imabigdave
Member
So, I've got a D5B with a 3306 motor. Had it for a few (maybe 10) years, put a few hours on it logging and so on. A few (sadly) years ago, I noticed it leaking oil, and discovered that there was a crack in the back left corner (literally the corner) of the block, where the flywheel housing and the bottom plate that the oil-pan seals to meet. So, after talking to a couple of people, I was told that the best way to deal with it was to clean it up, groove out the crack and then use devcon (like JB-weld) on it both inside (where the flywheel housing seals up against it (I was gonna attach a picture but can't find them on my computer) and outside, and that I'd have no more trouble with it.
So, I did...the crack actually looked like someone had HAD the block out with the flywheel housing off of it, and then put a bolt in about a 1/4 of the way and then tried to lift the block with that bolt... if the seal and the seal edge of the flywheel housing was just a little bit wider it would have sealed it off. Anyway, I used a cutoff wheel on a die grinder to clean out the crack, put a bolt with a bunch of washers on it in the involved bolt hole to hold it in place, mixed up the devcon and put it in, smoothed and sanded the edge on the back of the block and let it sit for whatever the recommended cure time was plus a few days. Put the thing back together, got my neighbor back over with his backhoe to put the motor back in the machine (I'd built a stand for the motor so it was easy to work on) then put all the accessories back on (hyd tank and hoses, hardnose, rops). Started it up and it ran like a raped ape, not leaking oil out of the crack, but it was spilling out the back, because like a MORON I spaced on replacing the rear-main-seal. I don't believe I've ever cussed myself out so much. The service manual had said it was "recommended" to replace the rear seal if you removed the flywheel housing. I'd looked at it and it didn't show any wear, so since when I'd ordered all of my parts, I'd given the number for the FRONT seal, I didn't have one to put in and I was in a hurry to get the machine back together....
Sorry if this is too long....anyway, after an some injuries and watching my body deteriorate, I'd started to rethink the "oh, who needs a college education" thing that had worked so well for me up until then, so I was actually ready to go away to school (I'm pursuing a DVM), so I ran out of time to work on the Cat. Fastforward a couple of years, finally have some time this summer, so I started tearing it apart this winter (no fun task, since I only have an open hay-shed to work in) and then finally got to the point of pulling the motor this summer. I've finally got it all back together with a new rear-main-seal (even splurged on the cat dealer with their handy seal installers to come out and put it in for me) and a freshly rodded out radiator (here's a hint for those playing at home, DON'T leave a radiator open and unattended for months at a time, the critters move in and make nests, and then your engine overheats).
So the rear seal is good, but NOW I've got a little oil seeping at the crack that originally instigated this. I'm NOT gonna pull this motor again until something else major needs to be done to it, so I was thinking of just cleaning the area that's seeping up with some acetone (and getting the paint off, of course) and smearing some devcon on top of it. I'm thinking that with the crack involving a bolt hole (and a couple of people that looked at it were baffled as to how it could have happened except for a mfg. defect) that taking it apart, torquing and untorqing that bolt might have spread it. I'd pondered when I'd had it apart to drill out the threads on the "loose" piece and then drill and tap the block deeper and use a longer bolt in that hole, so that the threading of the bolt wouldn't have the risk of spreading the crack.
My questions is: Is there anything ELSE that I could use to basically just seal that crack from the OUTSIDE? OR, should I just use 90wt oil in the crankase so it can't seep as easily Has anyone else dealt successfully with this kind of problem? Again, sorry about the lengthy back-story, it probably wasn't necessary except to vent my frustrations...I hate fixing something twice, much less THREE times.
So, I did...the crack actually looked like someone had HAD the block out with the flywheel housing off of it, and then put a bolt in about a 1/4 of the way and then tried to lift the block with that bolt... if the seal and the seal edge of the flywheel housing was just a little bit wider it would have sealed it off. Anyway, I used a cutoff wheel on a die grinder to clean out the crack, put a bolt with a bunch of washers on it in the involved bolt hole to hold it in place, mixed up the devcon and put it in, smoothed and sanded the edge on the back of the block and let it sit for whatever the recommended cure time was plus a few days. Put the thing back together, got my neighbor back over with his backhoe to put the motor back in the machine (I'd built a stand for the motor so it was easy to work on) then put all the accessories back on (hyd tank and hoses, hardnose, rops). Started it up and it ran like a raped ape, not leaking oil out of the crack, but it was spilling out the back, because like a MORON I spaced on replacing the rear-main-seal. I don't believe I've ever cussed myself out so much. The service manual had said it was "recommended" to replace the rear seal if you removed the flywheel housing. I'd looked at it and it didn't show any wear, so since when I'd ordered all of my parts, I'd given the number for the FRONT seal, I didn't have one to put in and I was in a hurry to get the machine back together....
Sorry if this is too long....anyway, after an some injuries and watching my body deteriorate, I'd started to rethink the "oh, who needs a college education" thing that had worked so well for me up until then, so I was actually ready to go away to school (I'm pursuing a DVM), so I ran out of time to work on the Cat. Fastforward a couple of years, finally have some time this summer, so I started tearing it apart this winter (no fun task, since I only have an open hay-shed to work in) and then finally got to the point of pulling the motor this summer. I've finally got it all back together with a new rear-main-seal (even splurged on the cat dealer with their handy seal installers to come out and put it in for me) and a freshly rodded out radiator (here's a hint for those playing at home, DON'T leave a radiator open and unattended for months at a time, the critters move in and make nests, and then your engine overheats).
So the rear seal is good, but NOW I've got a little oil seeping at the crack that originally instigated this. I'm NOT gonna pull this motor again until something else major needs to be done to it, so I was thinking of just cleaning the area that's seeping up with some acetone (and getting the paint off, of course) and smearing some devcon on top of it. I'm thinking that with the crack involving a bolt hole (and a couple of people that looked at it were baffled as to how it could have happened except for a mfg. defect) that taking it apart, torquing and untorqing that bolt might have spread it. I'd pondered when I'd had it apart to drill out the threads on the "loose" piece and then drill and tap the block deeper and use a longer bolt in that hole, so that the threading of the bolt wouldn't have the risk of spreading the crack.
My questions is: Is there anything ELSE that I could use to basically just seal that crack from the OUTSIDE? OR, should I just use 90wt oil in the crankase so it can't seep as easily Has anyone else dealt successfully with this kind of problem? Again, sorry about the lengthy back-story, it probably wasn't necessary except to vent my frustrations...I hate fixing something twice, much less THREE times.