Problem - B3300SU

[jeffjoseph1]

Was doing routine maintenance and found many all of the bolts that go through the backhoe sub-frame into the rear axle had loosened/stripped/fallen out.

I pulled one and noticed it seemed way too short to go through the sub-frame and into the outer rear axle housings.

They are 12MM x 1.5 by 35mm or so long. The hole in the axle housing goes at least another 25mm in.


Does anyone know the proper length of these bolts? I have called the dealer as I suspect they installed ones too short and asked if they knew.

Any help is appreciated......

 

[ibunker]

Are you talking about the six bolts (three each side) that the top backhoe pad attaches to the frame, the pad that the backhoe attaches to with the two large pins? These bolts on mine are 2" long, with the washer, lock washer and nut, the bolt sticks out about 1/16". Attached picture of right side.

 

[jeffjoseph1]

Are you talking about the six bolts (three each side) that the top backhoe pad attaches to the frame, the pad that the backhoe attaches to with the two large pins? These bolts on mine are 2" long, with the washer, lock washer and nut, the bolt sticks out about 1/16". Attached picture of right side.

No, they are 12MM and there are four that surround the axle as it goes through the backhoe sub-frame on each side.

I found today that 50MM ones thread in and I have ordered 60MM to replace the 35MM that are there. But I still would like to know what is suppose to be there.

 

[jeffjoseph1]

Kubota told the dealer that they are suppose to be 45mm long. The ones in there were 35mm.

 

[ibunker]

Got it, removed one bolt and it's 45mm long and noted it was very rusty on the end, about 3/4 inch of rust. Also noted some wear on the first 5 threads near the head that were flattened out some. Will have to look at the rest and maybe do some replacing myself. Thanks

 

[jeffjoseph1]

Got it, removed one bolt and it's 45mm long and noted it was very rusty on the end, about 3/4 inch of rust. Also noted some wear on the first 5 threads near the head that were flattened out some. Will have to look at the rest and maybe do some replacing myself. Thanks

I know 50mm will fit and I have ordered 60mm to see how far the threads go. I figure the first 5-7 mm are damaged so if I go 5mm or more threads further I can be sure to get the strength I need.

 

[ibunker]

Pictures, thank you. I reinstalled the bolt and checked the remaining 7 and found all but one were loose (17mm). I'll make a note in the maintenance to check these from now on but don't know the torque value, so very snug for now. Appreciate the post and for the other B3300SU owners, please check these bolts before major damage gets you. Thanks again for the prompt posts.
Noticed you have no washers, I did on mine.

 

[jeffjoseph1]

.... I'll make a note in the maintenance to check these from now on but don't know the torque value, so very snug for now.....

From the backhoe manual general spec for M12 is 57-66 ft.lbs.

 

[ibunker]

Noted, nice of them to put these torques in the backhoe manual and not the tractor manual. Love the Newton meters torque value, reminds me of all the torque values of the A184 Italian torpedo I use to work on before retirement.
Made a copy and put with my tractor manual. Thanks