My D4C is a real state. Any know how to find serial numbers when the plates are missing? Looks like someone has attacked the area under the engine plate with a grinder. Fuel pump has a plate saying Caterpillar - made in Great Britain so assume this machine would be a 24A. Has a number stamped under where the transmission plate would have been 9H5822.
What parts are interchangeable with a D4D? track frames have serious rust?
Someone has removed radiator mounts in the past and bolted some channels on. Are these mounts unique to D4C or would other machines with D330 engine use the same mounts?
Looks like I need to go right through this machine, any known problem areas to look out for?

Gary,
From what I've seen, the track frames appear to be the same as used on the D4D. Rest of the undercarriage is interchangeable.
Most of the finals and steering clutch components are also interchangeable with the early D4D's.
I'm not sure, but I think you are stuck repairing what you have as far as radiator mounting goes.
The blade setup you have is off some other brand or home made.
You certainly have your work cut out for you.

Caterpillar released a spec for using a acid in this situation, where the serial number tags had been removed, I reckon I saw it in one of the old Service Mags, I can't remember what the acid was but it somehow highlighted the numbers even though the eye couldn't see them. I'll try to find the info.

Your other option is to date the tractor by the casting codes on the engine block and tranny, that will give you the day and month and year they were made, look for up to 6 of the following letters on those main parts NUMERALCOD come back with what you find.

Has that crawler been in a fire?

Found It!! From Caterpillar Service Letter dated September 27, 1977, "SERIAL NUMBERS GROUND OFF OF STEEL CAN BE MADE LEGIBLE"

make a etching solution of

15 grams copper chloride
15 grams ferric chloride
35ml water
60ml hydrochloric acid

They warn only mix the acid to the water, not water to the acid

Then polish the surface with fine emery cloth or a polishing wheel in a electric drill.

Then with a swab apply the solution for 5-10 minutes till the numbers appear, longer time might be needed in cold temperatures, but too much swabbing makes the numbers less distinct.

After wash the area with ethyl or methyl alcohol, do not initially wash off the etch with water as this causes a film of copper to form.

Finally wash the area with water.

"Mike wrote:

Found It!! From Caterpillar Service Letter dated September 27, 1977, "SERIAL NUMBERS GROUND OFF OF STEEL CAN BE MADE LEGIBLE"

make a etching solution of

15 grams copper chloride
15 grams ferric chloride
35ml water
60ml hydrochloric acid

They warn only mix the acid to the water, not water to the acid

Then polish the surface with fine emery cloth or a polishing wheel in a electric drill.

Then with a swab apply the solution for 5-10 minutes till the numbers appear, longer time might be needed in cold temperatures, but too much swabbing makes the numbers less distinct.

After wash the area with ethyl or methyl alcohol, do not initially wash off the etch with water as this causes a film of copper to form.

Finally wash the area with water.

Thanks Mike, will try to get hold of the chemicals and give it a go, might have to wait till lock down gets eased a bit more first. There is no sign of a fire no blackening of any surfaces, I believe it has been left out in the open for many years. Looks like #2 big end failed and then got left in the bush.

Blade is a modified locally built model, has had multiple repairs and modifications. Anyone know if the blade from a D4 7U would fit on a D4C?