Head gasket sealer on John Deere 750

[ruffdog]

I'm certainly missing something. I'm also going to check and make sure the bolts are not bottoming out.

Bolts that go into a coolant cavity need sealer applied. Bolts can also "bottom out" on old sealer that is in the bottom of a blind hole. Those should carefully be cleaned out. What does the head/block mating surface look like? One other thread showed the surface that looked like a disk grinder was used. eek

 

[5030]

Sometimes a person needs to know their limits...

 

[Paul Campanis]

Some bad news !
I got a new torque wrench that was defective resulting in the over tightening of this bolt that cracked the block.

This is the end of the road for this machine. No more money can go into it. The bolt will hold the 94 pounds of torque required.

See photo...

Is there any hope?

 

[5030]

The price of scrap is pretty high currently.... Amazon imported cheap torque wrench I presume...

 

[LHF2019]

Or used wrong increments ft. lbs instead of in. lbs as an example. Guilty of that at work. Luckily nothing more than a turbo band I broke. Used ft. lbs instead of in. lbs. Wondered why it was taking so long to torque up, then it broke lol

 

[IH3444]

John Deere 750 Cylinder Block Casting Number 3416

Used Bare Block fits John Deere 750 750 3T80UJ CH18026 CH16658

Bare Block for John Deere Crawler Tractor(s) 750, Tractor(s) 750. Replaces John Deere OEM Number(s) 3T80UJ, CH18026, CH16658.

www.tractorpartsasap.com

 

[Williy]

I sure hope that you threw away the old head bolts
and replaced with new because you can't torque the
old head bolts to spec's

willy

 

[4570Man]

Some bad news !
I got a new torque wrench that was defective resulting in the over tightening of this bolt that cracked the block.

This is the end of the road for this machine. No more money can go into it. The bolt will hold the 94 pounds of torque required.

See photo...

Is there any hope?

That crack could likely be brazed up and the hole retapped for one size bigger bolt. That’s not the optimal solution but it’s really the only one short of a new block. I wouldn’t waste the time and money reassembling that without addressing the crack. It’s a little late now but the head needs to be surfaced before it’s reinstalled and the block needs to be checked for warping. The head bolts are one time use they need to be replaced. Also make sure the holes are free of fluid. Running a bolt into an oil filled hole can bust the casing. You also need check if the bolt calls for dry or oiled torque. There’s a big difference.

 

[pmsmechanic]

That crack could likely be brazed up and the hole retapped for one size bigger bolt. That’s not the optimal solution but it’s really the only one short of a new block. I wouldn’t waste the time and money reassembling that without addressing the crack. It’s a little late now but the head needs to be surfaced before it’s reinstalled and the block needs to be checked for warping. The head bolts are one time use they need to be replaced. Also make sure the holes are free of fluid. Running a bolt into an oil filled hole can bust the casing. You also need check if the bolt calls for dry or oiled torque. There’s a big difference.

I like where your going with this idea. I would make a few changes. I would just lightly tap the crack back together as much as I could and then lightly V it out and braze. I wouldn't go to a next larger bolt as the stretch characteristics won't be the same as the original bolts. Installing a heli coil or equivalent would let the op keep the original sized head bolt.

To the op. I wish I lived closer. You need a good experienced mechanic. I won't say I'm the cats meow but I would sure help you out.

 

[4570Man]

I like where your going with this idea. I would make a few changes. I would just lightly tap the crack back together as much as I could and then lightly V it out and braze. I wouldn't go to a next larger bolt as the stretch characteristics won't be the same as the original bolts. Installing a heli coil or equivalent would let the op keep the original sized head bolt.

To the op. I wish I lived closer. You need a good experienced mechanic. I won't say I'm the cats meow but I would sure help you out.

I considered the tap it back together idea and that would probably work but I’m not sure you’d ever get it as tight as it started. I wouldn’t want to go up an entire bolt size. If you could change the bolt from metric to imperial or opposite of what it currently is and get a bolt only slightly bigger I’d like that idea. I’m not sure I’d trust a helicoil with a head bolt. They make a C-Sert insert that’s heavier duty than a helicoil but I don’t think there’s enough meat in the block for that. I think you would have better luck holding a stud in the damaged hole vs a bolt.