RC4WD King Shock hydro-lock

[stpete40]

Anybody figure out how to get oil in these things without hydro-locking? At any kind of speed on the trail they are like pogo sticks. I enlarged the piston openings with a small round file and pumped it a couple of times as I was tightening the cap. Managed to keep some oil in this way and stop them from instantly popping out to full extension. Without opening up the piston I had zero luck .

[kaneohecrawler]

Bleed the shocks with the shock compressd. Like assemble them compressed. Then youll no longer have your issue. Done.

[stpete40]

Originally Posted by kaneohecrawler

Bleed the shocks with the shock compressd. Like assemble them compressed. Then youll no longer have your issue. Done.

Not bad, but not great. I'm coming to the conclusion these shocks aren't receptive to a lot of tuning with oil.

[kaneohecrawler]

Trust me it works.. I have my king shocks full of shock fluid and no hyd lock whatsoever. You have to fill them up then fully compress them with the top OFF gradually and I mean gradually tighten it a little at a time. Wiggle the cap as your doing this its most important when your almost fully tightened down. If you finish tighening let go of the shaft. If it pushes back out keep bleeding! Most all shocks need this treatment..

[Terra Nova]

I have the 90mm dual spring KING shocks and I have this problem also.The way I see it, you can't have a shock that will go smooth from in to out unless there is some kind of bladder for expansion. The problem is not that the piston won't go through the fluid. It is that when your shock is compressed, there is less room for fluid, because now you also have the shaft in there. kaneohecrawler, your idea does work for the compression problem, but then the shocks are trying to compress themselves because when you extend them, there is nothing to replace the leaving shaft. This is better than pushing back out I guess because the spring will slow down the compression, but the shock does compress faster than I would like, even with 50wt fluid.
I am new to this scale hobby, but not R/C hobby. In buggy shocks, there is always a bladder on top of the shock which can compress as the shock is compressed.

[05Fronty4x]

I prefer to build crawler shocks with zero rebound, which is done by doing what kaneohecrawler is talking about. Screw them together with the shaft fully compressed and be sure to bleed out any access. Sometimes you have to take even more oil out to get a zero rebound setup. Very rarely have I ran into the opposite problem where a vaccuum is created inside the shock trying to pull the shaft in, this would lead me to believe you have too much air in the shock (bled too much oil out).

[Terra Nova]

I worked at them a bit more and they seem to be good now. There is still a small bit of rebound, but the shaft only comes out about 3-4mm. After all this, the springs are way too light for my heavy SCX10. I used the stock Axial springs on the KING shocks and I think it will work out OK. Just have to take the truck out and test it.

[spookyseven]

just to expand on what others have said.

Whats happening is air can be compressed but fluid cannot compress. When you have a shock body full of fluid and try to push a piston in it is taking up space in the body and the pressure tries to force it out. If you leave a small space of air inside the shock body the air will compress and allow room for the piston. The downside is with enough movement the air will mix with the oil and your shocks will feel very spongy. The reason for having a diaphragm at the top of the shock is to allow enough air for the piston, yet keep it seperate from the oil.

If you feel like it you can find diaphragms from other brands like traxxas and add them to your shock.

[GravelDuster]

+1 the stock axial diaphragms work fine I have the 110mm kings, did the trick.

[stpete40]

Originally Posted by spookyseven

just to expand on what others have said.

Whats happening is air can be compressed but fluid cannot compress. When you have a shock body full of fluid and try to push a piston in it is taking up space in the body and the pressure tries to force it out. If you leave a small space of air inside the shock body the air will compress and allow room for the piston. The downside is with enough movement the air will mix with the oil and your shocks will feel very spongy. The reason for having a diaphragm at the top of the shock is to allow enough air for the piston, yet keep it seperate from the oil.

If you feel like it you can find diaphragms from other brands like traxxas and add them to your shock.

I'll give the traxxas diaphragms a try.

[vanwraith001]

I just picked up a full set of 110mm. For my wraith, what would be a good wt oil to use. Too bad someone hasn't done a video on thison YouTube or something. I

[JesterSpec]

Originally Posted by vanwraith001

I just picked up a full set of 110mm. For my wraith, what would be a good wt oil to use. Too bad someone hasn't done a video on thison YouTube or something. I

https://www.youtube.com/results?sear...ild+rc+shocks+

[Ohioskills]

I use a smig of teflon tabe