Tech-tip: slow or seized/stopped wipers

[VAG Fan]

This concerns a Mk4 Golf, but I'm sure that other models could be affected as well.

The wipers recently started to move more and more slowly, and sometimes they would stop completely about halfway through their upward motion. I would then hear a thermal fuse click, and a few seconds later, when it was cooled down and re-connected the motor, the wiper would slowly continue. So obviously there was a lot of mechanical resistance somewhere, either in the motor or in the linkage.

So I proceeded as follows:
1) Make sure that the wipers are in their resting position.
2) Remove the arms (13 mm).
3) Carefully remove the plastic cowling (Google it, there are good how-to's on youtube).
4) Remove the wiper linkage with motor (3 x 10 mm).
5) On the linkage frame, mark the position of the drive lever that is connected to the motor.
6) Remove the motor (13 mm, 3 x 10 mm).
7) Connect the motor to the wiring loom and test its function.
8.) If the motor runs freely at both speeds and reliably stops in the rest position, the fault is with the linkage.
9) Inspect the ball joints and the spindles.

In my case, the right-hand spindle was seized solid inside the linkage housing. I couldn't move it by hand. I soaked it with rust-solve (Liqui Moly Schnellrostlöser), but to no avail.

10) If a spindle is frozen inside its bushings, carefully remove it as best possible, to remove the corrosion. First remove the circlip, washer and O-ring from the spindle, then try to "turn and pull". (I clamped the spindle lever in a vice and worked the linkage to-and-fro while pulling up on it, so that I gradually pulled the housing off the spindle.)
11) If a brass bushing stays frozen to the spindle and is pulled out of the linkage housing, clamp the spindle lever in a vice at a suitable height, soak the bushing with rust-solve, then remove it from the spindle using two large, sharp, flat-bladed screwdrivers to lever from opposite sides. Make sure not to lose any washers or O-rings.
12) Use fine sandpaper (I used 600 grit) to remove all corrosion from the case-hardened spindle and from the inside surfaces of the brass bushings. If a bushing came out, carefully press it back into the linkage housing. Brush the inside of the housing to remove as much corrosion as possible between the top and the bottom bushing.
13) Grease the spindle and reassemble. While you're busy, service and lube the other spindle too. The spindles should move freely. The ball joints should have some resistance on the nylon bushes.
14) Apply some grease around the top end of the spindle (but not on the conical spline!) before fitting the dust cap.
15) Add a bit of red rubber grease to any ball joint that was opened. Service all ball joints if desired. But these don't appear to fail.
16) Install the motor and fit the drive lever to the conical spline in the original position.
17) Check for correct operation and reinstall in the car.
18) While everything is open, clean the windshield and the groove that holds the plastic cowling. Clean the wiper compartment, change the pollen filter if desired.
19) Assemble and check positions of wiper arms.