Reader assistance - wiper motor

Well, here is the update on the windshield wiper situation, and it is not good. To make a long story short, we need either an entire motor assembly, or at least the gear housing and the ring gear, and finding either of those is going to be a challenge, which is why I am posting here for help. Read on to find out exactly what we need. If you've arrived directly at this post, for example by following a link from my frantic plea on one of the bus boards, you may want to read yesterday's post for the background on how this came about, along with a photo of the wiper motor installation from when the dashboard was out of the bus.

Let me start by saying that, despite many apprehensions about drilling a giant hole in the front of the bus, this turned out to be exactly the right thing to do. I was very focused on the job at hand, and did not take time to photograph the process until well after the motor was out, but here is what the front of the bus looks like, minus the fiberglass trim that extends from just above the 'roo bars to above the wipers:



We've cleaned the area around the hole with alcohol in preparation for taping it over temporarily to keep the elements out; the fiberglass trim will keep it out of direct wind pressure while driving. I drilled a small test hole first, then used a wire probe to determine I needed to go up half an inch to clear the lower steel tube, and left half an inch to get the spindle mostly centered in the hole. My second test hole was spot-on, and I followed up with the three inch hole saw. The resulting hole got me clear access to the spindle pinch bolt as well as the three mounting bolts for the motor assembly:



You can just see the passenger-side actuator arm across the hole, and the pinch clamp at the very top. Along the bottom next to the square steel tube is a piece of armored electrical cable for one of the 120-vac outlets in the cockpit.

Once I had a 3" hole, I could watch what was happening as the motor ran -- we could get the wipers to do a single pass if we lifted them slightly first. That showed me that the spindle was moving laterally quite a bit, rather than just rotating -- not good.

Removing the whole motor revealed that the cast metal gear box housing -- really just pot metal -- was cracked almost all the way through at the cast-in gussets. This sort of pot-metal casting generally can not be repaired; any attempt to weld it would just end up destroying it. Here is a photo of the motor assembly; the shiny light gray material you can see on the cast housing that looks like plastic is actually J-B Weld -- I am hoping I can squeeze another few dozen swipes out of the thing this way:



I'm sorry the flash reflection obliterated the snazzy Mercedes logo immediately to the left of the part number on the silver sticker. Conspicuously absent from this photo is the spindle itself; that's because, having nothing further to lose, I disassembled the gear box and removed the spindle and ring gear assembly. You can see the extensive cracking of the housing from inside; I've tried to highlight just outside of the cracks in red to show where they are:



The three-pointed "star" shape is the result of the cracks traveling around the outside of the cast gussetts in the housing, visible in the previous photo. (As always, click any photo to enlarge.) Harder to see in that photo, after my hack-job with the J-B Weld, is that the gussets themselves are also cracked all the way through, adjacent to the spindle sleeve.

Once the housing was cracked far enough, it was only a matter of time before the steel worm gear on the left in the above photo started slipping against the plastic ring gear, and the gear started to strip at the point of maximum stress, which is at the "parked" position. If you look closely, you can see the worn-down teeth at the very top of the gear in this photo:



I am hoping that once the J-B Weld sets, the housing will stay together enough for me to tighten the gear down far enough (there is a pressure set-screw on the backing plate) that the worm gear will no longer slip against those worn teeth. It won't last long -- those teeth are just nubs now.

So what I need now is either a whole motor assembly, as shown in the third photo above, or the cast housing plus the ring gear. My Neoplan parts manual shows an exploded diagram of the assembly, with separate numbers for the gear/spindle as well as the housing, although I can't quite make those numbers out (nor would they really be useful -- they are Neoplan-specific). Getting just the housing and ring gear would be ideal, as there is nothing at all wrong with the motor itself.

I suspect, though, that I will have to buy a whole assembly. Despite the Mercedes logo and part numbers, the motor assembly is actually made by "SWF," who makes wiper systems for most of the major European brands. This exact motor assembly goes by several part numbers:

• DB 0018243001
• DB 0018241501
• 0018243001 SWF
• 0018241501 SWF
• 0018243001
  
• 0018241501
• SWF 401.729
• SWF 402.308
• SWMV 401.729
• SWMV 402.308

In addition to being used extensively by Neoplan in many coaches of my era, including the Spaceliner, Cityliner, Jetliner, and Skyliner, this was also the stock wiper motor on the Mercedes o-303 coach, common in Europe.

So here is my plea: if anyone reading this has a source for either the motor assembly or the parts, contact me as soon as possible. The Neoplan parts distributor here in the U.S. can no longer source this, and if they could, it would be close to $600. We've seen at least one European firm selling them aftermarket, but they do not seem to ship to the U.S.

In a perfect world, I would find one of these used, with perhaps a blown motor, from which I could at least salvage the requisite parts.

Tomorrow we will return to our regular programming, wherein I will post an update on our position and travel status, which now involves moving only when it is not raining.