Questions About my 112

Hello,

I've browsed the site for a while but this is my first post.

I have a 112 grader that i saved from being scrapped. After looking it over, we pull started it last summer just to prove it would run. I haven't done much to it as i searched for a moldboard, and now that i have found one i'm ready to start trying to fix it. So i have quickly discovered that information is scarce online for these machines and i'm hoping ya'll can answer a few questions.

First, can some one tell me for sure what year the machine is- 3U3274? Can someone tell me for sure what motor is in it? Can someone tell me what size and shape the seat cushions are supposed to be? My mother-in-law can make them, but i have absolutely nothing to go off of.

We believe the machine has transfer pump issues and injector issues. Is caterpillar a good place to go in search of parts, or do i need to look elsewhere?

Any Tips as i start to bring this machine back to life?

Thanks,

Dustin

Machine is a 1951 model with D315 engine.
Parts sourcing can be a combination of Cat and aftermarket depending on what you need.
Seats can be purchased ready made but they are a bit pricey. You'd have to find one to copy to get dimensions.

Hi Dustin congratulation on your old Motor grader, about 2 years ago I too purchased an old motor grader, 1942 No 12 and did not know a thing about it. The first thing I did was watch ebay for an operators manual, Servicemen's reference manual and parts manual. They are very explanatory and informative. I don't think I paid more than 25$ each and was able to find originals! I also asked a bunch of question to all these great guys on this forum. But those books are going to be an education for you in a great way. And as Old Magnet said getting parts will be a combination of your local caterpillar dealer and aftermarket sources there is always a thread at the beginning of the bulletin board with a bunch of great places to order parts from. As far as your cushions go I could measure mine but not sure if they would be the same. If you can you should post a few Photos for all to see thanks, Jesse

Most common problem with the transfer pump is the bypass poppet is not sealing.

The transfer pump is a positive displacement gear pump, so it requires a "pop-off". This is a simple spring and poppet located in the inlet fitting bolted to the transfer pump with a couple of 3/8 bolts usually. The fuel line from the tank screws into this little cast iron block. Turn off the fuel at the tank first and then usually can just unbolt the thing and let it drop down without even taking the line loose. May have to unbolt the fuel line clamp to get enough slack. Make sure to catch the spring and poppet. They don't tend to fly out or anything, just note how they are installed. The spring can rust away from water collecting in the hole it sits in and the seal on the poppet gets hard or damaged by debris flowing through it. Occasionally the surface of the pump where the poppet seats will be eroded from debris flowing through it and must be carefully filed or milled back flat to get a good seal. I would say this is pretty uncommon though. Usually a new poppet or both spring and poppet and your fuel pressure will jump right up there. Of course the pressure gauge is AFTER the filters, so if filters are plugged, the gauge wiill still read low. You can open the lower bleed screw (below the filter retainer plate) on the side of the filter housing and if the filters are plugged, you will get high pressure (well maybe 10-15 psi) fuel out, but when you open the upper bleed screw (big knob)on the front of the housing, you will get very little flow as indicated by the low pressure on the gauge. When you change the filters, drain and wash the housing at the same time and then pour clean fuel in to fill it before dropping the assembled filters, retainers and retainer plate back down into it. This will save lots of time turning the engine with the pony to fill the housing and there is no danger of bypassing any debris with this method.

While you have this bypass/inlet block loose, it's a good idea to turn the fuel tank valve back on and make sure you have a good flow of fuel through the tank outlet and line. Also a great time to drain any water and crud out of the tank drain which is near the fuel outlet valve. Debris in the fuel will quickly take a toll on the transfer pump gears and housing, causing some rather expensive damage, so either make sure the tank is clean or install an inline filter or strainer. Old Magnet has posted pictures of one neat way to install these, but there's lots of ways to do it.

One other thing I will mention to start with is to look in the vertical shaft/pedistal under the control box in the cab (the one with all the levers) and you will see a small cover. Lift that up and there should be a set of flanges you connect with a special soft shear pin available from CAT. Sometimes this has been replaced with a regular bolt and someone can drive one of the blade functions into the end if it's travel and snap one of the shafts. When the engine turns, the vertical shafts turn.

Have fun!