Originally Posted by
old_dude
Here is my trick to build any bladder shock.
Fill with oil with the rod fully extended then slowly cycle the rod in and out. You will see air bubbles form. Let the shock set until the bubbles are gone. It helps to have a shock stand to do this as it takes a few minutes.
Make sure that the oil is up to the top of the body with the rod extended then put the bladder in place on the body. The bladder should force out a little oil.
Put the shock cap on a few turns and compress the shock. This will push out some more excess oil.
Tighten the cap full and clean up the mess. If you do this right you will have a little rebound and a smooth air free shock.
If you have too much rebound loosen the cap and force out a little oil.
If you don't have any you will need to remove the cap, add some oil and repeat the bleed.
Good luck, there is a definite feel to this technique but with time you will build perfect shocks.
Great tips! I always build my shocks in a similar way but also use a shock pump to remove air bubbles and always build with as close to 0% rebound as possible. Of all the shocks I've built over the years Xray shocks seem to be the best and always build silky smooth with no air and no air gets in until after 10's of runs when i rebuild them and refresh the oil. I don't know if it is to do with the hole in the shock caps as shocks with no hole often seem to behave in the same way as the VBC shocks.
They build fine with no air and are super smooth whilst moving the piston slowly and not pushing it all the way in. Once the piston is pushed in all the way or moved quickly you hear/feel a squeak and then you get the tell tale feel and sound of air in the shock.
It's almost as if the bladder compensates so far then the pressure causes the seal to fail and air gets in? Similar to Johnny Wishbone's description. I haven't checked yet if oil is on top of the bladder but it does feel like what he describes is happening.