Öhlins TTX25 Complete Rebuild

Rebuilding a shock is something that can be accomplished with the correct tools and a little know-how, patience, and mechanical ability.  Below is an outline of our basic rebuild procedure using our recommended tools.  Always consult the Öhlins Workshop manual for a second opinion.  To help identify parts and seals see our downloads page for detailed drawings.  The keys to any shock rebuild are assembling the shock so that the floating piston is properly set and the shock contains no trapped air.

 

Release gas charge

  1. Remove torx head screw from gas canister end cap  Pic1
  2. Apply a small amount of grease to Öhlins gas fill needle adapter (U00050-16)
  3. Carefully pierce the bladder with the gas fill needle and thread in for stability  Pic1
  4. Depress Schrader valve core to release charge
  5. Carefully remove the gas fill needle adapter

Remove gas canister end cap

  1. If necessary remove the torx head screw from gas canister end cap
  2. Fully thread Öhlins end cap disassembly tool (00720-03) into the end cap  Pic1
  3. Push in the gas canister end cap to expose the snap ring (Sometimes a light tap with a dead blow hammer will help get it free)  Pic1
  4. Remove the snap ring, being careful not to scratch the bore of the gas canister  Pic1
  5. Clean out as much debris as possible before removing end cap
  6. Using the Öhlins end cap disassembly tool (00720-03) slowly pull the end cap from the gas canister (The o-ring on the end cap may hang up in the groove for the snap ring but a small rocking motion will help free it)  Pic1

Remove shaft, piston, seal head, and inner tube

  1. Open all adjusters to soft settings. This is counterclockwise on both the low and high speed adjusters.
  2. Clamp the shock in a vice with the shaft pointing upwards
  3. Using Öhlins seal head spanner (U00050-18) fully unthread the end cap from the shock body  Pic1 Pic2
  4. Remove the shaft assembly by slowly pulling it up and out
  5. If the shaft assembly comes out still attached to the inner tube set it all aside  Pic1
  6. If the shaft assembly comes out without the inner tube set it aside and pull out the inner tube from the shock body and set it aside as well  Pic1
  7. Pour old oil out of the body and into a suitable container for recycling

Remove floating piston

  1. Fully thread the Öhlins end cap disassembly tool (00720-03) into the floating piston and use it to pull the piston out of the gas canister  Pic1 Pic2
  2. Pour old oil remaining in the gas canister into a suitable container for recycling

Remove valve assemblies

  1. Screw in the high speed adjusters just enough so that there is ample room to access the circlips
  2. Clean out as much dirt and debris as possible
  3. Remove the circlips using a razor blade  Pic1
  4. Unthread the high speed adjusters to remove them  Pic1
  5. Each removed assembly will consist of the high speed adjuster housing, a spring, and a poppet  Pic1

Disassemble and rebuild valve assemblies

  1. Remove and replace the low speed needle o-ring.  How you do this depends on whether you have a new or old version adjuster design.
    • Old style with flat head version low speed adjuster
      • Thread the bleed adjuster so it is in the middle of its range of travel
      • Lightly clamp the hex head of the high speed housing in a vice (Clamping it tightly will deform the aluminum and ruin the adjuster)
      • Using a roll pin punch carefully tap out the roll pin
      • Fully unthread the bleed needle being careful not to lose the two small detent balls and spring
      • Remove the old o-ring and reinstall a new one from the rebuild kit
      • Thread the low speed needle with detent balls and spring back into the adjuster housing so it is again in the middle of its travel range
      • Reinstall the roll pin
    • New style with hex head version low speed adjuster
      • Thread in the bleed adjuster far enough to access the circlip
      • Remove the circlip
      • Fully unthread the bleed needle being careful not to lose the two small detent balls and spring  Pic1
      • Remove the old o-ring and reinstall a new one from the rebuild kit
      • Thread the low speed needle with detent balls and spring back into the adjuster housing
      • Reinstall the circlip
  2. Remove and replace the two o-rings on the high speed adjuster with new ones from the rebuild kit
  3. Install the valve spring and poppet onto the high speed adjuster

Clean shock body, partially refill, and install valve assemblies

  1. Take the empty shock body and clean it out to remove all debris
  2. Dry the shock body to prepare for reassembly
  3. Clamp the shock body angled in a vise and fill with fresh shock oil so that the valve ports are filled to the top  Pic1 Pic2 Pic3
  4. Fully open the bleed adjusters by turning them counterclockwise
  5. Place the adjusters into the valve ports and thread them in making sure fluid squirts out and no air is trapped underneath  Pic1 Pic2
  6. Reinstall the circlips that retain the high speed adjusters  Pic1

Prepare shock body for reassembly

  1. Once the adjusters are installed into the shock body, clamp the shock body vertical being careful not to spill the oil already in the shock  Pic1
  2. With the bleed adjusters fully open pour fresh oil into the gas canister all the way to the top
  3. Allow the shock to sit while the oil works its way through the adjuster manifold and the level equalizes in the body and the gas reservoir  Pic1

Disassemble shaft assembly and reassemble with rebuild parts

  1. Separate the shaft assembly and inner tube. The seal head on the shaft assembly is a snug fit into the inner tube.  If it will not pull apart easily, very lightly squeeze the inner tube in a vise and tap out the shaft assembly with a punch and dead blow hammer.  Pic1
  2. Clamp the shaft assembly in a vise using Öhlins shaft vise clamp (U00050-09)  Pic1
  3. Remove the eyelet from the shaft by heating it with a heat gun to loosen the thread locker and then unthread it
  4. Remove old loctite from the threads
  5. Remove the seal head assembly by pulling it off the shaft  Pic1
  6. Install the new seal head assembly from the rebuild kit by placing the Öhlins seal head install sleeve (U00050-10) over the shaft threads, applying some assembly grease, and then sliding on the new seal head  Pic1 Pic2
  7. Make sure the threads on the shaft are clean and dry
  8. Reinstall the shaft eyelet using thread locker and tighten until snug
  9. Remove the old wear band and o-ring from the solid main piston and replace with new parts from the rebuild kit

Rebuild and install floating piston

  1. Remove the old quad ring from the floating piston and replace with the new one from the rebuild kit
  2. Reuse the original wear band since this very rarely needs to be replaced and is not included in the rebuild kit
  3. Apply a small amount of assembly grease from the rebuild kit to the floating piston o-ring and wear band
  4. The low speed adjusters should still be fully opened and the shock partially filled with oil. Fill the gas canister to the top again with shock fluid and immediately insert the floating piston.  The key is to not trap any air below the floating piston.  Shock oil should spill out as the floating piston goes in.  Pic1
  5. Smoothly and slowly push the floating piston all the way down into the gas canister until it stops. This forces shock fluid back into the main body through the valving manifold.  If done correctly this will bleed out any air remaining in the manifold.  Pic1

Set floating piston depth

  1. Fully thread Öhlins end cap disassembly tool (00720-03) into the floating piston
  2. Make sure the floating piston is pushed all the way to the bottom
  3. Slowly pull up the floating so it is unseated from the bottom by about 2mm  Pic1
  4. Unthread the end cap disassembly tool

Fully fill shock and reinstall rebuilt piston assembly

  1. Insert the inner tube into the shock body with the holes up  Pic1
  2. Take the Öhlins piston install o-ring (00338-40) from the rebuild kit and wrap it over the piston band. This o-ring holds the wear band tight so it easily fits into the inner tube Pic1 Pic2
  3. Fill the body of the shock to the top with fresh shock oil
  4. Insert the piston into the shock being careful to not trap any air underneath. Again, fluid will spill out
  5. As the piston goes into the inner tube the piston install o-ring will be pushed off and must then be removed  Pic1 Pic2
  6. Once the piston has entered the tube, do not allow it to travel any further  Pic1
  7. Slide the seal head down the shaft until it contacts the piston  Pic1
  8. Now push the seal head down and thread it into the shock body. Fluid should again be pushed out as the seal head is inserted making sure no air is trapped inside
  9. Torque the seal head to 20 N*m (15 ft*lbf) using the Öhlins seal head spanner (U00050-18)  Pic1

Install gas canister end cap

  1. Clean the gas canister end cap, install the new o-ring from the rebuild kit, and lightly grease it
  2. With the Öhlins end cap disassembly tool (00720-03) threaded into the gas canister end cap carefully insert it into the gas canister until it is past the snap ring groove
  3. Reinstall the snap ring making sure it is fully seated in the groove
  4. Pull up on the gas canister end cap until it seats against the o-ring  Pic1
  5. Unthread the end cap disassembly tool

Charge Shock

  1. If needed remove torx head screw from gas canister end cap  Pic1
  2. Apply a small amount of grease to Öhlins gas fill needle adapter (U00050-16)
  3. Carefully pierce the bladder with the gas fill needle and thread it in for stability
  4. Attach Kaz Charge Tool to Öhlins gas fill needle adapter
  5. Screw in the plunger of the no-loss air chuck on the Kaz Charge Tool which will depress the valve core of the fill adapter tying all reservoirs together  Pic1
  6. Fill the shock with nitrogen at the Schrader valve of the Kaz Charge Tool
  7. Bleed off pressure using the Schrader valve until the gauge indicates the desired pressure
  8. Back out the plunger of the no-loss air chuck on the Kaz Charge Tool which will isolate the gas reservoirs preventing nitrogen loss from the shock  Pic1
  9. Detach the Kaz Charge Tool from the Öhlins gas fill needle
  10. Carefully remove the gas fill needle
  11. Reinstall the torx head screw into the gas canister end cap  Pic1

Verify shock operation

  1. Check that the shock is charged and will extend on its own
  2. Check that the shock will fully extend to a firm stop
  3. Check that the shock will fully compress
  4. If the shock does not fully compress or properly extend it is likely the floating piston is not positioned correctly, or the shock contains air and has not been properly bled
  5. Test shock in a shock dyno and verify the forces are correct, the adjusters behave properly, and there is no cavitation or excessive hysteresis
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