Changing shock oil.

Got questions? We got answers....
Post Reply
DirtRoller
Member
Posts: 25
Joined: 11:03 pm Feb 26 2005
Country:
Location: SoCal

Changing shock oil.

Post by DirtRoller »

Here are some tips for servicing your shock. Basic tools will get you through removal and install.

Parts to remove; fender, air box, left side sub-frame bar, right side dog bone (linkage), and of course the shock.

Grab a pencil and paper and write down your rebound and compression settings. Once you have the shock off, turn the clickers all the way out. Count the turns out from where you have them set and write it down.

You need to measure your spring pre-load or installed height, and write that down, too. Next loosen the spring all the way.

Pull down the lower spring seat so you can remove the split shaped collar or ring. A soft jawed vise will come in handy. If you don’t have one, put a rag over the jaws so you don’t damage the shock. (The shock should be clamped into the vice with the Schrader valve facing up.) Now push in on the schraeder valve to let the pressure out. Use a deep socket that will fit over the valve. Tap down on the reservoir top enough to expose the circlip. Remove circlip from the reservoir, be careful not to scratch the inner body with tool(s), small flat-headed screwdrivers.

Now you can remove the bladder from the reservoir. Twist, wiggle, and tap up lightly. Clean and set aside.

To remove the shaft assembly there is a cap that is pressed into the shock body. This cap can be removed several

ways, for example; chisel, pliers, a bearing puller is what I use. Softer and slower is better, tap up on the cap. The seal head is below this cap and there is a circlip holding it in place.

The circlips are not the same size so make sure you remember which goes where.

Racetec makes a tool for tapping the seal head down, but I’m sure you could make something else work. Just be careful not to damage or scratch anything.


With the seal head tapped down remove the circlip, and pull the shaft assembly out of the body. Yes, you should have

a catch pan or rag for the oil.

Having fun yet?

Clean all the parts with a cleaner that will not damage the rubber on the shaft assembly or bladder. Blow dry with compressed air.

There are different oils to choose from, brands and weights.

I used a 3 wt. but a 5 wt. works fine for me also. Do your research and get what shock oil will work best for you (3,5,7,10wt).

Now that everything is dry and clean enough to eat out of. It’s time to add your oil to the reservoir side of the shock.

Pour oil past the half way point in the reservoir. The oil will self-level in the shock body. With your catch pan in place,

push the bladder into the reservoir. The oil should overflow out of the top of the reservoir. Push the top of the bladder past the circlip grove slightly. Put the circlip in and make sure it is seated all the way around.

Add 25 to 35 lbs. of compressed air to the bladder. This is to bleed out the air in the reservoir.

Next add oil to the shock body until it’s about ¾ of an inch from the top. Now put the shaft into the shock body. Push down slowly and steadily. Watch for air bubbles in the oil as you push down. Cycle the shaft up and down several times. Be sure you don’t pull the shaft up too high, as it will allow air to suck in. Now pull the shaft high up into the shock body without sucking any air and fill with oil to the top of the shock body. Take a rubber hammer and tap hard (a quick strike) on the clevis end of the shock. This is to knock the air out from between the shims. Push the seal head in, holding pressure on it until it stops going into the body. While pushing down, release the air pressure from the Schrader valve on the reservoir. This will allow the seal head to go in further, just slightly past the circlip groove. Install the circlip. Again, make sure the circlip is fully seated.
Now fill the reservoir with 90 to 100 psi of compressed air. Test your shock on a block of wood by pushing it in and allowing it to come back up completely by itself. The shock should move smoothly in both directions. (check for leaks)
Bleed all compressed air out after testing.

Clean any excess oil off of the shock, and set spring preload and settings back to the positions you marked before removal.

Compressed Nitrogen (Danger)
You will need to research how much pressure you want to use for your type of riding. There is some debate about if there is any effect on performance within a certain range of pressure (130 to 180 psi.). I'm at 170lbs. nitrogen. Don't try this if you do not know what you are doingThe job time was just under 2hrs.
Have fun!
PS I have pictures wish I could have inserted them into the thread.
DirtRoller
Member
Posts: 25
Joined: 11:03 pm Feb 26 2005
Country:
Location: SoCal

Post by DirtRoller »

Yes there is more!! If you need to replace the seal head ( yes you need to)
Jason has covered that.

I'm not a big fan of g/v for this bike, but if you have the valve retaining nut removed (peened end ground off) then doing G/V valve might be and option.
User avatar
KDXGarage
KDXRider.net
KDXRider.net
Posts: 14047
Joined: 06:45 am Nov 01 2004
Country: United States of America
Location: AL, USA
Contact:

Post by KDXGarage »

I would just add that on removing the reservoir cap, get a $2 4-way air valve tool from an auto parts store. Point the threaded cap part down, and cut a little off the two side tools. You need to cut about 1/4 inch off so that the tool can thread all the way down on the valve. After it is threaded all the way on, just use some pliers to pull it up.

When you set the bladder back in the reservoir, hold a rag around the reservoir when the excess comes out. It is SUPPOSED to come out.

I have pressed down seal heads with and without my Race Tech seal head setting tool. I will never go back to not using that tool. :grin:

Also, don't forget the air bleeder bolt on the top of the shock. That makes it a breeze compared to taking out the compression adjuster, but that is another story for another time. :lol:

Thanks for the tips, DirtRoller!
Thank you for participating on kdxrider.net. :bravo:
To post pictures from a device: viewtopic.php?f=88&t=24128
Post Reply