Pinion Stuck...What do?

Bolshevikjoe

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Soooo, after realizing my Team Corally Python XP 6s had a ridiculously huge pinion on it and wanting to go to something a little closer to the stock flavor, I proceeded with taking the motor out of its mount and had my handy dandy Pinion puller and heat gun ready to go. Everything was going swimmingly until realizing this pinion was so large that you can't extricate the screws from the motor mounting plate because they jam into the pinion. Gotta love 2nd hand rigs. Well, I finally manage to get that screw out and of course because the pinion is ridiculously large even without the screws, the mounting plate wiggles around between the motor and pinion but cannot come free to give the pinon puller a clear shot at mounting on properly. No bother, let's go ahead and remove the set screw.

Hit the set crew with the heat gun and it breaks loose with a little bit of persuasion but it's not backing out. Cool. It's stripped. Or is it? Grabbed my drill with my hex tip and try to back out the set screw. Sure enough, it's not coming out. Alright, no big loss. Don't really think I'm going to need a 21t pinion as I'm not tryna do any Raz Shifrin s*** here and value my eyebrows. So now we're stuck with no way to get good leverage on this thing. Pinion puller can't mount up due to the motor mounting plate. So far I've broken three screw drivers and my pinion puller trying to get it off anyway. What's the next step? I do have a rotary tool and am considering just cutting the gear in half. Am I overlooking a better solution?
 

Diem Turner

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If you have one yourself or have access to a drill press, clamp the pinion gear in a vise and drill the grub screw out with a 3mm HSS drill bit and a little coolant/cutting fluid. Worked for me and should be easier than cutting a pinion gear in half.
 

Camaroboy383

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Does the motor output shaft have a flat all the way off the end of the shaft? Or a step at the end?..

If it's fully cut you can grab the pinion in a vice, grab a punch and drive the shaft out... but I would just slice it and pop it like you said.. definitely less fumbles.. lol
 

gotnitro

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If you have one yourself or have access to a drill press, clamp the pinion gear in a vise and drill the grub screw out with a 3mm HSS drill bit and a little coolant/cutting fluid. Worked for me and should be easier than cutting a pinion gear in half.
Or the on-the-fly method, grab a vise grip and a hand drill.

OP- Hand drill or a drill press, keep checking the progress. You don't want to accidentally drill into the shaft.
 

Diem Turner

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Or the on-the-fly method, grab a vise grip and a hand drill.

OP- Hand drill or a drill press, keep checking the progress. You don't want to accidentally drill into the shaft.
That can work, I just find keeping the bit on target much easier with the drill press. Same goes for applying a nice constant pressure. But perhaps it's just my drilling skills that aren't up to snuff. That's what she said...
 

gotnitro

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That can work, I just find keeping the bit on target much easier with the drill press. Same goes for applying a nice constant pressure. But perhaps it's just my drilling skills that aren't up to snuff. That's what she said...

I've done it so many times trackside that its normal to me lol.

Best part, most of the time when you get very close to the shaft, a small piece with like 2-3 threads left will back out in reverse using the same bit. The key, staying away from the threads in the pinion. If you don't nick any, you have a useable pinion still (y)
 

Diem Turner

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I've done it so many times trackside that its normal to me lol.

Best part, most of the time when you get very close to the shaft, a small piece with like 2-3 threads left will back out in reverse using the same bit. The key, staying away from the threads in the pinion. If you don't nick any, you have a useable pinion still (y)
Yeah, I've always been able to save the gear so far. If you happen to have a set, left hand drill bits are perfect for situations like these. You have excellent chances of just backing it out once the drill bit bites into the grub.
 

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I would try a left hand drill bit to drill out the set screw. The heat from drilling may cause it to back out and avoid having to drill all the way. This has worked for me a many strip bolts - RC and on 1:1 car.
 
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