anyone running an AC AllCrop ?

riverbend

Well-known Member
I have an Allis Chalmers All Crop and it has been having a lot of trouble. It has broken down 4 times in about 2 separator hours. It is a not a junker, but at first it was little things like the upper sieve bolts shearing, the lock screws for both sieves coming loose, and one of the wooden bearing block on the straw rack breaking up. Last time I was trying to thresh some oats and the cylinder sucked the rubber strip out of the threshing bar and made a mess.

Are these fussy machines to keep running ? Am I just having a run of bad luck ? Some of the failures seem like they could be vibration related. Is there a typical failure in the separator that causes excessive vibration ? It does not seem to shudder or make any odd noises when it is running good, but too much stuff is breaking down to be 'normal'.

Any ideas what to look for ?

Thanks

Greg
 
When you"re dealing with a machine 60 years old it"s a good idea to go over everything, tightening, etc. re vibration: make sure the back side of the cyl bars are clean...chaff builds up on them and they turn out of balance. When the rubber is so old, it can come apart.
 
Dad's 66 is about the same way. When it gets greased every morning it has to be looked over for loose/sheared bolts. It's a constant struggle. You can just about count on breakdowns. We replaced all the wood that supports the straw rack in his 66 with white oak but it actually busted it out as well. We reinforced it with metal on the last go-round. The wood is a pain to replace! We've checked various times to ensure correct speed. It's running a true 540 but it continually shakes itself apart.

I'm not sure this issue is specific to you and me. I have seen far more machines with busted wood for the straw rack than ones that were good. The little machines are neat and will do a great job of cleaning if you can just keep it together.

We complained about the shaking apart to a local farmer. He said it was just part of maintenance for an all crop to retighten all the bolts every morning. It seems as if all the old guys didn't think much about it.

My personal opinion is that the straw rack it far too heavy. If it were the same weight as the sieve and chaffer combined it should keep it from hopping around so much. I suppose if a guy was industrious enough he could make a straw rack out of aluminum.
 
Casecollector is absolutely correct. I had an uncle that turned up the rpms on a JD A and hooked it to their AC 72. Tore it all to flinders. I slowed the tractor down and never had problems after that. At Clemson experiment station, we had a plot combine that tore the separators out quite often. Changed the sprockets to slow them down and it ran for years with no more problems. I think it is still running at one of the stations 30 years later.
Guy I worked with always ran combines as fast as the engine would run. I cringed every time he did that.
Richard in NW SC
 
Get a hand held tachometer and check what your speed is on the combine. I would bet that your over speeding the machine. They will not live long at even 50 RPM too high. Brother and I have a AC 72 an rarely have to work on it when cutting. We do not do a lot each year but usually 10-20 acres of oats or wheat.
 
I agree with everyone when they say make sure you run the correct RPMs. I bought a beautiful 72 combine that was so low houred that I replaced the cylinder bars. That combine has had more break downs than any other combine I have been around. I have the 66 that my Grandfather bought new and has done thousands of acres, the combine is very wore in places but still runs like a top, but my Grandfather took excellent care of everything and ran it correctly. I know the last few years the 72 was ran by a hired man, Im sure he just ran the tractor full throttle and shook the crap out of it and now Im paying for it.

Also it sounds like you need to give the combine a good pre season checkover. I have done it to a few of my combines, I thought once that those straw rack blocks looked "good enough" on my 60, well guess what the block broke and the straw rack caught on the separator apron caused a slew of problems. Sounds like you need to give the combine a once over and you will have less problems.

Jim
 
re running at the correct speed: there is a decal by a pulley/sprocket on the rear of the machine where you should check rpm with a hand held tach. Without checking the book, I think it"s 535 rpm. I have Dad"s tach that he got in 1948 with the Model 60, and another just like it from an auction find.
 

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