I worked on a D8K about 15 years ago that had major main frame cracking issues, around the cross member and even the attach areas where the frame is welded to the bevel gear case. The flywheel housing was destroyed because it became the structural support for the cross member. The question is how many of those older D8's and D9's have you seen these sorta problems with, and what age etc approx?
I worked for Palmer Coal in the eighties and saw it on a D9G. The rear motor mount on the operator's right side had been working on the frame and wore into the frame. Cracks started there. They also had a high horse D8H 46A33XXX serial where the frame cracked on the right rear side above where the equalizer bar was mounted. Both machines were old and used hard during their lives. The D9G was from Alaska and was a dual nine pushing scrapers. They did away with the cushion blade and put a big U blade on it before I worked for them. I'm sure the hours on both were well north or 15,000. I'd bet some of the older Cat guys on here can talk more about it.
I almost went to work there, they tested me out on the straight blade 375, I decided not to. Too far to drive at the time, and would likely not been doing the kinda work I liked. I in later years spent many hours on that 375, but it was owned by Fanco then.
Thanks for the phone call. I enjoyed it a lot and will give you a call in the future sometime to talk old war stories.
I did as well.
Chidog..,I had a D8H where the front right engine mount started to migrate down into the chassis. TC Tractors spotted that problem and repaired it for me. Also had a D8K crack around the eq bar chassis.Only spotted that during engine replacement. Worked on a D9H that the transmission studs used to snap every year and wipe the transmission out.
Transmission and bevel gear case, oh yeah seen lots of those come loose, and always needs an occasional check to make sure it hasn't come loose. Clunk going forward and reverse is usually the first sign. Why the studs snapping on your D9? I guess they needed more and larger dowel pins for them? How about the rear plates on the bevel cases, ever see them have broken internal welds? I have. All these old machines can have so many expensive to fix issues, and a lot of these issues can not be casually spotted with out a tear down, like you mentioned nicky 68a. They are more for hobbyists or yard art in some cases. Welding up those cracked frame areas would be a thrill, in situ, as was the rear plate,(I didn't want anything to do with that job) in some cases its the surrounding material that has the fatigue and new weld sometimes is no help, out of position welding is no help either.
The D9H wasn’t my tractor,but I got to know it on a few jobs.The story went along the lines of it not being tightened up correctly at some time in its life,causing issues that you can imagine. I think it ate 2 or 3 transmissions before they cottoned on in accounts department. It was traded in for a good D9N. The next time I worked with it,was when it was hired in from Finning to help us out on a scraper job one season. It behaved itself on that job but we had pulled the cab one rained off day and checked it over.If my memory serves me right,there was evidence of fretting around the studs in the bevel casing itself,and was a ticking bomb.
I’ve never seen the bevel casing crack internally during steering clutch removal thankfully!!
I had an early D8H with a diesel torque converter that the transmission come loose. A class at a trade school had the transmission out and the teacher was of poor quality and didn't properly supervise his students when they reinstalled it. The mount bolts weren't properly torqued and the transmission came loose to the point of leaking between the transmission case and the bevel gear case. The machine was so old and I was so busy with other problems that I tightened all the bolts back up at the specified torque and it didn't leak again. A year or so later they pulled the front belly pan for some reason and left it off. Next time they used the machine it didn't have the belly pan and they broke the engine oil pan running the machine up on a stump.
I know Cat dealers had a special drill fixture or ? To address the messed up stud and pin problems on them. (Loose transmissions) I don't think a hand drill could be used?
I remember there was a Cat service magazine about fitting oversize dowels to repair fretted or broken dowels in the rear case of D8H/K and D9G tractors