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Strut Bar Installation
 
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Pelican Technical Article:

Strut Bar Installation

Jared Fenton

Time:

30 minutes30 mins

Tab:

$50 to $500

Talent:

*

Tools:

Socket set, hammer and drift, 4 M8x1.25x25 bolts

Applicable Models:

R50 MINI Cooper Hatchback (2002-06)
R52 MINI Cooper Convertible (2005-08)
R52 MINI Cooper S Convertible (2005-08)
R53 MINI Cooper S Hatchback (2002-06)

Parts Required:

Strut brace

Hot Tip:

Buy a unit that's manufactured out of steel, and doesn't have any hinges

Performance Gain:

Stiffer chassis, reduced understeer

Complementary Modification:

Install strut tower reinforcement plates and factory convertible support bars
How to Maintain and Modify your new MINI

This article is one in a series that have been released in conjunction with Pelican Parts' new book, How to Maintain and Modify your new MINI The book contains 240 pages of full color projects detailing everything from performance mods to changing your brake pads. With more than 500+ full-color glossy photos accompanying extensive step-by-step procedures, this book is required reading in any MINI owner's collection. The book is due to be released in late 2015. See The Official Book Website for more details.

"The MINI is well known for its agility and superb handling performance.  However, because of the design of the chassis, there is some room for improvement. The front shock towers are not well supported in the MINI chassis: they are somewhat isolated and unsupported.  As a result, the towers can bend and flex under heavy cornering.  This flexing can cause detrimental changes in the handling of your car, because in general, the stiffer the chassis, the better the handling. Strut braces are designed to maintain the distance between the shocks under heavy cornering.  A bar linking the top of the shock towers insures that the towers do not bend when the chassis is flexing"

Well, that's what the marketers say when selling these bars. The strut bars are yet another controversial product that many people feel the need to install on their MINIs. On some cars, the early Porsche 911s for example, the installation of the strut bar is an important chassis stiffening device. Because of their rear engine design, the front chassis can be decidedly weak, particularly when rust has started to affect the chassis stiffness. But the MINI chassis is different: it's supported by a much more rigid frame with boxed sections and crumple zones. The front strut housings however, do have an apparent weakness; there is no support tying them together. Under very hard flexing, it is reasonable to assume that the steering geometry could be affected.

The shock towers on the MINI Cooper hang out up over the front of the car. The only bracing comes from the front subframe that cradles the engine. It is well known that the shock towers themselves are prone to metal fatigue and deforming under stress. This has been well documented on various internet forums as "mushrooming" shock towers. It would appear that any additional bracing near the shock towers would be advantageous. Adding additional bracing across the top of the strut towers at the very least would help to add some additional rigidity to the frame.

It does appear that MINI has attempted to reinforce the strut towers in the later cars (See Figure 2). These two steel bars run from the top of the shock tower down to the frame rail. These bars can be added to any MINI, provided that you already have the threaded holes fitted to the car. If not, you will have to drill the holes and install nutserts in the holes to secure the bars to the chassis. If you want to add the braces, 51-61-7-123-515 (left) 51-61-7-123-516 (right) 07-14-6-957-269 (screw for braces, 8 required). Installation of these braces is pretty straightforward. My research seems to indicate that all MINIs from 04/2003 on had the pre-threaded holes installed.

With the car jacked up, remove the two inner nuts on the top of the shock tower (See Figure 3). These three nuts secure the shock mount to the car. Place a floor jack under the outer ball joint to support the strut assembly. Typically, you would now place one end of the strut bar over the studs, but if you have a set of strut tower reinforcement plates installed, the studs on the shock tower won't penetrate past the nut holding it in place (See Figure 3). This reduces the strength of the stud and possibly could break under heavy loads.

My solution was to knock the two studs out of the strut mount in the hopes of installing a longer stud. Typically, this is something you would want to do with the mount removed from the car and secured in a vise or other fixture to prevent the sheet metal of the mount from bending. What I did was place a section of pipe slightly larger than the diameter of the stud underneath the car on the mount, around the stud, using a floor jack to brace it. With this method, you can simply take a hammer and a drift and quickly pop the two studs out. Make sure that the area under the strut mount is well supported or you risk bending the mount. Also, make sure that you hit the top of the stud dead on. I've included a picture of an old shock mount with two studs removed to better show what I'm talking about (See Figure 5 and Figure 6).

I looked for a replacement stud with a longer thread through various hardware suppliers and could not find anything that had the same knurled lower portion to hold it in the strut mount. Ultimately, I decided to use 4 M8x1.25x25 bolts, fed up from inside the shock tower, through the mount and reinforcement plate.

The OMP strut bar we installed is designed with a threaded collar designed to tension the bar. That means that one side is reverse threaded. Loosen the lock nuts on either end of the collar and adjust the collar so that each end of the strut tower lines up with the holes on either shock tower. Now use a 13mm ratchet/socket combination with a long extension to hold the bolt in place while you loosely thread the 13mm nut on the top. It's a good idea to use new nuts here as the original nuts are intended as one time use items (See Figure 7 and Figure 8).

Once you have the bolts in and the strut bar is lined up, use the ratchet/socket combination to counterhold the bolt from below and torque the top nuts to 24Nm (18 ft/lbs.) (See Figure 9). Now, go back the collar to tighten the bar. The idea is to drive the two ends of the bar outwards and tension it. You should have a bit of play in the bar. You want the bar to stiff. Keep turning the bar until you have removed all play and then tighten the two lock nuts on either end of the collar (See Figure 10 and Figure 11).

Shown here is the OMP strut brace available from Pelican Parts.
Figure 1

Shown here is the OMP strut brace available from Pelican Parts. The piece consists of 2 bar ends with an adjustable center collar that allows you to tension the bar.

On convertible MINI models, the factory added these braces between the shock mounts and the front frame rails (green arrows) On cars from 04/2003 on, there should be threaded inserts in the shock towers and frame rails to add these braces for additional strength.
Figure 2

On convertible MINI models, the factory added these braces between the shock mounts and the front frame rails (green arrows) On cars from 04/2003 on, there should be threaded inserts in the shock towers and frame rails to add these braces for additional strength.

The first step in installing a strut brace is to remove the two inner 10mm nuts securing the strut mount to the top of the shock tower.
Figure 3

The first step in installing a strut brace is to remove the two inner 10mm nuts securing the strut mount to the top of the shock tower.

If you have strut tower reinforcement plates installed in your car, you may have trouble installing a strut brace as the stud length on the strut mount is not long enough.
Figure 4

If you have strut tower reinforcement plates installed in your car, you may have trouble installing a strut brace as the stud length on the strut mount is not long enough. In this picture, you can see that the studs (green arrows) do not penetrate all the way through the nuts with the strut bar installed.

ThisPicture shows a strut mount removed from the car with the two mounting studs removed (green arrows).
Figure 5

This picture shows a strut mount removed from the car with the two mounting studs removed (green arrows). The way that these studs are removed, this mount would fit on the driver's side of the car. For the passenger side you would reverse the removal of the studs along the rear edge.

Take a length of pipe slightly larger than the stud and place it up underneath the stud inside the shock tower.
Figure 6

Take a length of pipe slightly larger than the stud and place it up underneath the stud inside the shock tower. The idea is to brace the strut mount to keep it from bending. Then, take a hammer and drift and pop the stud out of the mount. Take care to hit the top of the stud dead on. The green arrows show the studs that must be removed from the passenger side. The driver's side would be a mirror image of this.

Place the strut bar in place over the shock tower.
Figure 7

Place the strut bar in place over the shock tower. Then, using a ratchet/socket combination, push the new M8x1.25x25 bolt up through the shock mount, through the strut reinforcement plate and through the strut bar mounting plate.

Shown here is the ratchet/socket combination with extension used to hold the bolt up into place from underneath.
Figure 8

Shown here is the ratchet/socket combination with extension used to hold the bolt up into place from underneath.

Line up the strut bar mounting plates on each shock tower and thread new 10mm nuts onto the bolts.
Figure 9

Line up the strut bar mounting plates on each shock tower and thread new 10mm nuts onto the bolts. Counterhold the bolt with the ratchet as shown above and torque the nuts to 24Nm (18 ft/lbs.)

Loosen the 24mm lock nuts on either side of the collar and turn the 17mm center bolt clockwise to tension the two ends of the strut bar.
Figure 10

Loosen the 24mm lock nuts on either side of the collar and turn the 17mm center bolt clockwise to tension the two ends of the strut bar. You want to remove all up and down play in the bar.

When you have tensioned the bar in place, tighten each 24mm lock nut to keep the collar from moving.
Figure 11

When you have tensioned the bar in place, tighten each 24mm lock nut to keep the collar from moving. And that's it, you're done!

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Comments and Suggestions:
Jimmy Jay Comments: if I was to install the mini madness under strut reinforcement plates and m-7 strut tower brace, what would be the correct new bolt length, M8x1.25x25 bolt? Do you sell the 6 bolts with washer and nut set?
October 25, 2016
  Followup from the Pelican Staff: I am not 100% sure. Check with our parts specialists a call at 1-888-280-7799. - Nick at Pelican Parts  
Sterling_Archer Comments: Is it a total bear to pop those strut mount studs out? I have new strut mounts installed and I'm worried I won't be able to get the studs out...
May 12, 2016
  Followup from the Pelican Staff: No, they pop right out when tapped with a soft-faced hammer. - Nick at Pelican Parts  
Dash Comments: Hi there.

Will the R52 under floor strengthening bars fit a mini mini cooper s R53?
Thanks
March 11, 2016
  Followup from the Pelican Staff: I am not 100% sure. To be sure, Give our parts specialists a call at 1-310-626-8765
- Nick at Pelican Parts
 
808R53 Comments: Just bought a m7 strut-brace. Wanted to know what's the torque lb. on the 3 bolt screw that will be holding the plate.
Thanks,ROD
June 10, 2015
  Followup from the Pelican Staff: Check with M7, I don;t know if the fastener type or length changes with the brace. - Nick at Pelican Parts  
sportster Comments: The big question in my mine of this strut brace is, does it fit on an '03 Mini Base? Here's why I ask: Under the hood is literally no room. The battery housing is too high anyway, but can be remedied with some modifications. The Fuse housing is higher as well and looking at the brace that bolts to the driver's strut tower, it raises upward to clear the housings. If this is bolted on, is there hood clearance for it to close properly? I went through this before and found the brace I bought before, not this product, it did not give hood clearance. So I'm still without a brace. Can I get some feedback on this? Thank you.
July 15, 2014
  Followup from the Pelican Staff: This tech article is for an early MINI. So I imagine it will fit without modification, as it is not mentioned.- Nick at Pelican Parts  

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