Hi,

I was wondering if the o-rings on a regular fork make a waterproof joint with the stanchions. I may sound like a newbie but I noticed some important snow build up over there during the rides and therefore water might actually be able to go inside the fork and start to trigger rust formation.

Even though the o-rings make water tight junctions, they may alter over time so does anyone knows about that, after which period of time should they be replaced, etc. ?

There shouldn’t be a lot to rust inside your fork as unless it came on a £200 bike, most of it will be made of some kind of aluminium or magnesium alloy, and coated in lubricating oil and grease.
The top “o-rings” (i think you mean what manufacturers call ‘dust seals’) on most big-name forks are pretty durable: I would be dismantling, cleaning and re-greasing/re-lubricating the fork quite a few times between replacing the dust seals. (most folk refer to this as a ‘lowers service’) -to put this into perspective, I have been known to ride my rockshox forks for a year between services and despite mud, rain, river crossings and of course lots of hosing down and washing, I have never found water or emulsified oil inside them when I dismantled them: if the stanchions are in good condition and there is adequate lubrication inside the fork, the seals on rockshox pretty much are waterproof.

What fork is it? -that will probably help people in here give advice.

Thanks for your reply. Yes sorry I meant dust seals.

My fork is a 2011 Magura Menja. I actually do remove the shit around the seals regularly and lubricate the stanchions with oil after muddy rides.

Good to have your feedback. So I guess I shouldn’t worry.

Use a dedicated fork oil or grease. Many people have their own way of doing things, but personally (as a workshop spanner)….

I clean everything, then drop lowers off (whole bike in stand, CBA dismantling headset that often), rake out all th oil, check for damage to seals and wear on bushs etc. Take out damper carts (if sealed ones), and hand test, if any play in them, then replace oil and/or bleed them till they are sweet again. Replace carts, clean out lowers with compressed air, lube dust seals/stanchion oil seals with fox float fluid, and the foam ring with fresh open bath oil. Put back together, fill with open bath oil, torque up the bolts, done.

Do that maybe every 3months, and replace the oil/dust seals/foam rings/moving part O rings (damper cart seals/air piston rings etc) about once a year.

Little and often is the way to avoid needing a new fork. Even a garden hose has enough power to push water past your seals and emulsify the oils within causing wear etc.

A geezer brought a bike with £800 fox forks on today, about 2 years old, never serviced, and they are a borderline right off, only thing worth a damn is the lowers and the damper cart, everything else is ****, repair bill is about half of that of a new fork. Vs. a regular oil & seal change every 3 months even at shop prices is only £40 all in, so yeah, little and often.

float fluid, judy butter, manitou prep m, motorex open bath oil & brunox are worth having on hand.
Or even just some silicon spray or oil once in a few months to rehydrate the dust seals, but don’t go crazy as it reacts with the open bath oil & fork greases.

Thanks BrickMan,

Since my fork does not feel quite as smooth as it used to be, I think it’s indeed worth to go for a decent servicing.

I’ll try to figure out how to do it without messing around! 😉