12 Motor Grader Pony: Been There Done It

Bed Time Story

In September 2007 I Filled Up A 150 Gallon Hand Crank Tank On The Back Of The Pickup With #2 Diesel. I Proceeded To Crank In Diesel Fuel Into My Number 12 (8t) And Filled It 3/4 Full.
Next I Used The Pony To Start 12, The Pony Had Been In Pretty Rough Shape When I Got It But It Started And Hammered Inside The Pony As Was Usual. I Drove The 12 Up From The Runway To It's Most Convenient Location For Winter And Shut It Down.
We Then Got Several Days Of Below Freezing And Fairly Close To Zero Days With A Snowstorm. I Proceeded To Start The 12 To Clear Snow. The Pony Started As Usual With It's Hammering And I Usually Tried To Keep Low Rpm. I Started To Crank On Diesel And Was Spinning Fairly Well Disengaged Compression Release And Cranked For A While It Should Have Started So Finally A Shot Of Starting Fluid....... Still Nothing Except From The Starting Fluid So I Ran The Pony Up A Ways And Cranked For A Long Time, Still No Main Diesel... After A Few More Minutes The Pony Just Stopped (too Quickly) But No Real Noise. The Pinion Was Still Engaged So Neither Engine Would Turn. So Because It Was Late I Came Inside And Watched The Packers Loose Thier First Game (now I'm Really Feeling Betrayed).
During The Week We Towed It With A Loader The Pinion Disengaged But Still No Diesel. We Then Gave Up Due To Time.. Another Day Came We Towed It Again On The Blacktop So The Tires Would Not Slip On Ice .. Nothing.. I Removed The Drain Cock Plug From Tank ...froze Up.. Removed Line At Other End ... Froze Solid... Got Some Fuel To Run After Digging Ice Out..put Back Together... Still Nothing Towing Is Not The Way To Start It With These Type Of Problems..no Fuel Pressure. Next I Removed Fuel Filters And Put Heat Gun Inside Fuel Filter Reservoir To Melt Now 3 Inches Of Ice In Bottom Of That Until It Drained All Out... Filled Res With Fuel And New Filters ....... Towed It Again Still No Fuel At Bleeders Or Pressure Gauge... Towing Still Not Best Way To Start And Now Starting To Suspect Fuel Transfer Pump... I Had Already Inspected Bypass Valve Ok.....after Evaluating Wasted Time Waiting For Towing Conditions And Time To Replace Pony I Elected To Get Going On The Pony Replacement. I Prefer Ponies Vs Electric Start Conversions, Because They Work Well In Cold Weather They Warm Up The Diesel And Will Crank All Day Long. I Purchased A Very Nice Pony From Our Fellow Member In Wisconsin, Got Out The Parts Book And Made A List, Called Cat And They Had All Gaskets And Parts The Next Day. The Removal Of The Pony Went By The Book Steps Very Well With One Exception.. There Is A Small Stud With Nut Way Back In The Corner In Line With The Others On The Port Side Right Where The Pony And Diesel Come Together, I Missed It Because Of A Little Greasy Dirt. I Later Found It After It Was Pulling Just Too Hard. After That It Came Right Off (i Used A "come Along" And Backhoe) It Was Perfect For The Job. The Dowel Pins Stayed With The New Motor So I Had To Knock Them Out To Fit The Ones That Stayed With The 12. I Took Advantage Of The Extra Room To Clean And Paint Some Items And Pony. I Washed Pinion Clutch Gear Box With Diesel Fuel After Removing Old Gasket And Shining Surface With Wire Wheel. New Belts On Pony And Hoisted And Bolted. A Little Difference On Throttle,choke And Pinion Since In The Later Model They Had Changed To Inside Cab Control (very Nominal). Fresh Oil In Pony..fresh Oil In Pinion Box.. Radiator Topped Off And Pony Coolant Bleed Valve Open Fresh Gas And It Fired Right Off No More Hammering, It Ran Like A Sewing Machine. I Used A Little Seafoam And Carb Cleaner Because It Was Sitting A While. The Coolant Started Bleeding From The Pony Bleed Valve Indicating Pony Waterpump Action.
Cranking On Diesel ...no Fuel Pressure. Removed Main Fuel Line
From Adaptor, Bypass Line And 3 Nuts And 1 Bolt And Removed Fuel Transfer Pump. The Drive Gear Had Broken Off Due To The Ice I Was Able To Reach Up With My Fingers And Extract The Gear And Shaft End. I Made Another List Of Parts Called Cat And While On The Phone The Cat Guy Said Oh Shit... I Thought That The Shaft And Gear Were No Longer Available, He Was Upset That I'd Have To Wait Till Tomorrow... What A Relief.
Rebuilt Pump By The Book, With A New # 8h-4726 Shaft And Gear And New Gaskets And Seals. Cleaned And Shined Gasket Surfaces And Reinstalled Pump. Started Pony Cranked On Diesel With No Compression Release And I Still Didn't See Indication Of Fuel, Then All Of A Sudden Fuel Started Coming Out Of The First Bleeder, Then As I Was Closing That The Second One, Then The Injector Bleeders, And As I Was Trying To Get All Of Those Closed She Fired Up And The Fan Almost Blew Me Off My Perch. It Kind Of Wakes A Guy Up .......... The End

Probable Cause: Weak Pony And Rainwater / Condensation In Fuel Storage Tank

A hard lesson well learned. I enjoyed the story.

I learned the hard way a long time ago that it is possible to break the fuel filter housing with enough water freezing. It is also not that hard to drain the bottom off the fuel tanks but even in dry country water seems to find a way into the fuel. Keeping fuel clean is easy to neglect because you can't see it. This is a great story of persistence. Glad you got her going. I once had part of the the linkage between the pony motor cab controls on a CAT 12 70D grader break and fall into the turning clutch. Made an awful sound. It broke off clutch parts and made it necessary to remove the pony motor and the big engine. I know the nut you mean that's hidden and rather hard to remove on the pony. I did the same thing. We pulled the diesel engine using a backhoe and found it was surprisingly easy to stab the shaft from the engine back into the clutch. Experience is always a great teacher but the tuition is high.

Nice story and glad to hear you got it going. Also very glad to hear that fuel transfer pump parts are still available as I am having very low fuel pressure problems with my 8T as well. No ice in mine though, this was during 70 degree weather.

Hey WarBird,

Good story. I really enjoyed reading. Must be pretty cold up there. Next time instead of using a torch to de-ice, just move it to Maui😄 -glen