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Adjustable Rear Control Arm Installation
 
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Pelican Technical Article:

Adjustable Rear Control Arm Installation

Time:

1 hour1 hr

Tab:

$300

Talent:

**

Tools:

Alignment Rack

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:

Adjustable control arms

Hot Tip:

Have a professional perform the final alignment

Performance Gain:

Better handling and tracking of your suspension

Complementary Modification:

Replace shocks, wheel bearings, tie rod ends, ball joints, tires
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.

One of the problems that occur with installing a performance suspension on a MINI is the increased negative camber that appears after altering the suspension height. When you lower a car, the roll center of the suspension is altered and the wheel carrier will tuck in at the top edge. This is called negative camber. While this is a good thing in a racing setup, it causes some problems with a road car as it increases wear on the inside edges of the tires. The solution is to adjust the length of the bottom control arm to account for the negative camber.

Unfortunately, our MINI has a set of stamped steel control arms that are non-adjustable. (NOTE: It appears that later MINI models have lower control arms with an amount of adjustability built in.) The solution is to add a set of aftermarket control arms that allow you to re-set the camber on the rear wheels. In our case, we installed a set of Hotchkis adjustable control arms. Hotchkis is well known within the racing world for making quality products and the arms they make for the MINI are certainly no exception (See Figure 1).

To install the control arms, begin by jacking up the rear of the car and placing it on jack stands. Never rely on only a jack to hold the car up. Once up in the air, you will see the lower control arms connecting to the wheel carriers on either side of the car. Loosen and remove the 18mm bolt at the end of the arm nearest the wheel carrier (See Figure 2).

Follow the control arm up to the inboard bracket securing the arm to the subframe. On one side, you'll see an 18mm nut. There is also an 18mm bolt that runs through the bracket and control arm. The problem here is that you won't see the bolt head due to the tight space between the subframe and the fuel tank. I found that you can just get a 3/8" drive ratchet and 18mm socket in between to counterhold the bolt as you remove the nut. Likewise, you may need to bend the heat shielding up slightly to get a wrench over the nut on the opposite side (See Figure 3 and Figure 4).

Once the mounting hardware is removed, you should be able to pull the control arm out of the two brackets. Take care as it will likely pop out with some force. I found this out as the end of the control arm clocked me in the forehead pretty hard. Now take the old control arm and lay it down next to the new, adjustable one. You need to check that the bolt hole centers on both arms are the same. You are basically making the new control arms the same length as the old ones. This provides a baseline adjustment for when you take the car to the alignment shop.

On the new arm, loosen the two locknuts on each end of the blue anodized turnbuckle. Now turn the turnbuckle until the arm is approximately the same length as the old control arm. One thing I like to do is lay one bolt hole over the one on the old arm, slide a bolt in there to lock it in place, then adjust the arm until the other bolt hole lines up with the hole in the old arm. Once adjusted, tighten the locknuts (See Figure 5). Be sure to keep the zerk fittings on the arm ends on the same side.

Now take the small tube of bushing grease that came with the arm and lubricate each side of the bushing very well. This will help to slide the control arm up into the brackets on both the wheel carrier and the subframe. (See Figure 6).Take the longer end of the control arm and push it up into the inboard bracket on the subframe with the zerk fitting facing DOWN. It will take a little effort to get the control arm to pop in, but should go easily once started. Move the control arm around in the bracket until the bolt holes line up then push the 18mm bolt through, thread the 18mm nut on the end and torque it down it 100Nm (74ft/lbs.) (See Figure 7).

Now take the other end of the control arm and pop it into the bracket on the wheel carrier, again moving the control arm enough to line up the bolt holes. Once in place, slip the 18mm bolt in and torque it to 100Nm (74ft/lbs.) (See Figure 8).

At this point, you repeat the procedure for the other side of the car (See Figure 9). Now you are ready to take the car down to the alignment shop for the final adjustment.

Shown here is a set of adjustable rear control arms for the MINI Cooper S.
Figure 1

Shown here is a set of adjustable rear control arms for the MINI Cooper S. These trick pieces from Hotchkis Sport Suspension are a great way to correct the camber problems you run into when lowering your MINI.

Remove the 18mm bolt at the outboard bracket holding the control arm to the wheel carrier.
Figure 2

Remove the 18mm bolt at the outboard bracket holding the control arm to the wheel carrier.

Here's the hardest part of the whole job.
Figure 3

Here's the hardest part of the whole job. The inboard bracket that holds the control arm is in a very tight area when it comes to clearance. In this picture, you can see the 18mm nut that secures the control arm in place. On the other side is an 18mm bolt that isn't very visible (purple arrow).

You should have just enough room between the fuel tank and the rear subframe to slip an 18mm socket in and counterhold the bolt (purple arrow) while removing the 18mm nut on the outside (green arrow).
Figure 4

You should have just enough room between the fuel tank and the rear subframe to slip an 18mm socket in and counterhold the bolt (purple arrow) while removing the 18mm nut on the outside (green arrow). You may need to bend the heat shielding around the nut slightly to gain access. Once the nut is removed, push the bolt out of the control arm and the subframe. Now pull the old control arm out of both brackets.

Lay the old control arm next to the new adjustable one.
Figure 5

Lay the old control arm next to the new adjustable one. What you'll need to do is adjust the control arm to the same size as the old arm. Loosen the locknuts on the control arm (yellow arrows) and turn the center turnbuckle (blue arrow) until the bolt holes on either end of the new control arm (green arrows) are roughly the same as the bolt holes on the stock control arm (purple arrows). One helpful tip is to lay the new control arm on top of the old one and adjust until the holes line up. Once adjusted, tighten the lock nuts (yellow arrows). Setting up the arm this way provides you with a baseline to make the final camber adjustment once at the alignment shop. Also make sure that both zerk fittings are on the same edge.

Use the supplied tube of grease to lubricate both ends of the control arm as shown here.
Figure 6

Use the supplied tube of grease to lubricate both ends of the control arm as shown here. This will help to push the new control arm into the brackets on either side of the arm.

Now take the longer arm of the control arm, and push it up into the inboard bracket on the subframe.
Figure 7

Now take the longer arm of the control arm, and push it up into the inboard bracket on the subframe. Make sure that the zerk fitting on the arm is facing downward. You'll find that it will be a little tough to push the arm into place. Just keep at it and once fitted, move the arm around until the bolt holes line up on both the bracket and the arm. Push the 18mm bolt in, thread the nut on and torque them to 100Nm (74 ft/lbs.)

Now push the other end of the new control arm into the bracket on the wheel carrier.
Figure 8

Now push the other end of the new control arm into the bracket on the wheel carrier. You'll find that it's a little easier to get it in on this side as opposed to the inboard bracket. Once in place, move the tire to line up the hole in the bracket with the control arm and thread the bolt in. Torque the 18mm bolt to 100Nm (74 ft/lbs.).

Shown here is the final product with both rear control arms installed.
Figure 9

Shown here is the final product with both rear control arms installed. All that's left to do is take the car over to the alignment shop to have the camber adjusted as needed.

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Comments and Suggestions:
sarah.jayne Comments: I have a mini cooper s 53 plate she has been lowered and rear camber.my rear wheels need pumping up every few days is this due to the camber if so how do I remove it
February 7, 2015
  Followup from the Pelican Staff: No, probably due to tire leaks. Check if the tire beads are leaking from corrosion. - Nick at Pelican Parts  
roll1320 Comments: I am looking to help a friend that just purchased a 2003 R50. Due to unusual tire wear, the car went in for tires and an alignment. Short story is that the right front caster is too little by about one degree and the totalrear toe is ok but offset to one side the car will be crabing down the road slightly. So I am suspecting a bent front right control arm and a misplaced rotated rear subframe. Ideas?
August 31, 2013
  Followup from the Pelican Staff: As far as the front adjustment goes, the pins will have to be rmeoved from the front struts, then the adjustment can be made. As far as to why it is out, if it is slightly, could be due to worn components.

Rear toe is adjusted via the trailing arm mounting plates. This can also be due to work components. - Nick at Pelican Parts
 

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