Drop Off 2 - Problem, Help Required

albo

HI,

I have a pair of 2004-ish Drop Off 2's, on my STP

There seems to be a major problem starting to occur; as i push down, then pull up fast on the front end (If i am hopping for example) It seems that the forks don't want to come up with the bike...

They judder and wobble as if they are rubbing? But i am not aware that this happens to forks...

I have heard lots of people saying that the seals break on forks from time to time and need replacing.
So please can somebody suggest what may have happened, and also explain to me what the 'Seals' on a fork are, and what will happen if they 'go'?

Sorry for the length of this plee but please help me

thankyou

albo

dave_hill

I'd say it's more likely the bushings that have gone.

See where the stanchions fit into the lowers? There's a rubber ring with a lip fitted into the top of the lowers - these are the wiper seals and are the first line of defence in stopping crud getting into the internals. Basically, as the forks extend and compress, the wiper seals "wipe" crud off the stanchions and keep the slidy bit clean.

Now, if you take the wiper seals out, underneath them are the seals proper. These will either be a foam ring, or possibly what's known as a labyrinth ring. These are the main line of defence for the insides of the forks and actually pick muck up. Eventually they wear out and break down, loosing efficiency and requiring repalcement.

However...

Underneath the seals are the bushings. These are usually a thin-section white-metal or polymer cylinder which fit between the sliders and the stanchions and allow the smooth movement of one through the other - like a linear bearing (which is really what they are) with no moving parts.

Marzocchi forks used to have a reputation when new for the bushings being REALLY tight and taking a long while to bed in properly. Since they moved production to Taiwan however, the quality of bushings has dropped drastically and the newer 'zocchis (particulary the 44s and 55s) have suffered from premature bushing wear and failure. Luckily for you, your old Drop Offs were made in Italy and are the higher quality models.

Anyway, back to the plot...

It sounds like the bushings in yours are now shot and require replacement. This being the case it stands to reason that the seals and the wipers will need doing too.

So, if you have really good LBS, time for a service. Either that or bang 'em off to Flooksy at TF Tuned, or Stendec for the specialist treatment.