Hi Folks, brand new to the forum and thus my first post. I recently purchased a D4D and am trying to confirm the specific model so I can purchase a shop manual and source the correct parts. No serial number on the machine that I can find but the Engine is a 91A designate. There seems to be lots of info out there on 78A, 82J, etc but I can not find much at all on 91A. This has the pre-cleaner forward of the exhaust and has a generator rather than an alternator so I suspect it is an earlier version even though it has higher designated serial number. Can anyone help with year, engine type, and what other model parts and shop manual might be suitable to use? Thanks in advance
Redgum, a 91A D4D is a Japan-built D4D, built approximately 1966-1969 - and it is virtually identical to the U.S-built 78A D4D, the Australian-built 85A D4D, and the French-built 86A D4D. The Japanese-built Cats were built during a Joint Venture between Shin Caterpillar and Mitsubishi in a Mitsubishi factory in Japan. They have small differences, mostly electrical, as the Japanese Cats used Mitsubishi electric components, whereas the U.S. built Cats used Delco-Remy electrics. The tractor serial number and engine serial number were the same number in this era. The tractor S/No tag should be on the upper vertical rear face of the steering clutch case. If the aluminium tag has been knocked off, the numbers will be stamped into the housing. Attachments such as a winch or ripper can mean the tractor S/No in this rear position is covered up. Sometimes, engine blocks have been swapped out from another tractor during overhauls, so you may find differences in numbers between engine number and tractor number.
Hi OzDozer, that helps a lot, thanks heaps. Japan made, interesting and that explains why it has a Mitsubishi tag on it. Yeah got a winch on the back so no chance of seeing the rear numbers. Just from the visual appearance I thought it looked like the 78A's that I see online and Youtube but I could not understand the serial number- that all makes sense now. Thanks again for your help.
For a 91A-prefix tractor these are the Parts & Maintenance Manuals. You can find them online at https://catpublications.com/ Maybe on eBay if you try Googling the reference numbers.?
Regarding a Service (repair) manual and bearing in mind your location if you could find a manual for an Australian-built 85A machine that would probably be somewhere close if not identical to a 91A.
Fantastic, thank you Nige. Great forum- very helpful!
Another option for a service manual would be to contact this company. They do not list anything for 91A but it would not hurt to ask. Official Caterpillar Service Manuals, Owners Manuals (OMM), and Parts Books for Engine & Construction Equipment Repair Official OEM Caterpillar factory service repair shop manuals, parts books, and operator manuals for sale for all Cat engines and machines. www.servicemanualpro.com email them at - [email protected] When you do I suggest that you ask about 78A/85A/91A manual options all at the same time.
Will do, Thanks Nige
You're going to want to get your hands on the manuals, for Cat equipment of the era you have it's near impossible to get the right parts the first time without the part numbers. Cat parts slingers, at least the ones I've dealt with tend to look parts up from the current tractor models, many of which have near the same letter/number combo but are a totally different animal than our antique machines. It helps if you mention you need parts from the legacy books, some seem to know what you are asking for, usually the older parts people that have came up through the changes.
Thanks for the tip Mcrafty- Now that I know what machine I have I will be chasing the correct manuals as a priority. Cheers.
We got all 3 versions in new zealand, 78A 88A 91A mechanically all are the same and 78A sevice manuel covers all of what you want to know. Only real difference between them was electrical items, but is easiest to give any of the starter, generator repair to a good auto electrician. They all suffered from the weak final drives that were cured with the 2nd series D4D 82J, 65J series. Interestingly here, the british built 88A seemed to have a whole heap more problems than the USA or japanese built versions. Ive got a 78A which has been a good old girl for me, but she mainly does easy work like towing a roller. But she did this big cut on one job, all by herself.
Hi Merv, thanks for the info. I got hold of a PDF manual that says 91A on it so thats a win. Can you expand on the weakness in the final drives? Do you know what failed and what was inhanced on the later models D4D's? Mate that side cut is impressive! The D4 looks cool with the blade angled! I am considering hydraulic tilt as an addition to mine. I had a Fiat 70CI that had manual tilt that I swapped to hydraulic, really made the machine. Thinking I'll do the same to my D4.
Not from somewhere in Eastern Europe via eBay I hope.? There have been a lot of comments about pdf manuals, mostly negative. Just to give you an idea a new genuine manual in paper form can cost up to around US$1000, on CD about $750.
Hi Nige, no it wasn't from ebay. It was from Jensales. Probable still pretty poor quality compared to a $1000 dollar original but it cover most of what I need for now.
I just got a PDF manual for my 931B from the site below. It cost me AU$68 (US$51) and the quality is very good, and the download was available within a few minutes. It contains 3,413 pages. DOWNLOAD CATERPILLAR 931B TRACK LOADER SERVICE REPAIR MANUAL 25Y CATERPILLAR 931B TRACK LOADER SERVICE REPAIR MANUAL 25Y It is Complete Original Factory for Caterpillar 931B TRACK LOADER. Covers all the service and repair information about Caterpillar 931B TRACK LOADER. The information in this manual covers everything you need to know when you want to... www.heavy-equipmentmanual.com
Ive got one of those D4ds built in Japan in the late 60s. She's a good runner. My serial number is 66J1316 if that helps at all.
Here's the history on the 78A's
Redgum The last 78A [in OM post] and next series 82J and 65J [usa and japan gear drive] and others with 4.75" bore engine had a stronger bevel gear case with a heavier deadshaft. After about the first year or so they came out with a stronger coarser gear bullgear and pinion. 52 and 9 teeth i think from memory. A 7K number ?? Early ones are finer teeth and 55 and 10 teeth. again from memory.
By parts book only the dead shaft and case changed on the 78A7627-up Pinion and bull gear were 58 and 10 tooth until the end of the 78A series. Later models went to the 52 and 9 tooth
Hi folks, I have been away working for a bit and didn't log on for a while. There has been a bunch more comments on my post! Thank you all for the information, it is most helpful.