Craftsman Tractor PTO Bolt

[lefty]

917.203910
Engine: 44R677-0019-G1 150202YG

I have this tractor that came to me because the PTO fell off while in use. The threads on the PTO bolt were mangled pretty good. The threads in the crank took a hit too. I'm guessing the bolt backed out and road on just the end for a while before falling completely out.

I have two questions: First, can I clean up the threads in the crank with a regular tap? Or is that crank harder than the tap?
Second, I ordered an OEM replacement bolt. But it's 4". The original is 3.75". I'm wondering if that matters? It has the same amount of threads but the shaft is longer.

Thanks.

[bgsengine]

Nah crank isn't hardened - You can cut em with a hacksaw, so obviously a tap will cut the threads too. As for bolt length, as long as it does not bottom out and leave the clutch loose, it'd be fine.

[KE4AVB]

First the 532179953 as being 7/16-20 x 3.75.

Actual bolt depends on how you measuring it. Normally it is measured under the hex head to the tip. If include it will added about 1/4 when 5/8 hex is involved. IF what you receive is a true 4" screw then you probably will need to use washers to get it down to 3.75. But I would just get the right length; although, you can try it before to see if it bottoms out or not when installed with the clutch and no washers.

I would use a good quality bottom tap not not some el cheapo from Walmart, Lowes, Home Depot, etc. And especially not one from Harbor Freight as those are true junk. Might have to use a starter tap and finish with a bottom tap.

BTW I would order a pack of screws from McMaster Carr as those Husqvarna screws lists for $5.99 and costs 3.90 ea here from the distributor plus shipping. From McMaster they are 13.19 for 10 plus shipping.

[lefty]

Thank you very much.

[Arkie]

I've seen those back out like you describe.
They are usually not torqued properly.
In your case I would carefully do the torque with a torque wrench, not a impact driver.

Since you have probably lost part of the threads inside the crank I would consider doing as KE4 suggests but try to not use any flat washers, just a lock washer. Slight chance the 4 incher might not bottom out without using flat washers. Those are fine threads so if your tap cuts instead of chase's the remaining good threads you are most likely sol.
When you add flat washers to the longer bolt and a lock washer you are weakening/defeating the securing purpose of the lock washer.
I would also try to use at least a grade 5 bolt and use a Blue of Green locktite AFTER cleaning the internal crank threads really good. If it comes loose again, you stand a good chance of losing the crankshaft. Do a test fit of the re-tapped threads and the bolts length and measure to make sure the bolt is not bottoming in the crankshaft threads BEFORE INSTaLLING THE PULLEYS.Do not assume the original bolt was the correct length. I've seen several different lengths of bolts used due to the difference in the pulley from tractor to tractor.
You need to examine the keyway's really good, especially the lower PTO pulley if of the electric type or two piece pulley type so as to make sure no twist torque wobble is being applied to the bolt's head and lock washer as the engine runs due to the key or KEYWAY being damaged or the bolt will work loose again.

[KE4AVB]

There is a thread repair tool that can work backwards to restore the threads but are high and prohibitive for one time jobs. They restore one thread at a time using a pad to track the threads. I haven't tried one due to costs.

[lefty]

I've seen those back out like you describe.
They are usually not torqued properly.
In your case I would carefully do the torque with a torque wrench, not a impact driver.

Since you have probably lost part of the threads inside the crank I would consider doing as KE4 suggests but try to not use any flat washers, just a lock washer. Slight chance the 4 incher might not bottom out without using flat washers. Those are fine threads so if your tap cuts instead of chase's the remaining good threads you are most likely sol.
When you add flat washers to the longer bolt and a lock washer you are weakening/defeating the securing purpose of the lock washer.
I would also try to use at least a grade 5 bolt and use a Blue of Green locktite AFTER cleaning the internal crank threads really good. If it comes loose again, you stand a good chance of losing the crankshaft. Do a test fit of the re-tapped threads and the bolts length and measure to make sure the bolt is not bottoming in the crankshaft threads BEFORE INSTaLLING THE PULLEYS.Do not assume the original bolt was the correct length. I've seen several different lengths of bolts used due to the difference in the pulley from tractor to tractor.
You need to examine the keyway's really good, especially the lower PTO pulley if of the electric type or two piece pulley type so as to make sure no twist torque wobble is being applied to the bolt's head and lock washer as the engine runs due to the key or KEYWAY being damaged or the bolt will work loose again.

The part number for the bolt was superseded. Maybe they went with a larger bolt for better engagement. Maybe that's why this one backed out in the first place. I'll know better once I check the depth and test fit everything. I'll keep you posted. I'm thinking about removing the engine to do this so I can see what I'm doing a little better. Looks like the toughest part about removing it is you have to pull the PTO and pulley, which are already off. Thanks to all.

[KE4AVB]

As far as the database provided by both of my distributors the screw [bolt] has only been superseded once and both the old PN and new PN says the screw is the same; just that Husqvarna add the prefix 532 to the part number and I use "HUS" to indicated Husqvarna PNs from say MTD PNs or STL PNs.

[lefty]

Thank you. I spoke with the seller of the part and they told me if it doesn't fit they'll replace it. I still haven't gotten a chance to check it out though.

[lefty]

Finally got this one back to my shop. I removed the engine because I'm too old to be crawling around underneath this thing and I thought I had a better chance doing it right if I had a good bead on the job.

I was able to chase the threads with not much effort. The first few were really banged up so there was some cutting there. But most of it I was able to do by hand with just a tap socket for grip.

I did a quick fitup and there's plenty of room for the longer bolt. I think that may work out better for me. Since there was some cutting, more bite can't hurt.

The original configuration was a beefy 3/16" thick flat washer that mates with the inner race of the PTO bearing followed by a split lock washer.

I learned my lesson removing this v-twin so I think I'll wait for a friend to help me put the engine back in place.

Should I use thread locker on the engine mounting bolts? It didn't look like there was any on them when they came off but given that it's a reinstall, I was wondering if some blue might not be warranted.

Thanks