JD 4320 Loader post

[Davo]

Hi all. I have a JD 4320 and over torqued one of the 4 bolts holding the post which the loader attaches to. It's an M16 bolt with course threads. I've looked for Heli-coil kits for this and they are in the $120-$140 range. I've never used a Heli-coil and don't want to spend the money and buy the wrong kit. My local parts stores don't carry any this big and I'd have to order over the internet and you know how hard it is to return things over the net if it's the wrong size. If I order a Heli-coil for an M16 bolt with course threads will that fit my M16 bolt? I'm sure you can understand my hesitation when dropping that kind of money on something I don't have a lot of experience with. Thanks for your help.
Davo

 

[JASTN70D]

The price really is steep.. Although it has been quite some time that I have purchased them.

The Kit probably has a drill bit and Tap that could be sourced stand alone. I would also recommend using Red Loctite on the Coil.

This will work very well if done correctly. Just dont break the Tap

If you have any machine shop tool suppliers in your area they should carry what you need.

The Kit will match whatever you speck. M16 course is just that and there is no variation. If your not sure of the thread or size take the Bolt to a hardware and find a Nut to match it

 

[Davo]

Thanks. I will buy the kit then. The tap itself goes for 80 bucks. It's a decent sized bolt. Everybody has them in the M12-14 range but noone has the M16 except the internet places.
Another question though: If it says a kit for M16x1.5 or M16 x2, what does the number after the x mean? I've looked on the web sites and even the Helicoil manufactuer site and couldn't find what that meant.
Thanks again

P.S. is this the kit you think i need?

HCMKC16

#5403-16 $ 115.33

THREAD REPAIR KIT: M16X2

5403-16
Weight: 2.50 lbs

 

[davkir]

The second number is the thread pitch in mm. (course/fine)

 

[Willl]

Davo, could ya use a longer bolt and nut combo ?

 

[Davo]

No I can't use a nut because it bolts into the engine block.

 

[Hooked_on_HP]

For what you are spending on the kit and shipping, I would check with some locale repair shops and see what they would charge you to do it. If you screw up drilling the hole or tapping the threads you are in deep trouble. There are also different kinds of thread inserts. Since it is going in the engine block I wouldn't want to take a chance of screwing up.
Bill

 

[Davo]

Well Bill it's in the Lord's hands now. I kinda wanted it done this week seeing as I've been stewing on this for a few weeks. I got it for $115 and $10 3 day shipping. I really appreciate the responses and I'll let you know the outcome. The machine shop was a good idea though. I hadn't thought of that.

 

[Wayne_H]

You need to be VERY careful when you drill the hole prior to tapping it for the heli-coil. I put several 5/8 x 11 tpi heli coils in my 48 B tractor last year. The problem is holding the drill so that it does not jump around and make the actual hole larger than the drill bit. If that happens, the heli coil may not hold as well. If you can, I strongly suggest making some kind of jig so that you can drill perfectly straight and not have it wander. I wonder if you could make a plate, drill two holes, one to put a bolt in where you have good threads, and the other as a drill guide.

I bought my SAE large sized heli coils on EBAY. MSC also sells them.

Good luck!

Wayne

 

[Davo]

Hey Wayne thanks. I saved about $25 buying it from Northstate. Ebay didn't have any that size. Great idea about the jig.. I'll have to look for some plate around here and make one. You guys have all been great. Thanks for all your advice. If you can think of any other techniques please let me know.
Thanks again
Davo

 

[jimmysisson]

Are there any threads showing? Could you get a bushing into what remains of the hole to guide a smaller bit for a starter? When that bit bottoms into free air you can stop and measure how deep you can go with the full size drill bit. That's some info you want!
If there's a little bit of the broken bolt sticking out of the hole still, you could thread a nut over the remnant and stick a bushing in that to guide a smaller bit. You really need to drill straight into the bolt. Lots of oil and sharp bits. That size bolt, you need to drill progressive sizes up to the final drill for the tap.
Jim

 

[Hooked_on_HP]

He didn't break the bolt , he striped the threads on a blind hole.