Started moving worn parts to the shop, about time and enough room now to get the trans and torque converter opened up for inspection. So far got the welded pump drive apart, should be relatively simple to remake the drive hub for a different spline then adapt a different style pump. Also pulled the HI/LO shaft support/shift oil supply head off, that looks not so good but maybe doable, external seals are shot falling apart, internal seals leak like a sieve.
Idiot previous owner welded all that and could have removed the drive hub to repair it right easier. What the hell is wrong with people? These are my 'spares'.
DMiller: Never understood the why behind mechanical repair approach -"just enough to get it back in service" particularly when the parts and shop manuals during the period where available. My sense is that you will concur this temporary setback. All the best on the Great Old AC 7G - BTW do any of the later 7GB parts interchange?
Concur - meant conquer
The tranny in the G-B is the same internally, minor exterior changes. Torque is completely different from the 4 to 6 cylinder engine series.
So, are the trans & torque from the donor machine, or did you remove from your machine that had been operable?
The trans is the take out from the existing machine, the donor unit is in it for now. The torque is off the donor and as I can validate it is not a chunk of scrap will set it up for a spare to swap the existing unit out as I know the output bearing has more than tolerable slop.
Got a little further inside. Clutches themselves look decent and may not need replacement on Either shaft. Minimum is .093 I can readily put .098 between the steel ears. Seals are absolutely shot, Lo/Hi will slide Kind of to Hi will not even move to Lo, For/Rev will shift both ways but cross leaks into other range. the small shaft directed shift oil seals on the upper shaft were still 'seals' on the lower somebody decided O-rings would work, if had used quad rings may have done it. Will take all after I get the shift piston seals apart to the hydraulics shop for some kind of match out. Then on to cleaning.
Glad to see you feel good enough to tear into things again there DM! Looks too complicated for me!
Actually busy keeps me from dwelling on the ache, kind of lose track of it being attentive to something else I can ignore it. As to the tranny, pretty simple two speeds two ranges on two shafts. Large aluminum hub to center slides either direction, applies the clutch for range and the other for speed desired. The old Allis transmissions were probably the simplest design beyond simple gear boxes. More photos on the shafts torn down, already done just no photo yet, also found the issue on the Lo/Hi range shift, debris in that sliding hub/piston assembly and the F/R hub was dubiously put together for some reason.
Shafts down to where can start cleaning. Hi/Lo had so much solids crap in the reed valve that shuts off one side from the other so oil will drain when swap clutch actuations, some but not much in the other. Allis used no springs, no need for soft components other than the aluminum shift drums, bronze clutch plates and the two piece reed style control valves.
Looks like you are really getting into the internals there DM. Wish I could be looking over your shoulder & learn how that all works! Can you still get what all parts you need?
Parts are scarce as hens teeth. I am glad the clutches mic'd out, average was .112 thick as to minimum .093. Going to hydraulic shop tomorrow, they finally got to my spare trans pump says it is pretty well crap. Clearances internally around .007 TOO wide, deep scores so not millable to get it very far. New pump $550 from Eaton(Cessna pump) with a 12-16 WEEKS lead time. Custom builder has pump parts to build what I have but am going to haul in the scraps from the torque to see if can go a more common spline. Allis used Detroit Diesel throw aways with a twelve spline shaft and couplings, industry standards are 9 or 13 and they can get anything I would rather have for versatility. They are going to see if can match the O-rings I will need and the six shaft shift seals by any stretch.
Best I can tell the debris, rust and left over crap inside the shift drums was screwing with the reeds seating up that in turn kept it from fully shifting or maintaining pressure on the clutches. Previous owner of the runner did not do well replacing filters or cleaning screens(didn't) ran oils low, used oils FOREVER and allowed beyond moisture(rain water), dirt to enter the system in a fairly heavy volume. All shows in the leftovers I am seeing. Idiots when parts were available using crap, being cheap and not correct parts seems to be the treat of the day.
As we read this thread we are seeing and expert AC 7G mechanic in the making - keep up the excellent tutorial Dave. Your photos are clear and help support the continuing use of these old machines. All the best! Orangeman
Well so much for the common spline pump, Eaton came back and stated they will not any longer build replacement Cessna pumps either with or without the OEM style spine shaft. Custom builder has them on the shelf with the AC spline so going with that. One fella on the Allis Forum found a shop to cut shaft and broach new couplers so trying to go that route for more spares.
Meant to add but missed, the Eaton Cessna direct long wait time was $550, the custom pump gonna run me $750 plus tax.
Would a weld on internal spline hub work? If so look at Hub City gearboxes on google and look at farm products. Do you know the mount, flow, pressure, ports ect of the Cessena pump, If so look at Honor gear pumps for aluminum or Geartek for cast iron.
Been all over it with the hydraulic shop techs. We can get close then the pump does not have one or another of the correct aspects. We spent a lot of time yesterday looking at similar pumps then found all the issues. Biggest is dimensions, has to fit such a narrow confines then the issues start popping up with too much difference in flows, pressures etc. Would be a good time to convert to something else but the Cessna is pretty specific to the application and the application dependent on the Cessna.
Dave: Since Cessna Hydraulic Division was in Hutchinson Kansas am wondering if there might be some possible leads on pumps in that area? Cessna Hydraulic Division Retiree Club? There has got to be something that will work. Custom pump still available at the $750?
Custom pump is on order and verified available. Eaton stated to the hydraulic shop they were ending the Cessna product line as to Allis applications as such a narrow market. The RBM series pump was almost expressly a Allis. I would sit and research a alternate but for now keeping the $$ monster functional is all I can hope to attain. All too many parts are fast disappearing that cannot be repurposed from another source so the machine lives on borrowed time. I will most likely move to a Deere or Cat at some point as I get to where I cannot trust the old Allis, it will then become a tractor show display.
Dave: You have mail in the UA Forum. Happy Holidays!
Got my associated Available parts in and the new replacement trans pump. Managed to locate a used pump drive shaft and coupler they should be here in a week and will ALL get changed when swap the transmissions out. Now just awaiting the current cold front to go away so can drag the case outside for cleaning!!
And yes, that is a replacement Cessna/Eaton, new with a custom splined shaft.
Need to add, Do not know if the shop owner cut me some slack as to costs, ALL the seals I received from him, old pump inspection, new pump shipped in and he sold ALL of it to me at basically cost. He could not get to the pump for almost three months, he had the seals as a normal stock item was just out when I asked for six; Did I missing something? Can't stay in business long if doing that with all his customers unless he is making it up on the big money boys.
Caught a break today, windy as crap but in the fifties so the bath commenced! Now it is NOT pristine, but is clean and I can actually SEE the old gaskets to remove them! AND can reassemble less than spooked if too dirty! Is hard to justify, I have $1000+ in parts that sit in less space than most gas engine re-ring kits.
Thanks for the update.........looks good so far!
As I get the shafts together will air test the mechanism if works decent on air goes back in the trans. Top shaft Hi/Lo forward. Lower shaft Hi/lo reverse.
About time you got something done If things go right in a week or two I may own a Pete with a 12v71
Well, not exactly excited of the used shaft, but know is NOT cracked but has been 'Stressed' a tad!! I took an old shaft to a production machine shop, they determined the spline is actually a gear angle and the shafts are NOT hardened. I more or less knew that as these were always the fuse link to keep from exploding a pump or ripping a more expensive component apart to save a locked pump. I may buy a cutter wheel for my mill, I already have a divider head and cut my own at this stage. The only hard part I would have trouble coming up with is the internal spline coupler or a broach to cut those.
Here is an alternative to fixing the Allis........this 955L with a blown engine for about $3,800 US. I tried to copy & paste the link but it wouldn't work. Now do we have you thinking??
Toronto, that could be the deal breaker! A little TOO far out for me. Have considered getting Fat Allis back into the game full strength, then opting to trade up(Zimmerman) or selling outright and buying a Cat closer to home. Is a hard choice to make once used to a machine, especially for an old fud as me! Have been a few relatively newer series Cats come up for sale locally needing work and not much interest so pricing drops. Will be after that when spring comes. Trans repaired/swapped, new trans pump, replacement rails(already have) and swap shoes adding two bars for grousers, swapping the brush cage I already have, some added exhaust repairs and a full paint job THEN I will make a decision.
Dave: With all that has been done on your ole 7G it will be pretty well near new! Hope you can stay the course with the old Allis. Can see where the Cats are much more available due to overall sales and parts interchange. Of course - wish you all the best! - 30 below this morning so more wood chucked into the wood stove to stay warm.
I will weigh out as I complete the piece meal repairs Is a relatively easy tractor to run currently Get what I have lined up done and should remain a good machine for awhile Wish I had gotten the 16b just was steered away from it in those times
These are old seals the quad ring two piece is the replacement Still have a bit of bypass in the freshly assembled shaft but believe is due to the reeds plate not seating with air pressure Also a photo of my high dollar hyd. ring compressor