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hufhouse

Mower deck leveling

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hufhouse
I purchased a Simplicity 7117 (circa 1990 or so) two months ago. It replaced a "Home Depot" Scotts tractor made by Murray. What a difference! My dad had a Simplicity (a little 6.75 HP tractor) that I mowed the lawn with when I was a kid. When I bought a couple of acres, I started looking for a lawn tractor, and was convinced that a cast iron front axle was a symbol of quality. Boy, was I wrong! Anyway, this 7117 is a real machine, not a toy! Sorry, I got off my topic for a second! When I bought the 7117, the dealer told me that it could only mow up to about 2-3/4 inches. I tried it out before I bought it, and I was so impressed with it I really didn't care that it cut pretty low. However, I started looking in on the conversations here, and I decided I would try some of the suggestions that I had seen posted here before about levelling the deck according to the manual directions. One evening a couple of weeks ago, I spent about 2-3 hours trying to get it just perfect. What a difference. It now mows up to about 3-1/4 inches, which is fine with me. I also replaced all the rollers, which probably helped, too. Here's my question (finally). I lengthened the bail assembly arms by turning the yokes. However, I really had to turn the yokes A LOT to get the front of the deck 1/4" higher than the back. The threaded part of the bail assembly arm that goes into the yoke is probably only threaded about 1/4"-3/8" into the yoke. For as much weight/stress that is probably put on that area, that doesn't seem like it is enough. Adjusting the yokes seems like a FINE adjustment. Is there another major adjustment that I need to make somewhere else so that I don't have to overextend the bail assembly arms?

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UCD
Length of thread is only as strong as thickness of rod,shaft,bolt etc. 1/4" rod = 1/4' of thread, 3/8" rod = 3/8" of thread, 1/2in rod = 1/2" of thread ETC. This & $1.00 might get you a small Coffee Maynard aka/UCD

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Dutch
Guy, I would feel uncomfortable with only 1/4" of thread in the yokes. Start at the beginning and make sure the tractor has the correct size tires with the correct air pressure. Are the wheel spindles loose on the axle? Next check every joint in the deck for looseness (there are quite a few). The yokes are for adjustment only, not for taking up play in loose joints. Are you using the correct disameter pins to attach the deck to the axle? You replaced the rollers, did they have bushings? Is the roller shaft worn? Last, does your deck use "straight" or "gull wing" blades?

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BigSix
Guy: I think I know this one: on my 1960 42" #190 deck, there are two sets of holes in the front "rocker arms" (that's what the manual calls them) that get pinned to the tractor itself. I believe the previous owner had used the rearward-most holes. For what I was trying to do (level deck AND have belt clear the deck bail, on a Landlord) I had to use the forward-most holes, and this meant a lot of change in the clevis's position. The action on those clevises is counter-intuitive, IMHO, (i.e., the higher "up" and rearward you wind them on the bolts, the lower the front of the deck drops. Anyway, see if you have a second set of holes, and try them, even if it looks like it will mess up your leveling. It worked for me, and front is now 1/4-3/8" higher than the rear. (The #401's manual calls for the former dimension, the #190's calls for the latter). Let us know! Peter

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HubbardRA
About the threads, to get the strength of the threads to match the strength of the rod you need a thread length of engagement of about 2 to 2 1/2 rod diameters, depending on the type of thread and precision of the fit. On a 1/4 shaft, if you only have 1/4 of thread, then the thread will always be the part that fails. Rod H.

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hufhouse
I just realized that I never answered Dutch's questions... 1. The tractor does have the correct, original tires. 2. The tractor's steering is pretty tight (not a lot of play), so I don't think the wheel spindles are loose on the axles. I guess I would need to lift up the front end to really find out. 3. The pins that attach the deck are tight in the holes, not sloppy. 4. The rollers didn't have bushings, they are nice and tight on the shaft with just enough gap to roll freely. 5. I replaced the roller shaft along with the rollers, because I discovered to my dismay that you cannot back up a Simplicity next to the driveway without bending or snapping the roller shaft. 6. The mower deck uses "gull wing" blades. The mower deck is Part Number 1691219. The only thing I don't know is whether there are any loose joints on the deck. Here in Ohio, we are having BEAUTIFUL weather this weekend, but everyone in the house has already planned my weekend for me. I will try to take the time (before fall!) to pull the deck off and give everything a jiggle.

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Roy_Wooten
UCD, If you look at all the bolts and nuts made today you will realize you are right. A nut for a 3/8" bolt is only approximately 3/8" thick, for 1/2" bolt it is 1/2" thick, etc. I believe 1/4" on the fine threaded rods are not going to cause a problem unless the deck gets bound up severly. Roy Wooten

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Al
;Hi, We usually set these decks about 1/8 to 1/4" high in the front. That is what they have suggested in serivce schools over the years. If you have wear in the front rockershaft or the bushings it pivots on, or on the ends or brackets on the rear shaft that the arms go to the roller bars, all of this slack will cause the front of the deck to droop. Also tires vary in OD up to an inch or more depending on brand. A little kint. we use 2 bolts with threads most of the length and put nuts on them. We set them on the floor and reach under the deck and run the nuts up until they touch the bottom of the cutting edge of the blade. Use opne for each side or 1 for front and 1 for rear. You can do this by feel without having to see under the deck. Take the 2 out and set them side by side and you can see the difference instantly. A couple of the feet out of appliances like a dryer etc work great as they have a large "head" and set well on the floor. Much easier than trying to measure any other way. Good luck, Al Eden

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hufhouse
Al- Right now, I'm feeling pretty smart, because I came up with a similar idea when I was leveling the deck. I used a 4" threaded bolt with a nut. To check side-to-side, I just adjusted the nut to the bottom of the blade on one side, then went to the other side to see where I was at. Same for front-to-back. That was a lot easier than actually measuring. (I do a little woodworking, and I usually only measure the first of something, then use it or a piece of scrap to measure the rest.) I think your idea about the feet from an old dryer would be perfect, though. I didn't mean to start a riot or anything about the strength of threads, but it was certainly interesting!

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HubbardRA
UCD, In wasn't trying to cause an argument. As a machinist, I'm sure that you know about the different classes of threads, and the different types of steel. With what I stated above, the shear strength of the thread will always be more than the strength of the bolt. This also assists with the galling effects of tightening and loosening rusted or highly loaded bolts. I just usually over design everything so that I don't have problems. No offense meant. Rod H. Rod H.

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