Has anyone got a fix for pivot shaft failures on the Cat D11R / T Series tractors. It has always been an ongoing problem, even with the N series with the rubber seal tearing and loosing all the pivot shaft lube oil. At the mine here in Northern Australia where I am working in maintenance planning, we are running 8 D11Rs & 2 D11Ts & 3 D10s. The most recent failure was on a T which had only done 500 hours since new! Regards, John
nice to see them big dogs working
What are you mining there?
We are mining manganese watglen. The orebody is at the bottom of the cut. We use a Hitachi EX2500-6 to load the ore into Cat 777Fs & Komatsu 785 trucks. John
Manganese What's manganese used in, I've heard of it before, is it used in metals manufacturing?
It's used to harden most metals steel being the largest followed by aluminum
John, I have replaced quite a few pivot shaft seals on D8R,T and smaller high tracks. One problem we see quite often is the metal ring that the seal is squished against gets wore out and slides too far onto the pivot shaft and doesn't seal properly. We have welded the ring in the correct position so it will not go on too far and that has solved our problem. I am not sure if the D11's are set up the same way but its something to think about.. Thanks, Quicktrax
Manganese Stinkycat, So something like T1 or AR400 steel would just have more manganese in it than carbon steel, or do they use combinations of stuff to achieve hardness?
Our quarries use maganese on their crusher mantels and plates. PS: Nice photos
John, In my experience i can not say there has been ongoing problems with that 8T1115 seal, i have changed at least 30 of them in the last 20+ years while working for both dealers and owners of D11,s, my current customer i look after has 8 D11R, 2 D11T and 2 84W D10 and pivot shaft seals never rate a mention when D11R issue questions are raised. It is a very basic setup at the end of the day and to tear a seal in operation can really only happen by 2 ways as long as the seal has been installed and oriented correctly, 1 would be sideways movement but it would have to be massive to tear it and the other is to much oscillation of the track frames up and down, again with everything right this is very hard to be considered the root cause. With good equaliser bar pads, minimal movement in the pivot shaft bearings it should last a lot longer than you are saying. I would put very stringent maintenance inspection process in place over a period of time and look at the application carefully, accordingly what is your method to repair these. What do the HD guys say?
Gavin, Since starting this post, I have heard that a guard has been developed to protect the seal from sharp stones and rock. On the D11T, the seal was damaged from a sharp stone wedged in at the top. John
Yep, that is correct John, i see you note that it was a rock that killed the 11T seal so maybe the guard will be a neat addition, it is retrofittable to earlier machines.
Did anyone work out why the pivot shaft seals fail on these d11N/Ts? We are stil having the same issues on the new D11 KSN dozers. They arent lasting ast much longer than 7,000 hours...
Cat makes a clam shell guard to protect pivot shaft seals.
Do you not swap out track frames as part of a major undercarriage overhaul on a tractor of D11 size.? That's what we always did. It reduced the time the tractor spent in the shop and of course the replacement track frames had new pivot shaft seals installed.
Yeah we do, but at around 15-18,000 hours. So we are replacing seals at least once in between frame swap outs. The problems we are having seem to be worse on the KSNs than the AMAs, I think it's related to the KSN EQ bar centre pin product issues.
You're lucky. We would normally be into frame work long before that. Hence my comment about frame swaps fixing the issue or at least giving the opportunity to replace the pivot shaft seals while the frames were being refurbed. My experience was that if you have a substantial sized fleet it's easier to have a set of swing track frames and swap them fully dressed than go in and try to replace rollers, idlers, etc, with the frames still on the tractor.
What material are you working in? I'm in coal
Hard rock. Gold & copper. Grouser life is about 1500 hours, sometimes less.
Know the part number?
Here's the announcement from a while ago, before the D11T2 was introduced. The 337-4045 Plate in the article is listed in Parts for D11T tractors with S/N prefixes AMA, GEB, JEL, JNS, MDG, & TPB.
Sounds like an engineering and manufacturing issue. How come Cat hasn't fixed the problem?
They have. Installation of pivot shaft seal guards fix the problem. The issue is that only certain types of operation (of which coal appears to be one) require the guards. In hard rock we never used them. Therefore they are an attachment, not standard. In these days with non-technical people buying equipment it's easy for stuff like this to get missed on new equipment then the Maintenance Dept has to come along and retro-fit......
You’re right there Nige,the man responsible for buying equipment will probably not even know what it is,certainly won’t understand its wonts and needs. All accountants these days
Looks like it's due to the pivot shaft retainer bolts coming loose due to them being installed without Loctite at machine assembly (SIS doesn't say to use Loctite). Who used Loctite when installing the pivot retainer bolts across the D10 and D11 size tractors?
How many tractors has this happened on.? What does the pivot shaft & bushes look like as regards wear.? Do the tractors have 3rd speed in the transmission disabled.?
CAT has released a support letter for a serial number range on the KSN. Potential poor surface finish on the pivot shaft, which is/could be the cause of the seal issue....