Special Considerations for rebuilding a Perkins AD4.203

jbshocks · Aug 13, 2021

I have a perkins ad4.203 in a 50a that I need to rebuild because of a #1 rod bearing spuns. I have rebuilt many gas engines from cars and equipment put never a diesel or a perkins are there any items that I need to consider? The crank and rod are out for machining now. I plan to get an engine kit and install new liners, pistons, rings and bearings. Also a new oil pump. I will check block and head for flatness (book says .003) I also plan to dye check the head. I am not planning to valve work to the head as it was running fine and everything looks good. This will also be a hobby machine that doesn't see a lot of action and the head can be removed in tractor if needed.

I really want to avoid splitting this thing again in the future. So additionally I plan to replace the input seal on instant reverse.

Anything else I should be considering?

jvin248 · Aug 13, 2021

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No engine help, but if want to avoid splitting the tractor again, replace the clutch disks, engine seals behind the flywheel, pinion bearing in the flywheel for the transmission input shaft, throw-out bearing, and most important the trans pinion seals, they get hard and dried out over the years then leak.

And get new shifter boots. $3 parts that can let water into the trans and cause all kinds of problems. This spring I stripped down the whole transmission of the family's TO35 because it was locked up from corrosion due to water getting passed those boots and the tractor sat unused for a decade because of them.

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jbshocks · Aug 13, 2021

(quoted from post at 09:00:01 08/13/21) .

No engine help, but if want to avoid splitting the tractor again, replace the clutch disks, engine seals behind the flywheel, pinion bearing in the flywheel for the transmission input shaft, throw-out bearing, and most important the trans pinion seals, they get hard and dried out over the years then leak.

And get new shifter boots. $3 parts that can let water into the trans and cause all kinds of problems. This spring I stripped down the whole transmission of the family's TO35 because it was locked up from corrosion due to water getting passed those boots and the tractor sat unused for a decade because of them.

.

Mine is instant reverse so it uses a torque convertor so some of this doesn't apply

MKinON · Aug 14, 2021

Check the control shaft needle bearing through the case of the instant reverse trans and change it out if the slightest
play.

derwen1959 · Aug 15, 2021

What about camshaft bearings?
I would never overhaul engine and leave valves
Do you know reason why conrod bearing spun so it
doesn't happen again

Special Considerations for rebuilding a Perkins AD4.203

jbshocks

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jvin248

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jbshocks

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MKinON

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derwen1959

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