could somebody tell me the whats the difference between a 955l big bottom and a 955l small bottom ?
I might be misremembering, but I think the small u/c was D5 sized, and the large was a D6 sized. There was a ser# change around 85J11000 where D6 started being used IIRC.
YEP D6 is the "big" bottom. my local cat dealer says the big bottoms are more $ to work on but they last twice as long. should be on late 85j models and all the 13x models. sure glad I found this out. now a late 85j or preferably 13x is what I want...
Sounds like when they changed over from the K to L model
Did some more looking and from what I can find the track and segments changed on 85J9510 and up. Guess if you put one beside the other you can see the difference but all have 40 links, and 8 segments (5ea 4 seg and 3ea 3 seg) per side. My serial number comes with 15 inch pads and shows no wider ones, the higher serial number shows 15 and 21 inch pads. All show the same pins 6B5502 and links 3P7153 (RH) and 3P7154 (LH). All use Roller group 9S3570, Sprocket group 7K1312 Maybe I'm not looking at correctly but from what I can see it may just come down to the size of the pads. The wider pads don't show up in my serial number because they were not offered.
cat told me there a different pitch on the d6 bottom and salt also
Cat made different size 955lmachines. #13x was larger d-6 under. #85j was what I had. D-5 under.count ur pads either 39 or 40
Early 955 models were equipped with 6.91" (175.5mm) pitch tracks, the same as the current model of D5 at the time. This would be 7P-3153/4 & 7T-4539/40 track links. These tracks would have 8.0" diameter track rollers. Later models of 955 were fitted with 8.00" (203.2mm) pitch tracks. This was the same as the D6C/D tractors. The links would be 8E-7405/6, 3P-1112/3, or 7T-4645/6. These tracks would have 8.25"track rollers. The changover from 6.91" to 8.00" pitch tracks is a bit hazy because of the number of Serial Niumber breaks in 955 production. For instance there is a model change from 955K to 955L within the same 85J machine prefix. So IMHO if you have 8.00" pitch tracks then you have a "big bottom" machine.
Thanks Nige, appreciate clearing it up. Guess the 0.09 extra in length didn't cause the change in the sprocket segments. Mine has 40 links (5044) and in the listing below is a 13X has 36 links, go figure http://eastky.craigslist.org/hvo/4878983629.html
No, you got that wrong - the difference in pitch is 1.09" per link (8.00-6.91). Just by simple multiplication 36 links @ 8.00" = 288" and 40 @ 6.91" only comes to 276.4", so the 36-link track is actually longer than the 40-link track. The sprocket part numbers would have to be different between 6.91" & 8.00" pitch tracks. For your machine, measure the distance between the centres of 2 adjacent pins on the track, you should easily be able to tell if your track pitch is 6.91" or 8.00".
One of the Doh moments for me again ops. Mine are worn out, with help here we calculated the stretch and they are shot, even adjuster is at max on one side and 1/4 inch to go on the other. I have new chains, sprocket segments and bolts to go on when it warms up. At least it's now easy to tell the difference between small (D5-40 links) and large (D6-36 links) by counting the links
Nige, don't mean to hijack this thread, but I am new here and to track loaders. Do you know anything about the Komatsu D 31 S Track Loader. Is it a good little machine, any faults in the "S" series. You strike me as very knowledgeable. Thanks for any help.