A VERY strange(?) problem with Manitou Dorado?

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A VERY strange(?) problem with Manitou Dorado?
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Posted: Jul 4, 2014 at 15:00 Quote
Hey. Something really strange happened when I was riding my dorado today. I did a little jump and landed not hard at all but I heard a very strange sound. It sound almost like I got a flat, but it wasn't. It was the Dorado getting STUCK at the bottom of the travel.
I could not move it, it was rock solid. I went home and took the fork apart, and this was the reason to the very strange sound

the rebound cartridge (?) looks like this

Unsecure image, only https images allowed: http://oi58.tinypic.com/15gpb13.jpg
Unsecure image, only https images allowed: http://oi62.tinypic.com/2i1l7qt.jpg
have this ever happend to any one of you ? have you ever heard about it ?

and where can i find a new one? Smile

Mod Plus
Posted: Jul 12, 2014 at 20:56 Quote
Ah, nothing like a crushed damper rod to ruin a ride, eh? I would know, as the exact same thing happen to my own Dorado back in the early 2000s, and it looks like your older Dorado has suffered the same fate. The root of the problem boils down to volume displacement, or rather, the lack of it. Dorados from 2002 and earlier depended on a closed-cell foam compensator that compressed down as the damper rod was pushed into the cartridge (the sealed stanchion tube), and the foam element allowed Manitou to completely fill the cartridge with oil rather than having to leave an air gap. It also provided back-pressure to minimize cavitation when pushed hard. It was a very simple and lightweight setup that worked well but proved to not be up to snuff in the long run, with the foam tending to break down over time. It didn't take long for Manitou to come up with a better alternative in the shape of a spring-loaded IFP for 2003 that, while weighing more than the foam and introducing some friction into the system, showed to be much more reliable.

So, what happened to your fork? My guess is that you were still running the foam compensator inside your fork, and that it began to come apart recently. The crushed rebound rod came about as a result of the foam element eventually becoming small enough that it could no longer compensate for the displacement of the damper rod compressing into the fork as it went through its travel, and the forces were so high that they simply crushed the thin-walled rod. Your fork being stuck down into its travel was caused by the rod no longer being round and not able to pass through the seal head. In other words, you've done some major damage to your fork, and you might have troubles sourcing the parts you need to get it back up and running simply due to its age. If you want to get your fork running again, your best bet is to look on the classifieds for a used Manitou Stance Kingpin with 170mm of travel - its rebound damper rod features the same dimensions and can be sub'd into your Dorado. You could also require a new rebound seal head if yours was damaged, which you'll need to score out of an old Sherman - the Kingpin's seal head sports a finer thread pitch and won't work on the Dorado's stanchion, but the Sherman's matches and it mates perfectly with OD of the Kingpin's rebound rod. Don't forget that your issue began with that broken down foam compensator, so you'll need to do something about that as well. Start by heading down to your local moto shop, or you can look for a 2003 Manitou Dorado spring-backed IFP assembly. That's a ton of sourcing and work, isn't it? Alternately, you could just pick up a used fork off of the buy and sell...

Posted: Jul 21, 2014 at 1:30 Quote
Thanks for the answer Big Grin I think my dorado is from 2006 or something, i dont have the foam thing you talking about, its spring based. It was very hard to find part, but im a mechanical engineerstudent and have my own workshop so I decided to make my own parts Smile a few hours with the lathe and I have made my own parts Smile it was kind of tricky to get the new "connectors" in the end of the pipe, but i did my own tools make it happen Smile a new radial sealing and it was good to go, better than new Smile i can upload som pic later !

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