Caterpillar Grader 112

[Cariboo4x4]

Good day all. A friend of mine is getting to the age where he is calling on his younger friends for assistance. I don’t know much about graders yet the braking system on this grader seems very simple. He definitely has air in his brakes and I see no drips at rear brake drums. The master cylinder definitely looks to be leaking at rear and the ground directly underneath seems dark from fluid. Does the boot on rear have a piece missing or does it come like that new? He went to use it after the winter and no brakes. Master cylinder was empty. He filled it up, and of spilt a bit of fluid and master cylinder casting is wet in photo. I arrived later that day pedal had symptoms of air in brake pedal. Id say over winter the master cylinder drained out rear of cylinder. He has bled brakes in years gone by and he bought a starter from caterpillar after he said pup motor stopped working several years ago. I expect if Caterpillar supplied him a starter a master cylinder or kit would be available. I’m curious if this is definitely a 112 model and if a service manual new or used is available from someone here. I’ll look on net if anyone can confirm its a 112. Thank you in advance.

 

[Cariboo4x4]

Just adding a couple more photos to confirm if anyone can say it’s definitely a 112.

 

[Cariboo4x4]

Here is a cropped photo I had to make it smaller to be able to upload it.

 

[docmirror]

It is a model 112. Mid 50s I would guess. Might start with taking the MC apart, hone the bore and find a new piston and cup seal. The cup seal is likely a common dia. Or, he can ask for a new MC or a rebuild kit. But - almost sure the bore will need to be honed. Harbor Freight has a brake cyl hone for 23 bucks.

 

[Scott 730]

The Antique Cat Owners Club is a great source of info. https://acmoc.org/

 

[MeanGene1]

A 112 is a smaller, light-duty version of the old 12, similar to a modern 120. Easiest way to tell is the 4-cyl engine. Had to fix the MC on my stepdad's old 12-7T (serial # 345, 1945), cup had split. Was pretty easy to find a kit by size and hone the cylinder

 

[trackrat]

It is an early 112 mg I have a much later model brakes are simple pull master cyl off the cups are standard size take them to napa they will have them. You can usually bleed the air out at the tee fitting on top of the chain cases if mine sets for very long I have to bleed it

 

[Jim.ME]

A good parts store can often match up many of those old equipment master cylinders with one that will work, as the same ones were often used on trucks.

 

[moresmoke]

3D-9334 is the part number for the kit for the master cylinder.

Aftermarket appears to be widely available for about $50.

 

[Old Magnet]

3U5382 is a 1955 #112 unit, uses D315 engine.

 

[trackrat]

My 112 is a 1966 model and is direct electric start neighbor has an older 112 that is pony motor they just push it off, nice thing about these old machines is that they are not hyd , they don't leak down when parked for a long time

 

[trackrat]

A 112 is a smaller, light-duty version of the old 12, similar to a modern 120. Easiest way to tell is the 4-cyl engine. Had to fix the MC on my stepdad's old 12-7T (serial # 345, 1945), cup had split. Was pretty easy to find a kit by size and hone the cylinder

112 is a 4 cyl motor 12 is a 6 cyl motor later 12 f's have gear reduction on the front of the machine to help with the blade lift and down pressure issues

 

[DWF]

112 is a 4 cyl motor 12 is a 6 cyl motor later 12 f's have gear reduction on the front of the machine to help with the blade lift and down pressure issues

1966 could be a 112E, 91G series or a 112F 46D Series. 112F must be similar to a 12F with the different blade lift. I had a 112 3U5290. When I got it I had no parts book, but the Cat salesman found a parts book for a 112 with a direct start 4 cyl engine. I forget the series but it was the same vintage as my 3U 5290 except for the starting. After I had the 112 I got 69 120 14K series. 6cyl direct electric.
DWF

 

[trackrat]

1966 could be a 112E, 91G series or a 112F 46D Series. 112F must be similar to a 12F with the different blade lift. I had a 112 3U5290. When I got it I had no parts book, but the Cat salesman found a parts book for a 112 with a direct start 4 cyl engine. I forget the series but it was the same vintage as my 3U 5290 except for the starting. After I had the 112 I got 69 120 14K series. 6cyl direct electric.
DWF

very last of e series it has all of f updates, he needs tp get his own parts catalog the holt dealer near me can't find listings for my machine

 

[moresmoke]

very last of e series it has all of f updates, he needs tp get his own parts catalog the holt dealer near me can't find listings for my machine

I put the OP’s serial number into the Cat parts app. It popped up with the model, but there is not much for parts information besides the part number I posted above for the master cylinder kit.

 

[m16ty]

Never was on one of those old graders that had brakes, you just lowered your blade to stop.

 

[trackrat]

Never was on one of those old graders that had brakes, you just lowered your blade to stop.

Yeah ran a 12f for 3 years for a contractor it never had breaks

 

[docmirror]

I run an Allis Chalmers D grader with no brakes. Never had them. Just drop the blade a bit.