ACBob Posted July 16, 2008 Posted July 16, 2008 Need advice on the practicality of using an AC 718H (1690357) Hydro transmission to replace the transmission in an Agco Allis 918H (1692144). The 918H has power lift and power steering. I just bought the 718H from a local dealer for $100.00 and it has a manual lift. The engine is a replacement 16 hp with no compression, probably a broken rod. The first advice I need is if this is a good idea in light of the fact that the axle tubes of the two tractors appear to carry a different part number. Does anyone know if the 718 axle tube is as durable as the one I broke? Are there any other differences in two transmissions that might be a problem? Broke axle tube on 918H after 400 plus hours on Johnny Bucket Jr. of hard use digging a pond. This tractor had bar tires, fluid filled and wheel weights. At 375 hrs I added three 50 Cal. ammo boxes filled with cement with a tool box on top. If I get another 400 hrs. of use with this transmission swap I will be happy. I just parked the two tractors side by side and other than the power lift and steering hoses and the placement of the trans. filter, there is no notable differences at first glance. If I make the swap I assume that I can later decide if I want to swap pump and motor unit or move the appropriate valves and hoses to the donor pump and motor. Also if I make this swap, would be easier to swap the BGB with the donor transmission? I am sure I will need more advice if I make the initial swap. Bob in hot Indiana
ACBob Posted July 16, 2008 Author Posted July 16, 2008 This shows the weight on the tractor. Has anyone else had a similiar setup without a problem?
Brent_Baumer Posted July 16, 2008 Posted July 16, 2008 I've heard of axle tubes breaking from changing direction too quickly with a heavy rolling load. I'd say while impressive, what you've done there is stressing your machine to the max. No offense, but I also have to question your sanity to tackle a job like that with a garden tractor and a johnny bucket. A couple days with a dozer and you'd been done. Probably with less in rental $ than you spent on fuel. The drawback is, it wouldn't have been near as much fun :D Anyway, to get back to your original question, I think the tranny's are essentially the same. Some have the oil filter remote and some do not but I've never noticed any difference as far as being able to swap them. Now, as far as the hydraulic lift goes, yes there are diffences there. You need to swap the little spring and the shims from your 918H into the check valve assembly. HubbardRA and myself (maybe others??) have both converted 700/7000 series tractors to hydraulic lift. If you do not do this your lift will be very slow and puny. I'll try to find some old posts for you to look at. Brent
Kent Posted July 16, 2008 Posted July 16, 2008 IMO, it would likely be easier to simply unbolt the BGB at the front, and swap out everything from there back (i.e. BGB, tranny, frame rails, etc), then change the check valves in the pump, as Brent describes.
Brent_Baumer Posted July 16, 2008 Posted July 16, 2008 Here are some links to perform the conversion, only yours will be easier since you are just working on the hydro pump and not the control valve and lift lever too: [url]http://www.simpletractors.com/club2/topic.asp?ARCHIVE=true&TOPIC_ID=51515[/url] [url]http://www.simpletractors.com/club2/topic.asp?ARCHIVE=true&TOPIC_ID=46227[/url] [img]http://www.simpletractors.com/club2/attach/HubbardRA/ValveWriteup.jpg[/img] [img]http://www.simpletractors.com/club2/attach/Brent_Baumer/smallparts.jpg[/img] [img]http://www.simpletractors.com/club2/attach/Brent_Baumer/lines.jpg[/img]
Brent_Baumer Posted July 16, 2008 Posted July 16, 2008 quote:Originally posted by Kent IMO, it would likely be easier to simply unbolt the BGB at the front, and swap out everything from there back (i.e. BGB, tranny, frame rails, etc), then change the check valves in the pump, as Brent describes. I am in agreement with this although neither way is much fun. It helps some to have a friend too if you are manhandling the swap but not necessary if you are good with jacks, blocking and maybe a rope. I'd also snap a pic or two of how things are routed prior to taking the 918H apart. I've found I have to do that more often 'cause I just can't seem to remember as well as I used to. :(
cwm1276 Posted July 16, 2008 Posted July 16, 2008 The biggest difference is how the tensioner works for the deck. They changed between the 700 and 900 series ACs. If you use a snowblower this might be important as the 700 drove the snowblower off the front of the engine, while the 900 drove the snowblower off the cone clutch. The 900 series also you to move a pully from snow blower to mower positions, the 700 rear end does not have that ability. But if you don't have, or need the snowblower then you don't need to worry!
Brent_Baumer Posted July 16, 2008 Posted July 16, 2008 quote:Originally posted by cwm1276 The biggest difference is how the tensioner works for the deck. They changed between the 700 and 900 series ACs. If you use a snowblower this might be important as the 700 drove the snowblower off the front of the engine, while the 900 drove the snowblower off the cone clutch. The 900 series also you to move a pully from snow blower to mower positions, the 700 rear end does not have that ability. But if you don't have, or need the snowblower then you don't need to worry! Ahhhhh! Forgot about that too. I'd have to look at the frames to see if you can switch that too. BTW - you CAN run a snowthrower from the center PTO on the 700/7000 series. Biggie*Rat has converted several that work fine. Just need to slightly modify one small part and buy a new belt. Very old, very sore subject....... In Bob's case though he may just need to mod the small part. Not sure about the belt length since the front half of the tractor would remain a 900 series.
RayS Posted July 16, 2008 Posted July 16, 2008 You can swap out the left side plate and idler arm between the 718 and 918.
Brent_Baumer Posted July 16, 2008 Posted July 16, 2008 OK. Couldn't stand it and went out to look. It APPEARS to me the rear frame is all bolted and the left side could be unbolted and swapped. This would eliminate the center PTO tensioner/idler pulley setup problem cwm1276 brought up. If it is possible I highly recommend doing it rather than leaving the 718H frame in place. I formed this opinion by looking at a 7016H and a 916H but I don't recall ever trying to remove the frame from the transmission (or the transmission from the frame depending on how you look at it. You conversion project just got tougher ACBob. Good catch cwm1276!
HubbardRA Posted July 16, 2008 Posted July 16, 2008 Just to clear up a couple things, the parts shown in the diagram that Brent Posted (I did that layout some time back), those parts are already in the 900 series hydro and should be swapped into the 700 series hydro when you change them. That will make the hydrolift work correctly. As Brent said, I currently have a hydrolift hooked up on my 716H. The trannys should swap relatively easily. Change the swing plate with the idlers from the PTO also to keep the 900 series PTO setup.
ACBob Posted July 16, 2008 Author Posted July 16, 2008 Brent, I think you have something about breaking axle tubes from changing direction too quickly. I was doing this on a regular basis to clean out the bucket when the mud stuck to the bucket. The axle tube just quit before the picture was taken and at the time I was pushing into the bank of dirt. Yes, I am doing this project for fun and I get a lot of relaxation out of a tank of gas. Guess it is good therapy. Also what am I going to do with the Johnny Bucket when I finish this project? Just dig another pond. Thanks for the additional advice and the pictures. Kent, thanks for the input about changing everything from the BGB back. Cwm1276, thanks for the info on the snow blower setup, however, I will only need this tractor for the Johnny Bucket. I have other tractors with different implements on them. RayS and Brent, I assume that dealing with the side plate as mentioned will not be necessary as I will only use the Johnny bucket on the 918H. Do you agree or disagree that the best approach will be to change every thing from the BGB back? Bob in Indiana
Brent_Baumer Posted July 16, 2008 Posted July 16, 2008 I recommend dealing with the side plate. Probably add an hour or so to the job but worth it. You may regret having a "cobbled" tractor in a few years when you need to mow with it or you decide to sell it. Simplicity changed the design for a reason. The V idler is fixed on the 900 series but swings with the backside idler on the 700 series. Some folks believe this transfers more power to the mower deck or snowthrower and why the design change. If you keep the 718 idler/tensioner setup you or whoever ends up with the tractor after you may (or may not) need a special belt to run a mower. I would just change it. Now, as far as the gear box goes, I am not sure it will save any time by changing the gearbox too if you change the side plate. If you haven't run a mower or tiller or anything off the center PTO or used it very little I would definitely keep the 918 gearbox but I would inspect if for cracks due to the stress you've put the machine under. You probably have no idea what kind of life the 718 gearbox has had to I would be inclined not to use it, at least not without draining it and looking inside first.
MikeES Posted July 16, 2008 Posted July 16, 2008 I would swap and rebuild the axle tubes. My bet is if you just swap the tranaxle without rebuilding the the axles you will have another broken tube almost immediately. The 718 is older iron and the axle tube is probably already stressed, maybe even cracked!
ACBob Posted July 21, 2008 Author Posted July 21, 2008 I should have gotten back sooner, had a bad week last week. I hope to address the tractor trans swap in the next couple of days. Thank all of you for your input, your experience has been valuable to me. Will get back for more advice after I have made the swap. Thanks again Bob
KenK Posted July 21, 2008 Posted July 21, 2008 If your worried about the hydro pump,just take it off of the broken tranny and put it on the replacment tranny.I think it is only 3 bolts and an o-ring. If I where doing it myself,I would put a new axle tube in the 918h along with bearings and seals. The difference in part #s is probably the width of the key ways on the axle tube.
ACBob Posted July 24, 2008 Author Posted July 24, 2008 Finally got a chance to pull the two tractors apart, I am thinking that I will go ahead and swap the BGB’s. It would not surprise me if the 918 does not have as much stress on the BGB as the 718. When I go the 918 it was well used as it had bad rings, need a new carb, and the stator went our after 50 hours. Also, the front axle bolt had made a large hole in the frame. All is fixed now. Both BGB’s seem to be in good condition no leaks and the gears are tight. However, I do understand the concept of the newer gear box would most likely be in better shape. I think that I will pull the pump assembly from the 918 rear end and see what is under it tonight. It looks to me as if this is the way to go; as I would have to remove the part below the 90 degree hose fittings on the pump to get them to come out. Thanks again Bob
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