Any input on a d8K? We like the idea of available parts and the fact they are simpler to work on than new dozers that are all electronic.
A D8K puts the BULL in bulldozer.... real good machines.
Can't kill them really. Hundreds of old 8K's in dismantling yards not to mention all the aftermarket parts available. Might use a bit more fuel at the end of the day, but diesel is still cheaper than interest on payments, yeah?
I agree the D8K is a great machine! Just be sure to at least oil sample all compartments before you buy. The trans,torque,steering clutches and final drives can be very expensive to repair.
Wonder what kind of a weekly or monthly rate one could get for an 8K these days. They were some machine in their day. Great push tractors where a 9 couldn't stand up.
Thinking about replacing your Allis? I stumbled upon your youtube channel year or 2 ago.
I would stick with an H. The K was one of those models where they had maxed out the horsepower to the point where liner problems were common and they woud tear up finals. The H held up better.
I had 2 late ones, 77V 17604 & 18843, both were good machines, any tractor that old you are likely to repair hopefully not until it's made some dollars. As mentioned they enjoy fuel but for the most part will deliver the work too. Your states air policy is something to inquire about, here in Ca. the unregulated engines are a dying breed
Are you planning on doing dozer work or installing drainage plow and using it to plow pipe? We have a d8k we use for dozer work. i feel that machine in our fleet is like having an ace up your sleve when you need it. The carco winch comes in handy helping our drainage plows through tough spots. But we run a 450 and a 550 Bron drainage plow and they are a tough machine to beat on the drainage side of things........ What do you expect this machine to do for you?
Another vote for an H. When Cat "turned up the wick" on the engine between the H and the K all sorts of nasty things started happening. If you want a steady plodder and can find a good one an H would be a better bet IMHO.
Boy Nige, I usually agree with you, but I have an ol 8k and its been running along for 25 years now with regular servicing,,, the only parts have been cutting edge's and tracks.... how could you ever beat that? But then again I bought a D6c new... s/n 12511 and the only work I had to do to it is replace a worn out radiator.... Cat prolly overbuilt their machines in that era....
If it does not have a cab, but the four post rollover protection, replace the rubber bushings on the bottom of the posts as soon as the d##m things starts to rattle. Other wise you will be very hard of hearing in a short time. The one thing I didn't care for was the huge muffler on top of the hood. After a while you get used to it sitting there in your view. They are awesome dozers though.
Grandpa, maybe you're right. All my experience is in the 24/7/365 world of mining and in that world the D8K was definitely not the best thing since sliced bread, it was right on the edge reliability-wise. We were very concerned when the D8L came out but after the first time I ran one I turned to my boss and said "pension all our 8K's off right now and get a fleet of these" ........ we did, and never looked back. I suppose before chiming in with my 2c I should have asled the OP what work he was planning on doing with the tractor. Quite frankly if anoyne wanted to stay away from electronic machines I'd "upgrade" and go for either an 8N or a 9N and have the benefit of the high-drive without all the electronics.
My thoughts on the D8L was.,, wow what a tractor.... but I have to move mine from time to time so I never got one. Lots of horsepower along with the weight. Then they made the N series, I was under the understanding that that was a tad underpowered.... and the R series was getting closer to being back on track.. thus I will keep the old K as she don't owe me and I can still move her relatively easy. Grandpa
no, the allis is working everyday, time to add a second machine
The 8L was a bit of a throwback. Cat realised soon after introducing it that there was a huge horsepower hole between and the 7F. At the next model update the 8L became the 9N and everything else moved up one, plus the 8N wss introduced to fill the hole. That's why I suggested either an 8N or a 9N depending on how much HP the OP was looking for. Neither have any electronics.
Really not fair to compare the 8L to an 8K when the 8L was a detuned 9 with an 8 sticker on the tank
Yair . . . Hey fellers, did any of the early high-tracks come out with "conventional" clutch/brake steering . . . and Nige when you say the 8N and 9N have "no electronics" does that go for the engine as well? Cheers.
Don't really agree with that. The 8L was the official replacement for the 8K. The 9L was the replacement for the 9H. Only after they were on the market did Cat realise the "horsepower hole" they'd left in between the 7F and the 8L. They fixed that later by bringing in the 8N and "upgrading" the 8L, 9L, & 10 to 9N, 10N, and 11N respectively. None whatsoever. A "complete electronics-free zone", both of them........
Go for H or a Komatsu 155 or 275
The D8L came out with clutch/brake steering, the 8N was the first with diff steering from memory.
The D-8K, in my opinion, is a good tractor for pushing power, but not so good on reliability. The H was far and away more reliablein my experience with them. Then the 8L came out, and Cat overshot the weight and horsepower for the D-8 market. Then, to correct that mistake, they undershot it with the 8N, and got back on track with the 8R. I have more horror stories caused by D-8K's than anything else, from the transmission pumps loosing prime on anything steeper than a molehill, to trashed differentials caused by transmission misalignment, failed seals cross contaminating compartments, like when a final starts to go bad and make metal, the pieces take out the seals and transfer contaminated oil to the diff, wipe it out, and by the time there are symptoms of a failure, the seals are shot to the right final and it is dead too. I seen it turn a $18,000 final repai into a $64,000 2 finals and a diff repair. The collateral damage can happen within a day and before you would ever know it. Leaking duocone seals have let water and SAND in when crossing the smallest of mud puddles, and working in a river was a death sentence to the rear ends of several. Never had those problems with any of the high drives. In my opinion, the R series tractor is the best made, and will likely never be surpassed due to all the rules, regulations, and electronics. Some electronic items were a help, but the new machines with all the electronics have been a nightmare. The N, with lower power and no electronics beyond the basics, is the most reliable, but the early 8N;s were underpowered, and used the implement pump to steer. Bad idea. The later 5TJ models were much improved. To sum it up, if I was going to look for an older tractor, I would hunt for a well cared for H, and if I could not find one, a L would be the next step, if you can move it.
Correct, but clutch/brake steering was also an option on the 8N.
The L and R are fabulous machines but they are not comparable to the H or K. The failures you ascribe to the K are all traceable to the animals who worked on or operated them. It takes a pretty steep slope to cause the transmission pump to loose suction, a place an inexperienced operator has no business being. Transmission misalignment is caused by a mechanic who had to cut corners to return a machine to service or by someone who didn't know what he was doing. Duocone seals take a lot of abuse. Cat upgraded the o-rings to toughen them up but its my understanding those o-rings are no longer available. I haven't checked to see if that's changed. As for material passing through the seals and taking out the o-rings, its more likely that the material traveled from the bevel gear case into the finals than from the finals to the bevel gear; usually brake material. This kind of damage doesn't happen in a day. It takes a long time and persistent negligent maintenance. Flat track machines weren't designed to work in water. The high track planetaries work above the waterline under similar circumstances. I don't doubt for a minute you've experienced all the things you've mentioned but sometimes things happen for other reasons, not the ones we've been lead to believe. If operators and mechanics treated the H-s the same way they treated the K-s, the resulting failures would be the same. I'm not trying to start an argument and hope I didn't misquote you. If you like the H, the K is no different in terms of reliability. However, that doesn't mean a used K is not an abused K with all the problems you described; problems that most will find are cost prohibitive to repair.
Im with the h camp the k stretched a good thing too far, along came the high tracks, hp gaps, electronics and on it seems to go. We'll run out of letters in the alphabet before Cat build another reliable rugged simple D8 made for reliable rugged simple owners and operators.
When I started for the company over 20 years ago, we had 3 D-8K's, and every one of them sent me for wild rides down slopes. I was told to overfill the trans 2 gallons to prevent this. That made it slightly better, but did not cure it. When on level ground 2 gallons over was normally fine, but on slopes 5 gallons was what it took for moderate slopes, and 10 gallons for steep ground. We also had a late D-8H, in the 31,000 serial number range. It did more work in the same time as any 2 of the K models put together because it kept running. The H NEVER ran away down a slope, and because of that I took it to all the steep jobs. In the time I wasw with these tractors, the H ran more hours than any 2 of the K's, and did it with less repairs. I agree the K would push more, and rip harder, but it came at a price in reliability
JDOFMEMI Never knew D8 K had [diferential].??????? I think some of the Cletracs did .????????? Regards
It was the 8N that first came out with differential steering, not the 8K. As posted before conventional clutch/brake steering was also available on the 8N, so potential customers could take their pick. Differential steering doesn't really use a differential, it uses a hydraulic motor to speed up or slow down one track relative to the other so that both tracks are pushing under power when the tractor is steered, as opposed to a clutch system where at the very least the operator's slipping the clutch on one track in order to steer the machine.
I've never operated an 8K, but they have been called "the machine that let Komatsu into Ireland" as the reliability was so much worse than the H's. You can't blame it all on the operators, they didn't all change with the model.
Yair . . . I am sure it was just the choice of words on Nige's part but there are folks on here who have never run a clutch/brake tractor and I would point out that steering clutches should never intentionally be slipped . . . they are either in or out, nothing in between. Cheers.
Reliability aside, I have always found the H to be a better balanced machine than the K. My choice would be a late model H machine almost every time.
anything but K or h series We never had any luck with either as far as finals go.If not ripping or pulling plow then go for it.Whats the matter with another Allis or a Dresser td 25?The dresser will put the hurt on alot of 8's even newer ones.
yeh go for the H or better still Komatsu 155 or 275 Check says K can,t work in the wet, the K does like nice though, one thing the K was good for was over time and as a yong laddien, mechanical education I. could take those heads off with me eyes shut in the rain.... The K coming out was the best bit of marketing Komatsu ever got, the 155 was a far superior machine in all ways
Hi Scrub.....I'm not sure I understand your comment. I release just the clutch if I want to make a gradual turn or correct the direction of travel. The clutch is totally released but the oil, friction, and what not keep everything spinning pretty good unless I clamp down on the brakes.
Did you ever consider you just have bigger ones than the other operators and your employer gave you all the jobs the other guys wouldn’t touch. The only suction incident we have had was with an H; a 300 HP repower. Best of the bunch. The operator was coming up out of a steep drainage and started to climb over a rock. The nose came up and while he was waiting for her to break over she lost suction and sent him backwards 300’ until she regained prime and locked up the tracks, killing the engine. We were stunned. That’s when we learned about the 5 over and a bit more (x2). No one ever gets an *** chewing for topping off the transmission. We’ve run all the K-s that way and none of them nor the H have ever broken suction again. One thing we’ve noticed is the H will go places the K-s won’t go. They seem to start slipping before the H does. We believe it’s related to weight and balance. As much as I’ve been plugging the K, I too prefer the repowered H but then I hate pilot valves and cabs. The transmission pump in your 31,xxx 46A should suck fluid from the same location as the K-s. The early H-s pulled fluid from a higher location if memory serves. The later and lower tap was an upgrade to late model H-s and carried over in the K-s. The solution to the wild ride is the 36A. There are still a lot of them in use in So Cal. They move the same speed up or down. Your comment about transmission misalignment brought back a bad memory. One of our K’s transmission was loose when we bought it, so loose that the studs were moving and had destroyed the threads in the case. It took out the cross shaft as well. Its fine now but it took some thought to figure out how to repair the damage. Something similar could have been happening to you. The K-s you were running could have been so damaged that they needed a near certified rebuild to put them back into action. The more you ran the H, the less time some animal was spending in the seat and the longer she ran between breakdowns. When the K was built we weren't moving a million yards of dirt a month and framing houses a thousand at a time. Things just got out of hand. The L can put the hurt to the dirt and the R is fast and extremely reliable. Different machines, different times. We don't move millions of yards of dirt so we weigh the cost of a new R against a completely rebuilt K and believe we come out ahead. I realize this doesn't work for most people. I know they have limitations but I don't push their limits and they don't take a $h$t.
I often thought of converting a 76V and using H parts for the conversion to get the best of both. The extra weight in the K's moldboard does something to the balance. You wouldn't think 3-4,000 lbs would make that much difference but there's no denying that it does. Maybe that's why we can't bring ourselves to scrap some of the H parts we have lying around.
I will admit to spending plenty of my days working on D8 tractors from the early 8R and 2U models, 14A's and the D8H and K's, there is still a few 14 A tractors working on sites in the U.K. the D8K might use a lot more fuel than the H series tractor but the extra poke and gallop in the beast makes this viable, in the right hands the K and H tractors can show great reliability fixing small faults correctly and knowlegable service work will return massive hours of hard work and Muck shifted from them, there is special service tools required to work on the flat drive tractors and they can be hard work to strip out compaired to the Hi-Track tractors, but to compare the D8K to the Komatsu 155 as a trouble free Chariot would be very unfair, as the 155 engine had its own dramas with Camshafts, Valve Springs and head cracks, plus the final drives would shed flakes of metal off the Bull gear the size of rolled Oats and the Dead Shaft would spit off the end nut, I used to do a lot of work on the 155's but now they are very hard to find in the U.K. but the D8's are still about doing what they were built for "Moveing Muck" dont be put off the D8K as they can earn their keep still, tctractors
Here here..:drinkup
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Yair . . . OldandWorn Sounds pretty good to me, the rate of turn is controlled by pressure on the brake not slipping the clutch . . . they do that enough with out trying. Cheers.
I run a 8k and think its a great tractor.I think they are getting to the age when owner drivers will get the best out of them.Biggest problem i have with mine is fuel consumption.Has anyone ever turned the fuel pump down on a k to match more like a 270 h to use a bit less fuel?.I could put up with a bit less power to save cost.
TC, I did not say that the 155 was trouble free, no machine is and if they were we would all be out of work, I said the poster would be better of with a H or 155 than a K, fuel being one of the main reasons these days and as you say yourself the K needs alot of maintainance by experienced hands, You list faults with the 155 I could do the same and more for the K and a page full of modifications and reworks for it Still a few 155,s around but they were highly sort after by the exporters for obvious reasons The op also might be better of sticking with the same make of tractor they are using at the moment
I have run 7G's and 8H's on steep ground and have lost suction in both, but I don't recall having a runaway as the brakes still worked, no? The nimbleness, balance, and quickness of an 8R relative to an H or K put them in a different class in my opinion.
If you loose suction you loose your brakes. Perhaps if there was a reduced flow out of the transmission pump the transmission would starve and start acting up but I've never encountered that situation.
KWD, in my little Zone the older style 155's have all long since vanished, the only remains being their blades wrapped around the fronts of D8H and K series tractors, the 155 motor was only just better on the Vimto drinking than a K by a small margin, the Komatsu motor being around 19.5 litres to the CAT at 21.5 litres, the biggest trouble I always found with the 155's involved parts and the insane price of them, the fact that the blades, winches even cabs (I dont know why??) can be found poked onto D8H/K's but the big bit is possibly in China might be a clue here, the 155's never held any big value after the 1st owner had sucked out the best of it, the D8H and K series mount are well known for making grown Men drop the odd tear, but they fix up well and the parts are about, both the 155 and the D8 love spanners running over them but U.K. wise to run a 155 you need 2 of them, 1 ether for back up or to rob parts off, I love em all and have the kit to work on them I just dont get any jobs now on 155's. tctractors
Then how, with the engine off, can you set the brakes with the little lever below the right arm rest?
Yair . . . Dunno, it's been along time, but I don't recall the loss of suction thing ever being a major issue. I've had it happen mainly on a 7G but as I recall (as Oxbow mentions) I think the brakes still worked, I had a cable blade that went up and down and like-wise hydraulic rippers . . . I would not have thought a "runaway" would happen. Cheers.
The brake linkage is mechanical. You can push on the brake pedals and set the brake lever but that doesn't mean the brake bands are holding the drums tight. In order to get gripping power out of the brake bands you need oil pressure to the pistons in the brake covers. This hydraulic assist to the actuators is what is enabling the mechanical linkage to assert pressure on the bands and grip the drums.
I currently am on my 9th D8H in 20 plus years.in my experience they are far more fuel efficient than 8K,s or 155's of the same era yet shift a lot of muck.perhaps not as much as a K but it doesn't worry me.I had a K once and it was a beast of thing and would drag a 463 about like a cat with a mouse.It was a sweet sounding tractor and proved a reliable and profitable.I sold it to a friend who had good service out of it until it trashed a final a couple of years later and due to the worn u/c on it he broke it for spares.the engine went into one of his current tractors and has probably been rebuilt at some time.It's worth saying it was an American built 77v lump and not a UK built 66v. I never get rich out of these old D8's but they are profitable with the right servicing and fitter at the helm not to mention having a reasonable rate for the muck. I currently run 2 Glasgow UK built 68A 5800 series that work a few days every month in a quarry.One is currently back at the yard having an engine replacement as it's tired and has few oil leaks and won't be needed until the end of the year. It would be fair to say that any old D8 with a clean,unblocked cooling system and sealed transmission suction lines will go for ever with the right driver in the seat as long as he has a handful of spanners in the cab.
Jerry. I was rereading this thread and realized my response to your posting could be interpreted as implying you were not an experienced operator. That was not my intent. I apologize if you took it that way. I'm a collector of D8 horror stories as they help keep me from repeating someone else's bad experience. There is one other cause of 8K-s freewheeling backwards that I am familiar with but its hard to pin down given the catastrophic conditions surrounding the ride.
Check Break No worries. I did not take it bad at all. In regard to my comment mentioning a differential, I was not talking about diff steer or anything, just that I have always called the arrangement of gears that turn the power 90 degrees to send it to the finals a differential. I realize it is solid, and gives no differentiating action, but it gets caught up in the name by me anyway. I know that mnost of the trouble with the K's I was around can be traced ultimately to less than adequate care, but I would venture to say less than one in ten have been properly cared for. With age, that number goes down. At the age they currently are, I would say very few are left that have always been kept up to proper condition. The stories I relate are to help others stay out of the same situations I have found myself in over the years.