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The frame on my '96 Craftsman 50" riding mower had cracks develop in the frame several years ago. They are about midway between where the engine mounts on both frame rails. They started as small hairline cracks and grew slowly over time. I hadn't looked at them for over a year but I after noticing the mower was mowing lower than usual yesterday. No matter how much I tried to adjust the mowing height, it was still cutting low. I thought maybe something was broken in the raising mechanism so when I looked, much to my horror, I found the problem. The frame was completely broken on both sides. It looks like to the only thing keeping my front end attached is the engine. If I keep using it this way there's probably a good chance I'll bust the engine mounts of the engine. I don't have a welder that I could weld the frame back together so I am thinking to bolt some rectangular thick gauge flat stock steel on both side of the frame to reconnect the two parts. The problem is where can get some steel like that?
Has anyone else had an issue with their frames cracking on any riding tractor? It has a 25hp Kohler Command engine. Could just the weight of the engine caused it? I'm not a heavy man. I barely weigh 190 lbs.

My old Craftsman did that too just not in the same place. Mine was the front stamped axle and the slot it runs in.
I completely dismantled the entire mower and took it in to work and mig welded it all back up.

You should be able to get a couple of pieces of steel locally to shore it up but I certainly would line everything back up first and weld it in place. Then you could either weld or bolt the extra steel onto the sides.

It is a 23 year old machine, I am really not surprised. The frame may be rusted through in which case time to retire it, you have gotten your money's worth. Bolting some mild steel scabs on may buy you some time.

I managed to fix the frame. I got four pieces of 3"X7" pieces of 1/4" steel plates. I drilled 6 holes into each piece and did the same on each frame rail. I jacked the frame level to close up the cracks and bolted the plates sandwiching the frames. It's holding together really well. It cost me about $7 for all the steel and bolt hardware.
This should make the tractor last a few more years.
BTW, there is absolutely no rust on this machine.

Glad you got it fixed but I still would have welded the cracks up before bolting the steel in place.
Then again, this fix might outlast the rest of the mower.

Chris from Ontario said:

Glad you got it fixed but I still would have welded the cracks up before bolting the steel in place.
Then again, this fix might outlast the rest of the mower.

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I thought about welding the frame the last time I had the engine out but my welder won't weld the thickness of the frame. It's for very light gauge steel.
As you said I have a feeling the repair will outlast the tractor.

Old tractors are worth the effort to repair
Few newer ones are.

Bleach said:

I managed to fix the frame. I got four pieces of 3"X7" pieces of 1/4" steel plates. I drilled 6 holes into each piece and did the same on each frame rail. I jacked the frame level to close up the cracks and bolted the plates sandwiching the frames. It's holding together really well. It cost me about $7 for all the steel and bolt hardware.
This should make the tractor a few more years.
BTW, there is absolutely no rust on this machine.

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Nice work glad you fixed it up

I'm only fixing it because new good ones are really expensive. I've broken a lot of things on this tractor over the nearly 21 years of owning it. The engine and transaxle are the only items that haven't broken anything. It's always started even when it only fired on one bank. I probably haven't spent more than $400 on parts on the entire machine and I did all the work myself.
It's had a rough life. My yard has a lot of bumpy, uneven and sloping areas. I doubt any similar tractors made today would last a year. I guess I really can't complain.

No they won't.
Work out what the old tractor cost you in hours worked to pay for it.
Then equate that to what you get paid today .
Multiply that by 1.5 and that is what you will need to spend to get a good mower now days.
Down here the top of the line Honda S/P sells for a touch over $ 2000 and people are always asking me how good the $ 1599.99 ride ons are.
Some people never understand that that Santa Clause & the Tooth Fairy are not real.

Even a light welded should be able to do a fillet weld if the patch is over the break.
People forget that a weld is essentially a casting so needs to be at least 3 times as thick to get somewhere near the same tensile strength as plate.

I could run a few lap welds along where the plates attach to the frame to add a little more stiffness to the frame. I haven't mowed with it since repairing it. I'll see how much movement it'll have after a run today and then decide if welds are needed.

Very good idea because the bolts are in a shear situation when the mower is running.
Trousers held up with a belt & braces never fall down

bertsmobile1 said:

Very good idea because the bolts are in a shear situation when the mower is running.
Trousers held up with a belt & braces never fall down

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Indeed!
Where's the "like" button? This forum really needs one.

You use grade 8 bolts? They're pretty resistant to shear stress

I'm not entirely sure what grade bolts I used. They're 5/16"bolts I got from the bulk bin at Lowe's. I'll have to look at the head markings. I used 6 per plate with three on both sides and lock washers with the nuts.
I mowed for a few hours today and the plates didn't shift at at all.

Here we are nearly four years later and the repair is holding up well. I never got around to welding the plates. The welder I have is just a POS arc welder little more than a big battery charger.

I'm glad it's working out for you Bleach. The repair on mine is still holding up too.

Welding can be an art. When do right it is as strong if not stronger the original metal being welded. Done poorly it simply will break again. I do ACE/OX and wire welding here. I have yet to have many to fail afterwards.

When I first started wire welding the welds simply were no good. Then I found out my supplier was selling junk flux core wire. Now that I got the correct flux core wire the welds are very nice looking.

The repair should had been with angle metal as to re-enforce the area or make a lot closer to original design. Screws and nuts simply will not hold up over time.

The angle iron would have been the ideal repair but it would have been more difficult to find the size I needed. I wanted to do it on the cheap. The two pieces of steel I used look like it's still holding up fine. Sure it would have been even better welding them but there isn't too much stress on the repair that the bolts can't handle. The worst that could happen now is some bolts could could shear and that would be an easy fix.

Usually I just take bed rail angle iron and cut to size I need using the die grinder and a cutoff disc.

Usually I just take bed rail angle iron and cut to size I need using the die grinder and a cutoff disc.