Discussion Topic |
|
This thread has been locked |
adatesman
climber
philadelphia, pa
|
|
|
Topic Author's Original Post - Jan 31, 2013 - 03:55pm PT
|
Howdy Folks!
I've been quiet in the What You're building thread because the 1850's schoolhouse renovation hit a snag, which lead to a long story involving buying a 1950's Case 310 Loader/Backhoe.
Lots to catch up on the details, but right now anyone know much about spool valves? This spool is from the (currently non-functioning) power steering, and I'm unsure if the pitting at the end will cause me problems. Replacement is not an option (part was specific to this model, which is long since our of stock). Turning and sleeping is an option, but I don't have a toolpost grinder for the lathe so have concerns about surface finish for the o-ring seal...
If it makes a difference, the spool valve is bolted to the end of the steering cylinder, which runs the width of the front axle (as opposed to the rotary type on the steering column). I tried an old tractor forum with no success, so tossing the question here in hopes the wide scope of experience turns up a solution.
Oh, and I'be basically rebuilt the pump at this point, complete with remachining the bore for the gerotor. What a PITA that was...
Thx, and hopefully someone chimes in with an answer quick... I've got a weather window to get this assembled and working, at which point I have to put in 250 feet of French drain 5 feet deep. All to get the indoor plaster repairs to stop popping off...
-Aric.
|
|
Juan Maderita
Trad climber
"OBcean" San Diego, CA
|
|
|
Jan 31, 2013 - 05:03pm PT
|
Disclaimer: I don't know anything about the specific part.
I'd take it to a competent machine shop. The surface is round and steel. So it should be no problem to weld new material and turn it down to specs on a lathe. Good as new for a few dollars.
|
|
pud
climber
Sportbikeville & Yucca brevifolia
|
|
|
Jan 31, 2013 - 05:05pm PT
|
Can you replace the steering box (pump) with another?
Not enough info in your post to know whether or not this is feasible.
If so, they can be had cheap at most used farm equipment yards.
You can also check some of the bigger manufacturers to see if they can tool it for you. Machine tolerances in the 50's were quite different than today. You may be able to have a local machine shop turn it for you.
|
|
hillrat
Trad climber
reno, nv
|
|
|
Jan 31, 2013 - 05:17pm PT
|
If an o-ring rides on that surface you will definitely develop a leak there. Generally the outer passages of a spool valve are on the low pressure return side, but that can still run a couple hundred psi, so the leak could be significant. If its not a very hard assembly/disaspembly process you might smooth it down some and try it to see just how bad it is.
Otherwise, its probably better to turn it down and sleeve it as opposed to welding and turning. Spool valves are often very close tolerances and any warpage from welding heat will be likely to make it stick in the bore.
Good luck!
Oh yeah, don,t ever try to find a hydraulic leak with your hands- risks oil injection. And dont trust yer life to a load suspended by a hydraulic system.
|
|
adatesman
climber
philadelphia, pa
|
|
|
Topic Author's Reply - Jan 31, 2013 - 10:37pm PT
|
Was wondering if this would get a response, and not only thanks for the input, but thanks for input from folks this long-time-lurker has never heard of.
Juan- welding not an option, as it'll warp the spool and I have no way to grind it back to concentric.
Pud- It's an Eaton pump, which they last made ~1960. Neither replacements nor parts are available. And flipping through Grainger and McMaster for a 1200psi 6gpm pump I'm looking at $400, so given I paid $2600 for the whole shebang that's not really an option (especially since I'll be selling it when I'm done with this project).
Hillrat- best advice I've yet seen on ST. pressure + oil = bad juju. Learned that long ago. Not knowing whether the problem is the pump, the linkage, the spool valve or the cylinder I've gone ahead and replaced all the seals and bolted everything back together.
Naturally the factory seal kit included an o-ring I didn't need, and the parts diagram detailed a relief valve that isn't physically there...
Ah, the joys of old machinery......
|
|
FRUMY
Trad climber
SHERMAN OAKS,CA
|
|
|
Jan 31, 2013 - 10:43pm PT
|
Why not sleeve it? If you have a lathe cut it past the pitting & turn a sleeve then press the sleeve on .
|
|
TGT
Social climber
So Cal
|
|
|
Jan 31, 2013 - 10:46pm PT
|
Have it hard chrome plated up past size then ground back down and and polished.
good as new!
shrinking a sleeve on it might not be a bad option either.
|
|
hillrat
Trad climber
reno, nv
|
|
|
Jan 31, 2013 - 11:34pm PT
|
Guessing you don't have a schematic? I'm fair at hydraulic diagnosis when I've got the machine in front of me...
Non-functioning power steering makes for a long day in the field. If I knew how the thing was built (the schematic, naturally) I might point you in a direction to check.
So the valve is bolted to the end of the steering cylinder? How is it actuated and what does it do? It's a pretty short spool, and just from looking at it I assumed the pitted area is exposed to the elements. Too much to guess about being unfamiliar with that particular tractor. Newer ones have priority valves and such; but that's not necessarily what you've got.
One thing you can do is eliminate the steering cylinder itself by checking for internal leakage:
1. bottom out the cylinder in either direction
2. figure out which end should have the pressure going to it if you were to try to bottom it out further
3. remove the hose to the NON pressure side and cap off the hose, leaving the cylinder open
4. continue to try bottoming out the cylinder. No oil should pass through and come out the open cylinder port. If it does, the piston seals are leaking. Assuming the valve does not directly feed into the cylinder, which would complicate things.
It's a pretty easy test if you're good with hydraulics. If you're not, it can make a mess in a hurry. And of course you run risks opening the system and pressurizing things with an open line. That's really the abbreviated version. Remember things can move unexpectedly when you open a system, fluid under pressure is dangerous, don't get crushed, etc. Hell, probably best to get a textbook that covers the test in detail instead of trying to follow my advice.
Also would be a great idea to T in a gauge somewhere in the steering system and see if you've got pressure.
But, ya know... Heavy equipment is dangerous. Like climbing.
Yer gonna die!
Is it just the steering that doesn't work? The rest ok? Brakes, loader, backhoe?
|
|
adatesman
climber
philadelphia, pa
|
|
|
Topic Author's Reply - Feb 1, 2013 - 01:09am PT
|
TGT- repair along what you describe will cost more than I paid for the whole thing, so that's out.
Hillrat- You're exactly who I was hoping to smoke out... :-)
Only thing I have is a really bad parts diagram, which is a Java applet, so won't even bother to link. The "rebuild kit" I received today totaled 5 o-rings, but there's at least a dozen used in that general area. In hindsight, I now see all but 5 had part numbers, but they could at least have told me while I was on the phone with them.
Anyway, where I'm at is that I'm not sure the pump is even making pressure. After fiddling with it there is max .006" clearance between the ring and rotor (gerotor pump). Not much pitting/wear on either, and I machined the depth of the bore to allow .001" clearance. Lathe was a Clausing 5917 and I grew up working in a machine shop, and dear lord was that setup a PITA.... I really need a proper sized 4 jaw chuck, as that would have cut the setup time in half.
What I've done is "as it was", many, many iterations of left/right/left/right/left/right/why is the reservoir full of foam?, at which point I switched from "tranny fluid" (per the manual) to power steering fluid (supposedly less foamy, and seems to be the case).
Going by your numbering, 2: matched the pressure line per the parts diagram. Done that, not sure it's right given there's a mistake or two in the parts diagram. FWIW, Case has been bought out a half dozen times, and getting parts diagrams for the old equipment is not high on the priority list.
3. if I'm reading right, it's an open headed spool, and I'm getting oodles of flow even with the spool centered. Lots of foam though, and I'll be (once again) tearing the rexervoir apart tomorrow (today?) and replacing all of the gaskets I can find. The pump is getting air somewhere, and be damned if I can figure out where...
4.This is complicated by not knowing if the pump is any good. Will know later today (meaning Friday, at this point), so likely when you're coffee is cooled down enough to drink.
Thanks Hillrat, this is *exactly* the type of help I'm needing,
|
|
adatesman
climber
philadelphia, pa
|
|
|
Topic Author's Reply - Feb 1, 2013 - 01:20am PT
|
Also would be a great idea to T in a gauge somewhere in the steering system and see if you've got pressure.
But, ya know... Heavy equipment is dangerous. Like climbing.
Yer gonna die!
Is it just the steering that doesn't work? The rest ok? Brakes, loader, backhoe?
Done that, no pressure. Pulled the pump apart, cleaned and reassembled, got it up to 400psi when the 4L belt slipped. Should hit 1200psi deadheaded/relief opens, but poorly-executed 12V Positive Alternator conversion is not helping things.
Yup, gonna die... eventually. :-)
Loader works just fine, although a bit out of level. Picks up the front just fine. Stabilizers in back pick up the back just fine. Backhoe tries but fails to pick up the back. Found and checked the dipstick, an oil was barely touching it. Added a quart, no change. Another quart, no change. A third, no change. Then went to Google and found it's a 17 gallon tank. Never in my life thought I'd buy a 5 gallon bucket of oil to top something off. But that's next week's problem, as right now no power steering + 1000 pounds in the front bucket = I hit things I shouldn't be anywhere near. :-(
|
|
adatesman
climber
philadelphia, pa
|
|
|
Topic Author's Reply - Feb 1, 2013 - 01:27am PT
|
BTW Hillrat, if any of this makes sense and you don't mind, kindly drop me a PM with your phone number and a convenient time to call. I'll likely be tapping maple trees in the AM, but should be over working on the backhoe by the time you (presumably) west coasters are up and about. :-)
|
|
FRUMY
Trad climber
SHERMAN OAKS,CA
|
|
Sleeving it would be easy & not take long at all.
I've sleeved hundreds of input shafts & output shafts & thousands of clutch drums for automatic transmission. It would take no more than two hours to chuck up your shaft cut it down & cut a small piece of 4130 chrome molly to press over the end.
I'm sorry I'm on the road or I'd do it for nothing for you.
|
|
adatesman
climber
philadelphia, pa
|
|
|
Topic Author's Reply - Feb 2, 2013 - 12:34pm PT
|
Hey Folks,
Thanks again for the help. I think I'm finally on the road to getting this thing working....
Yesterday was spent installing and testing the pump, and looks like that's working ok. Not great, as it will only hit 800psi before the crank pulley slips, but not too bad since the relief is set to 1000psi or so. I suppose I could do something about the slippage, but the setup is more than a bit hokey... The belt on the crank turns the alternator and water pump, and a double groove pulley on the alt turns the power steering pump. And of course the main hydraulics come off a front PTO on the crank, so changing the main belt means unbolting the PTO coupling, which likely means removing the radiator. Hence deciding 800psi is good enough for now... :-)
Today I tore apart the spool valve again to chart out all of the oil passages, and I now understand completely how this thing works. Looks like it was entirely a problem with how it had been set up, so I'm about to head back over there to reinstall it using this handy chart:
Oh, and while I had it apart I went ahead and sleeved the end of the spool that was so worn and pitted. Much better now.
Actually, I think I'll go assemble it here in the basement as I suspect I'll have to make a new spacer or two to get the spool travel distances right. Nothing sucks more than having your tools scattered between two workshops, as the one you need is always at the other one... :-(
|
|
WBraun
climber
|
|
Thanks for the update adatesman.
I love your your stuff here .....
|
|
tooth
Trad climber
B.C.
|
|
And dont trust yer life to a load suspended by a hydraulic system.
The best advice when dealing with hydraulics. I had a full bucket decide to drop like a rock, it ripped the arm of my jacket on the way down, it was just luck that I wasn't any closer when it let loose - I would have been dead.
|
|
adatesman
climber
philadelphia, pa
|
|
|
Topic Author's Reply - Feb 2, 2013 - 01:17pm PT
|
Hey now... good thing I stayed home to put it together! Turns out that I need around 0.340" of spool travel to fully open the ports, and the way the spool's set up it only gets 0.150"! And that combined with the spool being incorrectly spaced to start with completely explains why I had a small amount of power yesterday one direction and not the other!
Here's a pic of how far it currently moves, which doesn't include all the washers, bushings, etc that actually limit the travel:
So yeah, sluggish, restricted hydraulics combined with immediately hitting the end of travel on the spool would completely explain why the steering was so heavy. New plan is to go machine the spool to accept a sleeve on the driven end to extend the length enough to allow full travel of the spool. After all, the slot for the driving pin is long enough to allow an inch of travel and there's no telling if this is actually the original, correct spool.
BTW, the full extent of the documentation I have on this is the following pic:
I'm really tempted to get the service manual, but it's $150 and I kinda doubt it would be much help for this (read: it'll say "replace part with a new one").
|
|
adatesman
climber
philadelphia, pa
|
|
|
Topic Author's Reply - Feb 2, 2013 - 01:21pm PT
|
And dont trust yer life to a load suspended by a hydraulic system.
Damned straight. Learned my lesson as a not-quite-teenager working in a machine shop with a 4000 pound rectangular forging hanging from straps on the crane. I didn't have it slung properly and the slings started slipping to center, and it put a 4" deep crater in the cement floor right where my brother had been standing. Quite simply: Never stand underneath *ANYTHING*. Also, machine shops aren't really the proper place for 12 year olds.
|
|
hillrat
Trad climber
reno, nv
|
|
Ah, different than I imagined. So the spool valve bolts to the end of the cyl with three bolts. Are the other two holes oil passages to feed the cylinder? Kinda eliminates the cyl test I described, having no access to the cylinder ports to cap them. Incomplete spool travel can definitely slow things down. Guessing one port on top of the spool valve is pressure, the other is return to tank. Where does steering input go into this thing? G46112?
Sure the ports at the spool are not offset a little differently?
|
|
adatesman
climber
philadelphia, pa
|
|
|
Topic Author's Reply - Feb 2, 2013 - 02:42pm PT
|
Hmm... Do you hear a whistling noise, Hillrat? Because that's the sound of your diagrams going over my head.
Ok, not quite... but close. This is my first foray into hydraulics and I have to say it's deceptively simple with a surprisingly steep learning curve. I suspect my problem is I'm completely ignorant of how to draw the diagrams, so no idea how to read them (I've got an excellent book on hydraulic system design from the 1970's, which left me even more confused than I was before I opened it).
That said, once I charted the valve out this morning it started making more sense and I think your #3 is the case (with the addition of an integral relief valve which is inaccessible inside the valve, due to a NLA cap I'm loathe to pop off since it's a press fit piece of aluminum and removal would destroy it).
My completely non-standard flow diagram looks like this:
And opposing views of the valve, including the drive pin:
Oh, and on the bottom pic- that ball bearing is swaged in tight to seal the end of the hole drilled for one of the ports. There's a bunch of them all over the valve body, but the rest are much, much smaller. The lighter colored plug is the aluminum cap for the relief valve, which the parts diagram shows an o-ring going on top of. Looks to me that this valve has been rebuilt to other than spec, but it seems to work to seal the port.
Oh x2- While the CAD drawings above aren't exact, they're good enough for government work as they were drawn to scale in Solidworks as I sat here with a vernier caliper measuring things.
|
|
adatesman
climber
philadelphia, pa
|
|
|
Topic Author's Reply - Feb 2, 2013 - 03:12pm PT
|
Hate to poke, Werner, but:
Thanks for the update adatesman.
I love your your stuff here .....
might be the first time I've even seen you say you liked something here on ST. I'm flattered!
:-)
-a.
|
|
|
SuperTopo on the Web
|
Let us know!