Drott 40BLC, Case 1280, Case 1187 final drive sprocket

reo12 · Apr 28, 2022

My Drott/Case 40BLC stripped the spline of the final drive output shaft and sprocket. The shafts are available. I've failed at finding a new or used sprocket. This is a weak point in these machines.

Is there a successful patch for keeping one of these machines working for a few months or more? Such as set screws in welded on nuts? Set screws on top of shear pins? Or removing the outside pillow block bearing and using a long drill to drill multiple holes into the stripped spline and inserting multiple dowel pins rather like multiple key's would be used?
Also:
Is there a newer bolt on sprocket of similar size that fits the type "C" track chain? I was thinking that a flange could be made and welded to the shaft so that a bolt on sprocket could be used. This option could help a lot of folks keep one of these machines out of the scrap yard.

AJ. · Apr 28, 2022

Last time I encountered that type problem on a crawler loader I had three keyways machined in the shaft and sprocket, we used hardened keys and as far as I know it was successful, it never came back.
AJ

jm. · Apr 28, 2022

30 + years ago had two 40b s and when they got to that point we took the shaft and sprocket to
machine shop and instead of square key way what they did was drilled about a 3/8 in hole right at
the junction of the sprocket and shaft where the meat came out of both pieces. Did that in two
places and then drove spring dowels or harden steel pins in and they ran for years.

jean claude marleau · Apr 28, 2022

Excuse me sir could you give me the part number of that shaft. thank you my e mail is [email protected]

AJ. · Apr 29, 2022

JC two shafts listed depending on serial # one is S59165, the other is S5603435.
AJ

reo12 · Apr 29, 2022

(quoted from post at 17:57:41 04/28/22) 30 + years ago had two 40b s and when they got to that point we took the shaft and sprocket to
machine shop and instead of square key way what they did was drilled about a 3/8 in hole right at
the junction of the sprocket and shaft where the meat came out of both pieces. Did that in two
places and then drove spring dowels or harden steel pins in and they ran for years.

Hi JM, Thank you for the reply. This is a version of one optional method of repair we were thinking of doing. It is where I was leaning - more work than my friend wants me to do. Do you think it really was only 2 spring pins/dowels that were used? I'd have thought it would require more of them. I'm being paranoid as to how much strength is needed. There are standard strength and heavy duty versions of coiled spring pins and there are several versions of slotted spring pins. Do you know what worked for yours? Honestly - I've not done much work with spring type pins and certainly not work that expected much from them so am always looking to learn from others.

Drott 40BLC, Case 1280, Case 1187 final drive sprocket

reo12

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AJ.

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jm.

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jean claude marleau

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AJ.

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reo12

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