I came across a 58 or 59 D4 with 5 roller frames, and pony start.
Over all the motors seam to be good, and it seams tobe complete.
The down side is that one of the front idelers needs a bearing,
the seal onthe hydrolics leaks realy bad, the injecter pump leaks
( I think its just a gasket) and it may need a set of tracks soon .
although the rest of the undercarriage is 50% or better. The guy
wants $3000. I would like any thoughts or advice, anyone has.
Also being a little bit of a newbe still, could anyone tell me why
They had 4 and 5 roller frames and advantages or disadvantages
to them. Thanks.

Ed

Like most of the attachments added to the standard 7U model, they came from the loaders where the extra long track frame and large front idlers were used to aid stability with the heavy nose. When it comes to maneuvering with a dozer I think you are better of with the 4 roller....if your doing long run discing or ripping the 5-roller helps with the traction. You can have your choice but as usual you are trading off advantages and disadvantages.

Considering about $3,500 will still buy a decent running tractor with serviceable undercarriage that doesn't sound like much of a bargain to me.

Yo Ed! If I had to choose, I would take the 5 roller frame. I have a 7u with a 4
roller frame; my cousin has a late 7u with the 5 roller set up. The ride with the
5 roller frame is WAY better. He has a blade for his and I never heard any
complaints about operating it. I have been on his 4 quite a bit....streching back
to this shot of it in action circa 1970 pulling a IH 51 Hillside combine. The ride
is better, and on the late 7u they went to a good DE start and this one had been "fueled" just a tad ( OK, more than a tad) Last time I ran this tractor for him was just a couple of years back doing some seeding.