How to Install a Bobble Strut

Last Updated - August 4th, 2004


Installing a solid bobble strut prevents you engine from rocking during launches and power shifts and reduces the likelyhood of several breakages that can happen under high power.  The bobble strut keeps the CV joints and driveshafts aligned reducing the chances of "wheel hop" and CV joint breakage.

Difficulty:    

Time Investment:  Under 2 Hours


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Go to Instructions:

Go to Tools Required:




Pictures:

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Bobble Strut
Top of Bobble Strut
Bobble Strut Bracket
This is the Kelly-Mulhern Performance Bobble Strut.
After removing the air box and looking down behind the engine, you can see the top of the installed bobble strut (or stock strut).
From underneath the car, this is the bracket that the bobble strut hooks onto.  It's located on tke K frame between the two front tires.
Bobble Strut Bracket 2
Preload
Jack Differential
Looking directly upward from under the car, you can see the top of the bracket.
Adjust the bottom bushing and the two nuts that sit below it so that the top of the hole in the cross tube sits ~1/4" below the bottom of the hole in the bracket.
Jack up the differential ~1/4" to slide the stock cross bolt through.


Instructions:

1. Remove the air box and inake plumbing behind the engine (if it is still there).

2.  Remove the old stock bobble strut.
This is actually the only part of the process that is a pain.  The stock unit is essentially a shock absorber with a threaded top.  The top above the mounting bracket has a rubber pad, followed by a large washer, and then a nut.  If you turn the nut, the entire shaft of the shock will rotate with it.  There is a small piece of metal jutting up above the nut that could theoretically be used in combinaion with a 2nd wrench to simply undo the nut.  Mike's 2 attempts at this however have failed and on both installations, he used an angle grinder to '"remove" the nut and the top of the shaft.  This is a one hand angle grinder operation, so be careful. As an alternative, Ed had success using a nut splitter to break the nut in half.

3.  Jack up the front of car and put it on jackstands.  You can get away with just doing the front driver's side corner.

4.  Unbolt the remaining portion of the stock unit.  (Keep the through bolt handy.)

5.  Prepare the Kelly-Mulhern Performance bobble strut for installation.
To do this, remove the top nut, washer, and bushing.  Loosen the lower two nuts and twist them down low to get them out of the way.  You're going to be moving the lower bushing to figure out exactly where you want it.

6.  Determine and set the lower bushing position.
Get under the car and push the bobble strut up into position making sure the end goes through the hole in the top of the bracket.  Note the position of the end that the bolt will go through.  You want the top of that tube to set about 1/4" BELOW the bottom of the corresponding hole in the bracket.  The bushing will move with some twisting so continue repositioning it until you find the right spot.

7.  Set the lower nuts.
Twist the top lower nut up so that it pushes the washer firmly against the lower bushing.  Just make sure not to move the bushing.  Put a wrech on that nut and then twist the other up to join it.  While holding the top one, torque the lower one against it to lock the position.

8.  Install the bobble strut from under the car.
Get back under the car and use your jack to lift up the differential just enough so that you can get the through bolt into the bobble strut.  Reuse the stock bolt and tighten it down.  You will probably want to use a block of wood or two between the jack and the differential.

9.  Lower the car.

10.  Install the top bushing, washer, and nut.
Getting the bushing on will take some twisting but it will go with a bit of effort.  You don't need to squish out the top bushing too much when tightening the top nut, just crank it down to the point where it's firm.  If the bushing bulges, you've gone too far.  In that case, just back it off a little.

11.  Reinstall the airbox and inake plumbing if appropriate.


Tools Required: