Air gap in shocks be gone

[wagn]

Found a way of getting the air gap out of the cap of the shock when refilling oil.MIght take a couple tries to get it right but it's well worth it.

You will need: roll of thin teflon tape (thinner the better)

Change your oil like normal, when it comes time to put the cap back on, cut 2 pieces of teflon tape about 4 inches long, turn cap upside down fill cap slightly less than half full with shock oil. Place teflon tape across cap, the 2 pieces of teflon tape should cover the cap opening. Now when you turn the cap over to put it on the shock the oil is sealed inside the cap. You only have 1 shot to get the threads right. The quicker you can get the cap spun down the more oil will stay inside the cap reducing the air gap. If you get it right the shaft should spring back almost the full length, if it only springs back a bit you have to redo it. This seems to work fine removing the air bubble from the cap but I'm not sure how the teflon tape will react with the shock oil if any of the tape gets into the shock but it seems to be working fine for me on my stock savage shocks. If the teflon messes with the shocks I'll post it. But WOW what a difference.

 

[Jeremy]

Thanks for the tip

 

[Bankrupter]

If they spring back its wrong... sorry. That is a over filled shock. The shock shaft should fully compress and not rebound w/o a spring to push it back down. If they spring back you are bound to blow off caps or the bottom seals when you jump it.

 

[Jeremy]

Bank is right .. 1 hard landing and you will have 8 blown shocks.. Not to mention a horrible oily mess

 

[wagn]

LOL great now i gotta change them. But thanks for lettin me know.

 

[Noakes75]

well they are supposed to rebound a little right? I was reading an article in Xtream CR Cars on how to service the shocks and it says they should rebound some. It really doesn't give an amount only that you want them to be equal. I'm about to service mine so we'll see what happens.

 

[X25]

i don't think any of mine rebound. they use to and i kept blowing off caps.

 

[pmp]

when I do mine they rebound about 1/4 in or so. I don't know how you can get your cap screwed down all the way without any rebound? you do need to have a small amount of rebound or you can not make sure your shocks are properly matched. once you fill up 2 shocks and they are caped extend them all the way push the to thredded ends together they should compress equaly against each other and bottom at the same time then when you pull them apart they should rebound at the same time. and always work in pairs fronts and backs.

 

[Larsenracing]

I usually try to get mine to spring back to about 1/4" but no more. They will leak some out in the process or driving and a little spring back doesn't hurt its just when there is more than 1/4" of it, it can blow them.

 

[HopIt]

Any amount of rebound is caused by too much oil in the shocks. This will put greater preasure on the seals causing leaks or blow outs in the extreme.
Basicaly you need a volume of air in the shocks which is equal to the amount of oil displaced by the shock rod when it is fully retracted. If no air is present then you will be applying hydraulic pressure to the inside of the shock bodies......not good ! You can get away with a small amount of rebound with the HPI stock shocks, because they are fitted with the rubber bump stops, therefore they don't compress fully.
When I ran HPI shocks, I used to bleed them without the rubber bump stops and fit them after to make sure there was no excess oil in them.