How important is sector gear to plunger alignment?

Hi all,

I’m new here bit am having an issue. I’m trying to put my gearbox back together but each time I do the gears jam and the plunger gets stuck halfway back. My question was how important is it to align the sector gears first tooth with the 15th tooth of the plunger rail. I’m aware of AOE, I’m asking specifically about the importance of the first tooth of sector gear to 15th tooth of the plunger.

I haven’t paid much attention to it in the past as (in my head) it shouldn’t matter too much initially as it would just do a half cycle and then “reset” to a full stroke?

I think you have another problem. Everything goes around so will eventually align. But I just make sure the sector gears are at the back of the plunger so no teethe are connecting.

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I had a problem with 15 teeth in my gen 9 gearbox. I ground out the 15th tooth and fixed it. I have 14 in one, and 13 in the other two.

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Thanks, I thought it might be another issue, I have managed to reassemble the gearbox with a new understanding of shimming. The gears have a much more solid connection now so are not grinding, the gearbox just seems to lock up now, I can hear the motor kick in as soon as I hit the trigger but the gears dont budge.

That sounds like the motor wires could be back to front?

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I thought of that and reversed them, exact same result

What blaster is it and what things did you change ?

It’s a M4A1 Gen 8 gearbox, had a tech install metal gears, new plunger,o-ring. It was working before I took it apart (silly me) so the motor should have enough power. I’m thinking it has to be something simple I have messed up.

If you didn’t change anything maybe the piston is not sitting in the rails on both sides? Did you put all the shims back in the exact same place ?
Why did you pull it apart ?

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Shims are back as best as I could get them, the gears turn fine when I test them without the cylinder and plunger in so you may be right in the assessment that the plunger is the issue.

I had taken it apart as when it came back from the tech it was shooting terribly barely 10 meters) after taking it to one of the field owners they crono tested the blaster and came out at an average of 79fps. They suggested it was a major air leak and after pulling the gearbox apart I found 2 things. 1. the nozel o-rings (off the smaller part that connects to the t-piece) were heavily damaged and 2. The t-piece was coming apart at it’s mould join (about a 1 mm gap all the way around except for a couple of points holding it together)

Lol good old techs !
Welcome to the world of gel blaster rip off merchants !
The reason I joined this forum was to help stop some of the complete rubbish misinformation in the industry :zipper_mouth_face:


Glad to meet you then!

I’ll pull the gearbox apart again tonight and check that plunger alignment, hopefully it’s an easy fix now.

It’s very difficult diagnosing issues like this on a forum and I would advise you to see if you can find someone local at a club or similar to help you out.
Hopefully it can be sorted quickly and you can get back to playing with your toy :+1:

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check your plunger guides, i bought a SHS for my gen 9 and the rails on the plunger were too tight causing the gearbox to jam. I had to file the rails on the plunger - widening them up. to check it try with the case in half and grab your stock piston and check it verse the new one it should glide without any effort.

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I’m with you @Rattler, tech of what, friggin toys lol.

I love the shop techs at games bragging about this and that and mine does this but I’ve dropped it down to this. Piss off there toys ffs, anyone with any sort of tinkering experience can be a “tech”

Anywayz I’m a gearbox black belt, 5th Dan, current UFC Gel Blaster champ, former navy seal and sas gel blaster inspector and also sometimes a decent guy…but not a “tech”


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I actually noticed this last night @Macgyver and some small blurring on the rail guides, I cleaned them up and threw the plunger back in but didn’t pay too much attention to it, I’ll give it another try tonight.

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Strange I had the same problem, but I noticed once I took off the really small o ring on the plunger allowed my plunger to reset back in the cylinder each time I fired… But do not know how much pressure I lose now.

Did you replace the o ring on the nozzle?

Just replacing the whole nozel, exact same part just new