BILSTEIN E4-WM5-Y631A00 MOUNTING INSTRUCTION
This instruction is for both left front (driver) 25-287806 and right front (passenger) 25-287813 B8 8100 shocks. A bill of materials (BOM) of the included mounting parts kits is shown on the next page.
IMPORTANT! READ THIS FIRST! ⚠️
Installation of shock absorbers or other suspension components requires special tools and expert knowledge. Accordingly, installation of all BILSTEIN products must be performed by a professional automotive suspension technician.
When replacing other brands, BILSTEIN shock absorbers or other suspension components should always be installed as a set. All BILSTEIN products must only be used for the specific, intended application as indicated in the application guide. Any use of any BILSTEIN product other than for its intended use may result in serious bodily injury or death.
Always use a chassis hoist for the installation of BILSTEIN products and make certain that the raised vehicle is securely attached to the hoist and/or supported to prevent the vehicle from slipping, falling, or moving during the installation process.
If you install any BILSTEIN product without the necessary special tools, expertise, and chassis hoist, you may subject yourself to the risk of serious bodily injury or death.
BILSTEIN shock absorbers are gas-filled and are highly pressurized. ⛽
- Never place any BILSTEIN shock absorbers in a vise or use a clamp on any BILSTEIN shock absorber.
- Never apply heat near any BILSTEIN shock absorber.
- Never attempt to open or repair any BILSTEIN product, in order to prevent serious bodily injury or death.
Any attempt to misuse, misapply, modify, or tamper with any BILSTEIN suspension product voids any warranty and may result in serious bodily injury or death.
While installing any BILSTEIN product:
- Do not use impact tools for loosening or tightening fasteners, because this may destroy the screw threads.
- Self-locking fasteners must only be used once!
- Reuse original equipment components only if they are in good condition, otherwise replace them with new components.
- Never remove the slight film of oil on the shock absorber piston rod and seal.
- All mounting fasteners for shock absorbers and other suspension components must be securely tightened before tension is placed on the suspension system, unless otherwise specified in the manufacturer's service manual or in this instruction.
After installing any BILSTEIN product:
- The suspension caster and camber must be checked and/or adjusted to comply with the vehicle manufacturer's specifications.
- The (load dependent) brake compensator and the anti-lock brake system must be checked and/or reset to comply with the vehicle manufacturer's specifications.
- The headlight aim must be checked and adjusted.
CAUTION for COILOVER TYPE SUSPENSIONS!!! ❗ If disassembling a coilover type suspension, refer to the vehicle manufacturer's service manual for proper procedures. The coil spring is preloaded and must be compressed with a spring compressor to release load before the upper mount is disassembled. Failure to follow the vehicle manufacturer's procedures may cause serious injury or death, and may damage the vehicle.
IMPORTANT!!! ❗
- This BILSTEIN product may or may not be compatible with non-BILSTEIN aftermarket products and/or vehicle modifications. It is the responsibility of the professional automotive suspension technician performing the installation to identify any non-OEM components and/or modifications on the vehicle that may interact with the suspension system. These must be evaluated for any potential physical static or dynamic interference with and/or effect on the function of this BILSTEIN product.
Product Description
B8 8100 bypass shocks feature a proprietary BILSTEIN zinc plated finish. This finish must be serviced in order to maintain its luster. Particularly in moist climates, a protective coating, such as a wax or lubricating oil should be periodically applied to prevent tarnishing. This finish is not covered under warranty.
It is normal to hear a slight audible clicking noise during compression and rebound strokes in the B8 8100 bypass shocks, most notably during low velocity events. This is due to the internal check pistons opening and closing to create the externally adjustable compression and rebound zones.
Bill of Materials
The following table lists the components included in the mounting kits for part numbers 25-287806 (Left Side) and 25-287813 (Right Side).
| Item # | Description | Qty. in 25-287806 | Qty. in 25-287813 |
|---|---|---|---|
| 1 | Reservoir Bracket Plate | 1 | 1 |
| 2 | Reservoir Clamp; Ø60mm | 1 | 1 |
| 3 | Flat Head Screw; M8x1.25; L=18 | 2 | 2 |
| 4 | Flange Head Cap Screw, 1/4"-20 x 1" | 1 | 1 |
| 5 | Flange Head Cap Screw, 5/16"-18 x 1" | 1 | 1 |
| 6 | Threaded Insert, 1/4"-20 Internal Thread | 1 | 1 |
| 7 | Threaded Insert, 5/16"-18, Internal, Hex | 1 | 1 |
| 8 | Socket Head Cap Screw; M6x1; L=50 | 1 | 1 |
| 9 | Nylock; M6x1 | 1 | 1 |
| 10 | Hex Head Cap Screw, 1/4"-20 x 1.25" | 1 | 1 |
| 11 | Washer, 1/4" ID x 3/4" OD, Grade 9 Steel | 1 | 1 |
| 12 | Serrated Flange Nut, 5/16"-18 | 1 | 1 |
| 13 | Hex Head Cap Screw, 5/16"-18 x 1.25" | 1 | 1 |
| 14 | Washer, 5/16" | 1 | 1 |
| 15 | Serrated Flange Nut, 3/8"-24 | 1 | 1 |
| 16 | Mount Bracket, Reservoir Hose, JL, Left | 1 | - |
| 17 | Socket Head Cap Screw, SS, M8x1.25, L=20 | 1 | - |
| 18 | Serrated Flange Nut; M8x1.25 | 2 | 2 |
| 19 | Loop Clamp, Hose, 7/8" Dia. | 1 | 2 |
| 20 | Button Head Screw; M8x1.25; L=18; SS | 1 | 1 |
| 21 | Rubber Strip | 1 | 1 |
| 22 | Mount Bracket, Reservoir Hose, JL, Right | - | 1 |
B8 8100 Bypass Shock Installation Procedure
B8 8100 bypass shocks are corner specific. The step-by-step procedure is shown with pictures of both sides. See page 22 for the end result.
Installation of B8 8100 bypass shocks requires the use of wheels with a maximum of 4.5" backspacing to ensure clearance between the tire and the shocks.
Step A: Remove Existing Shocks
Remove the existing shocks from the vehicle following all procedures in the vehicle manufacturer's service manual. Inspect the OE upper bolts/washers for any excessive wear. If damage or excessive wear is present in any of these components, purchase the required replacement OE components.
Step B: Mount Kit for Remote Reservoir
A mount kit is included to allow the remote reservoir to be attached to the vehicle frame rail behind the front bumper. This kit is depicted in Figure 1 for the left side shock (25-287806) and Figure 2 for the right side shock (25-287813).
Step C: Install Threaded Inserts
If you have access to a threaded insert gun or pliers, that may be preferable to set the provided threaded inserts (BOM item #6 & #7). Otherwise, using the items shown in Figure 3 (1/4"-20 x 1.25" cap screw, 1/4" washer, 5/16"-18 serrated flange nut, 1/4"-20 thread insert) and a 1/2" box end wrench, arrange them as shown and turn the 1/4"-20 screw (BOM item #10) by hand until it is snug as shown in Figure 4. Note that the screw will pass through the serrated flange nut without engaging the threads. The serrations on the flange nut prevent the threaded insert from rotating while setting it.
Figure 3 Illustration: Shows the components for installing a threaded insert: a cap screw, washer, serrated flange nut, and the thread insert itself, along with a wrench.
Figure 4 Illustration: Depicts the assembly of the 1/4"-20 cap screw, 1/4" washer, 5/16"-18 serrated flange nut, and 1/4"-20 thread insert, with a 1/2" wrench and 7/16" wrench indicated for use.
Step D: Install Threaded Inserts (Left/Right Side)
For the left side, insert the 1/4"-20 threaded insert (BOM item #6) into the hole shown in Figure 5. For the right side, insert the 5/16"-18 hex threaded insert (BOM item #7) into the hole shown in Figure 6.
Figure 5 - Vehicle Left Side: An image showing the vehicle's left front frame area with an arrow pointing to the location for the 1/4"-20 threaded insert.
Figure 6 - Vehicle Right Side: An image showing the vehicle's right front frame area with an arrow pointing to the location for the 5/16"-18 hex insert.
Step E: Tighten Screw for Threaded Insert
While keeping the threaded insert (BOM item #6) flange firm and parallel against the bumper support, tighten the screw (BOM item #10) using a 7/16" box end wrench or socket. Turn it 2 rotations to set the threaded insert. Tightening in 1/4 turn increments tends to work well.
Step F: Remove Temporary Fasteners
Remove and discard the screw (BOM item #10), washer (BOM item #11), and serrated flange nut (BOM item #12). The threaded insert (BOM item #6) should now be rigidly fixed in the hole.
Step G: Assemble 5/16" Hex Screw Components
Assemble the 5/16"-18 hex screw (BOM item #13), 5/16" flat washer (BOM item #14), a 9/16" boxed end wrench, the 3/8" serrated flange nut (BOM item #15) and hex threaded insert (BOM item #7) in the same manner shown in Figure 3.
Step H: Install Hex Threaded Insert
For the left side, insert the hex threaded insert (BOM item #7) into the hole shown in Figure 5. For the right side, insert the hex threaded insert (BOM item #7) into the hole shown in Figure 6.
Step I: Tighten Screw for Hex Threaded Insert
While keeping the hex threaded insert (BOM item #7) flange firm and parallel against the bumper support, tighten the screw (BOM item #13) using a 1/2" box end wrench or socket. Turn it 2 rotations to set the hex threaded insert (BOM item #7). Tightening in 1/4 turn increments tends to work well.
Step J: Remove Temporary Fasteners
Remove and discard the screw (BOM item #13), washer (BOM item #14), and serrated flange nut (BOM item #15). The hex threaded insert (BOM item #7) should now be rigidly fixed in the hole.
Step K: Prepare Reservoir Mount Assembly
Apply non-permanent thread locker to two Flat Head Screws (BOM item #3). Mount the Reservoir Clamp (BOM item #2) to the Bracket Plate (BOM item #1) using the two Flat Head Screws (BOM item #3) as shown in Figures 7 and 8. Tighten the Flat Head Screws (BOM item #3) using a 5mm hex. Torque both screws to 16 ft-lb (22 Nm).
Figure 7 - Vehicle Left Side Assembly: Diagram showing the Reservoir Clamp, Reservoir Bracket Plate, M6x1 Nylock, M6x1 Socket Head Cap Screw, and M8x1.25 Flat Head Screws for the left side assembly.
Figure 8 - Vehicle Right Side Assembly: Diagram showing the Reservoir Clamp, Reservoir Bracket Plate, M6x1 Nylock, M6x1 Socket Head Cap Screw, and M8x1.25 Flat Head Screws for the right side assembly.
Step L: Attach Reservoir Clamp to Bracket Plate
Place the Nylock (BOM item #9) in the slot of the Reservoir Clamp (BOM item #2) as shown in Figures 7 and 8. Then insert the Socket Head Cap Screw (BOM item #8) into the hole in the Reservoir Clamp (BOM item #2), threading it into the Nylock (BOM item #9) as shown in Figures 7 and 8. Using a 5mm Hex, tighten the Socket Head Cap Screw (BOM item #8) only a few turns, leaving it loose enough so the reservoir can be installed in a following step.
Step M: Left Side Reservoir Hose Mount Bracket Installation
Locate the hole in the front side of the left spring bucket shown in Figure 9. Using a M8x1.25 Socket Head Cap Screw (BOM item #17), and a M8x1.25 Serrated Flange Nut (BOM item #18), attach the Left Reservoir Hose Mount Bracket (BOM item #16) to the spring bucket and orient as shown in Figures 10 and 11. Torque the screw to 16 ft-lb (22 Nm).
Figure 9 - Vehicle Left Side Spring Bucket: Image showing the left side spring bucket with an arrow indicating the 'Hole for Bracket'.
Figure 10 - Vehicle Left Side Reservoir Hose Mount Bracket: Image showing the installed Left Reservoir Hose Mount Bracket on the vehicle's left side spring bucket.
Figure 11 - Vehicle Left Side Serrated Flange Nut Installed: Image showing the installed serrated flange nut for the left side reservoir hose mount bracket.
Step N: Right Side Reservoir Hose Mount Bracket Installation
Locate the hole in the front side of the right spring bucket shown in Figure 12. Using a M8x1.25 Button Head Screw (BOM item #20), and a M8x1.25 Serrated Flange Nut (BOM item #18), attach the Right Reservoir Hose Mount Bracket (BOM item #22) to the spring bucket and orient as shown in Figures 13 and 14. Torque the screw to 16 ft-lb (22 Nm).
Figure 12 - Vehicle Right Side Spring Bucket: Image showing the vehicle's right side spring bucket with an arrow indicating the 'Hole for Bracket'.
Figure 13 - Vehicle Right Side Hose Bracket: Image showing the installed Right Reservoir Hose Mount Bracket on the vehicle's right side spring bucket.
Figure 14 - Vehicle Right Side Serrated Flange Nut Installed: Image showing the installed serrated flange nut for the right side reservoir hose mount bracket.
Step O: Shock Upper Mount Installation
Install the shock's upper mount using the OE upper bolts/washers as shown in Figures 15 and 16. Do not tighten at this time.
Figure 15 - Vehicle Left Side Upper Mount: Image showing the installation of the upper mount for the left side shock absorber.
Figure 16 - Vehicle Right Side Upper Mount: Image showing the installation of the upper mount for the right side shock absorber.
Step P: Shock Lower Mount Installation
A mount kit is included to allow the lower shock mount to be offset away from the frame. This kit is depicted in Figure 17.
Figure 17 - Lower Mount Offset Bracket: Diagram showing the components of the lower mount offset bracket kit, including Clevis (23), Spacer (24), M8x1.25 Flat Head Screw (25), M10x1.5 Flat Head Screw (26), M8x1.25 Nut (27), M10x1.5 Nut (28), M12x1.75 Nut (29), and M12x1.75 Socket Head Cap Screw (30).
Step Q: Install Mount Clevis
Install the Mount Clevis (BOM item #23) using the M10x1.5 Flat Head Screw (BOM item #26) and M10x1.5 Nut (BOM Item #28) for the left side of the vehicle. For installation on the right side of the vehicle, use the M8x1.25 Flat Head Screw (BOM item #25) and M8x1.25 Nut (BOM item #27). Torque the screw to 31 ft-lb (42 Nm).
Step R: Position Lower Shock Mount
Place the Spacer (BOM item #24) between the flanges of the OE mount. Position the shock's lower mount between the outside flange of the OE mount and the clevis. Make sure the shock's lower mount is installed angling the shock toward the back of the vehicle and inward toward the chassis as shown in Figures 18 and 19. Do not tighten at this time.
Figure 18 - Vehicle Left Side Lower Mount: Image showing the left side lower shock mount installation, illustrating the angle and positioning.
Figure 19 - Vehicle Right Side Lower Mount: Image showing the right side lower shock mount installation, illustrating the angle and positioning.
Step S: Reservoir Mounting (Initial Attachment)
Apply non-permanent thread locker to the 5/16"-18 X 1" Flange Head Cap Screw (BOM item #5) and install the reservoir mount assembly with the screw in the bottom threaded insert. Leave the screw loose for now. Rotate the assembly toward the rear of the vehicle and slide the reservoir into the clamp as shown in Figures 20 through 23.
Figure 20 - Left Front Mount Assembly Tilted: Image showing the initial tilt and positioning of the left front reservoir mount assembly.
Figure 21 - Right Front Mount Assembly Tilted: Image showing the initial tilt and positioning of the right front reservoir mount assembly.
Figure 22 - Left Front Reservoir Slide Into Mount: Image showing the left front reservoir being slid into its clamp.
Figure 23 - Right Front Reservoir Slide Into Mount: Image showing the right front reservoir being slid into its clamp.
Step T: Secure Reservoir Mount Assembly
Rotate the reservoir mount assembly back to vertical. Apply non-permanent thread locker to the 1/4"-20 x 1" Flange Head Cap Screw (BOM item #4) and install it in the upper threaded insert. Torque both screws 10 ft-lb (13.6 Nm).
Step U: Position Reservoir Tube Height
Position the end of the reservoir tube approximately 40mm below the bottom side of the clamp as shown in Figure 24. With the reservoir hose exiting straight toward the back of the vehicle, tighten the Socket Head Cap Screw in the Reservoir Clamp so the reservoir does not move.
Figure 24 – Reservoir Height: Illustration showing the required 40mm distance from the reservoir tube end to the bottom of the clamp.
Step V: Apply Rubber Protective Strip
To protect the reservoir hose from abrading on the chassis, a rubber strip (BOM item #21) should be applied to the chassis body mount in the locations shown in Figure 25 on the left side of the vehicle and Figure 26 on the right side of the vehicle. To apply the strip on the curved surface, either cut the adhesive backed side of the angled Rubber Strip (BOM item #21) to allow for flexibility around the curve, or cut it in half, and apply to either side of the curve.
Figure 25 – Left Side Location for Rubber Strip: Image showing the left side of the vehicle's chassis with an arrow indicating where to apply the rubber strip.
Figure 26 – Right Side Location for Rubber Strip: Image showing the right side of the vehicle's chassis with an arrow indicating where to apply the rubber strip.
Step W: Left Side Reservoir Hose Mounting
Spread the Loop Clamp (BOM item #19) enough to wrap it around the left side reservoir hose. Apply non-permanent thread locker to the M8x1.25 Button head Screw (BOM item #20), and secure the Loop Clamp (BOM item #19) to the Left Reservoir Hose Mount Bracket (BOM item #16) as shown in Figures 27 and 28. The Loop Clamp (BOM item #19) should be pointed toward the front of the vehicle. Torque the screw to 16 ft-lb (22 Nm).
Figure 27 - Left Reservoir Hose Installed: Image showing the left reservoir hose secured with the loop clamp.
Figure 28 - Left Reservoir Hose Installed (Side View): Side view image of the left reservoir hose installed.
Step X: Right Side Reservoir Hose Mounting
Spread the Loop Clamp (BOM item #19) enough to wrap it around the right side reservoir hose. Apply non-permanent thread locker to the M8x1.25 Button head Screw (BOM item #20), and using a M8x1.25 Serrated Flange Nut (BOM item #18), secure the Loop Clamp (BOM item #19) to the Reservoir Hose Mount Bracket (BOM item #22) on the right side as shown in Figure 29. The Loop Clamp (BOM item #19) should be pointing toward the outside of the vehicle. Torque the screw to 16 ft-lb (22 Nm).
Figure 29 - Right Reservoir Hose Installed: Image showing the right reservoir hose secured with the loop clamp.
Step Y: Adjust Reservoir Hose Clearance
Loosen the Socket Head Cap Screw in the Reservoir Clamp, and angle the reservoir hose toward the inside of the vehicle. Adjust the reservoir angle so that the reservoir hose is 6mm from the chassis body mount as shown in Figures 30 and 31. Make sure to maintain the 40mm distance between the end of the reservoir tube, and the bottom side of the clamp as shown in Figure 24. Torque the Screw to 6 ft-lb (8 Nm).
Figure 30 – Left Side Reservoir Hose Clearance: Image illustrating the 6mm clearance for the left side reservoir hose.
Figure 31 – Right Side Reservoir Hose Clearance: Image illustrating the 6mm clearance for the right side reservoir hose.
Step Z: Final Tightening
With the vehicle back on the ground, tighten the OE upper and supplied lower fasteners to the vehicle manufacturer's service manual torque specifications.
Step AA: Reinstall Inner Fender Liners
If the inner fender liners had been removed, reinstall them behind the reservoir hose.
Final Installation View
Left Side Installed (Without Inner Fender Liner): Image showing the left side of the vehicle with the BILSTEIN B8 8100 shock absorber installed.
Right Side Installed (Without Fender Liner): Image showing the right side of the vehicle with the BILSTEIN B8 8100 shock absorber installed.
B8 8100 Bypass Shocks Adjustment Procedure
B8 8100 bypass shocks allow the user to tune the damping for the best possible ride quality of their vehicle. The shocks offer multiple zones of compression and rebound damping, depending upon the bypass configuration. The factory setting is:
- Rebound – 7 full turns out from fully closed
- Compression – 7 full turns out from fully closed
Note: The bypass adjusters allow adjustment up to 10 full turns out from fully closed.
Adjustment Procedure:
- Using an Allen key, hold the adjuster screw from rotating. Loosen the jam nut from the bypass adjuster housing. Back it off far enough that you can make the adjustment without the jam nut bottoming out.
- Rotate the Allen key to make the desired adjustment.
- TURN IN (Clockwise) the adjuster screw to INCREASE damping
- TURN OUT (Counter Clockwise) the adjuster screw to DECREASE damping
- Tighten the jam nut against the bypass adjuster housing while using the Allen key to hold the adjuster screw from rotating.
Make sure the bypass adjuster housing does not loosen during the adjustment process. It may be necessary to hold the bypass adjuster housing with the appropriate wrench while loosening the jam nut.
B8 8100 Bypass Service Information
For service of your B8 8100 bypass shocks, please contact:
THYSSENKRUPP BILSTEIN OF AMERICA13225 Danielson St.
Poway, CA 92064, USA
Toll Free: 1-800-537-1085
Website: bilsteinus.com
BILSTEIN Corporate - BILSTEIN
