This really is a simple job, not just on a Mustang but on most cars. The process should only take a couple of minutes to do with the correct tool. The basic principle is that the spindle from the wiper motor has vertical splines which are matched by the wiper arm. On the more modern cars the arms are also held in place with a screw, bolt or nut of some description. With the fastener removed the same process could be applied here. The very nature of the part it will usually be corroded to some degree and be difficult to remove. We recommend a squirt of Gibbs if this is the case.
For a Mustang the tool is simply a cut out reversed set of long-handled pliers. This tool is not very expensive, wont slip and protects your paint work. The underside has a been coated with a rubber for non-slip and to protect the paint.
Note: Always make sure that the wiper arms are in the correct resting or “park” position before removing and fitting new arms.
We have seen this being done with a screw driver in the past to devastating result. The screwdriver slips and goes across your paint job. Slip the pliers under the base of the wiper arm and squeeze the handles together.
The pliers force will force the wiper arm upwards leaving your other hand to catch the arm should it suddenly ping off and stop it damaging the paint work.
Here is a slightly corroded spindle and damaged splines.
Here is what is should look like before fitting a new one.
With the arm off clean the spline if you need to.
Align the arm where it needs to be fitted and simply press the new arms in place and it’s a job done. Simple as that.