B7100 HST cracked frame

[jhoglan]

Newcomer here,

I just bought this new-to-me B7100 HST. It's my first tractor so I'm new to just about everything. Went to finally move some gravel around for my driveway when it almost bogged down to shut off while picking up a bucket load. I was a little more careful on loading up the next bucket of gravel. I started to drive with the gravel in the bucket when it seemed like something was binding/bogging. So I dumped the load and noticed the front loader was a little bouncy and flexing like it shouldn't. (Yes, I had the throttle at an adequate speed. ) I pulled in into the shop to have a look and find that my frame is cracked.

I've already talked to a welder friend of mine who is going to try and touch it up, likely add some steel for support as well. I'll update this thread as I get some progress. I noticed on the other side it looks as if someone had previously welded in this same spot as well.

Does anyone have any experience with this issue? Why would it bog down and almost die? my thought was maybe under load the flexing made the driveline bind and cause issues? Curious what everyone's take is on this! My bucket has around a 500lbs limit so I know I wasn't putting too much on it.

 

[D2Cat]

Welcome to the forum. You have two things going for you, you know what the problem is and you know someone who can weld! Hopefully the welder has good maintenance background and can quickly see what needs to be done and how to do it.

That crack needs to be ground out to a "V" and welded. Then maybe a plate over it, but also a gusset going forward as room allows. Then check the other side.

Just be sure your welder feels comfortable and knowledgeable about the repair. If he doesn't, or not sure, look around for a repair shop to do the weld. Better to get it done correctly once and for all, no matter the cost.

I would agree with you about the bind causing the engine to drag down. Good that you quit when you did!!

 

[BruceP]

That failed weld on the backside does not look like the other welds. I wonder if someone attempted to repair this in the past?

Since you now know this is a 'weak spot', consider having BOTH sides reinforced in that area.

Consider yourself lucky that it is easily reparable by a competent metal fabricator. I am confident it will be a robust repair.

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I know someone who thought he got a GREAT deal on a tractor with bucket.... later to discover the cast CASE itself has a crack. Hydraulic fluid leaks all the time. Fixing this would require 'splitting' the tractor in half... and even then, a solid repair is not guaranteed.

It is thought that someone put too much weight in the bucket. It not a good idea to just add weights to the rear so the machine can lift more in the bucket.

 

[dirtydeed]

It would appear to me that what you said wasn't the only crack in the frame...

Is this cracked too?

 

[BruceP]

Is this cracked too?

Good eye!!!

It may be wise to remove the entire bucket-frame and have it inspected, repaired as needed.

 

[jhoglan]

It would appear to me that what you said wasn't the only crack in the frame...

Is this cracked too?

View attachment 71598

I had to go back and look after looking at the pictures at home as well. That is just a crack in the paint around the bolt. Someone had painted over the bolt and when it was removed or shifted, the paint separated where the plate meets the bolt. Everything else is fine. Good eye though!

 

[jhoglan]

Welcome to the forum. You have two things going for you, you know what the problem is and you know someone who can weld! Hopefully the welder has good maintenance background and can quickly see what needs to be done and how to do it.

That crack needs to be ground out to a "V" and welded. Then maybe a plate over it, but also a gusset going forward as room allows. Then check the other side.

Just be sure your welder feels comfortable and knowledgeable about the repair. If he doesn't, or not sure, look around for a repair shop to do the weld. Better to get it done correctly once and for all, no matter the cost.

I would agree with you about the bind causing the engine to drag down. Good that you quit when you did!!

That's what I'm picturing as well, thank you for the input (and welcoming). My friend builds and fixes trailers for a living as well as being a certified welder so I'm open to his input and expertise. I imagine we'll add plates to each side (assuming it will fit) and strengthening it as much as possible.

The tractor seemed to run fine when I didn't have a load in the bucket, so I'm hoping it's not a recurring issue after the fix. I'll keep everyone posted!

 

[jhoglan]

That failed weld on the backside does not look like the other welds. I wonder if someone attempted to repair this in the past?

Since you now know this is a 'weak spot', consider having BOTH sides reinforced in that area.

Consider yourself lucky that it is easily reparable by a competent metal fabricator. I am confident it will be a robust repair.

---------------------------------------
I know someone who thought he got a GREAT deal on a tractor with bucket.... later to discover the cast CASE itself has a crack. Hydraulic fluid leaks all the time. Fixing this would require 'splitting' the tractor in half... and even then, a solid repair is not guaranteed.

It is thought that someone put too much weight in the bucket. It not a good idea to just add weights to the rear so the machine can lift more in the bucket.

Thanks for the input! Yes, it looks like someone tried to just weld over top of a break on the other side without doing any grinding or adding a V cut to get more surface area. We're planning on removing the old weld and starting over on that side to do a similar repair on both sides.

 

[Lil Foot]

To me that loader looks huge for a B7100, (and also a lot newer design than was designed for the B7100) the so I'm guessing someone made the mounting setup.
Maybe they used undersized material or the wrong material for the subframe.
Might be interesting to see the whole subframe.
Here is the subframe for a B7100 with a B219 FEL: (complete with extra dirt & grease)

 

[Nicksacco]

Welcome @jhoglan !
Have you done a service to the machine yet?
Is it possible that you are low on hydro fluid?
Clogged filters?
Just some thoughts - it sounds like you have the right friend to do the welding!
Good luck and keep us posted

 

[Hkb82]

I think it has had some work done to it at the least if not totally fabricated. I’m with lil foot I think it looks big especially for the mounting setup. The broken weld actually looks like a sloppy job that was hit with a grinder and wire wheel to hide the bad welds. Also I don’t think you’ll find welds like this one I circled coming from the factory or I hope not. Plus cutting torch marks I think would be cleaned up.

Luckily for you it’s not the actual frame on your b7100 as your post states. Nothing a GOOD welder can’t fix. As far as the bog I’d fix the loader then work it and see if it still happens. I’m betting it won’t unless your overworking it.

 

[torch]

What gear where you in when the tractor was bogging down? The high range is for unloaded travel. Use the low range for driving into a pile, carrying a load up-hill, etc.

Also, be aware that an HST pedal is a bit counterintuitive for someone used to a throttle pedal -- it controls the transmission ratio, not the power input. Your car puts more torque to the ground as you press the pedal further, but an HST pedal puts less torque to the ground as you press it further. Think of it as selecting a higher gear the further you press the pedal and vice-versa. Backing off the pedal is like selecting a lower gear.

 

[Donystoy]

The only time I have had the engine in mine bog down and stall was before I installed my subframe to hold the back hoe. The weight of the hoe and full loader caused the top bolts that attach the engine block to the rear frame housing to shear off. This housing holds the hydro unit and since it was now out of alignment with the engine it caused a stall.

 

[jhoglan]

What gear where you in when the tractor was bogging down? The high range is for unloaded travel. Use the low range for driving into a pile, carrying a load up-hill, etc.

Also, be aware that an HST pedal is a bit counterintuitive for someone used to a throttle pedal -- it controls the transmission ratio, not the power input. Your car puts more torque to the ground as you press the pedal further, but an HST pedal puts less torque to the ground as you press it further. Think of it as selecting a higher gear the further you press the pedal and vice-versa. Backing off the pedal is like selecting a lower gear.

Great input, I started out in high gear, but switched over to low range after feeling it out. (newbie here, so it'll all come with experience and learning my machine). I appreciate the help!

 

[jhoglan]

The only time I have had the engine in mine bog down and stall was before I installed my subframe to hold the back hoe. The weight of the hoe and full loader caused the top bolts that attach the engine block to the rear frame housing to shear off. This housing holds the hydro unit and since it was now out of alignment with the engine it caused a stall.

That's what I'm picturing, I think when the frame of the loader broke it was able to move enough to cause it to bind. I'll take a look at the rest of the connections to see if it caused any other shearing within the tractor/mounts/connections.

 

[jhoglan]

Welcome @jhoglan !
Have you done a service to the machine yet?
Is it possible that you are low on hydro fluid?
Clogged filters?
Just some thoughts - it sounds like you have the right friend to do the welding!
Good luck and keep us posted

Not yet, fluids all check out fine. The hoses were all replaced recently. I'm going to be doing the oil soon, but I think the hydro fluid is good. I'll post pictures of the repair once we get done with it (busy time of year for sure).

 

[D2Cat]

Jhoglan, can't tell from the picture you posted, but there needs to be some steel support that goes from the metal frame that goes under the belly (transmission area) of the tractor to the front of the rear housing. There should be one on each side. That is what the long pieces in Bill's picture shows going back with the "C" with bolt hole in it. This support keeps the mount from twisting and turning. Make sure your loader mound has them and if not have the welder stick some on for you.

 

[mikester]

If you use a lawn mower grade piece of equipment and run it like an industrial loader backhoe then things will break. It's a fact of life, get used to making repairs. The scientific term is ABUSE.