? on the piston and shoe group. The book says ".005 end play on the shoe. Question is how in the heck do you hold them to measure the end play. Everything in the stat pump looks real good but I think the shoe-piston end play may be over ".005. I plan to lap the poppet,relief replenish seats. Any other reccomendations?
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I never measured mine, i just gave them a pull to see if they felt loose (really technical i know). If you have a suction line restriction they can actually pull the piston off the shoes. See if they *feel* good, if so i wouldn't be too worried.
Not sure how you will lap the valve seats though, do they look worn? The main part I'd work on is the valve plate, get the scores out of that brass plate.
Naturally re-assemble with LOTS of oil but that goes without saying.
Not sure how you will lap the valve seats though, do they look worn? The main part I'd work on is the valve plate, get the scores out of that brass plate.
Naturally re-assemble with LOTS of oil but that goes without saying.
OK just got back from my buddies (bobcat service managers) place I brought all my pump parts for his close inspection. He says all the hydrostat parts look excellent. He did say the best thing I could do though is to replace the wafer plates even though they look excellent. The aux pump at one time gobbled up some trash so that will be replaced though. I will tig weld a rod onto a poppet and use valve lapping compound to new up the seats. He also confirmed what vickers has told me DON'T EVER RUN MOTOR OIL IN YOUR BOBCAT! They both say that motor oil will not disipate heat like hydraulic fluid does - I guess I will run a good hydraulic fluid then. Now I just hope the wheel motors are in good shape. sounds like I may have a good chance of having decent wheel motors. The previous owner must have kept the filters changed. we'll see. thanks Taz
The valve plates can be lapped with a sheet glass and wet and dry sand paper. You don't want any scores on the plates, they should be smooth and flat.
The hydro pump, you do know you can buy kits for them rite? new rotor, vanes and cam (the other housing).
Ahh the engine oil vs hydraulic oil debate again!
sterlclan
Well-known member
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- May 1, 2004
- Messages
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CAT oil for hydraulics is 30 wt motor oil as far as I can tell.....the wrong oil is better than no oil......bobcat themselves say motor oil if their black gold isn't there.......I run 15 40 diesel oil in mine and have no trouble..yet.......... love a good dispute huh Tazza....Jeff
LOL i really do, a good battle is fun
even when i loose!Jeff, do you think the 15/40 is much stiffer in the winter than 10/30, I try to keep it in a shed in the cold weather but sometimes I need it when its down around zero or so. I suppose as long as it will start and it is run a few minutes first and not overworked right away it should be good.
Tazza thanks for the reply. Beleive me I will not get into a pissing match with a moderator. It's a no brianer for me, I have talked directly with 2 engineers from vickers on my stat and vane pump rebuild this week and I will take the manufacture of the pumps recomendations and warnings serious and all the BS is what it is. They don't sell oil but they do make some of the best hydraulic components in the world so again I would be foolish not to take their advice. And I will not be part of any argument on this forum. I brought the readers of this site the words straight from the manufacture and that is what I will post to help out the bretheren.
sterlclan
Well-known member
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- May 1, 2004
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Its all tongue in cheek for me......Just having some fun ..... As far as the cold goes Jerry I haven't had any trouble and it gets to -15 or so around here sometimes just let him run for a little while and its all good.....and yes the bobcat is a him.....
Skiddy - don't worry, i'm not the sort of person that cares if you have different views or opinions.
Thought I'd jump on an old thread to try and get some info on piston end play. I have an old 520 I'm working on that has as TA1515 pump. The piston shoes seem relatively loose. My best guess at measuring it with a set of calipers is about .010" of play on the worst ones. The manual says no more than .003". There's a bit of an audible "click" when I wiggle the shoe in and out, and if you hold the piston horizontal, and raise the shoe up to the top, it falls back down all on its own. Sound like these are sloppy enough to need replacing? Just don't want to spend $500+ on piston/shoes if it's not absolutely necessary... Also, the valve plate on this one is just steel or cast iron, with no bronze insert. There are some wear marks in between the holes. Will it work just as well (though I imagine take longer!) to use the fine sand paper and glass approach to resurface the steel valve plate? I imagine replacing the whole section would be rather expensive, so again looking to repair if at all possible. Thanks for the help.Skiddy - don't worry, i'm not the sort of person that cares if you have different views or opinions.
This machine i suspect is just for farm/home use, i'd just flatten the wear plates like you were going to and not replace the rotating group, just give it a good clean. I put together a pump for a mad mate that had end play like that, i have not yet started the machine, still a few months off being ready for that.
As you already know, the cast iron may take a little longer to sand down, you may alwo want to do the surface of the rotating group too, ensure there are no marks on it.
Thanks Tazza, I'll give it a go and see how it runs. I guess I can always pull it apart again and replace them later! Looking forward to some quality time over the sand paper with the big heavy pieces getting ride of the grooves...
Yeah, it's just as much fun as you are implying.... But the results make it all worth while. Just remember to keep moving the plate around as to not sand down just one point.
Ideally you are meant to do figure eights, i actually just went in circles. Do a few then rotate it say 1/8 turn, then do it again, keep going so you never focus on just one point. It takes a while, especially on deeply marked plates, but i found the results make the time spent on it worth it.
