Author Topic: oil level in rear shock  (Read 2164 times)

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Offline dave916

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oil level in rear shock
« on: May 12, 2011, 08:22:36 AM »
 i am currently rebuilding a smr510 rear sachs shock 
any tips on  oil level and bleeding??
 

Offline Magnus

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Re: oil level in rear shock
« Reply #1 on: May 12, 2011, 09:02:36 AM »
I dont know about the sachs shock, but on the KYB and Showa you fill them completely up..
On them you fill the bladder chamber about 3/4 full, put the bladder in and pressurize it to push oil through the shock body. then you fill the main chamber about 3/4 full and push the rod ( with complete valve assembly) hard down in the shock body and slowly up until the air is gone.
then you top it up and push in the seal head (oil will overflow). pushing the valve hard down opens the valve and lets air out.
hope it helps, though its not the same shocks I think most modern shocks with nitrogen are supposed to be topped up with oil. (I would wait for the professionals to answer before you take my word for it  :wink:)

Offline dave916

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Re: oil level in rear shock
« Reply #2 on: May 13, 2011, 01:13:16 AM »
cheers magnus

bleediing was easy enough , my main problem the correct ammount of oil,
end up with the shock full and the reservoir  1/3 full of oil [no bladder in shock}

would the reservoir 1/3 of oil be ok?

can still remove oil as have not gassed it yet

Offline Magnus

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Re: oil level in rear shock
« Reply #3 on: May 13, 2011, 03:19:37 AM »
I believe you need to have oil enough for it to overflow as you push the bladder in to be sure there is no air trapped, 1/3 is probably more then enough.
But if there is too much oil left in the chamber for the bladder to expand completely, it will put pressure on the seal when pressurizing the bladder..
I think that is the reason why one should put in the bladder and put a little pressure on it before bleeding( you could just use air and charge it with nitrogen when finished)
Perhaps you can call a suspension specialist and ask how they do it? I've only rebuilt two shocks and had instructions on how to do it...

Offline dave916

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Re: oil level in rear shock
« Reply #4 on: May 13, 2011, 08:07:37 AM »
cheers   no bladder in the sachs shocks ,  seal piston dividing the oil from the gas in the reservoir  ,when the shock stroked  it only moves around 15mm in reservoir ,
 i am thinking without a bladder  there is a little more room for oil in reservoir
i just pushed the nitrogen piston seal 2/3 of the way into the reserivoir when i was bleeding . want to leave room in case the 180psi of gas would push it further,

all seem to be working perfect now, rebounding perfect without spring ,  not still sure if the shock oil i got was ok {racing shock oil 5w-20w  {MOTUL  VI 400}