Wltoys 12428b (part 20: Oil filled standard rear shocks)

So, I'm very happy with the CVA suspension upgrade.  If i could justify it (and if the parts were available) I'd upgrade the other cars too.  But i can't and they're not.  So what I'm left with is trying to make good on the stock rear suspension.

Negatives:

1. It's very stiff especially compared to the horizontal front.
2. Ride height is quite high which accentuates body roll issues

 Positives:

1. I have multiple spares
2. Trivial inspection shows all the makings of something better.

NOTE: High precision drafting skills.

I'm not the first person to suggest filling these with oil. There is even a mysterious and seemingly useless little plastic tube (2.55mm x 4.85mm) located exactly where the o-rings would go (as per my recent experience with the CVA shocks).

Option 1: use the standard plastic o ring:

Kevin tells me the oil i needed was around 800cps (which he then retracted and suggested 1000cps).  I have some 750cps, so I've used that.

There's nothing like a categorical No.

Within a heartbeat it all just bubbled out the small end..

Option 2: source proper o rings:

So off to the internet i go to find some appropriate o-rings.. Looking online they're specified using their ID (internal diameter) 2.55mm and their CS or t (cross section) which for me is ~1.1mm (~4.8 - ~2.6/2).  So check out these guys.. this is a list of o-rings of various types .. or some reading on this extensive post suggests these will work

But before i got around to purchasing them..

Option 2a: Use some crappy foam instead of proper o-rings:

..I literally found this on the lab floor, i have no idea where it came from.  It's some kind of foam rubber:

it just .. appeared

I fashioned an o-ring around the shaft of the piston (in place of the small plastic o-ring), and also another around the large end cap.  It worked well enough to see that o-rings won't help..

the second issue is that the springs are very stiff.

Option 2b(?): Cut the springs..

I thought shorter springs = softer.  But it doesn't really seem the case.  It seems they're just .. shorter.  I wish there was more i could say, but even cut they don't seem to be any softer.

Option 3: Just do it properly..

Really.. these just work.  Unless you're on a total shoestring, just do it.

Engineering works..