Shock Tower Stud Replacement / Damaged Studs

[Les00x]

Shock Tower Stud Replacement / Damaged Studs - Tein Coilover Shocks

Damaged Studs - Not a common problem and so not much around on know how. Obtaining the correct spare Stud quickly may be an issue. These Studs are a class of Ribbed Neck Tensile Bolts. Similar principles apply to replacing some pressed in wheel hub Studs.

- Les Lothringer's Approach to Replacing Damaged Shock Tower Stud on a Tein SuperStreet Coilover, installed on a Nissan R32 GTR. Applicable to some other Tein Coilovers, also other coilover brands where Stud is press fitted, not welded, into Coilover top flange (upper bracket).

- Reason: Stud thread stripped. Also if bent. Note: The Stud thread (and nut) must not be repaired and must be disposed of.

- Parts Source: Tein importer for original manufacturer replacement Ribbed Neck Bolt - they only had two in Australia, I bought them both. Suspension workshops may not carry stud spares. Other sources include used shocks, similar tensile bolts and perhaps wheel studs (refer below for comparisons). Note: Shocks front to rear use different studs - perhaps M10 vs. M8. Tein Front or Rear Shock studs will not be the same across all their models.

- Cost: A$14 per Ribbed Neck Bolt (the Stud) direct from Tein Australian importer. Via retail workshop may cost more. Costs are 2010 A$'s. Tein US sell these studs for US$3.

- Duration: Depends on Shock geometry. For Tein Superstreets where the spring does not seat under the Studs in the top flange plate, say, 1 hour one person. If the coil spring seats under the Stud, the Shock may need to be partly dismantled unless adequate clearance is gained using a Coil Spring Compression Tool.

- Difficulty Level: Easy once you know how, unless something goes wrong.

- Disclaimer: This describes my approach. If you choose to follow it and make a mistake, remember - at all times, it's your fault. If you choose to follow it and get a different outcome, that's because you need to know more than what is described here. No responsibility for errors or omissions. Every car can be different. Torque settings as per Nissan WSM.

- Reference: Nissan R32 GTR Workshop Manual for coilover removal / installation.

- Special Tools: Coil Spring Compression Tool, Vernier. If the coil spring does not seat under the top flange studs, a Coil Spring Compressor is unnecessary. Stud can be simply tapped out. Otherwise the top flange plate will need removal (see photo). Note: Dismantling a Shock safely requires skill.

If using a part from another shock, a Vernier is needed to confirm match exactness.

- Other Tools: Torque Wrench, Levers, Sockets, Hammer, several Spacers / Washers to fit over Stud, Trolley Jack, Axle Jacks, Wooden Blocks for safe jacking / securing of car.

- Repairing Damaged Studs: Damaged studs (and nuts) MUST NOT be repaired and must be disposed of. The thread MUST NOT be recut (using a Threadcutter). This will weaken the bolt. Shocktower Studs (and wheel hub Studs) are examples of rolled threads, not cut threads. Bolts with cut threads have a lower tensile strength and may well fail in service with life-endangering outcomes.

- What Can Go Wrong: Over-tensioning bolts can cause bolts / thread seats to undergo plastic deformation. Under-tensioning bolts can lead to them loosening off. This approach applies to a one-piece unit coil spring and damper. It may be necessary to dismantle the Coilover.

Approach:

_____________________

A. Set Up & Access to Suspension

1. Lift bonnet and secure.

2. Remove Coilover shock tower Nuts, place Shock Tower Brace to one side.

3. Loosen wheel nuts, jack car and secure, remove wheel. Turn steering wheel to

improve access to suspension.

4. Unbolt bottom of Coilover from lower link Connecting Rod. Note the orientation of

the Coilover and Washer while sliding eyelet away from the Connecting Rod.

5. Remove the Coilover.

_____________________

B. - Remove / Replace Ribbed Neck Bolt (Stud)

For Shocks where the spring does not seat under the top flange studs (see photo)

1. Rest Coilover top flange on vice / block of wood. Tap out damaged Stud.

2. Compare Stud dimensions with replacement Stud - especially important if using one recovered from another shock.

3. Rest Coilover on firm base, place steel rod through bottom of Shock tube.

4. Install Stud into top flange from underneath. Use Spacers - torque nut to draw Stud into flange seat. Ensure completely in line, flush and well seated into top flange (see photo). Note: Upper assembly may twist on shock shaft, causing bottom shock eyelet to go out of line with lower suspension Connecting Rod. Can be twisted into line after inserting into Shock Tower.

5. Install Shock into Shock Tower, loosely apply securing nuts.

6. Using angled lever, twist bottom of Shock eyelet to line up with Connecting Rod.

7. If necessary, use long lever to lower / lift the lower link Connecting Rod, slide on Shock, torque up.

8. Torque up Studs.

9. Install wheel, road test.

_____________________

C. Alternative Approaches - Not Recommended / Higher Skill Level

These approaches require professional skill and appropriate tools.

Alt. Approach 1 - Used Stud from Another Shock

The Tein Superstreet used an M10x1.25 - 30 mm Stud. Other Shocks may use very similar looking Studs. This may not be apparent until removed from old Shock (dimensions of button head, shank and ribbing). They must then be compared to the original for exactness, using a Vernier. Removing studs from a used shock may require partly dismantling that shock if the spring seats under the top flange studs (see picture). Dismantling a shock is potentionally dangerous. A Spring Compressor tool may be necessary.

Alt. Approach 2 - Wheel Hub Stud of Same? Dimensions

I investigated this. Dimensions were not exactly the same. An M10x1.25 - 30mm Wheel Hub Stud I sourced had a larger button head, longer shank and a smaller ribbed diameter and so would not quite work out.

Alt. Approach 3 - Tensile Bolt

Some workshops may use a tensile bolt where they cannot acquire an aftermarket stud that fits. This involves using an oversized bolt, tapping a thread into the top flange plate so the bolt can be secured in the top flange or, alternatively, welding it in place. This prevents it turning when tightening / loosening shock tower nuts. The bolt may also need machining to correct dimensions.

_____________________

Torque Settings (ft.lbs): Connecting Rod (bottom of shock tube) = 90, Shock Tower Nuts = 40.

_____________________

[R.3.2.G.T.R]

well done

[MrStabby]

Nice post. In the future put stuff like this in Tutorials/DIY/FAQ. Hopefully a moderator will move this over there.

[Duncan]

moved to DIY section, great post!