POC
Gold Member
I'm having some trouble with my BH. Can anyone help me with this?
Mahindra 3710B backhoe, what Bradco model?
- Thread starter POC
- Start date
MtnViewRanch
Elite Member, Advertiser
- Joined
- Mar 19, 2005
- Messages
- 10,466
- Tractor
- Mahindra 7520, Mahindra 3215HST, Case 580 extendahoe, Case 310 dozer, Parsons trencher, Cat D6,
Not that I can help, but maybe list out what problems you are having. There are many knowledgeable people on this forum, some of them are dealers, it helps to know what they are looking for to be able to help you.
Good luck.
Good luck.
OP
POC
Gold Member
Mine is broken.
It has a bi-directional hydraulic cylinder below the main "Right-Left" knuckle, below where you sit. It uses HD chains to wrap around the end of the arm to move it right and left. There are some blocks welded to the cylinder on either end, that's where the chain attaches to it. The blocks have grooves machined in them for the chain to fit in. The center of one of the blocks "tore out" and the bolt broke. I put a different bolt in, but it keeps breaking. I'm guessing it was a hardened bolt, but I don't know what grade. I don't want to put one in that is too hard, I'd rather replace bolts than any other parts in this part of the system.
Let me see about some pictures....
Is this a known problem with this machine?
It has a bi-directional hydraulic cylinder below the main "Right-Left" knuckle, below where you sit. It uses HD chains to wrap around the end of the arm to move it right and left. There are some blocks welded to the cylinder on either end, that's where the chain attaches to it. The blocks have grooves machined in them for the chain to fit in. The center of one of the blocks "tore out" and the bolt broke. I put a different bolt in, but it keeps breaking. I'm guessing it was a hardened bolt, but I don't know what grade. I don't want to put one in that is too hard, I'd rather replace bolts than any other parts in this part of the system.
Let me see about some pictures....
Is this a known problem with this machine?
Last edited:
AchingBack
Elite Member
POC, I just went out and looked at my 3710. The bolt you need is a grade 8. Here is a picture, and an article about hardness. As far as this being a know problem; I've been on the Mahindra forum for 6 years, and you are the first person with this issue. All problems should be this easy to fix.
Google Images
LAWALLSTRACTOR
Veteran Member
Your backhoe is made by KMW, not Bradco. 10 years as a Mahindra dealer, I haven't heard of this problem before, and it may continue to be a problem with that center section gone. Some lubrication on the chain may help some of the stress on it. A good machine, welding, or fabrication shop could fix that.
J_J
Super Star Member
- Joined
- Sep 6, 2003
- Messages
- 18,928
- Location
- JACKSONVILLE, FL
- Tractor
- Power-Trac 1445, KUBOTA B-9200HST
Look at the head of the bolt, and it should tell you the grade of bolt. The bolt could be also be metric, so check the parts manual.
Are the holes in the tabs still in good shape? That is your parent metal, ans should be about the same hardness, or it will wear faster.
If you only have been replacing the one bolt, check the other bolt and get a matching bolt if it is an original.
Grade 8 bolts will have 5 markers on the head of the bolt.
I would have a machine shop make up a new tab and someone weld it in place.
If the bolts are metric, here is some more data.
http://mdmetric.com/tech/astmstruct.htm
Are the holes in the tabs still in good shape? That is your parent metal, ans should be about the same hardness, or it will wear faster.
If you only have been replacing the one bolt, check the other bolt and get a matching bolt if it is an original.
Grade 8 bolts will have 5 markers on the head of the bolt.
I would have a machine shop make up a new tab and someone weld it in place.
If the bolts are metric, here is some more data.
http://mdmetric.com/tech/astmstruct.htm
KRH2015
Member
POC, First off that chain is starving for lube. I would probably remove it , wire brush the rust off and or soak it in a mild rust remover like "evaporust" (tractor supply has it). Then maybe soak it in some oil or spray the crap out of it with a good chain lube. I also just checked the manual and it say's the broken bolt was a 3/8"-16tpi x 1-3/4"long grade"8". As far as the broken tab, I would do what Lawall's tractor said and have a new piece welded in. The manual say's to replace the chain bolts after 50 hour's of backhoe operation ( I never knew this). The manual also explain's the proper adjustment of the swing chain. I was told by my local mahindra dealer(Wallace Tractor)to always keep that chain in adjustment or thing's can break. Hope this help's Ken.
OP
POC
Gold Member
Thanks everyone. I'll put all your suggestions into play.
As I was taking the pictures I thought, "Hey, that other bolt is still here, I can just look at it!" Duh. Sometimes obvious answers are difficult to see.
I'll see about getting it off and taking it to a shop.
Thanks again,
Patrick
As I was taking the pictures I thought, "Hey, that other bolt is still here, I can just look at it!" Duh. Sometimes obvious answers are difficult to see.
I'll see about getting it off and taking it to a shop.
Thanks again,
Patrick
OP
POC
Gold Member
I doubt I have 50 hours on the hoe. I only have 150 hrs on the tractor.
nelsond7004
Silver Member
I thought I would add that I have a 3710 backhoe on a Mahindra 2816. I have had the tractor for about a year now and I have had no trouble out of the chains. I did have a grade 8 bolt snap after wear and tear when I was changing out the bolts. I would recommend at least every 20 hours of operation that you change out the bolts.
I also would recommend using chainsaw bar and chain oil as it has a good tac property and will stick to the chain. I have been using this oil since I bought the tractor with good results.
I wish you good luck on fixing your backhoe.
I also would recommend using chainsaw bar and chain oil as it has a good tac property and will stick to the chain. I have been using this oil since I bought the tractor with good results.
I wish you good luck on fixing your backhoe.