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716H PTO question

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I just purchased a 716H with a 48" mower deck to use for cutting lawn. Although the previous owner told me it ran fine and he had no problems, I ran it about 45 minutes and the clutch which drives the mower deck tore apart the key in the PTO shaft. Imagine my great suprise when I looked at the shaft and found that there were two keyway slots and they were both buggered up. Anyways, I am going to try and repair the slot with some two-part "steel" epoxy. I have the following questions and would appreciate some help. 1. Does anyone out there have a parts diagram for the PTO. At a glance, it looks like the hardened shaft I am looking at might be a bear to get out if I get desperate. 2. The shaft has two keyways but the clutch ony has a slot for one key. This looks strange to me. Does anyone know what is going on? Should there be two key slots in the clutch? If so, where do I get the right clutch. 3. I was unfamiliar with the machine and basically was revving the engine and then engaging the mower dec with the PTO lever. I now see that there is a tensioning spring also for the mpwer deck. I am assuming that I should detension the belt, run the motor at low RPM and engage the PTO slowly. Then I could speed up the engine and tension the belt. Does this sound right. 4. Has anyone else had problems with keeping keys in this shaft? 5. Does anyone out there have a used shaft? 6. Does anyone have a good idea about fixing the keyway yhay is buggered up on the shaft? Your help would be appreciated. This is a magnificent machine and I am thinking about spending time on restoration if I can fix this perplexing problem. If I can't fix it, then I have a very nice tractor for pulling a cart. Unfortunately, I need to cut lawn!!!!!

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Ishmael2k
I e-mailed you diagrams. Using an epoxy may be a waste of time. Depending on how bad the keyway slot is buggered, you could try dressing the slot with a file and staking a new key with a center punch. The torque spec for the large nut is 70 Ft./Lbs. (Be sure to support the shaft from underneath since you don't want to bend the shaft or damage the bearings or seal by hammering.) If that doesn't work, you may find a machine shop that can cut a new slot while the shaft is still in the tractor. A new shaft is available for about $50. The tensioning spring is for the idler pulley and should only need to be released when changing the belt.

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PhilD
The shaft that you are looking at is the output shaft of the bevel gear box. Parts are still available from a simplicity dealer. It would be best to do a full rebuild (shafts, bearings, gears, seals) One of the sponsors can help if you don't have a dealer nearby. Someone here on the site may have a rebuilt one they will sell you. I don't think that the epoxy will hold up more than a few minutes unless it is the special aerospace type they use on jet repairs. Even then it probably won't last very long. The shaft has only one keyway in it Engaging the PTO at 3/4 to full throttle is the way to go. The belt whips less that way and is less likely to flip over from whipping. Leave the belt tensioned or you will have plenty of fun trying to get the belt to stay where you want it (on the pulleys) while you retension it after the PTO is engaged. I had to do a rebuild of the box because the nut was loose and allowed the driven member of the clutch to wobble out the shaft slot. If you want to try to fix the existing shaft again, take it to a machine shop and see what they say Word of caution. The bevel gearbox joins the two halves of the tractor together. Not real hard to get apart butbut be carefull. The two halves (front and rear) are very heavy. Get a repair manual it helps a lot. Simplicity large frame garden tractors 7000 & 7100 Models I think the number may be TP-973. Anyway, your local dealer should be able to get one for you. Hope this helps some. PhilD

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Guest
Dennis, You're right, that is the bevel gear box. You can R&R the driven (cross, output) shaft without removing the entire gear box from the tractor. Besides common hand tools, you will need tools to remove the retaining rings (like snap ring pliers, small screw drivers, an awl, strong finger nails - a long brass punch will also be handy). Don't force anything, once you locate and release the retaining rings the shaft will tap or slide out. Just watch you don't damage the oil seals. The fastener which holds the clutch plate to the shaft should be a 1/2"-13 flanged lock nut. It does not use a spacer or lock washer and should not require locktite. I view the bevel gear box is a very special component of this tractor. It is constantly under load since it directs all engine power. It is precision engineered and should not be modified. In other words, take your time, fix it right, don't take any short cuts, and use genuine replacement parts. As already suggested, order the manuals from Simplicity before you begin the repair. You'll be surprised how quickly they arrive. While you're waiting for the manuals, you could remove the bevel gear box inspection cover (rectangular with 6 bolts). Carefully inspect the drained gear oil for metal particles. If there is any metal, or excessive gear backlash you should remove the bevel gear box and overhaul it. Mark all parts, and draw a diagram as you disassemble (some parts may look the same but have subtle differences). I'm sure you can do the job, and will find it very rewarding and satisfying.

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Les
My advice would be to get a hold of Dave Christiansen(dlc) and see if he can sell you a used bevel box. Since you will have to remove the box anyway, that would be the cheapest and easiest repair.

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Guest
This is the first time I have been on this site and I am impressed with the willingness to get back to me and help. I am going to call Simplicity tomorrow to order manuals. I also have the correct key and am going to install it and see if I can at least cut lawn. Does anyone know how I can get ahold of Dave Christianson??? Also, does anyone know exactly what manuals I would need for a 716H allis chalmers. I searched this site for a cross reference and it looks the same as a Simplicity 7016. What is a large-frame manual???

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Guest
Thanks much for the great help. I will try and get repair manuals. If I understand correctly the shaft is coming out of something called the bevel gear box. This is under the front edge of the seat. It sounds like the shaft should only have one slot????? The other slot must be custom!!! Does anyone know how difficult it is to get the shaft out?? I am a garage mechanic-but am not sophisticated or highly competent. Also-the nut that holds the clutch on-is there any kind of spacer or washer?? Should I locktite?? Thanks again.

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Les
On the clubhouse main page, click on member list, then sort by nickname, cursur ahead until you find "dlc", then click on his e-mail address. Dave is our club president and very knowledgeable and helpful.

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PhilD
The 716AC is the same as a Simplicity 7000 series Landlord, Sovereign, Baron. The Repair manual needed is the TP-973. Ishmael2k has provided part numbers for other manuals you might want. PhilD

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Ishmael2k
From what I can see in my manuals the nut does not have a spacer. I'd call Simplicitys publication dept. and request the appropriate manuals, (262)284-8519 It is easier if you know the numbers of the ones you want. Here are the ones I have: Large Frame Repair manual TP-973 7100 Series owners manual 1701323-01 Parts Manual 7100 Hydro Series TP 400-0843-04-SV-S Parts Manual Attachments & Acessories TP-861-05 Owners Manual Vacuum System 177850 Somewhere around here I have an original 700 series owners manual also. I will see if I can dig it up and get the number off of it for you. I also have all the books coving the B-series and attachments plus I just picked up a set for the Sunstar Series. This set includes an interesting "Do It Yourself Service Manual" book that has an immense amount of info on these tractors. Enjoy your machine, they are very addictive. ( I have 4 of my own and just finished rebuilding a 5th for one of my Pastors.) Rob

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Guest
Thanks again for the great info. I have one other question I could use some help on-When I detension the mower deck belt, how freely should the pulley on the driveshaft rotate. This is the pulley that contacts the clutch when the PTO is engaged. I would think that this should turn freely on the driveshaft out of the bevel gear box but am not certain. Help would be appreciated!!!!

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Guest
Yes, with the PTO disengaged the pulley should turn independant of the shaft BUT it should not "spin" or turn easily. That pulley is spring loaded, therefore there is considerable resistance (be careful). The pulley should have 1/8" movement (slide on shaft) between the PTO engaged - disengaged positions. You'll read all about it when you receive your manuals. By the way, have you asked the previous owner about the "extra" keyway? Was the bevel gear box worked on while he owned the tractor?

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Guest
Thanks for the info. I may be lucky on this and get the clutch to stay put if I get the proper torque on the nut. Although the keyway is damaged, everything works properly until the nut comes loose. The first time I put it back on, I did not torque it sufficiently. There is no wobble in the clutch and the shaft diameter has not been affected. I am going to tighten it down and see what I get. Also, the mower deck pulleys need to be lubed and the blades sharpened. If I do this, I beleive there will be less drag on the belt/clutch. I will keep you posted. I am going to order manuals. I tried all day Friday at Simplicity and all I got was a recording that they were out of the office. I left a name and no one got back to me. I am suspicious that the one "pamphlet person" was off for the Labor day weekend. I will try again Tuesday. After I get manuals and try this beast out, I will have a better idea where to go. Thanks for the great info!!!

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Del
Dennis, I just replaced the output shaft on my 712. Same situation, I could no longer keep the cone clutch from rattling (bad keyway and shaft no longer the right diameter). I removed the BGB and did the replacement on the bench, my bearings, seals and bevel gears were good. I just replaced the bad shaft. Time to fix the BGB about 20 min.>>> time to get the BGB out and back in about 3 hrs. (includes clean up of parts). Suggestion you only need to remove (or get very loose) the right side plate ( the plates that connect the BGB to transaxle), leave the left side connected. Good Luck, MS

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Del
Dennis, Read message #1725 for a discussion on BGB R&R. JeffNemes and DLCENT have considerable experience, their comments should be weighed accordingly. I agree with the time estimates given by MikeES for the actual work. However, since this is your first time working on a BGB, add some time to read and digest information found in the repair manual. If your shop is like mine, add more time clear out other stuff to make room for the project. And, don't forget "Murphy's Law."

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Ishmael2k
Dennis, you may try this: The new shaft I just installed came with a self locking nuts for both ends of the shaft. The new shaft has a larger nut on the cone clutch end than the original. So try a self locking nut on the cone clutch to keep it from coming loose. MS

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