Miata – Removing the Uni-body from the PPF

So you want to remove the Miata Uni-body from the PPF?  Its easier than you think.  There is basically 14 bolts below the car and 8 bolts on top.  But before you run out to the garage to destroy your Miata there are a few things you should know.

First, there is a whole lot of other bits and pieces that need to be removed before you pull the body off.  See the previous posts on this blog to get you to the point of loosening these last 22 bolts.

Second, when you do separate the uni-body from the PPF the suspension is no longer going to be able to support the weight of the PPF.  To solve this you can cut your self four 2×4 to wedge between the lower a-arms and the uni-body mounting points.  I used 8-1/2″ 2×4’s up front and 6-1/2″ ones in the back.  You could probably use 4 at 8-1/2″ long.  If you skip this step the PPF will drop down on you when you unscrew the bolts, CAUTION! Here are a couple of pics of these chalks in action.

Rear chock.

Front chock.

Third, if you do not have a spring compression tool at your disposal you should probably back off the nut on top of the shock before separating the body from the PPF.  The body makes for a handy spring compression tool.  I did not do this and I only mention it as others recommend it.  For the 35$ it takes to buy a half decent spring compressor with safety pins it worth it.  Springs take fingers so a word of warning.

Careful with these, springs under load.

Fourth, when you cut the fuel hose at the fuel filter to drain the fuel from the fuel rail (and that is where you want to do it) the fuel will siphon out of the tank.  A half inch bolt makes a great stopper.  If you can though, get as close to an empty tank as you can before starting this job.

Finally, do as much as you can before you lift the body off.  I know you are excited to pull the body but trust me it is easier to remove the brake lines, fuel lines, gas tank, and all the other bits an pieces before the separation.  Trying to working on a swinging body hanging from an engine hoist is not fun or safe.

Now on to the main show.  Below are a couple of photos where I have highlight the bolts holding the uni-body to the PPF.  I have elected to unbolt the fuel tank from the PPF prior to removing the uni-body.  The fuel tank will rest on the PPF and keep me from having to work under a hanging uni-body.  The fuel tank is held up by four bolts and there is a hook welded to the uni-body that hold the back of the tank up for assembly in the factory.  For this I used the cheater bar and a 4# sledge to bank it out of the way so that it does not hand up the tank.

The eight bolts holding the front to the PPF.

The rear six plus the fuel tank’s 4.

Despite the rust under the car most of the bolts came loose with the cordless impact wrench.  Two more came loose with a long cheater bar.  And the hardest of them all took heat and the cheater bar.  I count us lucky.  I was expecting to have to cut a few loose.

With all these bolts loose and all the wiring and tubing removed the body should be able to rock back and forth left and right on the springs.  If you can do that you should be caught up to where I am at.  Tonight I will be lifting the body off the PPF; lets see if I have to correct this post!