This was originally posted by All Cool/Randy on the original ORHQ site and is being re posted with permission by the author.

After seeing many posts asking about shock maint, I decided to do a shock 101 tutorial. Hope this helps some.
No need to send out a shock to get its fluid changed

If you can rebuild a motor or transmission…
a shock rebuild is a piece of cake!

In time from normal wear and tear a sealed stock shock gets oil black dirty from the aluminum wearing off the shock body wall.  This is an abrasive mix that will wear on the shock. This black gooey mix also keeps the valve stack from working correctly.


Before sending your shock out for a revalve try changing the shock fluid and cleaning it up so the shock can work as designed. Change shock oil often to preserve your shock.
With clean oil and valve stacks not gummed up and sticking together, imo the shocks on the lt500 work very well.


With clean oil and valve stacks not gummed up and sticking together, imo the shocks on the lt500 work very well for the average weight rider 150-220lbs.

double post

Now take apart and clean your reservoir.
Clean ressi same way as shock body, with brake clean

Leave the bracket on the ressi, put the ressi bracket in a soft jaw vise.
Take the hose off the ressi, drain all oil oil out from the hose end.

Now push the ressi cap down into the ressi just enough to get at the retaining clip, it is kind of like a wrist pin clip.
Remove it with small screwdriver or pick.
Might have to use a big socket and hammer to gently tap the cap down a little, depending on how slugged up ressi is.

See the retaining clip groove on ressi body


To get the bladder/pressure cap out of the ressi body
Screw a tire valve installing tool onto the schrader valve of the ressi cap and pull out the cap and bladder.

To help remove cap, you can put your air hose into the bottom of ressi where the shock hose attaches to ressi.
If you don't have a tire valve install tool, pressure in the bottom of ressi should work.
Be careful with how much pressure you use, don't want to make a projectile out of the cap.
Also remove any burs on ressi body you might have created taking out the retaining clip, this will make sliding out the cap easier.



DO NOT put pressure in the valve in the ressi top cap to remove the cap. It won't work.
You want pressure under the bladder from the shock hose end to push the bladder and cap out together from underneath.

Note the molded in o-rings on the bladder, they seal/seat on the cap and the bladder/cap assembly slides out of the ressi body.


Inspect ressi bladder for any rips or perforations

Your shock should be ready for a pressure charge now.

The manual calls for 143# of nitrogen pressure in the ressi bladder.

All nitro is contained in black rubber bladder only. None gets into the shock body at all

no nitrogen touches shock oil or gets into shock body, in a bladder type ressi.***


The nitro pressure on the inside of the bladder resists the shock fluid from returning to the ressi chamber under the rubber bladder.

Nitrogen is an inert gas,
unlike compressed air which is an organic gas.

What this means to you
With many posts about where to get your shock nitro charged here is my take on it.

An inert gas (Nitrogen) does NOT change its pressure with temperature changes.

With An organic gas, as temperature increases so does gas pressure... temperature is pressure.

The amount of pressure change depends on that particular organic gas.
Temperature changes effect some organic gases more than others, some are less effected by temp changes

So Comp air is effected, as are all organic gases.
Fluorocarbon organic gases have drastic temp/pressure swings

Compressed air is an organic gas, but is not effected drastically by temp changes. Thats why we have used it for years in our tires.

How much do your car tires change with temp changes?
Not much...10-20%... maybe, with big temperature swings.
How much temperature swing will your ressi see in your area on your quad?
On a very cold day check your ressi pressure and if it is down fill er up.
On the other hand, Will you even be able to feel a 15-20lbs change in your ressi pressure in your bikes handling characteristics
I can't, and would be willing to bet most of you guys can't either.

These are important to note in case you don't have nitrogen to fill you ressi bladder with.

IMHO dry compressed air is ok to fill our ressi bladders for recreational use
or at the very least temporarily till you can get a nitrogen fill.
I have nitrogen and have used both and can't tell a difference.


All I am saying is it is not as big a deal in our LT shocks to use comp air as some shock companies want you to think.

Now in a floating piston type ressi style shock that commonly leak their nitro charge into the shock oil,
do NOT use compressed air. our LT shocks have a thick rubber bladder not a floating piston design ressi. Big difference.

That being said, Yes it is politically correct to use nitrogen.
If anyone needs a nitro fill,
send me your shock,
just pay postage both ways, include shipping labels,
only FedEx or Ups
and don't be in a massive rush
I will fill it to 143# Suzuki specs or whatever you want.
free to all forum members

IMHO, don't skip a shock oil change because you don't have nitrogen.
Your much better off with new oil and a clean shock with compressed air in the bladder than a dirty oil sludged up shock with nitrogen imo.

Pictures are gone. Fantastic write up though. I am definately going to re-build my own rear shock now.

Pictures are gone. Fantastic write up though. I am definately going to re-build my own rear shock now.

If the photos are gone and it says "bandwidth exceeded" the photos will re-up on the 8th of every month so just check back them.

The photos help a lot with the rebuild.

All Balls