# Roll Pin Problem On Differential Lock Out



## Stang (Mar 28, 2015)

Can anyone share advice regarding the small 3/32" roll pin that holds the differential lockout knob to the hub on the common Ariens differential assemblies? Pictures are attached for reference. 

Getting it out was the biggest PITA in the first place. I ruined a Tekton 3/32" roll pin punch while I was at it - it bent almost immediately and then ultimately snapped. I figured getting it back in should be no problem but I was dead wrong. I've tried placing the knob in a bench vise and starting it with some light hammer taps, but aligning it with the shaft is difficult as it's spring loaded. The farthest I got was 1/3 of the way through before bending and ruining yet another roll pin. 

I read about a trick using a drill press but the round nature of the knob makes this difficult. Is there any slick trick to this that I'm missing?


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## E350 (Apr 21, 2015)

You need roll pin punches. 

They are available almost everywhere once you know what they are.

Brownell's has some for firearms. But you need bigger than what you will use on any firearm I am familiar with.

Or you could take a free H.F. (or old) Phillips screw driver of appropriate diameter and cut the head off...


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## Stang (Mar 28, 2015)

E350 said:


> You need roll pin punches.
> 
> They are available almost everywhere once you know what they are.
> 
> ...


I had a 3/32" roll pin punch that bent immediately when I took the pin out, and ultimately snapped. I tried starting the pin with the next higher size (1/8") that I have from a set of craftsman roll pin punches (much higher quality than the tekton) and I got the pin started, but couldn't get it all the way through before the pin eventually deformed. It's evident I'm gonna have the same problem if I buy another 3/32" punch. 

I'm hoping for a trick that I haven't thought of before. For people that have disassembled this particular lockout pin, any tricks?


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## E350 (Apr 21, 2015)

*Stang*: Please accept my apologies for assuming that you hadn't used the appropriate tool. You have. 

I punched mine out when I replace the broken differential lock on my Ariens ST1032. I will tell you this:

I NOTICED THAT THE ROLL PIN HOLE WAS TAPERED.

So, if yours is tapered too, maybe try punching the opposite direction?

Post up what you find.


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## Stang (Mar 28, 2015)

E350 said:


> *Stang*: Please accept my apologies for assuming that you hadn't used the appropriate tool. You have.
> 
> I punched mine out when I replace the broken differential lock on my Ariens ST1032. I will tell you this:
> 
> ...


Ahhh good info, but you're referring to the groove pin that secures the locking assembly to the axle. This pin is indeed tapered, and it's solid, not hollow like a roll pin. The grooves are on the larger side IIRC, so when inserting this groove pin you have to tap on the grooved side, and when taking it out you have to tap on the non-grooved side. 

You can see the hole for this large groove pin in the second picture I posted. I had no issue with that one. It's the smaller, hollow roll pin that I'm having trouble with. This is the one in the first picture, and it secures the lockout knob to the spring/piston through a hole you can also see in the first picture. Not only is it difficult to tap in because the knob is round, it also has to be tapped in when the spring is compressed (otherwise the hole is not accessible), as evidenced by how I'm pressing it in the first picture.

Hard to explain. Even harder to get this **** roll pin back in!


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## 43128 (Feb 14, 2014)

i have a cheap set of hf roll pin punches(i think they were 10 bucks or so with a 20% off coupon) and they have been holding up great. sometimes if a roll pin is being stubborn i will taper it with a bench grinder. the taper helps guide the roll pin in


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## Stang (Mar 28, 2015)

43128 said:


> i have a cheap set of hf roll pin punches(i think they were 10 bucks or so with a 20% off coupon) and they have been holding up great. sometimes if a roll pin is being stubborn i will taper it with a bench grinder. the taper helps guide the roll pin in


Ahh that's a neat idea. Maybe I'll do just that try grinding a 45 degree taper into it. Thanks!

I also looked to HF for extra punches, but they do not have 3/32"


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## ELaw (Feb 4, 2015)

How good of an assortment of drill bits do you have?

Although I've never done this particular job this is how I'd do it:

1. Find a drill bit that's just a few thousandths smaller than the pin (ie the largest possible that will fit in the hole in the knob/shaft without binding). If you don't have a properly-sized drill bit, try some other small round things like nails or a cut up wire coat hanger. All you need is something that can serve as an alignment pin.

2. Put the knob in a vise or something and get the roll pin started. Drive it in enough that it stays put, but not enough that it protrudes into the area where the shaft goes.

3. Pull the shaft out as far as you can and hold it with needlenose pliers or something similar.

4. Now put the knob on the shaft, and insert the drill bit from the side opposite the roll pin, through the knob and the shaft, to keep the knob and shaft aligned. If the setup is oriented in such a way the drill bit wants to fall out, hold it in place with your fingers or tape or something.

5. Tap the pin in, which will push the drill bit out the other side.

I may be wrong but I don't think you should need a punch to install the pin... just tap it in.


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## Stang (Mar 28, 2015)

ELaw said:


> How good of an assortment of drill bits do you have?
> 
> Although I've never done this particular job this is how I'd do it:
> 
> ...



This is really, really clever. I will try this ASAP, thanks.


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## Boosted3g (Oct 9, 2016)

I've used Grace USA roll pin starter punches and they work wonderful. They have a long set that I use quite a bit. Check out gunsmithing tools for an ar15. They have a tricky roll pin for the bolt release that is 3/32. You just insert the roll pin in the end and it will hold it until you get it started. Then use a regular roll pin punch to finish. I know amazon carries them if you wait out the shipping.


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## Stang (Mar 28, 2015)

Success. 

I ended up tapering the roll pin per 43128's suggestion by sanding the edge at a 45 degree angle, allowing me to start it straight. This time I used motor oil instead of grease. Once I got it started I went with ELaw's suggestion - brilliant. I used the bottom end of a 3/32" drill bit to hold the piston in place and just took my time tapping the roll pin in with a hammer until the pin itself caught the piston. 

What a pain. Let's hope I don't have to take a small roll pin like this out again in the future.


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