[billybob]

Dampening rod doesn't return all the way once pushed in.
So I replaced the stock compression spring in the fork cap assembly with a lighter one...1.1kg from Factory Connection.
Seems like with the lighter spring...the dampener rod wouldn't necessarily be pushed all the way out.
On a stock spring...if pushing the dampener rod into the inner chamber compresses the oil and compression spring and all seals are intact...the dampener rod would extend back out completely.
But if you replace the stock spring with a lighter one...like I did...shouldn't it be normal for the dampener rod to not be completely pushed out?

BTW:

Not sure how others are disassembling the fork cap assembly...but i ground down a 13mm wrench and stuck it on the aluminum nut inside the compression spring, then turned the top 19mm fork cap which basically unthreads the aluminum lock nut until it runs out of threads...then it locks up on the non-threaded portion of the shaft...then finally the top cap comes off so i can remove the spring.
This is sketchy at best. Seems like the fork cap had some thread locker on it of some sort.
Intially I did try to take the button 10mm staked nut off and found that yes, the bottom valve stack came off, but then I couldn't get the floating piston off or spring off from the bottom.

[mossman77]

I just rebuilt mine, and they didn't return all the way, no matter how many times I bled them. I replaced all seals, o-rings, and bushings and followed the directions exactly. They would return after filling the cartridges, but as soon as I did the full stroke (as instructed in the manual), the rods would no longer fully extend. From what I hear, this is normal, although is still bothers me considering the manual says they should. I believe full extension is about 12 7/8", and mine extend to about 12" if I remember correctly.

[JimDirt]

Welcome to the site !!

The issue your having is from the Free Piston Seal , this is the seal that is on the inside of the piston on the Fork Cap Assembly , all that changing the Pressure Spring will do is soften the initial hits in the beginning part of the stroke (stock would be 1.9 or 2.0 , i run 1.76), it has nothing to do with the Rebound Rod returning , but the seal on the Free Piston does , when you disassembled the Fork Cap Assembly , the piston on there is what seals the oil inside the Cartridge , so when you push the Cap Assembly in the oil stays inside (except what is pushed out as your inserting it)

This oil pressurizes the chamber and pushes the Rebound Rod out , the seal itself is only about $10 and you can get it at Factory Connection , or Race Tech , etc , its called a Free Piston Seal , replace the seals and the rod will extend all the way as it should (i have done lots of these and the rod will extend fully afterwards **except in mossman77's case , he tried and tried to get his to extend fully and it would not for some reason , but that is not the norm , it SHOULD extend all the way once the seal is replaced**)

As far as dis-assembly goes , you can do it the way you did , or you can clamp down with thin Vice Grips (i cut a notch in and ground thin my needle nose vice grips so they will go around the round Base Valve (the round part with the 2 opposing holes that the valving stack sits on) , and use a 32mm 6 point socket (i do this using a Electric Impact) and remove the cap that way (you still have to loosen the lock nut as you did)
Base Valve:


This is the way the Cap Assembly looks when disassembled properly to get to the seal (and change the pressure spring)



INNER SEAL inside this piston:


Vice Grips:

[mossman77]

Everything was fine with mine (rods extended quickly and fully) up until this last step. Once I did a full compression, they extended to about an inch shy of full extension. I'm curious to see what result you get. Please keep us posted as to your progress. BTW, I repeated the procedure at least 15 or 20 times with the same result, and I measured the fluid remaining in the cartridge and it was exactly the amount stated in the manual (175cc).

[billybob]

Thanks for the replies guys.
Nice write up with pics.

Couple questions:
1. once the free floating piston is off...how do you get the seal out and a new one back in? Any special tools needed?

2. Devils advocate...but if the seal is faulty inside that thing...wouldn't it continue to keep pushing fluid past it and therefore eventually out of the weep holes in the dampener...and the rod would return less and less as more fluid is pushed past the seal?
Also, wouldn't air get sucked into the fluid causing an aeration sound once you pump the dampener rod? (I do know when i first did this I had a lot of air in the system and it was very noticeable)

[JimDirt]

Thanks for the replies guys.
Nice write up with pics.

Couple questions:
1. once the free floating piston is off...how do you get the seal out and a new one back in? Any special tools needed?

2. Devils advocate...but if the seal is faulty inside that thing...wouldn't it continue to keep pushing fluid past it and therefore eventually out of the weep holes in the dampener...and the rod would return less and less as more fluid is pushed past the seal?
Also, wouldn't air get sucked into the fluid causing an aeration sound once you pump the dampener rod? (I do know when i first did this I had a lot of air in the system and it was very noticeable)

You remove the piston from the assembly as noted , then you remove the Teflon Bushings and the O-Ring on the outside , then on the inside there will be a snap ring and a washer , remove them , then take a Propane Torch , and heat (slightly) around the seal itself , this will slightly melt the rubber on the outside of the seal , then using a flat screwdriver , simply remove the seal (i hold the piston with vice grips **lightly** since it will obviously be too hot to touch , so you have some leverage when prying with the screwdriver , allow the piston to cool completely and naturally , then install the new seal , before removing note the orientation of the old seal , make sure the new seal is installed in the same direction , then put everything back together

Generally what happens is the rod will extend less and less as time goes on , with the seal bad , the oil can not only be pushed out of the cartridge , but also be sucked back in , so the oil will not always be pushed out and gone completely as you might think , but it still affects performance and how your valving functions , since the air in the supposed sealed cartridge is now foaming and now you have cavitation , so your valving action is now compromised and can't open and close when it should in the stroke

The purpose of the bleeding procedure is to remove the air from the cartridge BEFORE you install the cap assembly , the seal along with the O-Rings , seal the inner chamber so the air does not get back in (unless the Free Piston Seal goes bad) , if the seal on the bottom of the cartridge was bad then your rebound rod would have oil running down it every time you pumped it while bleeding (if it is wiped clean , and it continually gets saturated) , so the end result would be the same , but the symptoms would be different , so its easy to tell which seal is at fault , but unless the rebound rod gets a nick in the surface as to compromise the seal , then its usually the Free Piston seal that is the culprit

Hope that answered your questions , if not or you have more questions , just ask away ...

[mossman77]

An alternative to using a torch is to use a heat gun. That's what I used and it worked just as well. I clamped my pistons in my vice (gently but firmly). You'll know you're hot enough when you start to see smoke. I pried mine out with a small flat-bladed screwdriver. They were in there pretty good.

[JimDirt]

Yep , either way will work fine , just get it hot enough to make the seal loose so it will come out easier , and your good

[mossman77]

Curious if someone makes a seal removal tool for something that small? The type that goes in the center of the seal and expands outward to grip it.

[JimDirt]

Not that i am aware of , most every place i have checked just use the flat screwdriver method

[billybob]

So I changed the inner seal and both o-rings (valve stack and floating piston) and I put new 5wt fluid in the dampener and bled all the air out.
The dampener rod returned completely when I just pushed it in 4-6 inches, but when i completely pushed it in...it pushes the excess fluid past the inner dampener seal I'm guessing and then the dampener rod must be pulled out the last couple of inches after that extra fluid is no longer in there.
I'm pretty sure i did everything correctly.

While I had the inner dampener assembly out I took the opportunity to test the dampening by pushing and pulling on the dampener rod.
I've never really felt a big difference in messing with the compression clickers on the forks.
I noticed that when I push the dampener all the way in and pull it back out....both ways feel like they are 'dampening' w/out any stiffer or 'soft' spot in the entire stroke...or air gurgling...so I feel like it's doing its job.
I did notice that I could change the compression from hard to soft on the clicker and i didn't notice it making a bit of difference. I was able to push in the dampener rod just as easily on soft as on hard.
But if i move the clicker on the rebound to hard....and pull on the dampener push rod...it is definitely harder to pull the rod out.
So to recap I did put in the very light 1.1 kg compression spring and the compression on the forks is 'softer' due to this.
...and after understanding the forks better, i do think that the spring i changed would affect how much the dampener rod returns by itself.
I mean, if you took that spring out all together...would you still expect the dampening rod to extend fully?

BTW: The electric impact wrench and vise grips was definitely the way to go to get that cap off. Thanks for the detailed write ups!

[JimDirt]

No problem , glad to help

As far as the bleeding procedure , as long as your doing it the way the manual says and your certain you have enough oil in the cartridge so when you push in the fork cap assembly that it gets the excess fluid out , then there should be no air

Note that you must push the cap assembly in SLOWLY , if you go too fast , what happens is you will push more fluid out than you should and you will put air into the closed system , allowing the rod to get sucked back in , its very important to go slow inserting the cap assembly

The reason the clicker is not doing much is because by hand , you do not use as much force to push down as it would be when your riding and hitting ruts and rocks and jumping , so your not actually making the valving open as it should , so you would not notice the difference by much if at all , the thing about valving is if you look at it , its all tight together , it takes force to push the oil thru the Valve fast enough to open the valving and let the oil thru , otherwise it just bypasses the stack , also the valving is made to open up in different parts of the stroke , so not all the valving is just going to open up and let oil flow thru , some of it works at the beginning of the stroke , some in the middle and some at the end , so you have varying compression at given points in the compressing of the forks (make sense ??)

Unless your really talented at doing suspension , your not going to "feel" the difference by hand , it just does not work that way , its meant to be done under loads

As far as the Pressure Spring goes , you will note that while its assembled right , there is a ton of free slack before the spring touches anything , what the Pressure Spring does is soften the initial hits in the beginning of the stroke , it does not work the more the fork is compressed , that is not the function of it , its called a Pressure Spring because it maintains pressure , its a set pressure and not subjective to how far the fork is compressed while static (the bike just sitting under its own weight , this is controlled by the main springs , the main springs are what hold the bike up in the stroke , that is their function , that is why the main springs are sized for your weight (and skill level , as a faster rider will need a stiffer spring even if they weigh less than what the weight the spring is set for , so a 180 lbs Pro rider will use up to several ranges stiffer spring than a average rider would need for their same given weight)

also the rod your compressing by hand is the Rebound Rod , its not for the compression , it works as the fork is extended not compressed , the compression stack is in the Fork Cap Assembly , and the Rebound is in the end of the rod where it goes into the inner chamber that your bleeding , so your bleeding needs 2 bleeds done

The first is when you bleed the rebound rod by slowly extending it , then compressing it till you see no more air bubbles , this can take up to several minutes to get ALL the bubbles out , this must be done on a full stroke without compressing the rod far enough to allow the rebound stack to get out of the oil (remember the oil is set to a given height) , if it does , then you just introduced more air and the bleeding has to be done again

The second part is when you install the Fork Cap assembly , this as i mentioned needs to go in slow to allow the air to escape, and the Rebound Rod needs to be FULLY extended , but the oil level will be too low if you push it in fast because the force will push out more oil than it would if you pushed it in slowly , and you will have AIR taking up the space the fluid does not (make sense ??)

Hope that explained more for you without confusing you , any questions just ask

[mossman77]

but when i completely pushed it in...it pushes the excess fluid past the inner dampener seal I'm guessing and then the dampener rod must be pulled out the last couple of inches

I'm glad to hear I am not the only one experiencing this issue. I contacted Showa and asked them, but they replied by saying I should check with the "assembler" (Honda).

I SLOWLY compressed and released the damper rod to full compression with the same result (rod no longer extended fully). As I stated earlier, I drained the fluid out after this happened and it was EXACTLY the amount stated in the manual (175cc).

[JimDirt]

Yea , its weird , i have never had it not bleed out correctly , every dual chamber fork i have done (Honda Suzuki , etc) have all bled and extended fully when the seals are replaced , i do not get why 2 of you have had this same issue , but as they said to you , its to do with assembly , something is not being done correctly , or something , as the sign for a bad seal is the rod sucking back in , if the seal is replaced , then the rod should extend fully , i wish a was where you guys are so i could check it out firsthand and see what is going on

And you don't need to slowly extend and retract the damper rod , it actually needs to have a few quick pulls so it will open the valving and let the air thru , its the Fork Cap Assembly , that needs to be put in slowly , so it only pushes the air and excess fluid out , and not with enough force to push more fluid out than is needed and allowing air into the system , its kinda touchy on how its bled , its simple once you figure it out , but its critical that its done correctly , or you will keep letting air in the closed system

[mossman77]

Sorry to sound like a broken record, but my rods extended fully after inserting the piston assemblies. It was only after compressing the rods fully that I started having issues with the rods not extending fully (they did not suck back in). Sounds like this is the case with the OP as well. I wish you could be here first hand to check it out. Maybe I'll shoot a video and post it on YouTube. I really don't want to mess with the forks so soon after all that frustration though. My brother-in-law's forks are due for a service though. Let me know if you're ever in the DC area.