cracked block behind carb JD 420

ssgshelton · Sep 17, 2009

I didn't get a response on the JD board so I will ask you guys. This week while cleaning the tractor for painting I fould a crack in the block behind the carb. I noticed some moisture at first and after running pretty hard. I then wire brushed it and while sitting this week have found several "tears" of radiator fluid running down the block. The radiator has no oil in it and the motor oil is black as tar with no greying moisture. I think it may just be in the water jacket. How would you guys fix this? I put some radiator sealer both blocks and liquid copper but it still has a couple of drops running down the block. At this point should I try a thin coat of JB Weld? I really don't want to tear down the motor just yet and don't have access to a welder.
Thanks
Joel

LUCASBOY · Sep 17, 2009

i usually drill a tiny hole at each end of the block, rough up the area ,wipe down with thinner and apply devcon plastic steel putty .it works good.is sorta like jb weld , but better i think. ive bought it off ebay last time.gotta let it set 24 hours,longer in cold weather to cure.lucas

RayP(MI) · Sep 17, 2009

I'd give it a little time and see if you get lucky with the radiator sealer. Father-in-law had a Ford engine redone a few years back. Block was leaking in a number of places (exterior) when they finished. All sealed up within a little time with radiator sealer.

glennster · Sep 17, 2009

sodium silicate was used years ago to repair cracked blocks in the cooling jacket. it was like liquid glass. here is a link to a company that sells the liquid
sodium silicate

Nancy Howell · Sep 17, 2009

Why do you drill holes in the block?

Kentb of SWMO · Sep 17, 2009

My Father-in-Laws MT has the same crack.

Kent

rustyfarmall · Sep 17, 2009

(quoted from post at 06:04:31 09/17/09) Why do you drill holes in the block?

To relieve the stress and prevent the crack from going any further, even after it has been repaired.

greygoat · Sep 17, 2009

You"ve got to get it REALLY CLEAN, like with
m.E.K. or Laquer thinner, before usung stuff
like JB weld or similar, if you want it to
stick and seal. I usually scrub the crack with
an old toothbrush.

CWL · Sep 17, 2009

I have a crack in the block on my Allis WD above the oil pan. There isn't any real pressure on it, but it weeps a little bit of oil. I tried degreasing it and roughing the area up with coarse emery cloth. I even heated it to get rid of any moisture. I then applied JB Weld over the top of the crack. It lasted a little while, but now the JB Weld has cracked along the same line. I assume it's from the heat/cool cycle the block goes through. Sometimes I work that old tractor pretty hard with a box blade.

cracked block behind carb JD 420

ssgshelton

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LUCASBOY

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RayP(MI)

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glennster

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Nancy Howell

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Kentb of SWMO

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rustyfarmall

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greygoat

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CWL

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