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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.
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First get the spring off the shock.
Release all preload from the spring by turning the preload adjuster’s nuts.
Then slide off the spring retainer from the top of the spring.
Some springs will need to be compressed a little to get the spring retainer off.
If you don't have a spring compressor, in a pinch I have used a few large hose clamps or 2 tie downs on exact opposite sides hooked on one end woven through the other end and hooked back on the original end and then compressed equally, for the small amount needed to compress an lt500 rear shock hose clamps work pretty well. Most springs just need to be compressed a very little bit, then the top spring retainer clip slides right off.
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double post
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Let all the pressure out of the ressi. Remove the banjo bolt holding the ressi to the shock body.
At the top of the shock is an aluminum cap that is very lightly pressed on, gently pry it off.
This revels the shock seal under the cap you just removed.
Gently push the seal body down into the shock body a little to revel the seal retainer clip in a groove at the top of the shock body.
This clip looks like a big wrist pin clip.
Gently remove the seal retainer clip.
Now you can pull out the guts of your shock.
Do it over a pan to catch any oil.
Pour out all the old oil from shock body.
Clean out the shock body and shaft/ valve stack by spraying with brake clean only.
Blow off with compressed air...
repeat….repeat….repeat till inside of shock, seal head, shaft /valve stack is TOTALLY CLEAN.
Unless the valve stack is really gummed up bad no need to dis-assemble the valve stack.
If valve stack is to be dis assembled lay all washers out in order of removal for ease in the exact same assembly order.
After cleaning make sure to Tighten shaft nut till tight....
don’t know the proper torque…my elbow clicks when its right
DO NOT USE CARB CLEAN OR SOLVENT this could damage the seal and any plastic or rubber components. Brake clean is meant for rubber type components and will not hurt them and cleans very well.
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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
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The manual calls for 8.3 oz. of automatic transmission oil for an lt500,
Install the ressi hose back onto the shock.
Lube all seals, o rings, and shock body with atf, coat the inside of shock body with atf.
Hold the shock body almost vertical in a vise with soft jaws on top shock mount.
Dip the seal head ,piston and valve stack in shock fluid (atf) then slowly slide the shaft assembly back into the body. Insert shaft/valve stack till it bottoms out in the shock body.
Hold up the seal ring head and pour in as much shock fluid/atf as possible.
Clamped at an angle I tap on the end of the rod with a screwdriver handle while i rotate the rod around, and around...slowly...so all sides of the piston are pointing up at one time or another so all air can escape....once i think all the bubbles are pretty much done.......I re clamp the shock straight up and down.
Now push the seal ring down into its position in the shock body and install the seal head retainer clip. Rotate the clip to make sure it is seated completely and correctly. Tap the end cap back into place.
Now turn the shock in the vise so the ressi hose port is on top.
To get the remainder of the oil in the shock pour the rest of the atf shock fluid into the disassembled ressi body.
Black rubber Bladder must not be installed in ressi and ressi hose must be connected to shock body. Hold the ressi up above the shock to get the fluid to flow down hose into the shock.
Work the shaft all the way up and down SLOWLY to suck in the fluid and bleed out the sir. Continue till shock is full of fluid and there are no air bubbles escaping.
The manual calls for 8.3 oz. of automatic transmission oil for an lt500,
IMHO the more oil you can get into the shock,the more air you can bleed out, the better.
Assemble ressi and bladder, pour a little fluid in bottom of ressi before sliding bladder into ressi body. Some fluid should spill out from the top of ressi when inserting the bladder Put cap on bladder before inserting into ressi body. Reinstall ressi cap retaining clip.
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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.
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Sticky-ed!
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Pictures are gone. Fantastic write up though. I am definately going to re-build my own rear shock now.
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Heck yeah ... Makes me think I could tackle that job reading that killer write up!
Yeah right... My buddy has the nitrogen bottle tho hmmmmm -
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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.
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Where can I buy a seal head and o rings? Did these shocks come with bottom out bumper?
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All Balls
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