Misc JB Weld/two part epoxy repair goop

RememberGoliad

Veteran Member
Pic that I hope is somewhere in this post is of a freeze crack in a Yanmar 2cyl diesel tractor engine. It's where the water enters the engine. Apparently someone didn't bother draining the engine until the thaw :shr:

I know this type of crack can be sealed back up with the semi-liquid two part JB that one squeezes out of two tubes and stirs together. I've done that. This crack is on the bottom of the semicircular water passage that sticks out of the block like a wart. Gravity is not my friend on this one. So I have two options: one is to use the semi-runny two part and hold it in place with duct tape until it sets. Other is to use that knead-together stick. (I suppose the third option, which I would seriously consider if it was my tractor and not someone else's, would be to lay the whole machine on its side so that the crack is facing up :D but I'd hate for the young fella to swing by and see his tractor taking a nap!)

Now, all that said, the reason for my post is: Is the knead-together epoxy stuff as good at sticking and holding and not popping off as the traditional runny JB Weld? And if you had your druthers, what brand, if there's a difference? Thanks, y'all!20210529_135757[1].jpg
 

Shooter

Veteran Member
JB will work, dont try to fill the crack at one time, kind of paint it on is small batches, letting each coat dry a few hours,

I fixed a air compressor tank. bottom had rusted out, and new tank was gonna take weeks to order, so ground down to bare metal around the rust hole, and patched with JB, it took 150 pounds easy. worked for a couple months until new tank came in
 

slbmatt

Contributing Member
What millwright said and the last Yanmar I fixed. Also had an internal freeze plug
behind the timing cover. That came out when the block froze and cracked.
If you have water in your oil you will need to look for the internal leak.
 

RememberGoliad

Veteran Member
It was apparently nothing more than the crack on the side. Did the crack stoppage drilling, refilled it, oil staying oily, was at proper level and water-free when we started on this fix. It's been back together and running as well as a 2 cylinder Asian diesel can run. I did wind up using the squeeze tubes and not the kneading style putty. Sprayed the entire crack area down with brake cleaner and blew down into the crack with compressed air 2-3 times, waited for it to dry, and put two layers of JB on it and left it set for several days (even though they say 6hr cure time) before filling with distilled water, half a bottle of Bar's Leak (for the water pump lube aspect of it) and green antifreeze. So far so good.... kid's happy with his toy and his toy's happy to be getting used ;)
 

Griz3752

Retired, practising Curmudgeon
Just stumbled on this a few days ago as a casual acquaintance has/had a similar issue & for some reason, asked me what I thought; desperation makes some folks do inexplicable crap.

Anyway, printed of the whole litany above & gave it to him maybe Tues night & I guess he's testing it out now. I told him where I found the info so hopefully he'll sign up as a member.

In any event, score one for you guys.....I was thinking the 3rd solution had the most merit but never went to look at the beast so I can't say if that was practical in this situation; might not have been as its some sort of home-built zero-turn.

Good one, guys.
 

oleglass

Contributing Member
Had this happen on a John Deere tractor diesel fuel tank.
Used JB led and fiberglass mesh screen to repair.
Put light coat of JB, covered with mesh, waited 24hours, did it again, same procedure for 3 days, that was 6 years ago.
Still holding, no leaks
The mesh keeps the JB from dripping.
Cost of a new fuel tank was over $400, and Deere only listed a plastic replacement.
 
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