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View Full Version : 300EX Case Cracking around Motor Mounts



countypark
04-14-2003, 03:45 PM
Has anyone had their case crack around their motor mounts.

After I built my 330 last year I started to leak oil. Late in the season I realized that my case had cracked around the lower rear engine mount.

So over the winter I tore it down and welded the crack.

Well this year I built her up a little more and the front lower mount cracked and it is leaking oil.

What's the deal.

not2hi
04-15-2003, 01:04 AM
On ours it was the lower front motor mount...hairline crack drippped about a tablespoon of oil a day. After some suggestions here, I tried JB Weld and that seems to have fixed it. While putting it back together, i noticed why it cracked in the first place - the lower rear bolt was completely gone!

Keep in mind that the cases are very thin walled aluminum, and they are designed to stay stock, so any tweaks to the motor increases the stress on the whole quad. Not to mention that they're $300 a half and its recommended that you replace both at the same time.

It was also suggested to me that when you put it back together, loosen all the motor attach bolts, trying to get it into a "neutral stress state" (i.e. maybe its torqued a bit) then tighten the bolts slowly in a pattern.

Good Luck!

not2hi
04-17-2003, 01:32 AM
it started leaking again yesterday...

i'll have to get into it this w/e and see if the crack grew or what...