Originally posted by rustler753
When I just got the aluminum shock bodies and new insides, after rebuildinging them there seems to be alot of bubbles in my oil....what could be the source of the air leak...anybody have advice for building these evil serpent shocks? ( Yes the do get tiresome to rebuild....and yes they are evil...)
It should not happening.. try the following method I wrote in our website for Serpent damper and please give another feedback,
First thing is to assembly the top cap with its diagfram together (SER-909406+909402+6431). Then use `tapper` for M3 screws to pre threads the ball joints (SER-909403) deep enough so that you could have the piston rod (shock shaft) gets in and exposed maximum 0.5mm of its threads. Pay attention to its straightness when pre threading the ball joint. If the threads on piston shaft get too deep (shaft threads gets in beyond ball joint), you would be limited to have bigger droop (front is the most effected). Make sure all the piston-rod assy could slide easily to the shock housing without any bindings. Rule of thumb is to drop the piston-rod assy to the shock housing and it should drop completely straight (without the bottom cap installed).
Now it is the time to fill the oil and remove any air bubbles remaining by moving the piston-rods assy up and down several times. After all air bubbles cleared, do the following steps,
Close the top cap assy by threading it to the shock housing at about 1mm or so, then start pushing piston-rod assy up (to its maximum travel, then let go, do not hold up) to bleed some oil. When pushing the piston-rod assy up, you would also slowly begin to close the top cap assy further down until you could not possible (WITHOUT FORCE) go any further, shock shaft would automatically lengthen itself to maximum. At this point, your top cap assy will NOT close totally firm to the shock housing and that is OK. Remember, this step is only meant to make sure no air inside the top part of your damper. This is not the actual bleeding process.
Next, turn counter clockwise and open bottom holder (where your o-ring reside) just enough so that o-ring is no longer being pressed by its holder. Again, push the piston-rod assy up to halfway only to bleed some oil from the bottom. Then close the bottom part while the piston-rod assy stays at the point you stopped before. Now try to close the top cap assy firmly to its housing again and you should be able to close it firmly. While doing that, your piston-rod assy will lengthen itself to the maximum again. Remember, this step is to bleed just enough oil out so that you could close the top cap assy firmly to the shock housing. Again, this is not the actual bleeding process.
Now this is the real bleeding process. Open the bottom cap again, push the piston-rod assy up to its maximum travel. While still holding the piston-rod assy at its peak, use the same fingers/hand to close the bottom cap. Rule of thumb, your piston should not rebound more than halfway of its total travel, 3-5mm is the common results. You are done !!!
PS: If you feel that rebound strength is not the same between L/R or F/R as preferred, you would need to do it again from the beginning. If you open the bottom cap one more time to bleed just a little oil as desired, the `progressive` rebound feeling will not be the same and there is a good change for air to get inside.
Furthermore, in order to do less rebuilding maintenance due to small oil leaking from the bottom cap on usage, you could put 0.2-0.3mm shims (4x6mm such as Tamiya TA53586 or KOSE K1637-Teflon Motor Shims 3.4x6mm which is the best) inside the bottom cap to press the o-ring further (shim goes first then the purple o-ring) on its place and within the shaft when mounted. Rule of thumb, you must be able to use all 4 shocks at least 4 hours without the sign of air bubble inside and still having the same rebound stroke/strength.