I was going to take more measurements today, but for some reason the iBooster wouldn't turn on. I thought it had made some noises from being stressed, but it hadn't stopped working last time so not sure what happened between a few days ago and now. Luckily my minitruck is waiting for parts and has the exact same setup, so I stole the iBooster from that and that one fired up totally fine in the buggy. That was all the excuse I needed to tear the other one down. If you've watched the SuperFastMatt video of disassembling his, this is the same thing but I'll throw the pictures up.
All the fasteners are reverse torx or E-somethings, but a 5mm 6 point socket worked fine for me. The motor is its own subassembly and held on with six fasteners.
This is what shit itself on mine since I plugged the big connector into this motor while the small connector was in the body of the other one, and the motor didn't move or do anything. Which is good and bad, good because if that's what shits itself then in most cases you probably don't have to remove anything to swap the motor out. The downside is I can't find the motor as a stand alone part on eBay, though I haven't looked for the specific part number yet.
Opening up the body requires removal of the other fasteners, and then prying the two halves apart which are glued (more of sealed). The spring inside is compressed so the two halves try to fly apart a bit but the spring isn't very stout so not bad.
Along the lines of the questions of extending the output pushrod and if it's a 1:1 motion, the pushrod is actually not a single piece. The output shaft is a little stub held in place by the spring/master compression. It actually wouldn't be bad to extend it, but the booster would have to be taken apart.
The inside geartrain is pretty clever. The shaft coming from the pedal is a lead screw with a floating nut on it. When there is no assist the floating nut just moves with the lead screw. When assist is applied the nut is threaded down the lead screw and once it contacts the base it now stops floating and pushes against the base to push the lead screw forward and assist with braking.
Assisting (nut is all the way down):
And a mid point, no assist is happening. Spinning the white gear spins the black gear at the base which would spin the white splined floating nut but that nut isn't pushing against anything until it reaches the bottom like the top photo:
Moving back to the motor, it's not really meant to come apart. There is a two sided case which is bonded together, and it appears it could be pried apart if you push two locking tabs (top circles) and then drill out a bottom plastic pin:
I first sanded the lip on the housing, found the bond line, tried to cut that and didn't work, so took an angle grinder to the perimeter--which to be fair I don't think I actually fucked anything up, but reassembling it wouldn't be the prettiest result.
There are three poles coming off the motor, thus presumably it's a brushless motor but I haven't hooked up a controller to see if I can make it work to determine if the motor itself or the controller shit itself.
On the other side of the housing, the control board can be pried off. None of the connections between the housings are soldered to the board. There is a big heat sink on the one end.
The control board, I know nothing but here it is. Two contacts for two motor poles are at the top, and the third pole is part of the housing half in the above photo and you can see the pass through hole in the middle of the board.
Nothing looks messed up anywhere, so I'm confused why it shit itself. HOWEVER, I was not running a fuse and the pin out on the OP says to run a 40A fuse on the main power line. All I can figure is when I was pressing the brakes as hard as possible it drew too much current? But I would think it would shit itself instantly which I didn't notice the other day.
I actually became quite worried by this. The booster must have a max assist it can do, if you just absolutely hulk smash the pedal will the booster end up failing and/or the fuse blowing and you're screwed? Is there a mechanism where you can limit the power to the booster so it never draws more than 40A, but there's not a fuse that will blow in the event you hulk smash the pedal?
But I threw a fuse inline with the replacement booster, and I only had 30A fuses, and I pressed as hard as I could and besides making some noise like it was being stressed the fuse didn't blow and the booster was totally happy. I even extended the pedal another 1.0" and it was unphased with a 75% rated fuse.
So fuck if I know what happened or why. I'd still like to put a fail safe in that won't blow but just limit current in the event of an over current situation. I have a master kill switch so things shorting out aren't particularly a concern for me, but I most certainly don't want the brakes to randomly turn off. It looks like there's something called a current limiting diode which does exactly what I want.
