My 64 M151A1

[Ambush151]

This poor mutt sat unused in the backyard for I think about 7 years. Never could find the time to keep it running so it was forgotten about until I saw a neighbor with a M151.

Kind of got me interested again.

7 years of neglect showed itself when I tried to fire it up.

Engine oil at first looked OK but a short run from the backyard to the front yard yielded oil which now looked like chocolate milk. I thought maybe I'd cracked the block from low antifreeze and cold Alaskan winters.

Changed out a leaking water pump, refilled the radiator with water, drained out the oil,put on a new filter and refilled with used but still good motor oil. Idled the M151 up and down the road for about 20 minutes.

Dipstick and oil showed no water at all so it must have been condensation from 7 years in the bottom of the pan.I hope the oil pump is OK. Drained out the used motor oil, screwed on another new filter and topped off with fresh oil.

I once again slowly drove the mutt up and down the road. The clutch was shot mostly to the point of not working at all. I pulled the plug on the bottom of the transmission and only water came out.

I didn't have any rubber boots around the stick shift lever so I assume rainfall and snow melt filled the transmission. A leaking gasket on the side cover allowed the water to push the gear oil out.

Soooooo I put automatic transmission fluid in and again slowly drove around a short bit. Drained that out and hoped for the best.

Now to tackle the clutch. Under the bell housing sits the clutch pan. My mutt had the drain plug in so everything sat in a few inches of water.
It was a rusty mess in there. Time to pull the powerpack.

I removed the transmission, bell housing and discovered the rear block freeze plug had rusted through and was leaking into the bell housing. With the plug in the pan it simply filled up.

So a new freeze plug, installed a used but good flywheel, clutch and pressure plate. Throw out bearing was still in great shape. New rear main seal just because I had one.

Now I open up the transmission and surprisingly everything looks really good. Very little rust anywhere. Bright shiny gears. Seems the transmission fluid flushed all the gunk out.

Cut a new gasket for the side plate and reassembled everything.

With the powerpack back in, Transmission filled with gear oil, engine oil looking good, clutch working, no coolant leaks the M151 is running very well.

Two wheel cylinders leaked but I polished them out, starter bendix needs replaced but overall I'd say I dodged some real bullets.
She still needs some body work but for now I'll settle for nice but rough have fun M151A1.

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[markrdje]

If I remember right I replaced the clutch without removing power pack, one time

[Rickf]

If you did you had to cut the floor to clear the e-brake drum and rear of the transmission.

[Ambush151]

It does look possible to replace a clutch disc with the motor still in. Transmission could be slid back about an inch and a half. unbolt the pressure plate and slip the clutch disc off the input shaft. Might even get a little further removing brake lever and wheel.

I didn't try that but thought about it.

[markrdje]

Here is picture, can't make it bigger, this is on the 151, maybe you can see the bolts holding cover on. Ya, it is easier to pull the powerpack.

[Rickf]

Or, two driveshafts, a few wires a clutch linkage and a throttle linkage that snaps right off and four bolts. 6-8 bolts on grill. Done, engine and trans out and that way you can address any oil leaks, clutch, freeze plugs including the one inside the bell housing. drive shaft output seals are much easier done at this time also. I can have the engine out in a half hour or less. I seriously doubt doing the clutch in the vehicle can be done that quickly nor anywhere near as easily as it is when out of the vehicle.