Thread: hair line crack in diff

Originally Posted by matthewk

i intened to drain oil
drill 2x 2mm holes at ends of crack
back grind the crack out slightly
pre heat as to try burn away some oil from behind the crack as well as pre heat
and reweld hot so long as my little mig will handle it

i havent had this car that long maybe 2/halfs months if that
guy who owned it before me was from erica so i presume alot of 4x4 was going on

Matthew,

That one I was talking about had had NO off road work, the owner has had it since new, and it developed a small leak right next to the LH stabiliser bar bracket. SOMEBODY repaired it with an ARC welder, looks like chook poo, and consequently it worked its way along the factory weld 6", then went 90degrees up and over the top, and started to crack the OTHER side at the axle tube weld. When I removed the housing, it was far worse than I expected and he was basically lucky not to have had a complete failure
It may have started from a factory poor weld etc, but ended up a disaster because it wasn't rectified properly first time, and left too long.

JC

Originally Posted by matthewk

i intened to drain oil
drill 2x 2mm holes at ends of crack
back grind the crack out slightly
pre heat as to try burn away some oil from behind the crack as well as pre heat
and reweld hot so long as my little mig will handle it

i havent had this car that long maybe 2/halfs months if that
guy who owned it before me was from erica so i presume alot of 4x4 was going on

thats about how I'd handle it (Id pull the diff and clean it out properly tho)

BUT

when you're finished and start topping it up with oil fill it about half way (1l of oil) then add some hydraulic oil dye before adding the rest of the oil. in paint pen write on the front of the diff what colour dye you added. if and when you see that colour start to turn up on the housing its time to be thinking "perhaps I need a new housing?"

Originally Posted by justinc

Matthew,

That one I was talking about had had NO off road work, the owner has had it since new, and it developed a small leak right next to the LH stabiliser bar bracket. SOMEBODY repaired it with an ARC welder, looks like chook poo, and consequently it worked its way along the factory weld 6", then went 90degrees up and over the top, and started to crack the OTHER side at the axle tube weld. When I removed the housing, it was far worse than I expected and he was basically lucky not to have had a complete failure
It may have started from a factory poor weld etc, but ended up a disaster because it wasn't rectified properly first time, and left too long.

JC

this leak has only just turned up in last 2 days there abouts it werent leaking like this on friday other wise there would off been a puddle of oil on whiteconcrete

Matthew, in case you don't know, that is not a butt weld. See the flange that is pressed into the cover/pan, well it overlaps the banjo housing by at least that amount.

The thickness of the cover/pan is about about 3 mm. The banjo housing behind the flange would be 6 mm or more - it is almost identical to the flange on the other side which the diff centre bolts to.

I'm not sure how deep you were intending to drill - I can't see the point in drilling right through the banjo housing, and personally wouldn't drill it at all. If it was a butt weld, such as in the axle tubes, that would be a different matter.

There is going to be oil trapped between the flange of the banjo housing and the flange of the cover/pan, no matter how well you clean inside. Preheat will help draw a lot out and burn it away, but you should be able to handle it.

Edit: I'm assuming the crack is in the weld attaching the cover/pan to the banjo housing.

I had a D1 with a similar crack near the bottom of the front diff that I believe was caused by giving it a good bop offroad.

The previous owner had used a rubber compound to seal it, and it only just leaked when I got it.

I ground the crack back (good 50mm long) and got it welded. No problems or leaks a year later.