a bike. I will be following your build closely as we have the same ride. The difference being you plan on trying to retain the retro look and I want to upgrade to newer components until I retire the bike. I look forward to your build!

[fyrstormer]

You should seriously consider getting a Noleen NR-4 (or at least NR-2) from noleenj6.com. It's not the original shock, but it's still vintage and specifically designed for that bike, and it's so vastly superior to the friction-damped elastomer shock that you'll never regret it. If you've ridden newer bikes you'll immediately notice how mushy and inefficient the elastomer shocks are compared to a proper coilover; there's a reason bike companies stopped using elastomer shocks as soon as coilovers for bicycles became reliable enough.

Also, if you can find a strut for the '56 series, that will give you greater flexibility with your shock options in the future.

In any event, the bolt is just a run-of-the-mill 5mm hardened cap-head bolt, you can get them at any bike shop.

[Colin]

Thoughts:
That strut should be silver (all 855's I've ever seen were).
So, has it been hand-painted black, or as I'm suspecting, it's not an 855 strut........the shock has then been "bodged" with that black end cone piece to make it fit the strut. in the "855 Rear Strut" photo the shock piston shaft looks flared as if the black piece has been rammed into the threaded end of the piston?
we need to see some good photos of the strut and particularly the location point for the shock, is it a recess?
Agree with fyrstormer that an upgrade is quite in order, particularly as the shock may now be u/s after being disassembled, does it even work with the elastomers removed, i.e does it's movement work? An ODS with a coil spring would not be an out of period replacement.

Love the mag, we need some high quality scans of that article please!

Col.