Marzocchi cartridge cap not reaching specified torque

[kbroderick]

Short backstory: I have circa-2003, Marzocchi Shiver 50 forks (50mm USD forks) on my bike. They were leaking, so I picked up fork seals, oil, and a fork seal driver.

The seals themselves weren't a big deal. However, in reassembling them, the cartridge caps ("compression group cap" in the manual) won't snug up. The torque spec is about 40 Nm (29.5 ft-lbs). I've turned them a lot more times than I did to remove them, and still not joy. They are flush or slightly recessed to the main fork cap.

What am I doing wrong? I'm afraid I may have started stripping something by overtightening them, but they never bottomed out and certainly didn't reach 30 ft-lbs. Yes, I realize the torque spec is given dry and these did have fork oil on the threads (given that my online research basically said "you want to catridges very full", I intentionally put enough fluid in that the cap / compression assembly displaced some of it as I installed it.

Right now, I've got the fork legs assembled but not yet on the bike, and they seem to work (based on leaning on them); I realize the forces will be rather different with 500 lbs of bike plus my weight, but nothing was obvious with just me pushing on them.

[Kurlon]

I've always been told on fork caps that you really just 'seat' them and no more. They're under tension from the springs so they shouldn't back out on their own. I'd remove and inspect, if you've started stripping those fine threads it should be obvious and if so, I'd get new legs or caps depending on which are stripping ASAP.

[kbroderick]

I've always been told on fork caps that you really just 'seat' them and no more. They're under tension from the springs so they shouldn't back out on their own. I'd remove and inspect, if you've started stripping those fine threads it should be obvious and if so, I'd get new legs or caps depending on which are stripping ASAP.

Well, I pulled one of the caps...and found no damage that was obvious either to my eye or my finger tip when examining the cap threads or the cartridge body threads. I did email Marzocchi USA to see what's available for service parts, but I'm not holding my breath...the newer Shivers have a significantly different cartridge design, so I wouldn't be terribly surprised if parts availability was somewhat limited (or ludicrously expensive).

[Kurlon]

The new forks use the same bodies and sliders, so the parts are still out there. You can also get whole new drop in dual-adjustable cartridge assemblies to update your first gen units for reasonable too, which means there are used single adjustable and non-adjustable cartridges out there as well.

Edit: Wait, I'm thinking of the 35mm pitbike units... ignore what I said about used/upgrade cartridges as I've no idea if the 50mm units followed the same evolution as the 35mm units.

[Paul_E_D]

I'm confused about which cap you are talking about. Are these closed chamber forks?

[kbroderick]

I'm confused about which cap you are talking about. Are these closed chamber forks?

Yes, closed-chamber forks, and I'm talking about the cap on the actual cartridge system (i.e. the one that contains the cartridge oil, not the one containing the slider oil).

[Paul_E_D]

So it's the inner cap that you can see on the exterior top of the regular fork cap, right?

[kbroderick]

So it's the inner cap that you can see on the exterior top of the regular fork cap, right?

Exactly.