A friend of mine was pulling something out of the back of my 2005 T4R through the back window and he broke a piece off of the rear wiper arm. I ordered a new OEM wiper arm to replace it. The nut holding the rear wiper arm was rusted pretty bad and was seized on there pretty good, so I shot it with some PB Blaster and let it soak for 2 days. When I went to remove the nut, it snapped right off with almost no force at all, taking the threaded portion of the actuator or shaft (or what ever that threaded part is actually called) that rotates the wiper off with it. Does anyone know if I can replace this threaded shaft or do I need to replace the entire rear wiper motor? Anyone have the part number(s) I need and what needs to be done to replace it?

If you need pictures, let me know and I can upload them.

Thanks in advance.

I'm thinking that's part of the motor. I had the same problem trying to get mine off. In the end I took a dremel with a cutoff wheel to the nut.

Unfortunately, what broke was the threaded end of the shaft that turns the wiper blade arm. I am pretty sure it is only available as part of the wiper motor assembly.

Yes. Part of motor.

I can confirm that as well. Need to replace the entire motor. Now, that nut has anti-seize on it and gets loosened/tightened once a year.

It is a shame that PB blaster doesn't work in real life like you would think that it does by internet claims. Sadly the stud is part of the shaft. If you were real creative and cheap, you could drill the shaft and tap the hole then switch to a bolt.

Thanks for your responses.

Sungod, I may try to drill and tap this shaft. After checking part cost for the motor, it seems a little overkill to spend $200 on something I very rarely even use.

The socket that fits over the wiper motor shaft has a tapered opening, to fit the tapered shaft. There are slight grooves on the shaft end to help lock the arm in place when tightened down. This connection requires a good bit of pressure to keep it locked in place. You can try drilling and tapping the shaft, but I suspect it will be difficult to exactly center drill and tap a hole large enough to accommodate a bolt big enough to apply the amount of pressure to keep the arm in place on the shaft. Not saying it won't work, but it could be difficult. If it doesn't work, you still have the option of replacing the motor with either a used or new one.

Well, I got lucky. I found a used rear wiper motor from a nearby auto junkyard ($65 shipped to my door). Will install it in the next few weeks and will let y'all know how it goes.

Thanks for your help.

I installed the new rear wiper motor last weekend. Replacing the rear wiper motor was rather simple, once I got past removing the existing motor.

The original rear wiper arm was also seized on the motor's drive shaft and impossible to remove, so I also could not remove the motor from the tailgate. I whacked it with a cold chisel, soaked it in PB Blaster and other penetrating oils, and used a torch (used aluminum foil as a shroud to keep the torch/heat from damaging my rear tailgate). Nothing worked. Finally, I used a hacksaw to just cut it off. That worked very quickly.

The most difficult part of the motor swap was removing the two wire harnesses from the existing motor. It was very hard to get hands/tools inside the tailgate to remove the wire harnesses. Once those were off, replacing it was pretty simple.

The nut that came on the replacement motor was rusted out pretty good, so I grabbed a new one with a washer from my local hardware store. Before installing the rear wiper arm and nut, I added a good amount of antiseize compound to the drive shaft and to the threads in an effort to make this the last time I have to replace the rear wiper motor.

It works great now.