Sachs shock leak

[400_racer]

Has anyone had a problem with their shock leaking slightly after a service? The bike is an 07 EC300. I took it in to a shop (one recomended by a couple of people at work) last month for a routine service while it was off the bike as i wasnt sure if or when it had last been done, they fitted new seal, bush and oil.

During the first ride after re-fitting it, i noticed an oily ring around the shaft and slight residue on the shaft above the ring. Cleaned it, did another loop and it came back. Same thing was happening again a week later on the next ride out.

Obviously not happy, i took it back to the shop and they were quite happy to strip and re-check everything. They found nothing obvious, but still put another new seal in. I went out again on it this weekend and it seems the same thing is happening.

When it first happened i wondered whether it was residue left over from the service, but they said they tend to clean well to stop this happening as it can freak people out when they see it. So i doubt its that. They order in proper Sachs seals, so they arnt using some other random seal that fits. They also checked the shaft for straightness etc and said its fine. It wasnt leaking before the inital service.

I dont think they generally work on Sachs stuff, but a shock is a shock and they come with a good reputation and seem to know what theyre doing. But maybe thats been my mistake!

Anyway, do you guys have any ideas on what might be going on? Could it just be residue left over which will disappear with riding, is that normal? Are there any assembly tricks/subtleties with this particular shock? Maybe a different seal is generally recommended?


Thanks in advance,
Ad

 

[Synergy-Seals]

Ad. Not sure whats going on but the shaft may be damaged or the seal is not designed properly.

We have both 16-18mm seals available if your interested.

Rob

 

[400_racer]

Thanks Rob,

Pm sent

 

[Simmo737]

Hey Rob, what seals should I use for Sachs 48 mm, mud to dust and everything in between, rigid or flexible?

Sorry for post hijack.

 

[Synergy-Seals]

Use the flex-seal.
Pick the sfs-0948-r1
specify sachs forks in comments.

 

[Simmo737]

Thanks!

Cheers

 

[400_racer]

Having sent the shock to another shop who deal more with Sachs parts, they spotted the internal surface of the gas reservior has scratches and even evidence of sanding to try and remove those scratches! Scratches probably caused by careless removal of snap ring/piston they reckon.

Apparently those scratches can be enough for the gas to escape past the reservoir cap, lowering the pressure of the gas, which doesnt pressure the oil enough to push the seal lips onto the shaft, causing the slight leak.

Im not that clued up on the workings of shocks, but this does sound feasible, what do you guys think? Am i being strung a yarn here to make me buy another shock? The manual on the main ggriders.org site does say to be very carefull removing the snap ring, but doesnt say why.


Thanks,
Ad

 

[Simmo737]

If that's the problem, fit a bladder cap conversion from. http://checkpointoff-road.com/store.html. It feels nicer and will not have the problem your are having as it seals rubber to the wall of the res and then onto the cap itself. I don't know if that issue can cause a leak though.

Cheers.

 

[twowheels]

Apparently those scratches can be enough for the gas to escape past the reservoir cap, lowering the pressure of the gas, which doesnt pressure the oil enough to push the seal lips onto the shaft, causing the slight leak.

Ad

What did they measure the gas pressure at then? If gas leakage was the issue, and that's what they suspected, surely they measured the pressure before they evacuated it, right?

 

[GMP]

Did you notice the action going bad?

Some people are just savages, even so called pros. I had a well known west coast shop butcher my Honda Showa shock shaft some years back.

 

[Diggs345]

I have a used , just serviced ohlins shock for sale in the sale section for not much more than the cost of a rebuild

 

[400_racer]

Thanks for the replies guys,
GMP, I didnt feel the action going bad but just always saw the oil residue after each ride. I guess that wouldve come if i'd used it a few more times.

twowheels, I didnt get the actual pressure prior to teardown, he just said it was much lower than it should be. I'll ask when i speak to him next.

simmo, bladder kit looks tempting, but ive been offered good prices from two different people on used (and just seviced) Ohlins shocks. Thanks Diggs! The other is from the shop who currently have the shock. Leading to my suspicions they're just trying to sell me another shock and this scratched reservoir theory is just that.

Has anyone heard of scratches on the internal reservior walls causing gas to leak, causing an oil leak?


Ad