thanx cc. i am learning more every day.there are two 14a d8s in my local paper for sale.my question is being a cat owner with limited knowledge in driving and maintenance is. what woud be the difference in the d8 and driving my little 1936 rd4. my rd4 it seems i bog down easy. gotta be on my clutch alot. is it nite/day on a d8. does any thing stop a creature of this size? what is the diameter of tree a d8 can knock over?can you roll over a d8? does it ever get stuck in mud and gunk?just wondering what you old cat pros would answer ? dave.plus i have heard of a cat in a gully up here. i will try to snap some pictures for fun of it.

Never drove a D8, yet!

When you mention staying on the clutch all the time, I can relate to that. I grew up running an older D69U and as time went by it became increasingly hard to keep from choking down. Power was pretty good once you got going in a steady push. You just had to be very careful if you came up against something that suddenly increased the load. We finally had a major failure and got another newer 9U and the difference was like night and day.

It's not just power, though that is part of the difference. I believe it is mostly governor response. I can easily maneuver the D6 around at less than half throttle and the engine responds appropriately. The old machine had to be run at higher rpm to do the same thing without dying.

I would investigate fuel and power related problems and governor wear in bearings and pivots etc.

Sounds like you've been bitten good by the yellow iron bug:D

The gov. spring is very important for power & even if they appear ok they loose their tension so always replace it if low power is a problem. I always liked to install the 5F6413 spring for the D4 6U & 7U & the D6 8U & 9U for best power even if the book doesn,t show that spring in some models.If one is installed you must check the high RPMs & bring them up to specs.The weight rollers are important & other parts in there too as CC suggested.

I had a junk blade just like that, same side arm/leveling screw setup but for a D7. Man, was that moldboard heavy! I had to cut it in two before I could pick it up with my Scoopmobile!

I'd wondered who made it.

Jack

I have put many hours on my D8 14A. I live in in Sedro Woolley, Washington at the foot hills of the Cascade Mountains. We recieve a lot of rain most of the year and if you are going to get stuck, this is the area to do it. Being raise on a farm, I know when I am about to get stuck and I have always been able to back out or to continue on through in a straight line with out sinking the D8. When I am on questionable ground, I try go in a straight line with both tracks pulling. If I have to pull in a steering clutch very long, I risk a chance of the track still pulling burying it's self. Yes, I have had to jocky around in the sinking mud, but I have always been able to pull it's self out under it's own power. I have been high centered many times but my winch has always found something to hook to, to pull it's self out. The largest stump that my D8 has removed so far is a fir stump that was cut down 60 years ago and it was 12 feet in diameter at the swell of the stump. The root ball after all of the feeder roots were broken off was 24 feet in diameter. It took me most of the day to dig out the stump and the only way that I could move it was to spin it across the level ground. It was too heavy to push it in a straight line. The D8 usually never is at a loss for power as when it comes to a good push, it usually will spin it's tracks befoe it will stall out. I have many times have had to pull in on both steering clutchs at the same time to keep it from dieing. The reason for not throwing out the main clutch is because I didn't have time to move my hands from the steering clutches to the main clutch. The steering clutchs are hydraulic assist and when the rpms get too low, it is a test of strength to pull them both back at the same time when it is about to die. My blade is 13 1/2 feet wide and the bladee stands over 4 feet tall. When the D8 has a blade full of dirt and the dirt is curlling above it, the Cat is still pulling steady with power to spare. Dig too deep and you spin the tracks. It has a hard nose and hydraulics on the blade. The down side is thatwith the blade on, it is too wide to move without a moving permit so it hasn't been to any tractor shows. As the big old growth stumps roll out of the ground in front of your eyes, you feel like you have the power of God in your hands. If you can buy a D8 14A, do it, but make sure that the undercarriage is not all wore out, because if it is, it costs more than the D8 is worth to bebuild all of it.

D4David, I see you found my sister...cat..

That is a 1936 RD4 with a 1937 (after designation change) radiator support. The tank top should say RD4 on it, if it is the correct top, or caterpillar if it is later too.. the whole radiator has been replaced, if it says cat.. on top, and D4 on the sides.. It has the first generation D4400 engine in it,, and has no governor spring setup like the later ones do, it is weights up front, with a limiter in the odd-shaped-D being behind the injection housing,, so dont get too worried about adjusting it, there is basically no adjustment. It WILL need the rack slide cleaned up and never-seized to fix any problem it may have reacting sluggishly.

RD4 sprockets were more pointy than later generations, but if you look, your pins are riding over halfway up the side of the teeth, so they are very well worn,, i.e.95% worn. If you look up under at the pins, they are probably 1/2way worn thru the bushings. The pin bosses on the outside of the rails, are 1/2 worn thru toward the pins, showing the rails are well worn down, allowing the bosses to hit the bottom rollers. i.e.. those tracks are shot. Dont bother cutting the roller lips down unless you just want to totally waste them. You can find newer tracks elsewhere, on cats that have other worse problems. Willie will probably have a set, as he owns a very large share of the D4s in CA and the later tracks up thru 7J and the 2T/5T series can be used. There is also FlorinTractor in SAC that will probably have a 50% or better set, and there are BERCO tracks still available, but pricey.

I'd also bet, that the bottom rollers are well shot too. Pull the front of the track up on a 4x4, 6x6,etc,, and with a bar, reach under and pry up on the edge of the rollers,, if loose, you need em. See Florin or Willie again.. The two top rollers, probly bad too, can usually be re-bushed and re-pinned. I had a machinist friend here, make new pins and bushes, so I could keep them, instead of going to the later single-roller field mod ones.

I'm not trying to trash your project, and I could go on and on,, cause I have 4g2195, the exact one-before-you sister to it,, and have been totally through it, except for the accordian-bellows seals between the sprocket and bearing caps,, coming soon though.. I also have 4g7747, the 1937 D4 version, which is turning into a parts cat. No, no tracks, as I used them on 2195, they were like yours.. have most of the rest of it though, including the single top rollers, but so far, am keeping the bare engine blocks for my spares. All else is going.

Mine came with an old odd cable blade made by McAllister of L.A., and it had to go.. found a nice LaPlante-Choate angle to put on it. Heres some pics, before during and after. SJ knows these early-early cats, in his sleep, sage advise.

thanks for the info. i love this old cat(rd4)....BUT THAT 14A D8 SOUNDS KINDA KOOL. MIGHT CHECK IT OUT THIS WEEK...