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rfsmith1952

Hydro surges - I'm out of ideas -

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rfsmith1952

For the last couple of months the T-12 with a vickers hydro has been surging, throw you back in the seat, pretty dangerous surging. I found some things like the spring from the oil cooler to the fwd/rev valve wasn't re-installed, and the oil filter spring wasn't installed correctly, and the idler pulley spring was not installed correctly. So I fixed all those things (They were all self-inflicted by the way.) I changed the fluid, and filter (dexron III and a Purolator cross referenced filter to the NAPA 1300) Ran the starter till the bubbles stopped, and adjusted the neutral lever position so that the old girl sat still. Then I kept looking at the belt, it seemed too loose. Installing the idler pulley spring correctly took up some slack, but to me it was still too loose. I drilled another hole higher up from the top hole and moved the idler pulley spring up another half inch. None of these actions have helped. What next?

I got this hydro from Nathan out in Indiana, who got it from Maynard's stash when Rockon Dan spread the wealth, so it was good when installed and ran well for a year or so, even with the substandard installation by me.

The T-12 is the same as a 3415. It is Allis built. The hydro is a Vickers. The engine is a briggs 12hp. There are no other hydraulics on the tractor. I have the original Vickers that came with the tractor, and one option may be to rebuild that pump and motor. I'd appreciate any suggestions.

It's my cart puller, but I can use the T-10 for that, or even, dare I say it, the green and yellow one I actually cut the grass with can pull the cart too.8D

As always, thanks for sharing you knowledge and experience.

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BMinor8806

Try checking your frame bolts. My uncle's Allis 712H would surge like crazy when mowing and the bolts from the rear frame to BGB were loose. Check the one's in the front frame to BGB as well.

Brandon

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simple_stan

I would put the idler spring back where it was before you drilled the extra hole. Maybe the idler arm isn't moving due to dirt or debris. I would pull it off and make sure it is clean and lubed as needed.

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rfsmith1952

Thanks Stan, both arm and pulley move freely. I did check the BGB bolts. Out of six: 4 were loose, 1 is missing and 1 is tight. It's 10pm here so I didn't fire the tractor up to check it, but it makes sense. If the BGB is moving, so is the pulley. We'll see!

Thanks

Bob

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jverhaag

What about a restriction in the fluid flow? Pressure builds up, tractor shots forward dumping pressure, runs, builds up pressure and surges forward again, etc.

Just a thought. Sounds like you checked everything else.

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JimDk

Whew!!!!! Looks like I skated on that T-12 again.:D:D

I'm sure that the loose bolts were your problem. My HB-212 had the same problem when I got it. It made me seasick trying to mow with it.

Good luck,

Jim

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rfsmith1952

The bucking bronco has been broken and she rides like a saddle mare now. That was the issue..loose bolts on the BGB. Thanks Brandon and everyone else for the advice. Well, I have moved the T-12 out of the rehab category and back into the worker category. I had rebuilt the carb with a lot help from club members, and today I set the hi and low rpm with one of the light reflective tachs I read about here. 1000 low and 3000 high. Purrs like a kitten. Jim, that dinner had better be a good one!

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