Berg Inner Axle Shaft Fix
 

Since I have been running Holmes Hobbies 45T Hand Wound Motors. I have been breaking the pins off the inner axle shafts. When my wife broke a pin off this weekend running Integy 55T V11 it started getting old. I bought a few sets of spares but with the limited parts carriers for bergs out there I figured I would try to come up with a solution on how to fix or replace the pins on the broken shafts because that is all that is wrong with them. I am sick of paying for spare shafts and paying for the shipping, that is if you can find them instock. I have seen a few people that I know break the pins also. So I thought I would try to locate a replcement pin. I came up with some HPI pins that are close to the same length as the stock berg inner shaft pins. I measure the width of the pin and the original stock berg pin was .500" and the replacement HPI pins was .460". Since I am using axial stub shafts do to the increase stength, I also measured the pin width on a axial inner shaft and it measured at .420". I then stuck the replacement pin after it was installed on a repaired shaft into the outer stub shaft and it seems like it will work fine. I will do some testing with it to see if there will be any problems but I believe there will not be.

Berg inner long shaft with a broken pin:

http://www.thexota.org/d/15188-1/013_002.JPG

http://www.thexota.org/d/15194-1/016_002.JPG

I then punched the remaining portion of the pin out of the center of the shaft. I did 4 shafts and 2 of the pins was a major pain to get out. I started with a beefier center punch to move the pin and then used a standard punch that was smaller than the pin diameter to punch it out the remainder of the way.

http://www.thexota.org/d/15200-1/018_001.JPG

Here is the remainder of the pin sitting next to the shaft that the pin came out of:

http://www.thexota.org/d/15200-1/018_001.JPG

The remaining portion of the pins from three of the four shafts:

http://www.thexota.org/d/15206-1/020_001.JPG

Here is what I used for the replacement pins. The Part Number is Z260 from HPI. 12 come in a package for $3.00 at my LHS. .25 cents to repair a shaft versus $6.00 to $7.00 a pair plus shipping for replacement shafts. (Somewhere around $12.50 to my door with shipping) The pin size is 2.5mm X 12mm.

http://www.thexota.org/d/15212-1/022_001.JPG

I started installing the pins on the four using my vise as a press. I have aluminum jaws so the pins did not get gawled. Once they were started I tapped them in the rest of the way with the flat side of a ball peen hammer. Make sure you take your time to get the pins in with even length on both sides of the shaft.

http://www.thexota.org/d/15215-1/024_001.JPG

http://www.thexota.org/d/15221-1/026_001.JPG

Here is a comparison of the replacement pin versus the original pin: The original is on the right and the replacement is on the left:

http://www.thexota.org/d/15233-1/030_001.JPG

http://www.thexota.org/d/15236-1/031_001.JPG

Here is a picture of a replacement pin shaft in a used beat up Axial stub so you can see the pin clearly goes from one side to the other:

http://www.thexota.org/d/15242-1/033_001.JPG

Here is a picture of a original inner berg shaft in the same axial stub shaft.

http://www.thexota.org/d/15248-1/035_001.JPG

Here is the original berg shaft showing the measurement:

http://www.thexota.org/d/15251-1/036_001.JPG

And a picture of the replacement pin shaft.

http://www.thexota.org/d/15254-1/037_001.JPG

Again I will put them in a run them to see if there is any problems but I do not believe there will be.

If you have any questions feel free to ask.

I hope that works for you. If it does,I may have to try it. I've got over a dozen shafts here with broke pins. A few more that the ball section of the shaft exploded. I went as far as getting some drill rod the correct size (.098" if I remember right) from our vendors at work and making the pins out of that. That didn't cut it.

If it's a turning axle, do you think the shorter pin will cause problems at max steering angle (coming out of the slots?)

I was originally worried about that but that is the reason I measured the axial inner shaft pin. It is actually shorter than the replacement pin. Most berg guys run axial stubs and you can run axial knuckles so I wouldn't think it would to short. You are talking about a .020" differance per side.

Pin lengths:

Axial = .420"
REplacement = .460"
Berg = .500"

****ing sweet! im buying a set of those things, ive got a few broken berg shafts at home. even if they break like the stock ones theyre cheaper to replace.

i did the same thing but i used a old drill bit and used that fixed shaft for MSD nationals last week and didn't fail like my driving did

wow
 

sweet I paid 80.00 plus shipping for a set of "killer" shafts for my berg and after waiting a month for them 1 of them fell apart and after another month of SLOWWWWWWW communication with the vendor still no shaft replacement. They said I broke it in the grass!!!!! anyway Great idea, I am gonna stock up on these puppys!!!"thumbsup"

Would these fit a berg

http://www.ckrccrawlers.com/shop/ind...oducts_id=1646

Good work Tom! "thumbsup"

I don't think they will. The shaft lengths are different.

awesome! so glad you didnt keep this a secret lol!!! nice work and thanks.

Although I've yet to bust a pin that's a great fix.

How much for the dust collecting bender? :ror:

Juan, HR's shafts are shorter than Berg shafts. The HR shafts are crap anyway... stainless steel doesn't hold up.... I have a few bent and broken shafts from my HR MOA rig to show for it. The last one that bent was straightened out with a pair of vise grips (out of frustration):lol:

I laugh because it was non stop tube bending for about 2 years then it just stopped. I should get back into making tube doors and bumpers for cherokees it was good money for side work.:) Anyways I figured you have something bigger and badder than a JD2.8)

awsome info.. glad someone did it.

damn... i bought the pins at the LHS, ive got 3 old broken shafts sitting here and i cannot get these ****ing pis out! its so frustrating to have $60k in tools in your garage and get your ass kicked by a stupid rc car part!

4 flute carbide endmill and heavy on the coolant/misty spray or compressed air to keep the chips out. Cut like butter."thumbsup"

If your LHS stocks any Associated parts you might be in luck. The MGT uses 2.5x12mm axle pins as well. I don't have a part number handy. But being that it's an AE part over the HPI part, AE will be cheaper.

the HPI pins cost $3.00 for 12 of them, im not sure i'd want something cheaper. lol!

Thanks for this thread Cruzin "thumbsup" After seeing it I was able to find some longer pins on McMaster. I posted the info here in my build thread.