Rear Windshield Wiper Problems

Hello all,

I'm new here so please be patient. I have a 2001 Windstar and the rear wiper is acting up. It still works in the intermittant, slow, and fast settings, and the fluid still pumps. The problem is that the wiper rotates 360°! I have tried positioning it to the "correct" setting (rotating on the glass instead of the license plate) but that did not solve the problem. It is almost as if there is a "pin or screw" missing that holds the wiper in the proper postion for the proper limits of the wiper stroke. Any help would be appreciated.

Thanks.

Matt

I have a 2001 and have rear wiper problems too. My problem is it travels part way, waits and then finishes the stroke, stops and then travels back part way, stops and then finishes the stroke....After a few weeks of this, the motor stopped working. In trying to fix this, I have had the switch stick on the column off and after finding nothing there I took the entire windsheild wiper motor and gearbox assembly out of the van and all apart.

It is easy to get at, so I suggest you take a look inside to see if there is a problem with the gearbox since this is what causes the wiper to move in the proper pattern (back and forth). If your problem is that it travels around in a circle instead of changing direction, the problem is likely in the linkages in the gearbox... I have not posted a procedure, but here is a simple explanation and if you need help, I can walk you through it in more detail.

1) remove the windsheild wiper from the exterior of the van by lifting the cap at the base and removing the bolt on the shaft
2) open the door and remove the handle and the plastic door panel on the inside of the van
3) locate the gear box and motor assembly
4) remove the three bolts that hold the assembly to the door
5) un-clip the wire harness and remove the assembly from the door
6) remove the screws for the gearbox cover (do not open the motor - 2 screws from the gearbox assembly to motor housing)
7) look for a problem with the gearbox teeth or linkages; i.e. something broken or stuck, stripped teeth, problems with the linkages???

The motor shaft has a worm gear cut in the end of it that drives the bull gear which cause the linkage (which is attached to the perimeter of the bull gear) to move around the perimeter of the bull gear as the motor worm gear turns when power is applied to it. The motor only turns in one direction. The windsheild wiper shaft is attached to the linkage system which causes the wiper to move back and forth as the gears turn. The oscillation of the linkages cause the wiper shaft to switch directions.

In my case, I went one step further and opened the motor up too. Careful with this step because the motor brushes can get damaged and unlikely you can replace them so be gentle. The brushes are spring loaded and push on the motor shaft in the commutator area (copper shaft area inside motor housing). The stator (motor housing - magnet on the outside of coil which is wraped onto the shaft) when moved axially (along the shaft direction) away from the gears will drag the motor shaft (stator) out of the gearbox assembly which is where the brushes are mounted. I then pulled the shaft out of the motor housing. I had to clean the brush housings so that the bushes would freely move so they would better contact with the communtator when the motor is running as they were plugged up with carbon and stuck in one position so that communtator contact was poor. I also cleaned out the grooves in the commutator area (plugged with carbon from the brushes) with an exacto knife, but be careful because the copper is soft and you don't want to damage it. I also took some fine sandpaper (240 grit or higher) and gently sanded the copper area so that it was clean again and all the black carbon is removed. When sanding, hold the sandpaper and turn the shaft so that the sanding is done in the same direction as the brushes will rub otherwise you could groove the commutator perpedicular to the path which will cause the brushes to wear out quickly! With another cleaning of the commutator grooves after sanding you can then reassemble the motor. You need three hands to assemble it easily, but I did it myself. You gently push the brushes back (they are spring loaded) and then get the shaft in so the communtator area is centred on the brushes and the worm gear is mating with the bull gear. I then used a small screw driver to hold the worm gear in place firmly before moving the motor housing near the motor shaft because it is a magnet and will pull the shaft back out of the brushes as you try to put the housing back on (I found out the hard way!).

This got the motor turning again, but be warned, this will cause your gears to be out sync with the wiper and you have play with it a bit to get the stroke back in the corrrect position (found this out the hard way too!). I just moved the wiper on the shaft and tightened it down in the correct position instead of playing with the gears.

One thing I also did was I left the gearbox cover off with the assmbly not mounted to the van door (just hanging from the wire harness) and turned on the van power and intermittent to watch the gears and linkages move so I could see if there was problem, but I found nothing wrong. Be careful not to run the intermittent for too long without the van running or you will find out what I found out too (battery dies!).

The long and short is that now my motor works, but the wiper stoke is still not travelling the entire way without stopping. I think it is whatever applies the voltage to the motor is not applying it for long enough for the motor to do a complete stroke.

Thanks for the information, Andrew. I appreciate it and will tear into it as soon as I can. It may be a while but I'll post my findings once I determine the problem / solution. Thanks again.

Matt

I was able to correct the problem with the "loose wiper". I had to tinker a bit with it but by turning the wiper on/off (it helps if someone can assist with this), and relocating the wiper to its home position (roughly dead level and to the passenger side) it appears to be working properly. That was about a week ago and all seems well so far.

I did go through the exercise of removing the interior panel on the back liftgate (2 screws at the handle and 1 on either side - then just gently pull down on the panel - standard tinnerman type clips). Everything looked clean and in good shape. I did notice a bit of rust on the bottom of the gate starting to form. I'll wait until spring and clean that up - don't want the liftgate rusting out on me.

Thanks for the help from others.

Matt