09-20-2010, 07:36 PM
Drives: e92 M3
Join Date: Apr 2010
Location: Schaumburg, IL
VS Motorsports Chicago Area Sub Frame Reinforcement
Below we are going to show the process that we go through to fix the cracked sub frames. Also, this is for some that are looking for the preventive maintenance or peace of mind if they are not cracked. Normal time for this kind of work to be performed is 1-2 days.
We first start out looking for the cracks usually in the front right passenger mount or rear driver side mount. Most cracks are located here because the way the torque is distributed through the drive train. With just using a flash light and knowing to look in the right places most cracks can been seen with the naked eye. For the harder to reach places the camera below with a snake light is very helpful. Not only can it reach places you can not see but we also use it to take pictures to show proof of a cracked subframe to a customer or for them to show a dealership.
The next step is to start dropping the subframe by supporting with a jack, disconnecting under paneling, parking brake lines, shocks, brakes, and the sub frame bolts. Each car will then be prepped for the turner reinforcement kit.
Once the sub frame is down and underbody is exposed we are able to see all cracks underneath the car. The undercoating is stripped off to expose the bare metal.
Each crack is then welded closed to stop any additional damage. The welds are then ground even to the body to make sure the Metal plates are flush when welded on.
Now that the plates are welded on all the bare metal is primer and painted
The last steps of the process is then to clean out the trunk to get to the top of the rear subframe mounts. Here the top of the sheet metal is cut out where the three spot weld marks are. This is done so we can rosetta weld the mounts since it will be stronger than the spot welds.
This a picture of where the top of the trunk is cut open to reach the mounts
Here is where the three welds are cut out to make a stronger rosetta weld
The Rosetta weld
The last step is to cover up the trunk holes and primer & paint just like the underbody.
Once all the paint is dry everything is put back together and it is ready to go. We have decided to make this a winter special starting in November to March 1st. That way this will help out people looking to do this later in winter. For pricing on this please feel free to PM, call,email, or stop by.