gas shocks sumberged in water

[Oldragbaggers]

Slow, our husband uses our Jeep to launch our boat and the back end is very often submerged up over the tailpipe. No problems so far and he's been doing it for several years. That's not a professional opinion of any kind, not backed by any expertise, just our experience (so far).

[KCStudly]

I don't see an issue with it, especially with gas charged shocks; the pressure inside would be higher than out, so if there is going to be a leak the shock has already failed, more or less. Shocks seals are what is referred to as a dynamic linear seal; dynamic meaning relative motion between parts (as opposed to a static gasket) and linear meaning that the moving part drags on the seal lengthwise. These types of seal designs generally have harder nonmetallic compounds and greater pretension (squish at installation) than radial seals (rotating motion like axle seals).

For the 4-wheelers the bigger issue seems to be water intruding into the drive axles and contaminating the lube oil. Even if the third member vent is routed to a high location above the water level, the axle and pinion seals are designed for less difference in operating pressure; and rotary seals tend to have less pretension so as to avoid grooving the shafts due to constant friction in one location (whereas the linear seal on a shock is constantly working over a much larger area). The theory I have heard is that when the axles are up to operating temperature and they get dunked in cold or cooler water, the cooling action causes contraction which tends to draw water in past the seals. The seal lips face in because they are trying to keep oil in, but this means that they are not very good at keeping water out. That's why they always recommend changing transmission/transfercase/axle lube after each and every serious dunking.

This is also why it is so important to service boat trailer axle bearings on a regular basis, especially when used in salt water. In fact, the lips on the axle seals on my boat trailer are designed to face out, tending to keep water out. The tension in the seals is plenty enough to keep the grease in (your seal design may vary).

[deepmud]

Gas charged shocks on the trailer you can't see (carrying the cab) have been under water a LOT in the last 15 years or so.




Still got 'em, still nice damping nicely, no issues.