Cast iron rear swap

[farmall fred]

I am getting ready to start on my 1872 rebuild update and I need to repair the rear end as the previous owner ran it with broken off bolts and damaged the housing including breaking the front mount. I have a couple of options. I have a complete rear from a 1864 that I could change the reduction gears in and use it, a cast iron rear from a 782 that I could do the fine spline conversion on. Question, is the reduction gear the only difference in the pump between the 1864 and the super rear? The reason I ask is the other owner also ran it with a bad driveshaft and now it is leaking bad from the pump seal I have not tore it down yet but I am betting the input shaft is damaged. I was hoping I could use the 1864 pump. Any body have a link to the thread on converting a cast iron rear to work in a super. I did a search and so far I have not found it.
Thanks,
Tom

[Sam Mac]

Depending on how bad your existing rear is you may be able to install a set of rear end braces from Xtreme and not even need to worry about the front mount. As long as the 4 bolts that go into the axle tubes at the rear are good it should be savable. Post some pics of what you have to work with.

[farmall fred]

Thanks, Sam I have not removed it yet so I don't know about the lower mounting bolts yet. I did remove the drive shaft and the splines on the charge pump and the coupler are both worn and there is play on the pump shaft. This leads me to think I should do the cast iron swap using the reduction gears from the super rear end and the 1864 charge pump parts. If any one can point me to the thread on doing the swap to cast iron using the fine spline axles I would be grateful. I am sure I can figure it out using the manuals but it would be easier to follow the instructions of someone that has did the swap. I hope to strip the 1872 down today and I can look further into how much damage is done. I did get it power washed and got the Mag 18 running so I can check it out. I had to remove the driveshaft to run it as it was spraying oil out of the charge pump seal. The engine had good compression and starts easy, does not smoke but has a miss on one cyl. New plugs did not help so I think it has a weak coil.
Later
Tom

[J-Mech]

It's likely that the charge pump/hydro input shaft is egg shaped and not repairable. Changing the charge pump off one hydro to another does not change the input shaft. So... if your looking to get the splined input shaft on a non splined unit, it doesn't work like that. The swap is just a matter of changing parts from one unit to another, so nothing really to know. FWIW, Sam is correct. A swap to a CI rear is not really necessary. Just as easy to add a set of braces. However, I'd be looking at that input shaft, I'm betting it is bad.


As far as the engine goes, it uses one coil for both plugs. If one side is missing, it's possible that it has a bad plug wire, but a failed coil is unlikely. If it has a miss, do a compression check. Your problem is likely internal.

[farmall fred]

Originally Posted by J-Mech

It's likely that the charge pump/hydro input shaft is egg shaped and not repairable. Changing the charge pump off one hydro to another does not change the input shaft. So... if your looking to get the splined input shaft on a non splined unit, it doesn't work like that. The swap is just a matter of changing parts from one unit to another, so nothing really to know. FWIW, Sam is correct. A swap to a CI rear is not really necessary. Just as easy to add a set of braces. However, I'd be looking at that input shaft, I'm betting it is bad.
I finished tearing the tractor down today and the axle housings are damaged with pieces broken off on both sides from running it with broken bolts. The pump input shaft is loose where it goes in the charge pump so I will dissemble this rear to get the super reduction gears and then remove the hydro unit from the 1864 I have and then install the super reduction gears. in the 1864 rear. This should give me a good setup for my tractor.


As far as the engine goes, it uses one coil for both plugs. If one side is missing, it's possible that it has a bad plug wire, but a failed coil is unlikely. If it has a miss, do a compression check. Your problem is likely internal.

I did a compression check yesterday and both sides have 120 psi cold. I am betting a bad plug wire as the right cylinder comes and goes when running. What is strange is if you rev it up full throttle and remove either plug wire it will continue to run on the opposite cyl. I will find out tomorrow what is wrong when I tear it down and remove the covers. I have a spare mag 18 with the gov gear out so I can rob any parts from it I need. The previous owner had this engine rebuilt with new pistons and rods and had the heads reconditioned about 150 hours ago so I am hoping the bottom end is good. I was skeptical of the rebiold until he gave me the receipts for the work done by a repair shop. The guy that had it was a real hacker but in the last couple of years he spent a bunch of money on it as he also had receipts for a new pto clutch. a new driveshaft with the disconnect clutch a different rear end housing that he then proceeded to ruin by running with broken off bolts. Will let you know what I find.

[J-Mech]

How do you know it's the right side cylinder?

Why is it weird that it will run with one plug wire removed? It's a wasted spark ignition. It fires both plugs at the same time. Unless you mean it's weird because you think it has an ignition misfire.....

[farmall fred]

Well today I removed the tin from the M18 to check out the coil. It was completely covered with oil and trash. I spun the engine over and the spark was very intermittent so I removed the coil and solvent cleaned it and cleaned the laminations and flywheel magnets of rust and reset the air gap. I started it up and it started running on both cyl's. What really puzzles me is it would run on the left cyl, but the right side had an intermittent miss. I need to really look the plug wires over good incase there is a break in the insulation causing the spark to jump to ground. I did remove the head on the right side as I wanted to see what condition the valves, guides and cylinders were in. The bore has fresh hone marks, no signs of scuffing, the piston is .010 over, The guides are tight and the valves and seats look good so I guess the previous owner was telling the truth about the rebuild. I think tomorrow I will bolt it to a mounting plate and clamp it to my bench and run it for some time to check for leaks before I reinstall the tins and put it in the 782 I bought last week with a blown KT17. Hope it works out, if it does I will have a cheap 782 to mount my sickle bar mower on.

[ol'George]

Don't forget to retorque the heads after a couple of up-to-temp cycles !!

[J-Mech]

I hope you installed a new gasket......