Bubbles in Float dampers

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Bubbles in Float dampers
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Posted: Jan 22, 2020 at 4:39 Quote
So after much research and soul searching I took the plunge and bought nitrogen equipment to start servicing Float dampers. It's been an interesting adventure figuring out what works and doesn't, and what the inside of a damper that's been in use looks like as opposed to the pics of brand new ones being disassembled in the manuals.

So far, I keep finding that when I break these things open the oil is just full of gas and bubbling out the bleeder hole in the seal head. When you pour the oil into a small container it bubbles and outgasses almost as fast as a cup of soda or beer. I've only done a few of these things so far, so I don't have much of a basis for comparison and I'm super curious about the gas in the oil. I'm guessing that it's coming from leakage out of the IFP chamber. Is this something that happens to most Floats not long after reassembly, or is it a side effect of going a couple years or more without service?

Any advice from someone with first hand experience in this area would be most welcome.

Thank you Smile

Posted: Feb 20, 2020 at 14:20 Quote
Pretty normal from my experience. I don’t work on as many in-line shocks as I do external reservoir ones but yeah every DPS I have torn down was like that. Nitrogen in the oil from an IFP leak will definitely cause it to bubble and the oil will be pressurized when you open the bleed screw or loosen the seal head and start to bubble out quickly. I think it’s likely that the oil will bubble even if it was perfectly fine when the shock was in operation. Letting the ifp pressure out rapidly might cause a pressure drop in the oil and make it boil or agitate it in a weird way.

Posted: Feb 20, 2020 at 14:39 Quote
ZSW wrote:
Pretty normal from my experience. I don’t work on as many in-line shocks as I do external reservoir ones but yeah every DPS I have torn down was like that. Nitrogen in the oil from an IFP leak will definitely cause it to bubble and the oil will be pressurized when you open the bleed screw or loosen the seal head and start to bubble out quickly. I think it’s likely that the oil will bubble even if it was perfectly fine when the shock was in operation. Letting the ifp pressure out rapidly might cause a pressure drop in the oil and make it boil or agitate it in a weird way.


I've taken apart several more dampers, both inline and remote reservoir type and I'm finding lots of bubbles in all of them, so I'm guessing this must be the way of things and IFP leakage is more or less normal and unavoidable. What I'm really curious about though is, how long does it take for this to happen? A month? A year? More...?

Posted: Feb 20, 2020 at 21:50 Quote
I think it’s really a case by case thing. Time span between rebuilds is all over the place. Usage is a bigger factor than just time passed. A shock that’s heavily ridden for 6 months will be in worse shape than ones that’s lightly used for 18 months.

Ifp pressure, ifp shape, ifp material, temperature, shock stroke, and oil type are all factors into well a ifp seals

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