HOW TO: Boxxer R2C2/WC cartridge disassembling and repairing manual.

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HOW TO: Boxxer R2C2/WC cartridge disassembling and repairing manual.
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flag Chuvak
Posted: Apr 1, 2014 at 21:30 Quote
sorry, i don't know how these huge gaps appeared, everything was fine on preview and i have no idea what to do with it. anyway, i had to move all the photos from hosting server to PB album and post them here as far as i receive PM massages about missing photos.




Hi guys. Some days ago my mate asked me to repair his boxxer WC fork with damaged adjusters. LSC was stoked, HSC and Ending-stroke rebound rotated, clicked, but had no end positions. As far as have a little workshop, I decided to take a closer look, coz buying new cartridges is a stupid idea whet your hands grow not from your ass. And idea to make photos has come to my head only when I was assembling all this stuff back, so there may be some missing pictures, but I’ll try do describe all the process pretty detailed.
The text below describes homemade repairing. This procedure requires advanced mechanic skills. I do not guarantee anything, but if you use your head and work with proper accuracy, you get your stuff repaired and well-working. Also these manipulations void any fork warranty.

Okay, let’s start.

mission control cartridge disassembing
Take cartridge out of your fork at first. Everyone knows how it looks like.

Scheme of the cartridge. Following one is for version with gate. That’s not critical. I case of no gate version, details 1 and 2 made like one single detail.

photo

How does it work:

When fork compresses with low speed, oil flow is regulated by screw 4, that opens or closes holes of LSC oil path. But when you got fast kicks from the trail, a set of compression rings is involved. That is HSC damping. It is very simple: grey “pipe” holds these rings under pressure, being pressed by white spring. That does not allow rings to open oil flow at low speed compression of your fork. When you got fast hits that pipe slides back allowing compression rings to bend an open HSC oil flow. By rotating blue HSC adjuster you just preload this white spring. Notice, that when HSC oil path opens, LSC path is still working, so both of these paths are parallel.


Now about disassembling. Firstly we need to take off head of the cartridge by unscrewing the black nut.

photo

Slide black “pipe” down and hold it. You see a ring with narrow slots for 10mm key. Insert the key and release the pipe. Now, using socket wrench, unscrew the black nut.


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Take off the cartridge head, black pipe and preloading spring. Make sure you’ve not lost any rings and secure them.
photo

Now we need to unscrew the tip of cartridge from the blue body. LSC screw moves in this tip. You need flat 19mm key. Heat the connection of details (there is a red thread locker) and unscrew one from another. It is very easy to destroy thin sockets as far as you need much power to unscrew this tip. If so-have no worries, you can grind these slots to 9mm key.

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When tip is separated, you can find LSC screw. I my case it was stoked in the thread in the end position. Also I had to repair needle slots with loctite and very thin metal plates. Never leave adjusters in the end position, always make 1-2 clicks from it!

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Now release this ring and unscrew the top cap. Do not lose 2 detent balls

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Now remove the C-clip (you can hook it with a flat screwdriver, near the holes). Now you can pull out LSC needle. Do not loose one more ball.

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That’s it. Now you can make any maintenance you need. The most common problem is damaged slots in the LSC needle (I’s tip looks like allen key) or stoked in the thread LSC screw.

photo





Now let’s move to rebound cartridge. It has a problem with ending-stroke rebound: adjuster rotates, but has no end position.

photo

Operating of rebound cartridge is very simple and similar to one of compression cartridge, the only difference-it is reversed. Plate 5 moves down on compression, that lets oil move through rebound head with no difficulties. Also it closes at rebound, closing that window and making oil move through rebound paths. Beginning stroke rebound (I will call it BSR) is regulated as LSC-with the needle that opens/closes the hole in the BSR oil path. But when fork was compressed somewhere at 1/2-3/4 of it’s travel-decompressing power is so big, that BSR oil flow is not enough, so a set of compression rings 4 is being involved. Oil bends these rings, flowing through the ESR (ending stroke rebound) path. When you rotate ESR adjuster, you rotate part 1, using sockets, it rotates screw 2, that preloads spring 3, that pressurizes rings 4 with help of red detail with a little hole, that located between 3 and 4. More preload-slower ESR.

Now-disassembling.
Remove the C-clip, place keys as on the photo and unscrew the cartridge head. LEFT THREAD!!!

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Now remove the grey nut (LEFT THREAD). Notice how it was screwed, it is not symmetrical.

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Remove all the stuff.

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In the bottom of the cartridge remove black nut from the silver tube. Now press grey tip (with from the C-clip was removed) inside the silver tube. Remove it. You can see BSR needle in the grey part. You can disassemble grey part by unscrewing one nut, but I had no necessity in it.

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I was expecting to see that. Internal sockets in the 2 part were cut off. They are needed to it to be rotated by the part 1. SRAM, are you drunk? What sense does making loaded parts of very soft aluminium? There are tons of different types of it, that much harder!
Okay, let’s repair. Using the needle files, I ground part 1 socket, making them wider keeps them from being cut off. Then I used a spacer from chain guide. It is thin and hard enough. Make a hole that matches the ground part 1. Notice, I’ve not ground part one’s tip. That’s an early photo, it was ground too, coz other way it is impossible to fit a spacer. While grinding part 1, make sure you don’t make it extremely thin or even grind to holes. Now make some scratches around the hole in the part 2, that will increase a gluing surface. Clean part 2 and your spacer with alcohol and dry it. Apply some loctite 401 and glue your spacer. Now drop some loctite around it. Leave it for an hour on the fresh air to dry. loctite secures very good if you need connection with high resistance to sliding loads. Notice that you lose a part of ESR range from fast side, coz this spacer is being stopped by the c-clip earlier, that red cap without spacer. That's why you need pretty thin spacer (the thinner it is-the less range loss), but thick enough for it's sockets would not be cut off by the part 1.

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After that, assemble the cartridge and check it. I was rotating ESR about 20 minutes till I bored. Thus stuff worked fine. Now assemble the cartridge.

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Okay, that’s all. This fork repairing cost 100$ to my friend. All manipulations took about 5-6 hours of work. Also I had to repair threads on the LSC screw and needle, there it’s being screwed, top cap slots, find and change O-rings and some more stuff. It is faster and cheaper, than buying new fork or new cartridges.

Thanks for attention. Any questions are welcomed.
Maybe pin this thread?

Tags: boxxer repair, ending stroke rebound issue, boxxer cartridge fail, mission control dh rebuild, hsc leaking, lsc leaking, boxxer hsc and lsc leaking, boxxer cartridge leaking
flag dav85
Posted: Aug 8, 2014 at 1:42 Quote
Hi,

My boxxer has been leaking from the top of the damper - hsc/lsc adjustment dials... I have been messing with it for a week before i found your post. Already found out how to remove the black sleeve and lsc, but still leaking. Your post will come in very handy! Thanks a lot for sharing and putting so much effort in it!

I think you should put mission control dh rebuild and hsc lsc leaking in the title, it will make it a lot easier to find your post with google, since many people are looking for this.

Any tips for the leak? Next step will be to check the o- ring on the hsc blue unit thing. The dials also get stuck in max hsc/lsc position...

Maybe its worth mentioning that you dont have to remove the bottom tip to undo the parts at the top of the damper? I think you can remove both hsc and lsc adjustment parts without undoing the top.

Again, thanks a lot, fantastic post!
flag Chuvak
Posted: Aug 10, 2014 at 3:36 Quote
ddkoetsier wrote:
Hi,

Maybe its worth mentioning that you dont have to remove the bottom tip to undo the parts at the top of the damper? I think you can remove both hsc and lsc adjustment parts without undoing the top.
yes, you're rright, there is no need to unscrew grey tip from the blue body to disassemble the rest, but in my case, LSC adjuster was stoked coz of damaged thread on the LSC needle, that moves LSC pin in the grey tip. so i was neet to get it out to repair.

thanks for appreciate, I'm glad that this post was helpfull to you. I have added some new tags you mentioned.

BTW, was my text easy to understand? I know english language very good, but having no practice for a long time makes it's bad job
flag nordland071285
Posted: Aug 11, 2014 at 5:07 Quote
awesome guide thanks bud
flag dav85
Posted: Aug 11, 2014 at 7:06 Quote
Looks like someone else found it with the new tags! And your english is very easy to understand!
flag dav85
Posted: Aug 12, 2014 at 8:24 Quote
Hi,

I did not secure the shim stack and they mixed.... any idea of the sequence? do you know if the ring in the picture where you have put a strap through the rings is also part of the shim stack?

Thanks!
flag dav85
Posted: Aug 12, 2014 at 9:44 Quote
Found it:

Note: All shims listed have an ID of 8mm

From bottom of damper to top

2010(old):
20x0.15
20x0.11
20x0.11
16.5x0.15
14x0.15
14x0.15
10x0.4

2010(newer):
20x0.15
20x0.11
16.5x0.15
14x0.15
14x0.15
10x0.4

2011:
20x0.1
16x0.1
14x0.1
20x0.15
20x0.1
20x0.1
20x0.1
14x0.1
10x0.4
flag dav85
Posted: Aug 13, 2014 at 11:07 Quote
Hi,

My boxxer is still leaking... Do you know whether there is a o-ring beneath the c-clip holding the lsc adjuster in the hsc adjuster?

I noticed that in the 18th picture - the one where you sorted all the parts from the compression damper in little trays - has two black o-rings in the bottom right tray. I have one hard plastic o-ring from the adjuster knobs. Is the other one from below the c-clip?

Do you know if they are both hard or is there a softer one?

Many thanks!

Cheers
flag Chuvak
Posted: Aug 13, 2014 at 20:47 Quote
no, they both are plastic. and no rubber O-rings under the C-clip. if you have leaking from the compression adjusters, you can replace 2 O-rings. look at the photo you mentioned. at the right side of blue and black parts, lying together, there are 2 O-rings. one on blue and one on black. replace them, and I am 90% sure, your problem will be solved. If you can't find similar O-rings, just take off existing from the parts of the cartridge and apply 3-4 turns of folded along teflon tape on the seatplace of O-ring. then place O-rings back. that will help.

about the plastic washers. as far as I know in the fork of different years there may be as 1 and 2 washers. just check for vertical play of the LSC. if no play-1 plastic washer is enough.
flag donpinpon29
Posted: Nov 9, 2015 at 12:47 Quote
ddkoetsier wrote:
Hi,

My boxxer is still leaking... Do you know whether there is a o-ring beneath the c-clip holding the lsc adjuster in the hsc adjuster?

I noticed that in the 18th picture - the one where you sorted all the parts from the compression damper in little trays - has two black o-rings in the bottom right tray. I have one hard plastic o-ring from the adjuster knobs. Is the other one from below the c-clip?

Do you know if they are both hard or is there a softer one?

Many thanks!

Cheers

hi. same problem here. been changing o ring that sits around lsc needle and no luck. any idea of another o ring? it leaks so much that it moves my rubber bumper for the frame
cheers
jimmy
flag Sweaty
Posted: Nov 11, 2015 at 21:25 Quote
Guys, have you got an idea where I can get spare LSC needle? :/ snapped mine in half...
flag Chuvak
Posted: Nov 16, 2015 at 20:30 Quote
donpinpon29 wrote:
hi. same problem here. been changing o ring that sits around lsc needle and no luck. any idea of another o ring? it leaks so much that it moves my rubber bumper for the frame
cheers
jimmy
you mean a ring that you can see at 8th photo?

Sweaty wrote:
Guys, have you got an idea where I can get spare LSC needle? :/ snapped mine in half..
aaawww, that really sucks. looks like you have to buy a new cartridge or look for a broken one as a donor. I've never seen LSC needles sold separately
flag smuggly
Posted: Dec 9, 2015 at 0:48 Quote
Many thanks for posting this Chuvak.

Rebound stopped working after a basic oil change and clean, no ending to either rebound dials, a disassemble and rebuild following your pics and all is working again.
flag Chuvak
Posted: Dec 11, 2015 at 19:20 Quote
You're welcome, man) glad that this topic still helps
flag mammal
O+
Posted: Feb 5, 2016 at 14:57 Quote
Chuvak:

Thank you very much for this thread! I just bought a 2011 Boxxer RC that had been converted with the Mission Control Damper and Air Spring, but still has the single adjust rebound damper.

The Low Speed Compression was jammed in the fully closed position, like yours. The owner of the fork had a "friend" modify it, and they obviously didn't dial back the LSC adjuster as they threaded on the grey cartridge tip.

I was able to fix it by following your instructions, and now I don't have to find a way to return the fork.

Thanks so much!!
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