07 sachs? rear shock packing/hard/no rebound?

[stainlesscycle]

welp, i'm thinking my sachs has the infamous no rebound deal. gotta tear into it today.

symptoms: when cold, i bounce the bike and it appears to have rebound and work fine, etc.

when riding. beats me to death. kinda a mixture of pogoing, packing, and just hard. it would bottom occasionally. never had an issue with it before...

it doesn't make any funny noises, and the seal/shaft look fine/no leak. i've not torn it apart/removed it yet.

i'd like to send it out, but i have a race on sunday, don't think i can get it back in time. so i'll probably just tear into it myself. i read the writeup on les' site, anyone have a source for the proper o-ring? or one that works?

or is it case of just changing oil/refilling nitrogen and it will be fine for a few weeks until i have time to send it out??

also - what psi on the res?

[GMP]

I have to look into doing mine as well. Always had Les go through it in the past. From what he told me the early '07 ones were better, the latter ones had the check valve issue. Mine is just spent and needs basic service, got a bit rough in a race yesterday. I put a lot of this stuff off on the '07 figuring the '12 would be here and I'd get back to the '07 later. Now I'm faced with a few mid season service issues.

[stainlesscycle]

in general will just a fluid change and nitrogen refill solve problem? obviously i'll have it open and see if anything is wonky. once i get it off, i can check it without spring and see if it's fine (which means it's the rebound issue i would think)

[GMP]

If the oil is hammered it will fade quick, and if its real bad it could foul the valving, but thats pretty bad. Rebound is the first thing to go. I have no idea if your shock has the check valve or not.

[stainlesscycle]

did a quick purge/refill. filled through the compression adjuster hole - seemed easier than pulling the shaft ( collar wouldn't budge..). gotta take it over to the shop and get some nitrogen put in. 195psi? then to check it, and hope that fixes the issue.... or else it's gotta come off again..

[GMP]

Can you do it that way? How are you sure about the seperator piston position? I heard of a guy assembling shocks in a fish tank full of oil to avoid any bleeding problems.

[BrentMartell]

My opinion: If your bike is cold and has rebound it is oil related. If you bike is cold and there is no rebound it is internal. On my ohlins I spin the rebound to see if it is making a click sound, if not, it is usually related to NO NITROGEN. BTW, I think 150-160 is normal in Nitrogen. 195 seems high but I am not experienced on sachs. Showa, WP, and Ohlins are around 150-160.

[moto9]

Originally Posted by GMP

Can you do it that way? How are you sure about the seperator piston position? I heard of a guy assembling shocks in a fish tank full of oil to avoid any bleeding problems.

You can do it that way, just pull the rez cap and push the rez pistion into place and let the excess oil flow out the comp adj hole.

Probably would be pretty messy though.

I have a rez cap with a fitting that I hook up my (home built) vacuum pump
bleed system.
For a quick oil change I remove the bladder/rez cap only, hand pump out the old oil into a bucket...then install the rez cap with the fitting and cycle in new oil and bleed the shock at the same time...quick, easy almost no mess.

Also I get a complete bleed with degassed oil...you wouldn't beleive how much air is trapped in non-degassed oil.

[stainlesscycle]

you can position the separator piston with a few psi of air. holds it still while you fill it. then just pump/filll.. before you reassemble adjster, you gotta play with it a bit to burp the last air outta the res side..

i might have made an error. doesn't the seperator piston go all the way in when you fill on the sachs? or is there a specific height it has to be at?

[stainlesscycle]

Originally Posted by BrentMartell

My opinion: If your bike is cold and has rebound it is oil related. If you bike is cold and there is no rebound it is internal.

this is what i am hoping.. i took the spring off, and it had compression and rebound. spun the clickers a bit and they all seemed to make a difference..

Originally Posted by BrentMartell

On my ohlins I spin the rebound to see if it is making a click sound, if not, it is usually related to NO NITROGEN. BTW, I think 150-160 is normal in Nitrogen. 195 seems high but I am not experienced on sachs. Showa, WP, and Ohlins are around 150-160.

i know the ohlins won't click without nitrogen. i think the sachs will still click - dunno.. there was nitrogen in there, the oil was not great, but i've definitely seen worse. hopefully it'll work, can't run over to shop to fill till tomorrow. so if anybody knows the correct psi of nitrogen, let me know


i have stock valving, and i've got all adjusters at around 13-15 clicks out. i have it written down, but not with me now.


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