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hewson

Falcon Rear Shocks

6 posts in this topic

Hi all , can falcon rear shocks be refilled with oil and air at home ????? my 6 year son thought they looked like tyre valves , and let one down , he did'nt like the oil coming out on him .If so how much do i need ??? or do i need too send them away......

Edited by hewson

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Hi all , can falcon rear shocks be refilled with oil and air at home ????? my 6 year son thought they looked like tyre valves , and let one down , he did'nt like the oil coming out on him .If so how much do i need ??? or do i need too send them away......

Hi,

The gas in them is nitrogen not air, and unless you drain the intact one you won't know how much oil should be in there.

I would return them to Robin, you will get a rebuild with new seals etc fresh oil and a recharge of nitrogen. I would get some proper brass hexagonal Schrader caps and do them up with a spanner. Or amputation at the wrist would also do it ;-)

Cheers Trev

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if oil came out then there is something wrong. The nitrogen chamber is less tha 1 cubic centimeter- Its there to comensate for when the oilk gets hot and expands.It is NOT conected to the oil. It is separated by a membrane- Your membrane must be AWOL. You dont actually need any nitrogen in them!

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if oil came out then there is something wrong. The nitrogen chamber is less tha 1 cubic centimeter- Its there to comensate for when the oilk gets hot and expands.It is NOT conected to the oil. It is separated by a membrane- Your membrane must be AWOL. You dont actually need any nitrogen in them!

There's no membrane in the trials shocks Lee, oil and gas sit in the same chamber. If you touch the valve stem even for a split second, oil will come out with the gas. They are different from motocross shocks.

They are straightforward enough to take apart and refill with oil. I can't remember the quantity but you can get it through trial and error. You won't have lost too much through the valve. Removing the damper rod assembly is a bit fiddly as you need to tap off the seal holder carefully with a drift of some sort as it doesn't screw in, it's a press in fit. Then you need long nose circlip pliers to reach the second circlip which is down inside the body, the first circlip is right at the top.

At a guess, as it's a long time since I did mine, top up the oil level to about 3/4 full. Then refit the damer rod, turn the shock upside down (as it sits on the bike) and push the damper rod in. There shouldn't be any free play caused by not enough oil and the piston travelling though an air gap, nor should the piston hydraulic lock through too much oil. It's trial and error getting the level right but doesn't take too long.

You can fill with air, it doesn't have to nitrogen in a trials shock,they work ok with air. A mountain bike shock pump from Halfords for

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sorry to disagree but standard Falcon trials shocks don't have a membrane separating the oil and the gas.

Oil can be replaced by releasing the gas pressure with the valve as high as possible (to minimise the amount of oil that comes out with the air).

The valve body can then be unscrewed from the shock body and the remaining oil drained out the hole that the valve body came out of - no need to disassemble further.

When all oil is drained/pumped out, put 100ml of new oil of your choice in each Falcon. I use 5WT fork oil and I use a syringe to add the oil.

Screw the valve body back in and pump them up ideally with nitrogen or argon, to somewhere between 70 and 100psi. Dry compressed air will also work fine, but may cause the oil to degrade quicker than if an inert gas was used.

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Thanks for the advice , ill give it a go :thumbup:

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