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Convertible Strut Brace Install
 
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Pelican Technical Article:

Convertible Strut Brace Install

Time:

15 minutes-1 hour

Tab:

$50-

Talent:

**

Tools:

Torx driver, drill, 10mm bit

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 braces, bolts, nutserts

Hot Tip:

take your time when marking and drilling holes for the nutserts

Performance Gain:

Stiffer chassis

Complementary Modification:

Install upper strut brace.
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.

In the case of the convertible MINI Cooper, there is additional bracing added to the front shock towers of the car. This suggests that extra bracing was required for additional resistance against flexing due to the lack of a permanent roof. There are two braces incorporated into the front shock towers as well as two supports under the rear suspension.

The front suspension on the first generation MINI Coopers has problems with both deformation and flexing. Therefore, it is reasonable to assume that any additional bracing added to the car will certainly help, even if to a small degree.

Both struts are available from BMW for about $20 each so it's a relatively inexpensive upgrade for a factory part. The part numbers are 51-61-7-123-515 (left) and 51-61-7-123-516 (right) (See Figure 1). You will also need eight M6 bolts to secure the struts. BMW calls for the use of part number 07-14-6-957-269. This is an M6 x 14 oval head Torx bolt, which we decided to use in our case.

If your car has the threaded inserts already installed, it's a very simple install as you simply have to pull out the plastic plugs in the holes and bolt the braces in. This seems to be the case on all MINI Coopers, either convertible or hardtop from October of 2003 on. There will be a plastic plug in each of these holes. Unscrew the plugs and you will see the threaded holes underneath. All that's left to do if you have the threads is to line up the struts and bolt them in. NOTE: Read through this article completely as you will need to reposition a harness connector. Our car has a build date of March of 2003 so it does not have the pre-drilled and threaded holes (See Figure 2).

If you are so inclined, you could simply weld the struts into place, however this method requires fabrication knowledge and preparation of the metal, guarding the vehicle's electronics from damage and protecting the metal from corrosion. You also lose the ability to easily remove the struts if needed.

The other solution is to use what is called a threaded insert or a nutsert. A nutsert is a small plug that fits into the hole that has threads cut inside. In our case, you will need eight nutserts with an M6 internal thread. These are available at any industrial supply house or a good hardware store. The idea is that you drill a hole through the panel, and then install the nutsert in the hole. This leaves a set of threads inside the hole that can accept a bolt or stud. In this article, I will go over the steps involved with retrofitting the struts into a car without the holes.

Jack up the front of the car and place it on jack stands. Now remove the wheelhouse linings for each side of the car. You will need to do this to access the bolts that hold the struts in. On the passenger side of the car, remove the two 10mm nuts that secure the ground strap from the frame rail to the engine mount (See Figure 3).

Take the passenger side strut and mock it up inside the engine compartment. The idea is to have all mating surfaces flush with both the shock tower and the frame rail (See Figure 4). Hold the strut in place and use either a Sharpie or a permanent marker to mark the hole locations on the car. Remove the strut and you will have the locations for where to drill (See Figure 5). Now line up a center punch in the dead center of each hole and give it a good blow with a hammer. The center punch puts a small divot in the sheet metal which will act as a guide, preventing the drill bit from 'walking' out of the hole (See Figure 6 and Figure 7).

It's important to use the correct drill bit for the brand of threaded insert you are using. Typically the manufacturer will list the recommended size along with the package. In our case, a 10mm bit was used. Be sure to coat the surface with either oil or cutting fluid and use low speed to prevent dulling the bit (See Figure 8).

Now move over to the driver's side and pull the wire harness connector out of the clip mounted on the frame rail and twist the outside sleeve to separate the two halves (See Figure 9). Then remove the 10mm nut securing the plastic bracket to the frame rail. Once the harness connector is removed, pop the circular armed clip out of the metal bracket it fits into and set this clip aside.

With the nut removed, you will see two brackets secured by a rubber 19mm grommet. The upper plastic bracket fits around one of the A/C lines. Remove the 19mm grommet and it will release the metal bracket underneath. There is a hole on the strut that takes the place of this bracket, so you can throw the metal bracket away (See Figure 10 and Figure 11).

Now, mock up the strut on the driver's side into place and mark the hole locations. You will notice that the holes on the bottom are elongated. This is to allow a bit of play when installing the strut. (See Figure 12 and Figure 13). Now center punch and drill the holes on the driver's side. As before, be sure to use either oil or cutting fluid. Clean the hole afterwards to remove any sharp burrs and to remove all metal filings (See Figure 14).

Take care when drilling the holes in the bottom frame rail, to not hit the A/C line port to the left of the top-most hole. You can't really bend the line out of the way, so you may want to have a helper carefully hold it back while you drill the holes (See Figure 15).

The next step is to install the nutserts in the holes. The manufacturer of the nutsert specifies the use of an expensive tool in order to install it, however you can simply use an M6 x 40 bolt, two M6 washers and an M6 nut. Put some Loctite on the inside threads of the nutsert and thread the nut onto the bolt, followed by the two washers and then the nutsert (See Figures 16, 17 and 18).

Here's where it gets a bit tricky. The idea is to keep the nutsert from turning when it is inside the hole. Hold the bolt at the top stationary with either a wrench or a socket as you turn the nut at the bottom. It will take a bit of force to get the nutsert to collapse. Once you feel it start to go, tighten the nut down until it stops. Then loosen the nut and unscrew the bolt (See Figure 19 and Figure 20).

Now, on the drivers side front frame rail, thread in the 19mm rubber grommet in the same location without the metal bracket underneath. Since the new driver's side strut has a hole for the wiring harness connector, you don't need to use the old bracket (See Figure 21). Refit the black plastic bracket that snaps over the A/C port and slide it over the 19mm grommet. Now refit the 10mm nut and tighten it down (See Figure 22).

Now mount the driver's side strut into place. Make sure that you route the wiring harness to go under the strut. This is so that you can re-fit the harness connector in the retaining bracket (See Figure 23). Now thread in the oval head Torx screws and tighten the strut down. At the same time, mount the passenger side strut, install the bolts and torque them to 11Nm (8.1ft.-lbs.).

Now take the circular armed clip and pop it into the extra hole on the driver's side strut (See Figure 24). Reconnect the harness and pop the connector into the clip mounted on the strut (See Figure 25). Now re-fit the wheel house liner on the driver's side and you're done on that side. (See Figure 26). On the passenger side strut, reconnect the ground strap from the frame rail to the engine mount. You will have to reposition the strap slightly to fit under the strut (See Figure 27). Now refit the wheelhouse liner and you're done.

These two struts were a factory reinforcement added to the R52 convertible MINIs and can be retrofitted directly into all MINIs from September of 2003 on.
Figure 1

These two struts were a factory reinforcement added to the R52 convertible MINIs and can be retrofitted directly into all MINIs from September of 2003 on. Cars prior to that will have to drill holes and install nutserts as shown in the article. They are pretty inexpensive and a nice little addition to help the stiffness of the front strut towers.

If you have a MINI with a build date of September of 2003 on, check the upper shock towers and frame rails for the pre-threaded holes.
Figure 2

If you have a MINI with a build date of September of 2003 on, check the upper shock towers and frame rails for the pre-threaded holes. These holes will be plugged with black plastic inserts (green arrows).

On the passenger side of the car, remove the two 10mm nuts that secure the ground strap from the frame rail to the engine mount (green arrows).
Figure 3

On the passenger side of the car, remove the two 10mm nuts that secure the ground strap from the frame rail to the engine mount (green arrows).

Take the passenger side strut and mock it up inside the engine compartment as seen.
Figure 4

Take the passenger side strut and mock it up inside the engine compartment as seen. The idea is to have all mating surfaces flush with both the shock tower and the frame rail.

Hold the strut in place and use either a Sharpie or a permanent marker to mark the hole locations on the car.
Figure 5

Hold the strut in place and use either a Sharpie or a permanent marker to mark the hole locations on the car.

Locate dead center of each marked hole and line up a center punch in each hole.
Figure 6

Locate dead center of each marked hole and line up a center punch in each hole.

Using a hammer, give the center punch a good blow.
Figure 7

Using a hammer, give the center punch a good blow. The center punch puts a small divot in the sheet metal which will act as a guide, preventing the drill bit from 'walking' out of the hole.

It's important to use the correct drill bit for the brand of threaded insert you are using.
Figure 8

It's important to use the correct drill bit for the brand of threaded insert you are using. Typically the manufacturer will list the recommended size along with the package. In our case, a 10mm bit was used. Be sure to coat the surface with either oil or cutting fluid and use LOW speed to prevent dulling the bit.

Now move over to the driver's side and pull the wire harness connector out of the clip mounted on the frame rail (green arrow).
Figure 9

Now move over to the driver's side and pull the wire harness connector out of the clip mounted on the frame rail (green arrow). Then remove the 10mm nut securing the plastic bracket to the frame rail (yellow arrow). Once the harness connector is removed, pop the circular armed clip out of the metal bracket it fits into and set this clip aside. Twist the harness connector in the center to release and pull it apart.

With the nut removed, you will see two brackets secured by a rubber 19mm grommet.
Figure 10

With the nut removed, you will see two brackets secured by a rubber 19mm grommet. The upper plastic bracket fits around one of the A/C lines. Remove the 19mm grommet and it will release the metal bracket underneath (green arrow). There is a hole on the strut that takes the place of this bracket, so you can throw the bracket away.

Remove both the plastic and metal brackets and clean the frame rail underneath.
Figure 11

Remove both the plastic and metal brackets and clean the frame rail underneath.

As with the passenger side, mark the two holes in the upper part of the strut, using the holes as a template (green arrows).
Figure 12

As with the passenger side, mark the two holes in the upper part of the strut, using the holes as a template (green arrows).

Mark the bottom holes in the strut on the frame rail.
Figure 13

Mark the bottom holes in the strut on the frame rail. (top hole not shown) You will notice that the holes on the bottom are elongated. This is to allow a bit of play when installing the strut (green arrows).

Drill the holes on the driver's side.
Figure 14

Drill the holes on the driver's side. Be sure to use either oil or cutting fluid. Clean the hole afterwards to remove any sharp burrs and to remove all metal filings.

Drill the holes in the bottom frame rail, taking care to not hit the A/C line port to the left of the top-most hole.
Figure 15

Drill the holes in the bottom frame rail, taking care to not hit the A/C line port to the left of the top-most hole. You can't really bend the line out of the way, so you may want to have a helper carefully hold it back while you drill the holes.

Show here is the nutsert setup so that it can be installed in the holes on the chassis.
Figure 16

Show here is the nutsert setup so that it can be installed in the holes on the chassis. The manufacturer of the nutsert specifies the use of an expensive tool in order to install it, however you can simply use an M6 x 40 bolt, two M6 washers and an M6 nut. Put some Loctite on the inside threads of the nutsert and thread the nut onto the bolt, followed by the two washers and then the nutsert.

Install the nutserts into the drilled holes.
Figure 17

Install the nutserts into the drilled holes. Here's where it gets a bit tricky. The idea is to keep the nutsert from turning when it is inside the hole. Hold the bolt at the top stationary with either a wrench or a socket as you turn the nut at the bottom (green arrow). It will take a bit of force to get the nutsert to collapse. Once you feel it start to go, tighten the nut down until it stops. Then loosen the nut and unscrew the bolt.

Shown here is a nutsert collapsed.
Figure 18

Shown here is a nutsert collapsed. The green arrows point to the gap that will form when you tighten the nut. This gap will grip around the edges of the hole and the knurled portion will keep the nutsert from turning.

Shown here are the nutserts installed in the front driver's frame rail.
Figure 19

Shown here are the nutserts installed in the front driver's frame rail. Do the same for the passenger side as well. It's a good idea to clean out any threadlocker that may have congealed on the inside of the threads with a pick or a paperclip.

Here are the nutserts installed in the upper strut tower.
Figure 20

Here are the nutserts installed in the upper strut tower. Install the nutserts in the passenger side strut tower at this time too.

On the drivers side front frame rail, thread in the 19mm rubber grommet.
Figure 21

On the drivers side front frame rail, thread in the 19mm rubber grommet.

Shown here from the other side is the plastic bracket that clips over the A/C line.
Figure 22

Shown here from the other side is the plastic bracket that clips over the A/C line. Clip it into place and secure it with the 10mm nut you removed earlier.

Now mount the driver's side strut into place.
Figure 23

Now mount the driver's side strut into place. (this is the strut with the extra hole on the side) Make sure that you route the wiring harness as shown by the green arrow. In needs to go under the strut. Now thread in the oval head Torx screws and tighten the strut down. At the same time, mount the passenger side strut, install the bolts and tighten them.

Now take the circular armed clip and pop it into the extra hole on the driver's side strut (green arrow).
Figure 24

Now take the circular armed clip and pop it into the extra hole on the driver's side strut (green arrow).

Reconnect the harness and pop the connector into the clip mounted on the strut.
Figure 25

Reconnect the harness and pop the connector into the clip mounted on the strut.

Shown here is the strut installed with the harness connector re-positioned into the extra hole.
Figure 26

Shown here is the strut installed with the harness connector re-positioned into the extra hole. Reinstall the wheelhouse liners.

On the passenger side strut, reconnect the ground strap from the frame rail to the engine mount.
Figure 27

On the passenger side strut, reconnect the ground strap from the frame rail to the engine mount. You will have to reposition the strap slightly to fit under the strut.

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Comments and Suggestions:
none Comments: Hi-
I've purchased and installed the convertible strut braces on the front of a 2004 Mini Cooper S hardtop and would like to do the same on the rear. Any tips for this installation process?
Thanks
October 9, 2014
  Followup from the Pelican Staff: We don't currently have that tech article. If we get a chance to perform the procedure, we will be sure to document it.

Did you get them from Pelican? You can call our parts specialists a call at 1-888-280-7799. They may have some documentation. - Nick at Pelican Parts
 
Brett Comments: 25ft/lbs for the OEM 6mm bolts is way to tight- One of the heads broke off! Tried to use an EZ Out removal tool but it broke off in the damaged bolt so now it's going to cost a lot of money & time to fix.
May 20, 2012
  Followup from the Pelican Staff: Thanks for the note, we have investigated and corrected the torque value in the article. - Wayne at Pelican Parts  

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Page last updated: Wed 5/24/2017 02:16:20 AM