Craftsman Riding Lawn Mower cutting uneven

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  #1  
Old 05-04-13, 03:47 PM
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Question Craftsman Riding Lawn Mower cutting uneven

Hi guys,

I'm having some trouble with a Craftsman 38' Riding lawn mower (about 6-7 years old I believe, not quite sure as it is my mothers). It's a two blade model. I'm getting an uneven cut in the middle of the deck. It's cut maybe an inch or so deeper than the rest of the lawn leaving a deeper cut streak almost right in the middle. I believe it's possibly something to do with the left hand (opposite of grass discharge) side. I've replaced both blades (triple checked, they're the right side up and properly installed), and have adjusted/measured the deck to the best of my ability after watching a couple youtube vids on it. No luck.

Worth noting, I'm also hearing what sounds kinda like mechanical/metal noise when the blades are turned on..noticeable and consistent noise, but I don't believe the blades are hitting anything. Sounds a bit rough. Could this be the mandrel? is that piece an entire assembly or are their multiple parts to check (pully etc.)?

Worth noting I think the front of the deck might sit a tad lower than it should. It's roughly an inch to an inch and a half lower than the back. Is that about right or should I raise it up some?

My mom had mentioned that she ran over one of those metal pieces from the bottom of a newspaper mailbox (blades running) in a section of lawn that she never used to mow(last season). I'm not sure if that correlates exactly to this or not as I wasn't around for the before/after. Not sure if it was having this problem last season. Mom's getting a bit older and I doubt she'd be able to tell me if there was an instant change when she hit it or not.

Any help would be appreciated guys! Just trying to get her mower cutting even again so her lawn quits looking all jacked up. She mows regularly so it's a shame that it looks uneven. Thanks in advance!
 
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  #2  
Old 05-04-13, 08:11 PM
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Could be a lot of things given your description. Anything from a warped deck to a bad bearing. Do the blade tips line up evenly under the deck? Do either of the blades wiggle up and down?
 
  #3  
Old 05-04-13, 08:30 PM
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The blades don't seem to wiggle.

They're not even from tip to tip under the deck. Like, if I spin them slowly by hand past each other there is a noticeable difference in height between the two when the blades reach the middle.
 
  #4  
Old 05-04-13, 08:56 PM
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Ok, then leave one blade there and rotate the other so that you can check the other tip. Is it higher or lower? If it's the same, leave that one and rotate the other blade and see if the level changes. If so, the shaft of the blade that is different from one end to the other is bent. If not, then look at the mandrel housing where it is bolted to the deck. Many times it will break at one of the places where it bolts to the deck and allow the entire assembly to tilt. If so, replace the mandrel housing. If not, the deck is warped. It can be straightened, but you'll need to remove it.
 
  #5  
Old 05-04-13, 09:27 PM
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Ok. I'll do the blade thing you mention tomorrow as well as check the mandrel housings to see if there is any obvious breaks. I'd do it right now but I'm pretty sure my wife would kill me for heading over to mom's this late at night lol.

I've never taken the deck off of this lawn mower before, but I have taken other decks off lawn mowers so I'd be up for it if need be.

Do you think if I posted some pics that could help? I'll be out messing around with it tomorrow anyway.
 
  #6  
Old 05-05-13, 05:11 AM
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I'd bet the arbor (shaft) is bent on the spindle (the housing with the bearing where the blade mounts to).
I'd just buy a whole new housing with the shaft and replace it.
Make sure to also get the bolts and nuts that hold it to the deck. More often then nut the old bolts will snap off.
 
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Old 05-05-13, 06:24 AM
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Likewise, I think it is "tower" change time. Hitting metal is not a good sign. Don't worry, my mom did the same thing.....more than once.
 
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Old 05-05-13, 02:21 PM
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Pics and such

Ok guys, here's some pics. I did the blade rotation stuff you mentioned Cheese. It seems both of the blades vary in height when rotated. The grass discharge side almost hits the top of the deck at points it's probably about an inch(moving upwards toward the deck when rotated), maybe slightly more off it seems. The opposite blade of the grass discharge side, height doesn't change much, but it dips down (in the opposite direction of the other blade) by maybe a half inch in the middle. There is only one turn combination where they are about even. Both combinations showed in the pictures.

I found the parts manual and posted some stuff from it. Also posted a picture of where the bolts attach the housing to the deck and they seem in good shape with no breaks and no rust. One of the pulleys seems to have a bit of rust on it, but otherwise it doesn't really seemed warped or anything. Also some pictures of the uneven cut. After taking the pictures I think I should probably clean the grass from the deck....haha

Now I have a ton of questions so bare with me lol...

1. Will I need to replace both complete "towers"? Or should I try and just replace the shaft assembly's (no. 13 in the parts picture) in both?
2. Would it make sense to try and only replace one (to save some money) and see if that resolves the uneven cuts, or would that be wasting time?
3. What parts in the picture diagram that I posted create this "tower" that is being refered to? does that include or not include the pully?
4. Would these parts be available at a sears store I would think? About how much does a "tower" cost? any good place online where I could get them cheaper?
5. Anything special about getting this "tower" off? or is it just taking the blade off, and then removing the 4 bolts attached to the mandrel housing like it seems?

Really appreciate the help thus far guys. Up until recently I didn't know much about the inner workings of the deck portion of riding lawn mowers. It's starting to make some more sense now.
 
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  #9  
Old 05-05-13, 03:02 PM
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Did a little searching online. Is this the "tower" mandrel assembly? It fits the part number from the manual.

http://www.amazon.com/Husqvarna-1928.../dp/B0057INPHK
 
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Old 05-05-13, 03:34 PM
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IF it matches the numbers, yes, you need part 13 and 14, plus possibly new bolts. Part 16 is not listed, so not sure if it is replaceable or if it is reusable.
 
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Old 05-05-13, 06:06 PM
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If the bearings are good, and the housings are not broken, then you just need the shafts (#13).
 
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Old 05-05-13, 06:36 PM
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Can the housing become bent/warped as well? or is it good if it looks alright and isn't cracked or showing obvious wear?

At this point I feel pretty certain both shafts are bent and I should get two of them. So just trying to figure out whether or not I want to buy that entire Mandrel Assembly that I linked to, or see if I can just find the shafts and save a couple bucks.

Concerning the bearings, will it be pretty easy to tell if they are still good? and should I spray some wd40 in them once I have it apart for maintenance sake?


Thanks again guys, very helpful and informative.
 
  #13  
Old 05-05-13, 06:50 PM
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Well this is disappointing...I can only find the shaft online for roughly $23 dollars each. The entire Mandrel Assembly (bolts, shaft, housing) I found for $30 each. Almost seems like I should just bite the bullet and get two of the entire assembly just in case? Price difference would only be about 14 dollars.

Here's hoping the bearings are still good.


Update: actually, I just found the Shafts for $15 each. Now I'm not sure which route to take lol
 

Last edited by darcyw; 05-05-13 at 07:17 PM.
  #14  
Old 05-05-13, 07:33 PM
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I know it sounds strange but check the tie rod between the two front wheels. It's part # 32 in this diagram http://www.searspartsdirect.com/part...dMod=917275351.

I had a similar problem last summer and after replacing blades, mandrels, etc. I finally corrected a problem with my steering and the uneven cut went away. The tie rod should be straight, with no bend at all.

Good luck!

Jim
 
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Old 05-06-13, 09:45 AM
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For $30 total difference I'd be inclined to change the whole assemblies. The housings don't generally warp, they break. The center link between the front wheels won't cause the blades to become misaligned like in the pics above.
 
  #16  
Old 05-06-13, 03:30 PM
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I ended up picking up two of the mandrel assemblies online. They came with the bearings as well so I figured why not. I also got the bolts for the housing as well in case mine break when I'm taking them off. Should be here near the end of this week. I'll keep the board posted on if it resolves the issue. I feel pretty confident about it now after this process.

I'll also check the tie rods next I'm out just to be safe. Thanks much so far!
 
  #17  
Old 05-06-13, 05:34 PM
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Well, the tie rod seems to bow up slightly in the middle. Doesn't seem as straight as in the pictures I found for the part online. I'll post a pic of it here in the next day or so. oi...lol
 
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Old 05-06-13, 06:37 PM
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If the bar is bent, it causes the front wheels to splay outward.
 
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Old 05-07-13, 05:03 PM
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Cheese,

Don't be too quick to rule out the tie rod. I have a similar Craftsman mower that mowed a path about like the pictures shown. I posted on it last summer (this post -- http://www.doityourself.com/forum/ou...neven-cut.html)

I had replaced the mandrels & blades, adjusted the deck and it still mowed that way. I was ready to replace the deck this spring but noticed the wheels splayed as you say so I replaced the tie rod. I didn't expect it to have any effect on how it mowed. I still don't understand how it could have that effect, but it did!
 
  #20  
Old 05-07-13, 09:58 PM
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Yes, it can change the way the mower sits, changing the way it cuts by letting the front down... but it can't possibly cause the problem shown in the pictures. The blade tips are uneven, meaning something is wrong with the deck and/or related parts. Yours was cutting uneven for another reason.
 
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Old 05-08-13, 12:53 PM
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OK Cheese. I'll bite. The first time I mowed this spring it was still cutting as in the pictures he has. I didn't see the need to take my own, but when I look at my place on google maps satellite view you can see the rows, so yes it was bad! The only thing I changed was the tie rod and then it mowed properly! Since you obviously know everything about this machine, please tell me what self-corrected to make it mow properly. I've mowed 5 or 6 times since then and it is still mowing properly,
 
  #22  
Old 05-08-13, 03:56 PM
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Jim, I think what Cheese was saying is that your issue was very possibly different, even if it created similar uneven grass symptoms.

I think when he referenced the pictures in his post (saying a bent tie rod couldn't cause that) he was referring to the pictures I took of the blades, and that it would be unlikely that a bent tie rod would cause my blades to be displaced under the deck like they are in the pictures. I noticed in your thread that you mentioned your blades were level under the deck...Mine, even though I replaced the blades are not unfortunately. I don't think he was referring to the grass picture...and thus, your bent tie rod could have caused the uneven cuts you were experiencing and when you replaced it, it resolved your issue.

Anyone please correct me if I misinterpreted that, but I think it's about right. Keep it civil folks

I'll post a pic of the tie rod next I get a chance to see what everyone thinks of it. My wheels don't seem to be splaying outwards and I didn't notice any steering problems however, so I still have high hopes simply replacing the mandrel assemblies will resolve it (crosses fingers). Anyway I look it it something was up with my blades turning probably in a tilted circle style fashion. I've also paid particular attention to the sound it makes last I ran it...and it is pretty incredibly noisy just with blades on sitting still. So here's hoping the new assemblies (which also came with bearings as well) help with that.

I'll keep everyone posted once I get the new parts in and get a chance to take some more pics. Thanks much guys!
 

Last edited by darcyw; 05-08-13 at 04:18 PM.
  #23  
Old 05-08-13, 05:43 PM
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Jim1957, actually, I DO know everything relevant about these mowers. I own and operate a small engine shop and have done maintenance and warranty work on mowers just like yours for over 20 years. This is my most commonly worked on mower and I can work on them with my eyes closed and even tell you what size bolts are where, and I know part numbers off the top of my head, but that's beside the point. Please tell me how you think a bent steering rod can cause the blade tips to not align with each other like shown in the picture? (the picture showing the blade tips under the deck).

You want to know what happened with your mower? I'll indulge you. The center bar that connects the two wheels commonly gets bent when the mower hits a solid object (like a tree trunk, the corner of your house, or whatever you hit). It pushes the bar upward in the center, which also splays the wheels outward and reduces the steering radius. Also, since the kingpins aren't perpendicular to the ground, when the wheels splay out like that, the level of the axle lowers. When this happens, the front of the deck dips down. Well, if you pay attention to the blades on your deck, one is in front of the other by a few inches. When you dip the deck down in the front... you guessed it... the blade in front cuts deeper than the blade in the back, because it is closer to the ground. This causes your uneven cut with a bent steering tie rod.

When I see this, I pop the little cotter pins out, lift the tie rod out, straighten it, and put it back in. Sometimes, however, the tie rod bends up far enough that is rubs the engine pulley and I have seen cases where it rubbed the tie rod so thin that it would have bent easily again and replacement was required.

That should be sufficient discussion for that topic. Darcyw, let us know what you find! Hopefully it's the shafts that were bent rather than the deck warped.
 
  #24  
Old 05-09-13, 02:50 PM
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A DIY check on my deck/alignment. I set my cut height to 4", cut a piece of 2x4 4" inches long. I use that with the 2x4 standing on end, ground level to bottom of blade, rotate the blade 360 degrees and repeat every 90 degrees on both blades to see if it is setting level, adjust as required. Left/right & front/back. ??
 

Last edited by Mike1555; 05-09-13 at 03:05 PM.
  #25  
Old 05-12-13, 05:59 PM
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Mike, Seems like a more thorough way to check the deck alignment then what I did. I just went around the deck with measuring tape and adjusted according to the manual to try and get it as best I could.
 
  #26  
Old 05-12-13, 06:19 PM
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More pics, got parts in.

My parts arrived Friday! I got the chance to put them in today. I replaced both whole mandrel assemblies (tower/housing, shaft, bearings). It sounds a lot better than it did. No metallic sound when blades are running and it sounds like it did when first bought awhile ago. The mower seems to be running better with the blades on as well now. It struggled a little before to get the blades started and now they get moving instantly. I only got a chance to cut briefly cause it was getting dark, but the cut was much improved, and it looked even as far as I could tell. No streaks in the grass like before. I might adjust the deck a little more depending on how the cut looks next my mom mows her lawn...but overall, much much much improved.

The blades are now even under the deck together and that is sweet!

I think both old shafts were slightly bent, or at least one of them and one of the housings was actually broken in two sections (see pics). I just didn't think to check under the deck as I've never worked with the housing before...novice mistake on my part. Glad I got the entire assemblies. Some of the bolts broke like people mentioned they likely would, glad I got new bolts. The biggest pain in the butt was getting the nut off that was right above the spindles..it was on incredibly tight, but was able to get it off by wedging the blades, and then a good hard push with a large adjustable wrench.

I took pictures of the tie rod. It is bent in the middle, although not much. Think you guys could take a look at the pictures of it and let me know if you think i should do anything about it(replace or bend it straight)? Not sure how severe it is. The tires don't seemed splayed outwards and I haven't noticed any issues with the steering...but not sure.

Again, thanks for all the help guys! This was something I've never done before...I feel mechanically inclined but haven't done much on riding mowers. All of the advice given proved to be very very very helpful. Much appreciated.
 
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Old 05-12-13, 06:34 PM
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Good job! Yeah, the broken mandrel housing will definitely cause the problem. I t allows the assembly to tilt, and that causes the uneven cut and it creates slack in the belt which is why it struggled to get the blades up to speed.

The tie rod bar is bent, although not severely and probably not enough to be creating any cutting problems. It should be removed and straightened. It is bent enough that the wheels are not quite aligned (when you set them to be straight, the right one is going to be slightly more right than center, and the left one more left than center). Maybe not enough to notice, but it will effect steering ability and tire wear.
 
  #28  
Old 05-12-13, 07:28 PM
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Kk. I'll see if I can bend the tie rod straight next weekend when I get the chance. Yeah, I'm surprised I missed the broken housing. It was the one on the left side if sitting on the lawn mower. Was in really bad shape.

A nice plus though is the other replaced housing seems in decent shape, so when my mom inevitably hits something and breaks one of the new ones I'll have an instant replacement lol! (I hope I'm joking)

Thanks again man
 
  #29  
Old 05-24-13, 06:56 AM
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i have a craftsman 42 inch and i have had this problem since the day i bought it.
while it was under warranty, i have sears come out and adjust it. they couldnt find anything wrong.

since then, i have replaced the blades, removed the deck and checked everything.

i have the similiar symptoms where the center is cut lower. on the left blade side. it looks like crap when cut.

i have been trying for years to figure it out.

very interested in everyones outcome.

I dont have broken or bent mandrels. but will check the tierods.
 
  #30  
Old 05-24-13, 08:19 AM
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Hey gofly

Hi gofly,

Well, I'm not a total expert, but I can summarize what resolved the issue for me. Cheese's post #4 was very informative for me (the one explaining how to check and see if the blades are lining up with each other under the deck). If you haven't checked that yet, I'd give that a try for sure.

I had already replaced the blades, and adjusted the deck best I could before starting the thread. After suggestions from some people I replaced the entire mandrel assemblies (housings, shafts, bearings) and that resolved my issue. My left side housing was actually broke in two places, both shafts seem to have been slightly bent, although I haven't taken apart the old housings to see. The old bearings look ok I think.

I haven't gotten to straightening my tie rod yet, but it doesn't seem to be effecting my grass cut, so I don't think it's bent very bad. I do notice when turning while cutting that it looks a little rough on the cut, so maybe the tie rod's slight bent is contributing to that. Figure I'll get to the tie rod eventually when I have the time.

If I were you I'd consider starting a new thread (because most people checking this one realize my issue was resolved), and taking a lot of pictures to post. Not only did the pictures make me more conscientious of what could be the issue, but I think it provides a layer of information to the experts that is difficult to explain in words.

Hope some of that helps man, good luck!
 
  #31  
Old 08-02-13, 07:22 AM
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Just wanted to chime in and say thanks to Cheese for his replies. I let me neighbor borrow my mower two weeks ago and I started having the same problem with the abnormal cutting pattern. After trying to level the deck and figure out the problem, I came across this thread.

Last night, I went home and pulled both spindles. The right spindle was fine, but all 3 mounting studs were broken off of my left spindle. I'm lucky nothing else was damaged. Parts on order now. Thanks for the info.
 
  #32  
Old 08-02-13, 08:26 PM
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No problem, glad you found some useful info!
 
  #33  
Old 05-13-14, 11:48 AM
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Aksmith

I've mowed once with my new Craftsman 19 HP, 42" mower, Model 917-20381.
My problem is uneven mowing when mowing on a curve. The inside of the row is nearly scalped and the outside is at the set height. This occurs when mowing slowly or faster. On the straight it mows evenly. What could I do to keep the deck flat?
 
  #34  
Old 05-13-14, 09:38 PM
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I would suspect the front of the deck is much lower than the rear.
 
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