hutchman
Veteran Member
- Joined
- Mar 11, 2014
- Messages
- 1,447
- Location
- Central Virginia
- Tractor
- LS R3039, Deere SST16, Ariens APEX 60", Polaris Ranger 900 XP EPS
Anyone that followed my backhoe subframe build knows that my dealer didn't properly do my warranty work on the engineering change LS did to address the engine subframe cracking on early R3039 tractors.
So I did the repair the "right way" myself. When I tried to tighten the new 10.9 grade bolts to the new 80ft. lbs. spec, one of them would just pop! Stripped out!
So having access to a Mechanical Engineer at work that used to work for Catepillar ... he said "heli-coil" it. I said "don't you have to use some kind of install tool to put it in the hole?" "Yes" was the reply (which I already knew). "No Way" I said.
In order to install the heli-coil, I'd need to remove the loader mount and engine subframe from the left side of the engine to get directly to the bolt hole in the engine block. To get the loader mount off, you have to remove a hydraulic hard line from the pump that runs on the outside of it. Taking the engine subframe off is even a bigger deal. I took the loader mounts off before and liked to never got it back together. The hardest part believe it or not was getting the banjo bolt to that hydraulic hard line started. There is practically zero clearance to get to that thing with a wrench or socket. After experiencing that once ... no way was I going to sign up to do that again. So my next bright idea was to drill the hole out ... going from a M12 to a M14 leaving the loader mount and engine subframe in place.
And that's where the drama begins.
The new "reinforcing kit" mount is pretty thick. With the thickness of it and the engine subframe ... I'd say 1.5 to 1.75" thick (the bolt is 70MM). Yea, for your entertainment, I thought I could drill through two different existing holes (the loader mount and engine subframe mount) and hit the hole going into the cast engine block. Is this getting good yet?
I used my handy dandy hydraulic cylinder kit to wiggle around the loader mount best I could to get all 3 holes to line up. I verified the new M14 tap would clear the loader mount and engine frame holes (more on that later).
I used a 15/32 drill bit and drill the threads out in the engine block. So far so good, no drama since the drill bit cleared the mounts and only engaged the engine block threads which were easily drilled since they were already stripped. Next I ran a M14 taper tap as far as I could (pulling out every once in a while to blast the hole and tap with break cleaner and compressed air) and that went well too.
At this point I decided to try the new M14 bolt ... I knew it wouldn't go all the way because I needed to run a bottoming tap (that I didn't have yet) in since it's a blind hole. Boom. Dead in the water ... the non-threaded part of the M14 bolt was too fat to clear the existing loader mount and engine frame holes (I can hear you starting to laugh).
Next bright idea was to take my super high torque low speed drill and open the holes up (that don't perfectly line up - some of you know what's coming next) with a 5/8" bit.
I get maybe a little over an inch in and the bit binds and I get it jammed. I try reversing it and the bit breaks off in the hole :shocked: I sat there just staring at it wondering how in the world I was going to get that out with visions of having to remove all of the painful stuff I mentioned above.
So I researched methods others have used to remove big broke drill bits from blind holes and was about to attempt one when I went back out and looked at it again. There was a sharp shard of the broken bit that actually stuck out of the hole just a bit. I grabbed it and noticed I could wiggle it. At first I thought it was just a small part of what broke off but then I noticed the whole thing was connected and moved a bit. Starting to get happier! I got my welpers (mig welding pliers) and reached in there on either side of the flutes and was able to grab it and wiggle it out!
I had a spare 5/8" bit so I lubed up the hole and the bit with cutting fluid and decided to tempt fate again. When it caught again, this time it bent the drill bit! Defeated, I gave up for the night.
Next day I go to one of our local suppliers and buy a US made bottoming tap and US made 5/8" HSS bit. That evening I ran the taper tap in one more time just to make sure the drilling I did didn't hose something up. Next I ran the bottoming tap to finish tapping all the way down the hole. After cleaning the hole up I decided one more time to run the new bolt in and to my surprise it cleared the sides of the hole and ran all the way in. The previous night of drilling opened the hole deep enough so the bolt would clear. What a relief!!! I didn't even care that I didn't get to use my new shiny $20 US made drill bit!
I applied blue locktite and was able to tighten it to 80ft. lbs. so now my loader is back in action.
I've stressed before how important it is to keep an eye on the torque of loader bolts ... don't let this happen to you!
Here's a pic of my destroyed drill bits:
Loader reinforcing plate bolts (one of us is not like the other one):
The original bolt is a M12 1.75 thread pitch. New bolt is M14 2.0 pitch. The new M14 is 8.8 grade and if memory serves me right can be torqued to 134ft. lbs.. My plan was just to tighten to the original bolt spec in an attempt to have the same clamping force as before. My Mechanical Engineer friend said the greater surface area and 2.0 thread pitch will have more clamping force at the same torque than the old bolt but we didn't do the math to determine what it would be ... he said it would be in the ball park and close enough.
So the pucker factor was quite high at times but it all ended well.
So I did the repair the "right way" myself. When I tried to tighten the new 10.9 grade bolts to the new 80ft. lbs. spec, one of them would just pop! Stripped out!
So having access to a Mechanical Engineer at work that used to work for Catepillar ... he said "heli-coil" it. I said "don't you have to use some kind of install tool to put it in the hole?" "Yes" was the reply (which I already knew). "No Way" I said.
In order to install the heli-coil, I'd need to remove the loader mount and engine subframe from the left side of the engine to get directly to the bolt hole in the engine block. To get the loader mount off, you have to remove a hydraulic hard line from the pump that runs on the outside of it. Taking the engine subframe off is even a bigger deal. I took the loader mounts off before and liked to never got it back together. The hardest part believe it or not was getting the banjo bolt to that hydraulic hard line started. There is practically zero clearance to get to that thing with a wrench or socket. After experiencing that once ... no way was I going to sign up to do that again. So my next bright idea was to drill the hole out ... going from a M12 to a M14 leaving the loader mount and engine subframe in place.
And that's where the drama begins.
The new "reinforcing kit" mount is pretty thick. With the thickness of it and the engine subframe ... I'd say 1.5 to 1.75" thick (the bolt is 70MM). Yea, for your entertainment, I thought I could drill through two different existing holes (the loader mount and engine subframe mount) and hit the hole going into the cast engine block. Is this getting good yet?
I used my handy dandy hydraulic cylinder kit to wiggle around the loader mount best I could to get all 3 holes to line up. I verified the new M14 tap would clear the loader mount and engine frame holes (more on that later).
I used a 15/32 drill bit and drill the threads out in the engine block. So far so good, no drama since the drill bit cleared the mounts and only engaged the engine block threads which were easily drilled since they were already stripped. Next I ran a M14 taper tap as far as I could (pulling out every once in a while to blast the hole and tap with break cleaner and compressed air) and that went well too.
At this point I decided to try the new M14 bolt ... I knew it wouldn't go all the way because I needed to run a bottoming tap (that I didn't have yet) in since it's a blind hole. Boom. Dead in the water ... the non-threaded part of the M14 bolt was too fat to clear the existing loader mount and engine frame holes (I can hear you starting to laugh).
Next bright idea was to take my super high torque low speed drill and open the holes up (that don't perfectly line up - some of you know what's coming next) with a 5/8" bit.
I get maybe a little over an inch in and the bit binds and I get it jammed. I try reversing it and the bit breaks off in the hole :shocked: I sat there just staring at it wondering how in the world I was going to get that out with visions of having to remove all of the painful stuff I mentioned above.
So I researched methods others have used to remove big broke drill bits from blind holes and was about to attempt one when I went back out and looked at it again. There was a sharp shard of the broken bit that actually stuck out of the hole just a bit. I grabbed it and noticed I could wiggle it. At first I thought it was just a small part of what broke off but then I noticed the whole thing was connected and moved a bit. Starting to get happier! I got my welpers (mig welding pliers) and reached in there on either side of the flutes and was able to grab it and wiggle it out!
I had a spare 5/8" bit so I lubed up the hole and the bit with cutting fluid and decided to tempt fate again. When it caught again, this time it bent the drill bit! Defeated, I gave up for the night.
Next day I go to one of our local suppliers and buy a US made bottoming tap and US made 5/8" HSS bit. That evening I ran the taper tap in one more time just to make sure the drilling I did didn't hose something up. Next I ran the bottoming tap to finish tapping all the way down the hole. After cleaning the hole up I decided one more time to run the new bolt in and to my surprise it cleared the sides of the hole and ran all the way in. The previous night of drilling opened the hole deep enough so the bolt would clear. What a relief!!! I didn't even care that I didn't get to use my new shiny $20 US made drill bit!
I applied blue locktite and was able to tighten it to 80ft. lbs. so now my loader is back in action.
I've stressed before how important it is to keep an eye on the torque of loader bolts ... don't let this happen to you!
Here's a pic of my destroyed drill bits:
Loader reinforcing plate bolts (one of us is not like the other one):
The original bolt is a M12 1.75 thread pitch. New bolt is M14 2.0 pitch. The new M14 is 8.8 grade and if memory serves me right can be torqued to 134ft. lbs.. My plan was just to tighten to the original bolt spec in an attempt to have the same clamping force as before. My Mechanical Engineer friend said the greater surface area and 2.0 thread pitch will have more clamping force at the same torque than the old bolt but we didn't do the math to determine what it would be ... he said it would be in the ball park and close enough.
So the pucker factor was quite high at times but it all ended well.
