Looking for info on my machine as not much is available I In SIS. Serial number is 78U0986 It has the 3204 in it.
What kind of information are you looking for? Something simple such as year of build, etc., - or maintenance information, and major repair information? 78U0986 is an early model 931. It was built in 1974, the 931 and D3 were built from 1973. It has a precombustion chamber design of fuel injection, in the late 1970's Cat went over to Direct Injection for the 3204. The 3204 is one-half of a 3208 V8, so there's a large amount of interchangeability with 3208 components. If you go looking for parts, use 78U00986 as the Serial #, because Cat part systems and many others parts systems operate on 5 digit Serial #'s with the prefix. The D3, 931 and 910 loader were all built on the same design plans, with an 80% commonality of parts and components. Initially, only a 3F/1R transmission was available, within a couple of years a 3F/3R transmission became available as an option. 78U identifies your loader as a 3F/1R transmission. If you had a 3F/3R transmission, the Serial # prefix would be different. Early D3's, 931's and 910's had ROPS canopies that were only 2-post design. Within 2 or 3 years of release, the ROPS design was changed to a more robust 4-post design. All D3's, 931's and 910's were built in Japan by Mitsubishi as part of a Caterpillar/Mitsubishi joint venture. They were built in an under-utilised Mitsubishi factory and you'll find the Mitsubishi "3 Diamonds" logo on many castings. Below is a link to an interesting article about the engineering behind these machines. It was written by a Cat engineer, Richard K. Liess, who was in charge of design and development of the D3, 931 and 910 product line. https://www.jstor.org/stable/44734469
Thank you. That was what I was looking for. I will have to try the serial number like that today and see what options for parts I come up with.
With a machine of that age the specific machine configuration information for your Serial Number will not be there, but you should find all the parts & service information. You will have to “interpret” a bit based on the Serial Number unfortunately.
This is what you will be up against. Basically it is another way of telling you that your machine is too old.....
Without tearing down the lift cylinders, do you know what the differences in the 2 options listed are? 240-6899 233-9205 The second one has more parts. Machine is operational in the field, but is getting to the point they need rebuilt. Don't want to down it just to tear a cylinder apart. Would rather have the parts on hand when I pull cylinders and minimize down time.
The second part number appears to be for a much later model cylinder, as fitted to later model machines. Even the first number may not be correct, I can only find it referenced to later 931B models, and not the 78U series. Do you have the parts book for the tractor? Go off the cylinder part #. It will be clearly marked in the book, the cylinder part # is called the "lift cylinder group", and the page gives you the breakdown of the individual seals and o-rings - but not any seal kit numbers. So you get the lift cylinder part # and go looking for a kit to suit that particular cylinder part #. There are plenty of aftermarket seal kit suppliers, Cat is usually a lot more expensive and not necessarily much better quality. Your lift cylinder part #'s are indicated as 7J-5893 for the R.H. cylinder and 7J-5894 for the L.H. cylinder. If you don't have the parts book, here's a link to your book, online. Your tractor is covered by publication UEG0711S, this is for 931 Traxcavators, 78U00001-03913. Click on the link below where it says "UEG0711S 931 TRAXCAVATOR 78U00001-03913". There were obviously enough major design changes at 78U03914 to warrant a different and revised parts book - SEBP1190 - which parts book is not applicable to your machine. 931 TRACK LOADER Caterpillar parts catalog SIS online | AVSpare.com spare.avspart.com
For the early 931 the only listing for the 240-6899 is for the ripper cylinder. 233-9205 is listed for later versions of the ripper cylinder. Nothing listed in the way of kits for either the lift or tilt cylinder. Seal kits are 2nd last column on the RH side for Std size and last column (if listed) is 0.030" oversize. TBH I'd go for individual seal Part Numbers taken from the appropriate Parts Manual
Nige, it appears the lift cylinders were unchanged through the entire 931 and 931B range of machines. There was a change in the size (cylinder bore diameter) of the 931B tilt cylinders in the early 1980's, but it appears the lift cylinders never changed right through to the 90's. I've found numerous suppliers of aftermarket seal kits, the 931 lift cylinders are pretty much universal, and they fit dozens of Cat machines. The first site I encountered neglected to list the early 931 as a fit, others don't. The P/No for the seal kit is 7X2789. I put 7X2789 into the Cat parts store and it tells me 7X2789 has been replaced by 240-6899. However, the kit lists as AU$206.86 here, I would think Boomhowar could pick up an aftermarket kit for around US$80 or less. I have used genuine Cat seal kits and aftermarket seal kits, and I didn't find any serious deficiencies in the aftermarket kits I used. https://grizzlyseals.com/wp-content/uploads/2021/10/Grizzly-Supplies-Hydraulic-Seal-Kits-Reference-Guide.pdf
Thank you both. I have found plenty of aftermarket kits for around $50 US. They just list them as fit for 78U1 and up. Cat wanted $150 US and had to be ordered. Everything I found on SIS pulls up with just using 78U. I will have to use that link for the book. Been trying to find a reasonable place to get new books for it. Last one I found was over $500.
More sellers and cross-references and fitment information in these links - however, there are still gaps in the fitment lists of some of these suppliers, and some fail to even list any 931 models. Cat 931B Loader Lift Cylinder Seal Kit See our Cat 931B Loader Lift Cylinder Seal Kit, now online. See more. hwpartstore.com 7X2789 Tilt Lift Cylinder Seal Kit fits Caterpillar 920 930 936E 950-966F 14E + ZerksPlus is a supplier of Hardened Steel, Stainless Steel, and Brass Grease Fittings. We carry a wide range of Couplers, Button Head, Adapters, Dust Caps, UNF, Drive in, and Flush Fittings in Inch, British and Metric Threads. The Terms Grease Nipples, Grease Fittings and Grease Zerks are... zerksplus.com 7X2789 Cyl Seal Kit Fits CAT Fits Caterpillar 920 930 936E 950-966F 93 Fits CAT Aftermarket 7X2789 Hydraulic Cylinder Seal Kit This is a New Seal Kit that fits the following Models and Cylinder part numbersModel Num. Application Cylinder 920 BUCKET 7J6789 920 BUCKET 8J5663 920 BUCKET LH 6J2806 920 BUCKET RH 6J2805 920 M.P. BUCKET LH 6J2806 920 M.P. BUCKET RH 6J2605... www.reliableaftermarketparts.com
Boomhowar, keep an eye on eBay for a parts book, they appear on a regular basis for a reasonable price. Steer clear of the manual dealers there, they think all books and manuals are gold-plated.
This company produce all Cat's OEM Manuals. See this LINK A Parts Manual is $109 on CD, or $156 if you want a paper version. Both plus S&H.
I wrecked a 78U some time ago. Still have Steering,Finals,Loader tower,Mainframe,Tanks,Sprocket covers,& odd bits. From memory,the year 1973 was stamped on the Valve bank.