Shock Rebuild Question

pkovo

pkovo

Well-Known Member
I have an "extra" bike in the fleet (2016 Salsa Horsethief) that uses a Rockshox Monarch Debonair RT3. I started riding it again recently and after a trip to Stephens the shock ended up losing it's travel. After some research I guess a bad seal let the air push into the negative chamber pulling the shock down into it's travel. Fast fwd., I decided a 50 hrs. service would fix. Got a kit, released the pressure and took the can off last night.

What I've run into is the O-ring that I assume is meant to prevent harsh bottoming out was torn and floating around in there. I did bottom out solidly a few times on that ride as I was losing shock pressure, so I guess I shouldn't be surprised. Anyway, I have very little experience working on shocks. Seems like I need to dive further into working on this thing to replace this ring. I guess my questions are:

Is there an easy way to replace this ring? I guess it would be something done during a full (100 hr.) service anyway, so am I best just doing the full service? If so, do i need nitrogen for that, or can I use air?

I haven't done a ton of research on this, figured I would ask the "experts" here first. Any suggestions would be appreciated....other than suggestions of lighting it on fire 😂

IMG_5477.jpeg
 
You can’t service that side of the shock without legit shock tools. You can ride it as-is and if you bottom out the shock all the time and it’s annoying, just buy a shock for like $100 on FB Marketplace.
 
If you tackle the 100 hour service yourself you can use an air pump instead of nitrogen. I will probably get bashed for recommending using air. I have rebuilt a lot of suspension in my 35+ years of rebuilding all types of suspension. Using air in a shock that is being used for our trail system will not degrade the performance of the shock. Only a professional MTB test rider may push a shock to the limits of feeling a difference between air and nitrogen in the shock.
 
I have collected a couple shaft clamps over the years, not sure with out check-in with a caliper but this might help…..

Amazon.com: Generic Fox RockShox Rear Shock Damper Shaft Clamp : Sports & Outdoors

Buy Generic Fox RockShox Rear Shock Damper Shaft Clamp: Suspension Service Parts - Amazon.com ✓ FREE DELIVERY possible on eligible purchases
www.amazon.com

Or this


With these and a good vise you can fix a lot of shocks and dampers….
 
NonLefty said:
If you tackle the 100 hour service yourself you can use an air pump instead of nitrogen. I will probably get bashed for recommending using air. I have rebuilt a lot of suspension in my 35+ years of rebuilding all types of suspension. Using air in a shock that is being used for our trail system will not degrade the performance of the shock. Only a professional MTB test rider may push a shock to the limits of feeling a difference between air and nitrogen in the shock.
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Air is 78% (ish) nitrogen. Close enough for me.
 
It's more about reducing corrosive potential in bicycle shocks. If you will service it regularly, atmospheric air won't hurt it...if you don't, though, there's a good chance to simply start corroding the shims/other assorted parts.
 
Thanks all. I'm having trouble bringing myself to put it back together without addressing that missing O-ring. Feels too wrong to do that. I'll pull some vids of the full service procedure, and if I can get away with using air, and it doesn't seem too bad, I'll probably give it a whirl. Unfortunately the shock isn't a common size, so it doesn't seem like the easiest to sort a cheap replacement for. And this shock looks like it's had an easy life, and/or was looked after.
 
pkovo said:
Thanks all. I'm having trouble bringing myself to put it back together without addressing that missing O-ring. Feels too wrong to do that. I'll pull some vids of the full service procedure, and if I can get away with using air, and it doesn't seem too bad, I'll probably give it a whirl. Unfortunately the shock isn't a common size, so it doesn't seem like the easiest to sort a cheap replacement for. And this shock looks like it's had an easy life, and/or was looked after.
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should be able to find nitrogen cartridges which fit into CO2 heads

I have some nitrous!
 
Years ago I shimmed an RS Monarch with similar plastic washers in the same spot as the oring that tore:

It's a large quantity, but I needed them and they were cheap. I found a link on MTBR.com who mention put a slit in the washer diagonally and twist it on. I used & rebuilt the shock at least 5 times and it showed zero wear on the shaft. I shimmed a 55mm stroke shock to 50mm (same eye2eye) and they worked perfectly.
 
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Aresab310 said:
Years ago I shimmed an RS Monarch with similar plastic washers in the same spot as the oring that tore:

It's a large quantity, but I needed them and they were cheap. I found a link on MTBR.com who mention put a slit in the washer diagonally and twist it on. I used & rebuilt the shock at least 5 times and it showed zero wear on the shaft. I shimmed a 55mm stroke shock to 50mm (same eye2eye) and they worked perfectly.
Click to expand...
This is super helpful! I've been trying to find/think of something I could install that wouldn't require full disassembly. This looks like it could be the hot ticket.
 
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