The Weekly Adventures of Mikuvan: Operation I-Fixed-Too-Many-Things-At-Once-To-Give-It-All-One-Smarmy-Name
As you can see, I’ve already given up on my promise from last time. Or perhaps I didn’t?
When last week wrapped up, I had just finished replacing my front right wheel bearings. On the immediate agenda was repairing the front blower motor, which seems to have gone dead long ago, and I was getting pretty desperate because this past weekend was an early heat wave in the area with temperatures in the low 90s°F. I had already verified that the (resistor based ;___; ) speed regulation circuit was fine with exception of the lowest speed, and that the motor did not respond to direct 12v input.
Like Fanvan. Do you remember Fanvan?
In the Official Derpy Van Strategy Guide, the heater unit had its own dedicated disassembly page:
As you could imagine, it was not very helpful. The gist of it was basically
1. Disassemble everything.
2. No, we mean it. Everything.
The entire dashboard structure had to come out. Not to mention, even, that the step page before this was to disassemble the heater control unit linkages (the things which deflect air to select heat or A/C, floor or … face? vents, etc.)
In my usual style, I suspected something was amiss and that there must be an easier way. Basically what the past few weeks of pretend-automotive-tech has taught me is that everything in a vehicle may have an ‘official” repair procedure, but Raúl and Jimmy at the shop up the block most likely have figured out a way to do it quickly. My plan was to be Raúl as often as possible.
For me, the possible quick route was an in-situ replacement of the fan motor’s brushes.
The motor, for the record, is the little silver can with the round nub near the lower center of the image. Keep in mind all this is well hidden under the lower dashboard. What you’re seeing is me aiming the camera up from the footwell, with the lens under the brake pedal and the flash unit above the brake pedal. The metal rail that dips down in the foreground is the throttle pedal.
After staring for a while, I determined through empirical trials that I could reach my arm under both pedals and up to the motor, leaving just enough space to wiggle a stub Phillips head screwdriver to undo the rear brush cap screws. To get into this position, I would have to extend horizontally out from the driver’s side footwell, facing the base of the driver’s seat. In other words, totally away from the repair point, and the entire repair is to be done by feel. I wish there were pictures of this whole process as it was happening, because it was truly one heroic position.
So why on earth did I think I could just pull the brushes? Typically, in a robot motor, you don’t replace the brushes at all – if they’re gone, that’s it, and the motor is done. More expensive and larger robot motors make it such that you can just remove the brushes by themselves, one by one. Being derived from industrial motors, that’s how the typical robot motor is put together, and it’s what I’m used to.
However, automotive motors tend to be a little modular if they’re not designed to be disposable. I obtained this replacement blower motor online, and was curious as to the internal construction, so I popped it open. Two screws later, the entire brush plate was dangling from the motor commutator for dear life. It turns out I could replace the brush plate as one assembly. A little more research showed me that this is incredibly common for major automotive accessory motors – starters, for instance. Most little motors like power windows seem to be disposable.
Discovering this was basically what led me to think that in-situ repairing the motor was a good idea. Typically, the brushes will go first in a DC motor if it is otherwise mechanically sound and well-lubricated. Being that these automotive motors are basically made of
reinforced concrete and solid cast iron stamped steel everywhere with big sintered iron-bronze bushings that last forever, I was betting hard that the brushes had simply disappeared and the rest of the motor was sound.
Here’s the brush assembly removed. Now, if I had just pulled the plate out without thinking much, the brushes and springs would have escaped and scattered very quickly. Drawing from past experience disassembling robot motors such as the venerable EV Warrior, I prepared a Round Thing of Brush Retaining and slid the brushes onto it. The round thing was just some random rubber bump stop discovered in MITERS, besides which I was conveniently yet illegally parked.
When I Assumed the Position and removed the two brush plate screws, this is what fell out at me.
Hey! I didn’t know they made these vans with brushless fan motors! That’s pretty cool, and is just a testament to the legendary reliability engineering that the Japanese put into thei…
I digress. What you see is a small pile of
chocolate-flavored cocaine carbon brush fluff where brushes should be. This stuff must have been micro-scale fine. When I blew on this pile, which was caked to the inside of the steel back plate, it generated a cloud of dust completely disproportionate to its original size.
So this confirms the hypothesis that the motor brushes were just toasted.
The harder part was getting the new brush cap back on. I basically only had one shot to do this, and any misalignment or dropping would result in the brushes and springs disappearing forever into the dark crevasses of the dashboard. To facilitate this, I made a doubly-aligning Round Thing of Brush Retaining from a spare bronze bushing. The ID of the bushing was bored out to just over that of the silver sleeve behind the commutator (measured on the spare motor and then increased just a little for margin). That way, if I can get the thing roughly aligned at all, the sleeve will help with placement. The OD was just barely larger than the commutator, which was good: as soon as I push the brush caps off, they should land on the commutator.
And here was what I was dealing with, getting that brush plate rig back onto the little copper nub there. I was concerned enough about this process to actually simulate it on the spare motor with it sitting around a corner (out of sight) and me wiggling the brush plate through feel alone. I wanted to make sure I knew exactly what the features on the motor back felt like. I “dry ran” once or twice with the old, used brush plate to make sure I could snap the board’s mounting bushings (little rubber blocks) in place.
And after a heartstopping OH MY GOD THE BUSHING IS FALLING OUT moment, the new brush plate is in. Notice the blue things sticking out of the motor now.
Now, I have no victory pictures or videos of this repair, because it’s a fan for crying out loud and the only thing in the video would be a whooshing sound. But it worked! I ran the fan for a little while on low (2nd) speed to seat the new brushes.
I did have a new resistor block, but that one was located too far down to even get a screwdriver into. I tried for 15 minutes with putting bits on universal ratchet joints to no avail. Whatever, I’ll live without the lowest (generally not very useful) fan setting.
After this repair warranted a victory lap to Advance Auto Parts for even more brake cleaner, I came back and took apart the left front wheel to check on the bearings and clean everything up.
This time, I didn’t replace them. The rollers and races did not appear to have any wear or damage, so I just re-stuffed it with grease and torqued it back to spec. I know you’re supposed to symmetrically replace bearings, but I was not in the mood to pound on the races one more time. Again, we’re assuming I don’t grenade everything within 10,000 miles (I’m currently up to 230.)
So what’s next on the list? The next day was a little less intensively hot and I initially brought Mikuvan out to get the Massachusetts state inspection done, but it turns out they really want you to have a front license plate. I was issued two plates, but it was never made with a front license plate holder; and no, stuffing it on the dashboard apparently didn’t count. I was turned down by 3 area shops that I drove around to.
Whatever. I’ll rig up a fix later. For now, let’s rewire the radio.
This post brought to you by K2 Energy. That’s the brick I dissected powering an AC inverter which is running a small soldering iron. Inefficient conversion of power, yes, but I neglected to pick up a cordless iron or butane powered crack torch iron so it’ll have to do.
The van came with a cheap but reasonable modern head unit with CD, aux jack, USB power, and SD card slot, but it was wired incorrectly. I could only get the thing to turn on if I had the ignition in the ON position *and* the headlight switch flipped to accessory/daytime lights. Yes, both. This made no sense whatesoever.
But after reading the electrical manual which is far more helpful, I found that the main power was wired to the dashboard gauge lights (hence requiring the headlight switch to be engaged to accessory) and the backup power was wired to to the ignition switch! That would explain why it never remembered stations or equalizer settings when the key was out.
A quick rewire later and I was in business. The sound system on this thing is truly a product of the 1980s. No highs, no lows, and not even Bose at that. There’s no subwoofer by modern standards – the sub is a small, roughly cookie tin shaped box affixed to the front console’s underside. There are no door speakers, probably because the doors aren’t thick enough to put any in. I’m fairly certain my old $25 computer speakers had better clarity.
Alright, with the sound system now playing a horrifyingly hollow rendition of Vocaloid Dubstep playlist, it’s time to start moving towards the rear. Next on my impromptu list was to repair the center row seats.
For the uninitiated, the center row seats in the 80s Japanese Van Squad could all spin around in a circle, but only the Mitsubishi Van had them on a set of beefy drawer slides so they could also be shifted front and back. Basically, my two seats combined have more degrees of freedom than a Segway. You pull a latch and it unlocks the mechanism (a big steel locking crossbar mounted on a spring which catches in slots in the slides) and move until the mechanism snaps back into another slot elsewhere.
The trouble with mine was that they were stuck in eternal drawer slide mode. The mechanism was jammed or broken, so for the past few weeks I’ve actually been stuffing toolboxes and milk crates of parts in between the seats to hold them in place. Friends going on van adventures were told to brace themselves or be sectioned neatly by the seat belts.
I don’t have any pictures of the mechanism or the underside of the seat. Why? Because as soon as I undid the 4 bolts and started lifting the seat, the mechanism popped back into place.
Well how about that. I decided to not press further and dissect it – instead, I slathered the whole thing with spray-on lithium grease and also thoroughly greased the track. It has yet to be a problem again. I surmise that someone pulled the worn mechanism too hard and caused the locking bar to pop out of its guides, becoming stuck in the loose position.
I confirmed this suspicion by tugging really hard on the handle and trying to move the seat – at least once, I was able to stick the mechanism. But with the path now greased, a hard slam into one travel stop put the locking bar back in its place. Should have tried that to begin with…
I performed the same jiggle dance to the drivers side center seat.
The seats can lock rotationally in only two positions – full front facing or full back. The mechanism is just a pin-in-a-plate kind of detent stop, so I have half a mind to waterjet a new one that has like 15 degree increment clicks or something, for maximum hilarity.
license to print
All this being said and done, I was still out a front license plate holder. The cheap and hacky way would have been to just drill some holes in the bumper and screw it on. When I was at one of the local garages, I saw someone with this and it was perfectly legitimate.
But surely there’s a better way to do this than machining my exterior. There’s two hidden bolts in the grill-like slit on Mikuvan’s from bumper which I decided to take advantage of.
I don’t know about this solution being “better” so much as “lol a 3d printer” when a bent piece of aluminum would have sufficed, but I whipped up this solid ABS license plate bracket holder in a few minutes and set it running on the Lab Replicator™. The post coming out from the front is a designed-in support structure to hold up the ceiling of the counterbored hole which the bumper bolt will reside. The hole around it is large enough to slip a 1/4″-drive deep ratchet into.
The finished bracket adapter with the artificial support post removed with some wiggling.
Nobody will ever know that it wasn’t OEM!
Now that it’s CERTIFIED LEGIT (until June 2014, anyhow), I’m slowly running out of problems to solve. It just means that soon, I’ll have no choice but to tackle…