There's 1 or 2 cracked flexible drive coupling on my 85J7889 955L 3304 PC. I was wondering if they need to be replaced now. I don't notice any out of the ordinary vibrations, but I'm still learning about the machine. When reinstalling, do they need to be checked for alignment, or does the alignment only rely on the engine mount shims? Thanks!
If there are any pucks cracked now then IMO you should replace all of them rather than waiting for one to fail. Regarding alignment there is a procedure using a dial test indicator to align the coupling which uses different thicknesses of shims under the engine mounts. It's quite probably that currently the coupling could be well out of whack.
Thanks for the advice. I will go ahead and replace them all. Is the center rubber and 2 outer metal plates all one piece?
Yes they are. Here's the parts breakdown for the coupling for machines 85J6247-9509, which includes yours. Also the R&I procedure which includes the alignment check.
If your referring to the plates that the pucks are bolted to, the answer is no. They are separate pieces that are splined to the shafts. If they have excessive play, they will also need to be changed. If you don't check run out with dial indicator as Nige said, you will lose the pucks prematurely. Nick
Thanks for those uploads Nige and the info Nick. I've got a parts manual and a service manual, but still difficult interpreting some parts. 7M-1848 - https://www.ebay.com/itm/266422809395 Are these the engine shims? I'm 99% sure I have a 3304 PC but there's no serials anywhere so I'm going by the 955 serial # that was passed down with each sale. I will certainly be addressing the cracked pucks before the engine gets any more run time, AND checking for excessive play. I don't need to damage a transmission bearing, or who knows what else. Nige, would you put an aftermarket puck from offroadeq.com on your 955?
Offroad Equipment have been recommended numerous times on HEF for their service. Apparently on the phone they are a pleasure to deal with. The "puck assembly" (two plates with the elastomeric material bonded to them + a stud sticking out from each side) are all one unit - Part Number 5S-7893. See the attachment. I know this is for a higher S/N of machine than yours but I think the numbers are still good for 85J7889. EDIT: They are but there is no illustration which makes them impossible to identify. I do recall they were bloody hard to find....... Fortunately we've been here before.
Do you happen to know the part number for the engine shims? I've called Cat and some other places and no one has any reference to a part number. Just spoke to an old timer and he says I could use washers to adjust the height. I would try to find the highest grade washer steel I could, like 12.9 if I went that route. I'm not sure the flex coupling drive is out of alignment, but the pucks are cracked (Possibly just from sitting a lot for many years) and I'm trying to go into the fix with everything that may be needed.
Just got a call back from local Cat technical assistance. Rear Mount Engine Shims 6K7195 - .035" 6K7194 - .065" 6K8715 - .120" Front Mount Engine Shims 6K8717 - .035" 6K8716 - .065" 6K8714 - .120" I think the guy said that 2 of each are required for a 'factory' fit, but I might have misunderstood.
I beat you to it….. See Page 7 of the attachment in Post #7 above.
You sure did!!!
The Maintenance Dept motto - "We may be rough but by ***k we're quick..!"
You guys are great here. So helpful to have a repository of so much great information.
The Drive Puck's are the same ones used on the D5 Dozer they don't have studs fixed to them only specific length bolts and spring washers 4 to a puck, usually the engine has tipped down at the front mounting you will need your loader frame all the way up and a safety support in place, sometimes its easier to tackle this job from underneath.
It does look a lot easier to access from underneath, or at least most of it. There's a 1" ID rubber connecting hose that is leaking next to the flex coupling drive, I think it's hydraulic cylinder fluid because the hydraulic fluid reservoir was losing fluid, fairly fast. So I'm planning to get the belly pan taken off. Was thinking I should rig up a double chain hoist to lower the pan (Somehow attach the hooks). Seems doable. I'm on compacted dirt, so no chance of getting a jack underneath, and the thought of using a jack even on concrete bothers me.
If you have something like old railroad ties or other suitable cribbing, run the machine up on top of that to make yourself a bit more height underneath and have more space to work.
You can change the pucks from above or side, it's tight but can be done. Nick
I usually put a jack under the machine,apply some tension, remove the bolts in the belly pan,lower it down on the jack and then pull the machine forward or back it up onto my cribbage. Might not be the best method but it has worked for me a good many times and it’s pretty simple.
When installing the pucks leave all the bolts loose until you get them all fastened this will help with alignment