So I did a thing... Agria 8900D

[Topzide]

Cheap and qualified for the job!
At least you know how to fix the next issue that may crop up. Sometimes it's worth the effort regardless! Looking forward to seeing it all together and being able to be used in your orchard

 

[ptsg]

The more I work on this tractor, the more I realize that this thing had loads of issues, but since it would still somewhat run, they just kept going. The last straw was when the engine let go and they just parked.

Oh well, too bad I enjoy this type of work/challenges. By the way, this not a rant. I do enjoy this type of work and I knew it would be a long project before I bought it. Although, I'll admit that I wasn't expecting to find so much wrong.

Today I spent some time dealing with the shift handle. It had so much side to side play that you wouldn't know if you're engaging 1st gear or 3rd. Took me an hour to enlarge the holes for the next size up and machine two new oversized pins. It's now perfectly and pretty much 0 play. Much much nicer to use.

I don't even know how they could use this tractor like this. I mean, they lost the clutch pedal return spring. Instead of finding another one to put there, they kept running it till the release bearing lost all the balls from being constantly pushed against the pressure plate. This, eventually, caused the pedal to hit the stop before disengaging the clutch. The solution? Smacking that pedal so hard, it bent the stop out of the way. I can't even imagine the amount of noise it was making when they pressed the clutch pedal.

 

[Topzide]

Look at how satisfying it'll be when up and running!

 

[ptsg]

Been doing to more more work, mostly small stuff but takes some time. Working mostly on the rear brakes. Had to machine two new bushings for the cams that push the brake shoes out. The old ones were flopping all over the place.

Painted the backing plate/bearing housing because when assembled, I can't get paint in some areas of it.

Still waiting on the seals and on the head. Can't wait to hear this thing running to get some more motivation but it is what it is.

Spent the afternoon taking the center section where all the pivots happen.

This the pivot points for the steering. Just like the lack of care on the rest of the tractor, this area didn't go unnoticed either. The top bearing gave out a looong time ago, as you can see in the picture, so they just kept on running it till it ate part of the housing. Another thing to fix. I was hoping it was just a bad bearing.

On the other hand, the parts where the front half twists in relation to the back half, like the front axle pivot on a regular tractor, still had the nylon bushings in decent shape. Decent enough to put some shims behind and run it that way. I was afraid the bushings were gone and it had already started eating some material.

On the bright side, and this was another worry of mine, is that both driveshafts were in fairly good shape. Splines still in nice condition and the U joints, while not perfect, still in good enough shape and very little play.

 

[etpm]

I can hardly wait to see how you fix that hole in the head and how well the repair works. I'm a retired self employed machinist with over 40 years experience working in machine shops. I have been watching your work and so far have been impressed. I see lots of amateur folks do great machine work and I encourage people to try machining because it's so much fun.
Eric

 

[ptsg]

I can hardly wait to see how you fix that hole in the head and how well the repair works. I'm a retired self employed machinist with over 40 years experience working in machine shops. I have been watching your work and so far have been impressed. I see lots of amateur folks do great machine work and I encourage people to try machining because it's so much fun.
Eric

I live in a city where mold making, plastic injection and glass making are the tree biggest industries here. You can literally throw a rock anywhere and you hit at least 4 different mold making shops. From small garages with a couple machines to big shops fully equipped to the brim with the latest technology and tooling.

So, whether one likes it or not (I like it), one ends up learning a little bit of machining regardless. Then, it up to that person if he/she wants to expand that knowledge or not.

Living in a city like this, creates a little bit of an issue for an hobbyist, although I do some costumer work as well. Which is the price of tooling. Not small guy friendly at all. Everything gets super expensive.

As far as repairing the head, if the engine shop guy doesn't fix it himself, I'll do it my self. Nothing fancy. The valve stem poked a 8 mm hole on the head, so I'll drill to 8.5 mm and tap to either M10x1.5 or M10x1 mm fine thread and probably countersink the hole and put a countersunk bolt there. Depends on the space and thickness of the material.

Another option I thought, was to simply machine a plug, probably aluminium and press it in there. Maybe some Loctite 603, although, it may no hold the heat. Finally I would hammer the plug on the inside of the exhaust port, almost like a rivet, to make sure it doesn't come out.

 

[MTGreen]

That top bearing is really something. I hope you have a vertical mill with a big enough table or a large swing lathe to be able to bore and sleeve that.

For that plug, I would be concerned about aluminum having substantially different expansion contraction properties with the inevitable heat cycling. I would think steel would be safer with cast iron.
See the attached chart -aluminum has about twice as much as cast iron, while steel is about the same as cast iron

Metals - Temperature Expansion Coefficients

Thermal expansion coefficients metals.

www.engineeringtoolbox.com

 

[etpm]

I live in a city where mold making, plastic injection and glass making are the tree biggest industries here. You can literally throw a rock anywhere and you hit at least 4 different mold making shops. From small garages with a couple machines to big shops fully equipped to the brim with the latest technology and tooling.

So, whether one likes it or not (I like it), one ends up learning a little bit of machining regardless. Then, it up to that person if he/she wants to expand that knowledge or not.

Living in a city like this, creates a little bit of an issue for an hobbyist, although I do some costumer work as well. Which is the price of tooling. Not small guy friendly at all. Everything gets super expensive.

As far as repairing the head, if the engine shop guy doesn't fix it himself, I'll do it my self. Nothing fancy. The valve stem poked a 8 mm hole on the head, so I'll drill to 8.5 mm and tap to either M10x1.5 or M10x1 mm fine thread and probably countersink the hole and put a countersunk bolt there. Depends on the space and thickness of the material.

Another option I thought, was to simply machine a plug, probably aluminium and press it in there. Maybe some Loctite 603, although, it may no hold the heat. Finally I would hammer the plug on the inside of the exhaust port, almost like a rivet, to make sure it doesn't come out.

Your description of repair options is what has me interested in the repair. For what it is worth I would not use the Loctite option. Not because I don't trust Loctite, which I do, but because of the application. As I recall no Loctite works very well on aluminum. The head is aluminum, right? If I am wrong then I stand corrected. Even if not aluminum, or a bronze alloy, heat is certainly a concern. I think tapping the head and using a countersunk bolt would be best. If the head is aluminum I would even consider using a custom made aluminum bolt to plug the hole. That way the plug would expand and contract with the head. A steel plug in an aluminum head would not move with the head as it changed dimension with heating and cooling. In any case I am sure you will come up with a suitable solution and I look forward to your posting of this solution.
Cheers,
Eric

 

[ptsg]

That top bearing is really something. I hope you have a vertical mill with a big enough table or a large swing lathe to be able to bore and sleeve that.

For that plug, I would be concerned about aluminum having substantially different expansion contraction properties with the inevitable heat cycling. I would think steel would be safer with cast iron.
See the attached chart -aluminum has about twice as much as cast iron, while steel is about the same as cast iron

Metals - Temperature Expansion Coefficients

Thermal expansion coefficients metals.

www.engineeringtoolbox.com

I have the classic Bridgeport milling machine and an Italian Giana lathe, if I recall correctly, about 24" or 25" of swing and about 60" between centers. However, being an Italian lathe, it's, what they call, a double bed style lathe. Basically raised headstock and tailstock. No need for a gap in the bed and huge amounts of swing for the size.

I've swing some big stuff on this lathe.

I've noticed a lot of factory welded parts to cast iron on this tractor, so I suspect it should weld relatively well. My plan is to fill the wore out part with weld and then machine it back to spec. Either on the mill or, preferably on the lathe if there is enough room.

For the head, the head is aluminium. The guy at the shop said he would do it after I suggested the bolt idea.

 

[ptsg]

Your description of repair options is what has me interested in the repair. For what it is worth I would not use the Loctite option. Not because I don't trust Loctite, which I do, but because of the application. As I recall no Loctite works very well on aluminum. The head is aluminum, right? If I am wrong then I stand corrected. Even if not aluminum, or a bronze alloy, heat is certainly a concern. I think tapping the head and using a countersunk bolt would be best. If the head is aluminum I would even consider using a custom made aluminum bolt to plug the hole. That way the plug would expand and contract with the head. A steel plug in an aluminum head would not move with the head as it changed dimension with heating and cooling. In any case I am sure you will come up with a suitable solution and I look forward to your posting of this solution.
Cheers,
Eric

Yes, the head is aluminium. Personally, I don't usually rely too much on Loctites. I try to avoid if possible. I have a couple of variants I need to check the specs on for temps.

The aluminium bolt is a good idea indeed, I think I the material to do it.

I'm still waiting for the head to address that. The guy at the shop said he would do that fix as well after I suggested the bolt idea, so I don't know if I end up doing that work or not.