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If you directly linked to this thread, please visit our Fox Factory Service Information - Main Index for additional resources.



Brain Fade Rebuild


Disassembly

1. Prepare your work area. Lay out clean shop towels to store and organize the shock parts on.

2. Put on your safety glasses and use rubber gloves.

3. Remove mounting hardware before disassembly.

4. Prepare work area—lay out clean shop towel to store and organize parts on.

5. Put on your safety glasses (always protect your eyes); rubber gloves if desired.

6. Clean exterior of shock before starting to disassembly of shock.

7. Un-thread the air cap and deflate all the air out of the air sleeve.



8. Remove the travel indicator O-ring from the shock body.

9. Un-thread the air sleeve from damper (counter clockwise).



10. Clean the inside area of the damper with a shop towel.

11. Remove the plastic ball with a dental pick and remove set screw slowly with 5/32” hex key, to release 200 PSI nitrogen charge.



12. Remove the rubber filler pellet with a dental pick.



13. Un-thread the 2mm set screw on the side of Brain Fade blue knob (you do not need remove the screw completely).



14. Lift the Brain Fade knob off. Remove the two detent balls and spring from reservoir cap. Clean and set aside the balls and springs with knob.

15. Remove the white back up bearings and seal.

Caution! Be very careful; do not scratch the seal gland.



16. Clean and inspect the bottom out O-ring and the two thin washers.

17. Place the body eyelet into a soft jaw vise, and remove the bearing housing by un-threading it counterclockwise with a 22mm open end wrench.



18. Pour the used oil into a drain pan. Clean the body and set it aside.



19. Place the shaft end eyelet into soft jaw vise, and un-thread the damper piston bolt with a ½” socket wrench. Keep the piston and bolt and piston valve assembly together, and set everything aside on a clean shop towel. Inspect the shims, piston, and glide ring. Replace as needed.



20. Remove the bearing housing from the damper shaft.



21. Remove the bottom out washers and urethane (yellow colored) O-ring; clean and set aside.



22. With the reservoir eyelet end of shock clamped in the soft jaw vise, remove the nitrogen reservoir end cap with a 15/16 socket wrench.



23. If the reservoir assembly comes off, remove the nitrogen filler end cap by holding onto the 16mm wrench flats on the opposite end.



24. Set the shaft eyelet aside.



25. As the nitrogen reservoir end cap un-threads from the reservoir body, you will see the Brain fade adjuster rod and Brain Fade adjuster tip with a spring inside the adjuster rod.



26. Gently pull the Brain Fade adjuster rod from the silver adjuster assembly (be gentle, as you will find a very small O-ring inside the silver adjuster.



27. Un-thread the Brain Fade adjuster assembly with an 11mm open end wrench.



28. This photo shows the Brain Fade adjuster assembly taken apart.



29. Clean, grease, or replace the Brain Fade adjuster assembly O-rings as needed.



30. Grease and assemble the Brain Fade adjuster assembly back together.



31. Using a plastic O-ring pick, remove the Brain Fade adjuster rod O-ring. Clean, grease and replace as needed.



32. Grease and install the Brain Fade adjuster tip and the spring back into Brain Fade adjuster rod, and set the assembly aside.



33. Place the reservoir assembly into a shaft clamp, and clamp the assembly into a soft jaw vise.

Caution! Do not over-tighten the shaft clamps, or damage will result to the reservoir body.



34. Un-thread the IV “Brass Mass” assembly from the reservoir body with a 16mm open end wrench.



35. A view of the IFP inside the reservoir body.



36. Remove the IFP by pushing it out of reservoir body with your IFP setting tool, or a self- made tool.



37. Remove the IFP ID/OD O-rings with a plastic O-ring pick.



38. Grease and replace the IFP O-rings as needed.

39. If you suspect problems with the IV assembly “Brass Mass”, it is recommended that you replace the assembly with a new one. Test the IV assembly by pressing the IV “Brass Mass” down and letting it return on it’s own. The Brass Mass should feel smooth!



40. Grease and replace the O-ring and at the base of the IV assembly, and set aside.



41. Replace the O-ring in the threads of the shaft eyelet/reservoir mounting hole, as needed.



In most cases, the rebuilding of the brain fade damper shaft/eyelet is not required, so you can choose to proceed directly to the Assembly section.

If you feel the need to work on the damper shaft/eyelet, please follow the damper shaft and eyelet maintenance procedure below. The photos shown are from the DHX Air service section, so the parts in the photos will be a little different than the ones found on the Brain Fade shock.


Damper shaft and eyelet maintenance:

1. You will need to heat up the top of the eyelet to soften the red Loctite; warming it to the touch works best. Do not overheat.





2. Using a 1/2" bar for added leverage, remove the eyelet from the damper shaft.

Caution! Do not allow the damper shaft to spin in the shaft clamps while also taking care not to over-tighten the vise, or damage to the shaft finish may result.



3. Clean the Loctite from the threads on the shaft, the eyelet threads, and the eyelet shaft threads.

Slide the rebound adjuster knob out from the eyelet.



4. Remove the rebound adjuster rod while holding onto the rebound knob (it may fall out as you slide out the rod). Inspect the rebound adjuster rod O-ring, and clean or replace as needed.

Remove the rebound knob. Take note of the knob's orientation; the slots on the knob will point to the DU bushing.



5. Remove and inspect the O-ring located inside the threaded bore of the eyelet. Replace as needed. Set this assembly aside for now.



6. Rebuild the bearing housing with a new shaft seal, and install a new O-ring on ID threads (where the damper body threads into).



All the major components have now been disassembled. Clean and inspect and all the metal parts! Inspect, replace, and grease the seals and O-rings, as needed.

Assembly


1. Install one bottom out washer, O-ring, and the second bottom out washer onto the damper shaft.



2. Install the bearing housing onto the damper shaft.



3. Install the damper shaft hydraulic top-out washer onto the damper shaft.



4. Install the piston assembly and the piston bolt onto damper shaft.



5. Torque the piston bolt with a ½” socket wrench to 75 inch lbs.



6. Install the Brass Mass assembly onto the eyelet. Thread it in all the way until it bottoms out in the eyelet.

Note: Final torque will be applied in step 23 when torque is applied to reservoir end cap.



7. Grease the ID threads of reservoir and install the IFP into the end that has the smaller ID bore.

Note: The ID of the reservoir has two sizes of ID bores.



8. Gently push the IFP past the reservoir end cap threads as seen here. The IFP should fit correctly in bore.



9. Using an IFP setting tool mark the height to 1.380”.



10. Set the IFP to the depth of 1.38” and set reservoir aside.



Note: The FOX Racing Shox Production line uses a different method to fill the brain shocks with oil.

We are going to show you how to fill the shock with oil with out using a expansive vacuum filling machine. You will need a deep oil tub and clean oil. We also recommend that your wear rubber gloves during this under oil fill procedure.

11. Major components are ready to submerge into the oil tub.



12. Submerge reservoir eyelet end with brass mass assembly into oil tub.



13. Under the oil move the brass mass back and forth to remove any trapped air in the assembly.



14. Submerge reservoir with the IFP preset to 1.380” into oil tub.



15. Submerge shock body into oil. All major part are now submerge in oil tub.



16. Under oil thread IFP reservoir onto the brass mass assembly until tight by hand.



17. Keeping assembly under the oil push the bearing housing all the way down to the damper piston and then thread the shock body onto bearing housing until hand tight. Let assemblies lay in oil as you move onto the next step. This will allow any remaining air bubble to escape from the parts.



18. Make sure the Brain Fade adjuster rod tip and spring have grease placed on them. This helps to keep them in place for the next step.



19. Carefully left reservoir out of the oil. You want oil to remain in the reservoir above the IFP. Install the Brain Fade adjuster rod with spring loaded tip into oil and down through the middle of the IFP.



20. Now you can pour the excess oil out of the IFP chamber. Note: with adjuster needle through the IFP no oil or air will get into the damper unit.



21. You can test the Brain Fade adjuster by pushing on it with your finger tip, you will feel the rod move slightly in and out as you apply and release your finger pressure.



22. Install reservoir Brain Fade reservoir end cap. Make sure you center the Brain Fade adjuster rod so that it will correctly set into the O-ring that is in the Brain Fade reservoir end cap.



23. Torque the reservoir Brain Fade reservoir end cap to 110 inch lbs. with a 15/16 socket wrench. This will also apply the proper torque to the bottom nut that secures the assembly to the eyelet.



24. Torque bearing housing with 22mm crows foot to 20 ft. lbs.



25. Grease the detent spring and ball for the Brain Fade blue adjuster knob.



26. Install springs and balls into detent holes (2) in the reservoir end cap.



27. Lightly grease the bottom side (detent pockets) of the Brain Fade blue adjuster knob.



28. Install Brain Fade blue adjuster knob onto the hex adjuster being careful not to displace the small balls from the detent pockets.



29. Using a 2mm hex key thread in the set screw until tight. The torque required 14 inch lbs.



30. Test function of knob by turning back and forth, It should have smooth action. Install the rubber filler pellet and set screw.



31. Charge shock with 200 PSI of Nitrogen.



32. Torque pellet retainer (set screw) to 110 inch lbs. After filling and press fit the white plastic ball.



33. Test Brain Fade shock on your hand dyno. Test the shock in the soft and in firm modes. You should be able to tell the difference and the shock should feel smooth and pure free of air bubbles.



34. Grease and install bearing housing back up rings and air chamber main seal.



35. Grease and install bearings,seal and dustwiper into the air sleeve as needed.



36. Install air sleeve.



37. Install Travel indicator O-ring.



38. Pump up the air sleeve to your customers requirements or set to the stock pressure setting of 150 PSI.



39. Install air cap.



40. Clean the shock, install new decals if required.

Note: Shock mounting bearings and long arm extension are Specialized bicycle company parts! FOX Racing Shox does not stock these items.

_________________
http://about.me/marpilli

I'm sure I'll have a million more questions, this forum rocks!!!!!! I love the attitude, I feel at home with people who want to be 100% self reliant and fix/service things themselves.

I've a 2014 Epic WC Brain shock I'm going to rebuild, possibly this is the best place for me to post, not starting a new thread? Mods?

I'm in the process of getting screwed with a warranty claim being denied, so I'm going to stick it to em. Current shock has terrible cavitation noises. Loss of IFV nitrogen pressure?. Bike sat unused for two months due to injuries (popped a rib out of place, damaged muscles, etc) I've spent a few nights pouring over the patent. I've a spare second hand shock on the way hopefully.

http://patft.uspto.gov/netacgi/nph-Parser?Sect1=PTO2&Sect2=HITOFF&p=1&u=%2Fnetahtml%2FPTO%2Fsearch-bool.html&r=6&f=G&l=50&co1=AND&d=PTXT&s1=specialized.ASNM.&OS=AN/specialized&RS=AN/specialized

Very well written for a patent. Strikes me that possible Michael McAndrews wrote the detailed description and the attorneys edited.

Anyway, one beauty of the remote reservoir brain design is it puts the nitrogen charge port at the bottom of the reservoir, allowing a retrofit of a shrader valve that won't interfere with air can removal. How bad is the use of air instead of nitrogen? I do have scuba equipment, wondering if I can fill a small pony bottle with nitrogen and set the intermediate pressure to 200-400 psi. Any suggestions on what the nitrogen charge pressure would be? Oil weight?


Whilst absorbing as much info as I could about shocks and specifically the "brain" system (love marketing names btw), I'm wondering if an electronically controlled inertia system is achievable. I'm thinking 1 axis accelerometer, a microprocessor (raspberry pi?) and a solenoid to control valving. Could be a interesting retrofit to an rp23?

BTDT by Magura´s eLECT forks and RockShox/LaPierre's Ei shock.

Might be a cool project tho.

Thanks for the heads up on Magura's eLECT and RS/LaPierres Ei shock. Off to google and see if I can get a ride of these techs.

I'm still going to document the current brain system rebuild, as a to Specialized and Fox.

I've acquired a 2012 SWorks Epic rear shock assembly in working condition that I plan on documenting the disassembly and rebuild. I've already popped the air can off, no RP23 style bleed port on the bearing housing to be found sadly. Working out how to bleed will be fun. Hope to vacuum bleed. Possibly vacuum bleed up the hose to shock and make another hose to bleed brain, all whilst submerged in bucket of oil, then join shock to brain?

I've a pile of questions.
What weight/brand oil do I use? Fuchs Pro RSF 2.5 10w 1L Silkolene?
Nitrogen charge pressure?

First step will be pop the nitrogen set screw and pellet and measure IFP depth. I will keep oil and measure volume. Maybe try and measure viscosity?

Why I can´t see the pics??

Hi There! I´m From Brazil, and have same problems as U. Here I have heared some people use Atmospheric air in place of Nitrogen, and 10w oil to fill brain.
Searching on internet once I found (but now I don´t know where it is anymore) one diy of 2012 Brain, where in assembly, he has set the IFP (but didn´t say the depth) and dive everyting in a bucket with oil until stop popping bubbles and close the oil chamber.

I still looking for a damage brain to use as tryout for my own training.

Anyone have some information of this kind of problems??

Thx

The photos are hosted on Google account. Some employers filter images from Google accounts. Are you viewing this from home or from work?

_________________
http://about.me/marpilli

Sorry I haven't updated this thread here, thanks to thread subscriptions...


I successfully rebuilt my brain assembly 2014 fox brain off an epic World Cup and documented on rotorburn http://www.rotorburn.com/forums/showthr ... in+rebuild


I've now ridden on the shock for approx 800km and am very happy with the results.
Andraus have a read of the thread (it's huge) and hit me up with your questions.

Link1896, nice job on the rebuild (and fielding all those questions)!

_________________
http://about.me/marpilli

Thank you marpilli. I had a blast working it out. Going to rebuild a rear brain from a 2012 s-works soon, and I'm about to tackle the fork cartridge rebuilt. My only disappointment so far has been I didn't get enough photos or video like the photos near the top of this. Until I do I don't believe anyone will tackle themselves.


Andraus, if your going to have a go yourself at rebuilding, I'll make the bleed port adapter for you, and a new nitrogen stopper with schrader valve if you don't want to keep the nitrogen bung/grub screw arrangement.

You're alright, man. If you find yourself in the Dallas, TX area let me know and I'll buy you a beverage of your choice.

_________________
http://about.me/marpilli

As this is my first post I'l say Hi.
Hi!

Can't believe my luck that this thread still has some activity on it! You have made me a very happy man!
I have a 2004 s-works enduro with what I think was the first incarnation of the remote brain shock on it. To be fair I don't get out on it that much (work, children, other DIY projects, road bike) but I have recently dusted it off and discovered that the brain doesn't seem to be doing it's bit anymore (it's like riding a bouncy castle!). Was fine 18 months ago, but alas no more. Main shock holds air, so after some googling I stumbled across this site and the issues with nitrogen loss.
What excited me more was the information you had about rebuilding brain shocks - albeit none as old as mine.
Then I see that Link1896 has also done a rebuild (just registered on that forum so I can have a read!).
I'd like to have a go at doing mine, but I've had no luck getting any technical info/diagrams/ etc about the 2004 version. To keep me going I've sourced a 2nd hand RP3 off ebay that I hope is fully working - I don't want to have to service 2 at the same time!
Anyway, I'll do some reading and come back once I've got a list of questions.

Thanks again,

Jason

Welcome, paceman101! I might be able to offer some help on the RP3 if you need it. However, I'll have to defer to Link1896 if you have questions on the brain rebuild.

Since you mentioned DIY projects, have a look around the sub-forums. I think you'll find an interesting post or two.

_________________
http://about.me/marpilli

Paceman101, your shock should be very similar to the shock detailed in the beginning of this thread.,I've never seen one this old, I understand there are zero parts for these available from Specialized so you will need to source parts from your local hydraulic repair shop. Vacuum bleeding is only needed for the modern style brain shock assembly that uses a hose between assemblies, the older shocks just need assembly while under the surface in a bucket of oil, so don't panic you don't need to vacuum bleed.

I'd love to see close up photos of how the extension bolts to the damper tube, the pictures at the top of this thread show the damper has a huge hex head shape to it, making me believe your rp3 isn't going to mount up.

Photos are not visible of this brain rebuild got a link please??

Pleaase post a link to photos. Your description and labor are worthy of a donation! Thanks

I can fix the brain shocks that look like this. https://www.ebay.com/itm/152588097323 Please read the details.

I know this thread is old but is it still possible to view the pics in the rebuild description somehow? They are not currently showing for me...

Thanks