I've been collecting 1950s model Caterpillar dozers for the last 20 years.  I may have something you need.  I've got a tractor trailer full of parts in addition to the 15 tractors I have.  I have mostly 7UD4, 9UD6, 3TD7, 17AD7 & 14AD8 parts. I have running machines that I use, so I can't get rid of everything.  I know where other dozers are.  I only have track type machines.   I'm located in Spartanburg, South Carolina. 

My dad had a D7 17A17260, been trying to find it, it had a hyd angle blade. I now have a 17A19040 I'm restoring. Do you have any spoke sprockets with good bolt on segments? Are the segments still available?

Everything I have is cable except for 1 3TD7, 3 7UD4s, and the tilt cylinder on a heavy five shive pulley straight blade 14AD8. I have segmented sprockets on a worn out 14AD8 but that's it. I would imagine the sproket segments are still available. Check with some track shops on the segments.

do you have a d6 9u engine for sale?

Ricky, 
I've got two D318 engines I would consider selling.

One came out of a dry clutch 9U that needed transmission work.  The UC on the machine was new.  I've kept it standing up right, outside, on blocks, with the hood over it and the exhaust covered.  It has no pony motor.  The pony was removed and a manually engaged electric starter (no solenoid) was put on by the man I bought it from.  I've never heard it run, but the man said the engine ran great.  

The other D318 I have is for a Crain or power unit.   I think it was rebuilt by Caterpillar a long time ago and put away.  The hour meter shows 00000 hours and when I got it years ago the crank case was dry.  The crank shaft isn't locked up.  It turns easily if you put a short pry bar or large flat head screwdriver to the teeth on the flywheel.   You'll have to swap some metal on this one to make it work on a 9U tractor/frame.  The flywheel and housing and front engine mount will need to be replaced at the very least.  It's been kept under a roof with the holes covered up (pony and main engine exhaust, water pump, main engine intake).  The oil filter assemblies were missing when I got it so I put two of those on there to seal that up while it was stored in my open shop.   It was in an enclosed building when I got it.  It doesn't have a pony or electric starter. 

I can provide pictures later if like. 

Neil, 
I've never seen a D5 down here anywhere.  I wish I could help you.    

Do you have any D4600 motors that would have a good ex manifold?

what is the serial number on the running 9U?????