John’s Mk4 Build Thread

[John Ibele]

Next up was the wipers, and I spent a lot of time tweaking these. You can find a number of threads where people have made these work well, many of which leave the details out. So I'll tell you what I did. For me, this was somewhat like the e-brake: not ideal, but with some blueprinting or more significant modifications, can be made to work decently well.

Here's what one looks like when it's been sitting around in a garage for 10 years.


Untitled by John Ibele, on Flickr

Shockingly (or maybe not), I'm not cleaning them up. Most importantly, notice that the cable isn't forced to engage with the gear by the housing. I bent the center curved piece of the housing to keep the cable against the gears, with a small allowance for clearance, figuring that if there was any binding when I tightened things up, it was the tubing alignment that needed to be adjusted, not the center piece of the housing. After doing that, it looked like this:


Untitled by John Ibele, on Flickr

That's a good start, but there was a lot of additional bending, filing, creative language ... used to get the tubing in line with cable when positioned this way. One tip, make sure that when your tubing flares are done, there is no way the cable can touch any part of the flared part of the tube: just shouldn't happen. Take any offending material off with a small round file or your favorite Dremel attachment.

When all done, the finished housing looked like this:


Untitled by John Ibele, on Flickr

I ditched the brass 8-32 screws that came with the wipers and tapped for some 10-32 button head hex screws. Same pitch, larger diameter should give me more engagement surface area. There aren't many threads there but I trust myself not to over-torque. When properly tweaked the setup doesn't bind, and there's no way the cable can pull away from the gear teeth.

One more mod: when you tighten the gear housings onto the car, the threads really want to pull the housing into a 90* entrance / exit with respect to the body, and you don't want that. Anything you can do maintain the angle defined by the drilling jig is worth it. Here's a Paul (edwardb) tip that works well - go to Ace and get some of the square aluminum channel that fits nicely over the housing. Use the drilling jig or a bevel gauge to mark the angle on the channel, and cut it at that angle. You get something that looks like this:


Untitled by John Ibele, on Flickr

I epoxied mine in place after dry fitting everything. No need to have anything moving that shouldn't be moving. Anything you can do to keep these housings at the right angle w.r.t. the body and not moving is worth it.

In addition, I cut out some 1/16" neoprene rubber to go over the square channel, so that the channel doesn't rest directly on the bottom side of the body.


Untitled by John Ibele, on Flickr

The end result is a system that doesn't make a machine-gun noise when I turn it on, works without any binding, but also can't be stalled out with any amount of finger pressure on the rotating studs coming up from the gear housing. Once I had gotten that far, I stuck on the wipers and ran it dry, and got the same satisfying smooth action. These are as bullet-proof as I can get with what I have on hand, and I can't think of what could make them better (other than getting packed with grease, which I'll do before the last install), so I'm calling it good, and moving on.