Mandrel Threads self tapping?

[GreeCguy]

Howdy fellow bitogers.

I have an Ariens riding mower
model #93604600/A175BG42
42 inch deck
Gear drive tractor with a 17.5 h.p. motor

About two weeks ago while cutting my grass, I hit a piece of metal with my mower blade. At first, it didn't seem to do any damage and I finished cutting the grass. When I went to cut my grass last week, about half way through, the deck started shaking very badly and when I shut the mower down, realized that the four "ears" that hold the mandrel in place were broken, (the bolts that hold the mandrel to the mower deck pass through these "ears"). Apparently, when I hit the metal these "ears" cracked and finally broke all the way. I ordered a new one and it came in Friday of last week.

This evening I removed the old mandrel and was about to install the new one when I noticed that the old one is threaded where the bolts pass through the mandrel while the new one is smooth with no threads.

Two questions:

1. Are the bolts self tapping? When I install them, will they cut new threads into my new mandrel or do I have to find a tap and die and thread them myself or find new bolts with nuts to attach this new mandrel.

2. Through a mix up or misunderstanding, the mandrel I received is the mandrel only, nothing inside, so I have to remove shaft and bearings from the old broken mandrel and put them in the new mandrel. Any hints or tricks to doing this or is it just a matter of bumping the old ones out of the old mandrel and tapping the new ones in with a hammer?

Any and all help will be greatly appreciated as my yard is starting to look like a hayfield.

 

[Donald]

I fixed someone's John Deere and thought something was odd as the holes in the new mandrel we not tapped. The bolts they give you are self tapping. They want them tight and never come out, that is what I was told. I think I snapped half the bolts on the old mandrel getting it out.

 

[Rand]

are you referring to the deck spindle?

 

[GreeCguy]

Yes, deck spindle, (though in the parts catalog it's called a "mandrel").

They didn't give me new bolts, just the empty mandrel. I did manage without much difficulty to removed the old bolts out of the old mandrel. Was planning to tackle it tomorrow by putting the new mandrel in a vice and slowing working the old bolts in the bolt holes. Now I'm a little worried they might get stuck and break off. I'm thinking however if I go slow working the bolts slowly in and out allowing the cut metal to fall away and clear and using plenty of oil, I should be okay. Sound okay to you guys?

 

[Charlie1935]

I have in the past cut a couple of groves in a bolt at the end a 1/4 of an inch long and they cut threads as they went in.
Have to keep steady pressure on them to get them started.

 

[tnt31]

The threads are self tapping. I always order new bolts whenever I do one but my guess is the old one's are OK but maybe someone else can chime in on that.

I have never just used the mandrel body and replaced the guts as I can usually find the whole mandrel assembly for not that much more so I just do that because it just seemed easier.

 

[GreeCguy]

Originally Posted By: tnt31
I have never just used the mandrel body and replaced the guts as I can usually find the whole mandrel assembly for not that much more so I just do that because it just seemed easier.


That's really want I wanted to do, (order a whole new assembly for the very reason you mentioned), but either I didn't say it clearly enough or the fellow at the parts counter didn't understand me but I ended up with just the mandrel which I'm going to try to swap out today. I'm thinking as well of adding a grease fitting to this new mandrel as long as I have it apart.

 

[Oldmoparguy1]

My rider, Poulan 42", (ayp) Is 16 years old and I have broken 6 or 7 of those spindle castings. I have broken the bolts on at least 2 of them. My first fix was to tap the holes and use some grade 8 surplus bolts I had. I used blue loctite to secure them. That worked but they still rusted. The last one I used stainless bolts on. Haven't had to replace once since so don't know if I created some new issue.

Going to have to replace the carb soon, E10 has trashed it. ~$140. Yikes!!

Wayne

 

[dwcopple]

Originally Posted By: Oldmoparguy1

Going to have to replace the carb soon, E10 has trashed it. ~$140. Yikes!!
eBay

 

[GreeCguy]

Thanks to all for guidance and wisdom. The great swap out went off without a problem, however once I had all installed and I installed the mower blade, that's when I noticed the shaft was slightly bent. Am going to try it today to see if it's bad, if so, looks like new shaft time.

I did install a grease fitting on the mandrel, removing the inner seal on both bearings so that I can grease the bearings with my grease gun. Following Charlie1935's advice, I used an old bolt to cut the threads for the grease fitting which was surprisingly easy. The whole job took about 30 minutes.

 

[GreeCguy]

Finally got the mandrel, spindle, blade back on the mower this evening and managed to cut my grass (FINALLY). As I was mowing the back yard, I seriously thought I could park a car back here and no one would know.

As you might recall, it wasn't till I had everything back together that I noticed the shaft was slightly bent. However, I went ahead this evening and reinstalled mandrel hoping it wouldn't be that bad. Mower does have a slight vibration, (it's not the blade as I sharpened and balanced it before I reinstalled it), but I'm thinking it will get me through the season. My only real concern is that this slight vibration will crack the new mandrel as the metal is very soft, (like lead), but I didn't want to be down another week as by that time the house might have disappeared behind the grass.