eBay clutch vs. OEM

torch

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Equipment
B7100HSD, B2789, B2550, B4672, 48" cultivator, homemade FEL and Cab
Jun 10, 2016
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843
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Muskoka, Ont.
In my recent "Third B7100 clutch in 4 years thread", NIWolfman said he'd had good success with aftermarket clutches from a particular eBay vendor, so I ordered one in case Kubota was out of stock. As it turned out, once the Christmas break was over the dealer got one in a day so now this one is a spare against next time. And I will say that the fit and finish of the eBay version seems equal to the OEM. But I thought it would be interesting to compare dimensions:

First the bit that kept breaking on mine. OEM:



and the eBay version:



Almost 1/4" smaller in diameter, meaning there is much less material at the specific place mine kept failing. The thickness of the material is equal, about 0.060".

I never had any problem with the spline shaft, but I note the collar around the splines is a smaller OD as well. OEM:



And the eBay version:



You may have already noticed that the OEM springs have 5 coils where the eBay springs only have 4 coils. The wire is the same diameter, the coils are spaced further apart. OEM:



eBay:






This last measurement may be meaningless, because the OEM friction disk being measured is 2 years old. However, it's in an HST machine so the clutch gets very little use in practice -- once when starting the tractor and when engaging the PTO or changing ranges. So my gut feeling is that it has very little wear and in fact the pictures above would seem to confirm that.

In any event, the used OEM friction plate has 16 thou less friction material than the new eBay version, so I think it is fair to assume they start off pretty close to each other.

OEM:



eBay:

 
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GreensvilleJay

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Equipment
BX23-S,57 A-C D-14,58 A-C D-14, 57 A-C D-14,tiller,cults,Millcreek 25G spreader,
Apr 2, 2019
10,307
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Greensville,Ontario,Canada
One measurement you can't do, well normally, is to see what the grade of steel is that is being used. Kinda unlikely you have an optical emission spectrometer and a Xray version in your basement.
It 'might' be the unit that's dimensionally smaller is using a higher grade of steel.
BTW, if you pop the upper cap off the calipers and you see 4 or 5 PCB etches, you can make a cable and send the caliper data to your laptop...
 

#40Fan

Active member
Jul 21, 2022
270
152
43
USA
I was thinking the same thing. A hardness tester to check the material would be nice.

You can definitely see where it kept breaking. Between the hub and the round holes on perimeter of the spring cutouts. Is the eBay clutch wider/further distance apart, in these areas?
 

Yooper

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Lifetime Member

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3901 LA525
May 31, 2015
1,468
439
83
NE Wisconsin
Just read your other post and I am glad you found the issue causing the disc failures. When you think about it, they are asking an awful lot from that transition plate. Hopefully you don’t have to split your tractor again for a long time! Great job on the reinforcement bracket!
 

SDT

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Equipment
multiple and various
Apr 15, 2018
3,100
948
113
SE, IN
In my recent "Third B7100 clutch in 4 years thread", NIWolfman said he'd had good success with aftermarket clutches from a particular eBay vendor, so I ordered one in case Kubota was out of stock. As it turned out, once the Christmas break was over the dealer got one in a day so now this one is a spare against next time. And I will say that the fit and finish of the eBay version seems equal to the OEM. But I thought it would be interesting to compare dimensions:

First the bit that kept breaking on mine. OEM:



and the eBay version:



Almost 1/4" smaller in diameter, meaning there is much less material at the specific place mine kept failing. The thickness of the material is equal, about 0.060".

I never had any problem with the spline shaft, but I note the collar around the splines is a smaller OD as well. OEM:



And the eBay version:



You may have already noticed that the OEM springs have 5 coils where the eBay springs only have 4 coils. The wire is the same diameter, the coils are spaced further apart. OEM:



eBay:






This last measurement may be meaningless, because the OEM friction disk being measured is 2 years old. However, it's in an HST machine so the clutch gets very little use in practice -- once when starting the tractor and when engaging the PTO or changing ranges. So my gut feeling is that it has very little wear and in fact the pictures above would seem to confirm that.

In any event, the used OEM friction plate has 16 thou less friction material than the new eBay version, so I think it is fair to assume they start off pretty close to each other.

OEM:



eBay:

Interesting.

I have had bad luck with several aftermarket suppliers (can you spell A & I?) and try to avoid such regardless of the price of OEM components.
 

GeoHorn

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Lifetime Member

Equipment
M4700DT, LA1002FEL, Ferguson5-8B Compactor-Roller, 10KDumpTrailer, RTV-X900
May 18, 2018
5,947
3,198
113
Texas
I too am a fan of OEM parts…. but after 4 OEM clutch-failures…..I’d be willing to try aftermarket.
 
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fried1765

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Equipment
Kubota L48 TLB, Ford 1920 FEL, Ford 8N, SCAG Liberty Z, Gravely Pro.
Nov 14, 2019
6,981
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Eastham, Ma
I too am a fan of OEM parts…. but after 4 OEM clutch-failures…..I’d be willing to try aftermarket.
My aftermarket clutch (Ford 1920) lasted a whole 2-1/2 hours, before it failed!
 
Last edited:

mikester

Well-known member

Equipment
M59 TLB
Oct 21, 2017
3,239
1,717
113
Canada
www.divergentstuff.ca
Good post and measurements.

My tractor has to earn it's keep so I don't try and cheap out on parts and filters. K has been very good for me at stocking parts at reasonable prices, I want to keep it that way. The tractor doesn't earn any money sitting in a repair shop.
 

lugbolt

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ZG127S-54
Oct 15, 2015
4,938
1,670
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Mid, South, USA
My aftermarket clutch (Ford 1920) lasted a whole 2-1/2 hours, before it failed!
I did a 3301 for a customer and had similar results. Ebay clutch. I hate having to do the same job twice, even IF they pay me to do it twice.
 
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