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Les

Why did your bevel box go bad?

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Les
Why don't we start a survey about the root cause of bevel box failures. I had one, a Simp 7016, which came with a heavily used tiller. Since this tractor had a front PTO, my deductive reasoning concluded that it was 100% tiller related, since I also had 40 year old grass mowing only tractors with fine bevel boxes. Note that I bought it as-is with the box out. It apparantly was traded in, in that condition. Also the 16 hp Briggs had fairly good compression, but the engine knocks due to the crank bearing being out of round(at least that is what my neighbor-mechanic told me). Could the evil tiller have caused that too?
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thedaddycat
The 2012 I just got has a severely beaten up keyway on the input shaft. Though it is purely speculation on my part, I believe this tractor was used for a lot of sickle bar mowing. If it was used for plowing or other tasks I have no idea.

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RonT
The box on my 912H looks to have been ran without oil at one time by the previous owner. It caused the input shaft to have a lot of wear and the bearings were ground up as well. Ron Thomas #3
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LBS
DIESEL ENGINES!!! Mine is just about gone and I think it was only used with a mower and loader (just a guess because it has marks on both sides of the frame like I think a loader would make). All 3 keyways are all mashed out to and nothing will stay on! When I shut it off it shakes and rattles and bangs like nothing you ever saw! I guess thats what you get when you get a mower with an engine big enough to rock the thing from one side to the other on two wheels (seriously)! If I had a video camera I would show you. Have a great day! Lawrence
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UCD
My 7790 must be the exception to the rule. The BGB is in good shape and engine hardly shakes at all, a little on start up when its cold. I don't think any tractor has been used as hard as I have used this one. Even the local dealer don't believe the shape it's in. The rest of the ones he sold are long gone. Anything free is worth what you pay for it This & $1.00 might get you a small Coffee Maynard aka/UCD

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ReedS
My bgb on my 700 went bad because 1)it was low on oil 2)the driveshaft was bent 3)the keyway was worn on input shaft 4)the driveshaft angle was wrong due to 10 hp eng that i had it 5) because it was older than I am and worked all of it's life. The 2nd time it went bad ( I rebuilt it once) was because I didn't replace the bent shaft and believe the front bearing race is ovaled. Hopefully I will replace the bgb as part of this tractor's overhaul.

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BradT
Ok here's my tale of woe. I bought a 7016H trade-in with a trashed BGB for $300 from my local Simplicity dealer a few years back. Here's what I found. The only attachment that it had(and never looked like it was ever taken off) was the 48" deck. This puppy had a lot of hard mowing based on the worn tires, blades, deck roller assy, etc. The 16Hp Briggs was already bored 30+ over and the con rod knocked because of the same oval condition. The BGB had worn keys and very worn retainer ring seats on the cross shaft. The input shaft was fine. Somebody had already been in the box once and replaced the bevel gears but obviously didn't pay attention to the poor shaft condition or reused the old retainers or something which caused it to self destruct-again-and probably made the owner throw in the towel. I rebuilt everything 100% in the box and had the Briggs resleeved and 100% professionally overhauled. Since then I've added a snow blower (front PTO) and plow and never had a bit of trouble with the BGB. A recent check of the BGB oil looked just fine. I've often wondered just how much stress these BGB can take. There has to be a design limit for horesepower input. The one in my 725 has never been out for 40 years so I guess some do just keep ticking.

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UCD
I talked to my local Simplicity dealer about the BGB's yesterday. He said the biggest cause for failure he has seen is the front seal leaking and the set screw on the yoke not being tight enough causeing wear on the keyway. This & $1.00 might get you a small Coffee Maynard aka/UCD

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Kent
All I can say is that if BGB went bad, it must be either the fault of his parents, peer pressure, the "village" that raised him, or our social system, somehow... I just hope he doesn't sue us for restitution.... By the way, do those initials stand for "Bobby George Barnes" or "Billy George Barnes".... I don't think I know him! On a serious note, I haven't found time to pull my bad BGB and inspect it yet. I did buy the used one that Woody found for me, but that's as far as I've gotten... My son wants me to repaint the tractor while its apart, so this is beginning to look like a major winter-time project. The foot-draggin' Clubhouse Custodian...

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KSever
I think I found out why my BGB went bad tonight after tearing it apart. Besides the input shaft being tore up and no bearings left on this shaft, There was no oil in the box JUST WATER. I think I have to find a different way of making a vent plug so it's not directly facing up for water to get in. Anybody have any ideas? Kris

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roma3112
kris While i dont have an answer for your question, I do have a ? for the masses. On my 3112h i went on a search for the bgb vent plug with no results, any idea where (the vent) should be visible from, or do i nees to remove some sheet metal. Also as far as the set-screws on the BGB imput goes. I think i need to do some disassembly to get to them, is this true? Also as part of my pre-winter service i replaced the 90w oin in the tranny and the bgb with a good name brand 90wt, i was thinking would any of you guys see a benefit to using some of the new synthetics out there, or should i stick to what has worked since 1968 or so thanks john

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MikeES
John, I use Mobil synthetic gear lube in the transaxle and the BGB. The BGB spins easier at 20 below with synthetic, thus makes it easier to start the tractor. Good Luck! Mike S.

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gregc
John, I'm not sure about the 3112 but here's a pic of the vent plug on my Big Ten. The plug looks to be 1/4" red plastic pipe plug with a hole in center of it. And here's a pic of the set screw access. Hope this helps you. Greg

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Les
Looks like we dont know WHAT causes bevel boxes to go bad! Years ago when I lived in Indiana and was considering buying my first AC, a B-112, my neighbor, who was a former AC farm dealer mechanic, told me one thing to watch for was the bevel box, as sometimes water gets into them and causes them to go bad. That advice got me a reprimand on this site, by someone who said that it was impossible to get water in a bevel box! Hey, where IS the faulty-misleading advice judge! He must be asleep at the job or something. Just like when I said the closest match for AC yellow that I FOUND, was Rustoleum Sunset yellow, I got jumped on all over for that, saying that it was NOT a match(which I already knew, because I said it was the CLOSEST that I had found, meaning not a match.) Later, we learned that there are at least THREE different shades of AC yellow, and I would still bet a dollar that Rustoleum sunset yellow is close to one of them. Come on faulty-misleading advice judge! We need you! We probably need a english-diction-spelling judge too! Because I am just not too sure that "closest" is even a proper word. Maybe that is my problem!

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roma3112
thanks mike/greg think i will hold off on the synthetic till next season. thanks for the pic i think i have an idea where to look for the plug now. ohh 1 more thing when swappin over to the synthetic, how critical is it to remove every trace of the non-synthetic oil, i hear they are not compatible

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Jonjacobson
my 2012 bgb was noisy but functional and appears to have only run a 42 inch deck. keyway on output shaft (to trans.) wallered out due to loose nut and age. the internal keys were also worn enough to give noticable play but the keyways were measured and ok'd by my machinest. as to the cause of these internal key wear i think probably age. 35+

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Roy
John, I have put Mobile 1 in the engine, transmissions (manual) and rear ends of several vehicles. Just did a normal drain and fill. Never had a problem with Toyotas & Mitsubishis. The Mazda B-2200 engine didn't like it. The valve stem seals started leaking and the rings on one cylinder floated around until the gaps lined up. Then it started sucking oil like crazy. One caution. Synthetic oil "creeps" more than regular oil. If you have a gasket or seal that is the least bit leaky the synthetic products will leak/seep more. Mobile 1 engine oil does make engines run quieter & cooler with less consumption. The gear oil will make a whinning rear end quit down. My experience what what it is worth.

Roy

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dlcentral
Why they ever used that stupid box assy. is beyond me,prob box salesman took out Mr. Sim for drinks,etc.Should have been made more like Cadet driveline,,NO belts!,,just a $15 disc to replace when abused,, noo,, instead lets make something thats gonna cost owner HUNDREDS of bucks to fix,,I will say,,I rec'ed a lot of these tracs because of that prob,,so not complaining too much,,

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Les
Dave, how many bad bevel boxes have you had? Just a quick survey here shows 8 or 9 bad boxes out of hundreds of tractors all 30 or more years old. I brought this subject up because there has been a lot of discussion about bad bevel boxes, but from the actual number of people speaking up about it, the problem seems almost insignificant. It is clear that cub cadet has the superior drive train, but that is about the only cub advantage that I see.

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MDB
Since most bevel gear box problems acure after 30 years of use and abuse I would say that is a fairly good record. Ive rebiult at least 12 of these boxs and the imput bearings are usually the cause of the problem. MDB

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