17" Hydrashift spindle locked solid

Friend of a friend has this problem. Pretty well spelled out in the title. Spindle will not budge. He let some "machinist" come into the shop to use the lathe and this is the result.

I looked it over today and here's the deal....With the headstock cover off, the motor runs fine, you can turn the shifter knob and all the shifters move except one. Farthest one back wiggles, but it is stuck. Countershaft in the bottom of the gearbox is also locked up (tied to spindle at rear end with bevel gears). Normally, I'd have dove in and had the headstock in pieces without hesitation, but the hydraulic shift system intimidates me. I know once that is out of the way it will be as simple as my 1918 L&S, but I don't want to screw up the hydraulics. Any help greatly appreciated.

Sounds like he jamed a shift, I have seen this once before. I powered up the machine and was able to pry it out of gear once the hydraulic system pressure was released. I probably just got lucky I had the same feelings you have when I opened her up.

They have tried and I tried to pry it a little, but didn't want to get carried away and break something. One of the gears has moved so far it has knocked paint off one of the walls inside the headstock. I'm afraid they have somehow done some major internal damage to this machine. I'm pretty sure it is going to have to come apart to fix it, I just don't want to go in blind trying to work on the hydraulics.. and that's the FIRST thing that has to come off.

Sound like two gears locking each other in place. I would think one didn't shift to the right place.

Looking into the gearbox, I can't see two gears locked at the same time.

Somewhere I have a copy of the service manual for the Hydrashifts on a CD, just can't seem to put my hands on it tonight. If a copy of this would be of service to you, I'll keep looking. Improper shifting can lead to the type of jam you describe. One should always turn the dial to the desired position before depressing the clutch, not the other way round.

Barron, that would do me a WORLD of good! I just want to know how to properly remove and then reassemble the hydraulic shift system. If I can get that off, I'm sure it's just another gearbox from that point on and I can certainly deal with that. Thanks for the offer!

One problem is that I have no idea HOW the machine was screwed up. Maybe it was a bad shift, maybe it was a bearing going out that finally toasted... no idea. This lathe is in an offroad mod shop, so nobody there is really machinist. No telling how badly it has been abused, but right off, I'd say severely. They would be far better off with a nice manual shift machine than with something as complicated and delicate as a hydrashift.

Mike,
When I posted my offer, I thought I would walk in my office and lay my hand on the disc straightaway. Hasn't worked out that way. Turns out that we have moved to a new house since I last used that disc and it is still stored in one of those boxes sitting in my office and garage. I spent a couple hours this morning looking before I had to go to work, and looked again this evening. I know that you needed it yesterday, and I'll keep looking. I just feel bad that it's taking me a while to find it.

No huge hurry. If and when you find it, I will greatly appreciate it, but the guy isn't breathing down my neck or about to go out of business because the machine is down. Nobody there is a machinist, so they can find a way to do whatever would be done on the lathe with a hammer, pipe wrench and a big prybar.

Mike C,

I found it! If you want to PM me your email address and a physical address, I'll try to get this headed your way tonight. Its a PDF file, so I think I can figure out how to email that to you. If not I'll burn a disc and drop it at the Post Office in the morning.

Mike C,
email sent your way.

Got it! Thank you immensely!

If this is a LeBlonde servo shift it's not uncommon for the plastic shift valves to break. Undo the hydraulic feed line, a few capscrews and the whole shift mechanism pulls right out. I set the knob to neutral and mark where the hub is that the shift drive shaft engages. If you find something broken, it was just it's time. While your at it, screw a pressure gage into the supply pipe, forget the pressure but a quick call to Leblonde will get you an answer. Those crappy plastic shift valve plates are not cheap. Not easy to make either.

Bill

Cincy HYDRASHIFT, not servo-shift. It's not a valving issue, the fork is locked up solid and there is a shaft that is not moving and moving where it shouldn't be. Going to take a whack at it Saturday... if we are still alive.

How did it go ? Would be interesting to see the insides of that machine. Maybe too late to request pictures now though

Mike
Keep in mind that I am a noob. (fools rush in where angels fear to tread)
I have removed the spool from my 15 and found it to be an elegantly simple spool using a rotating ported tube to route pressure to each shift rod. Stick your camera into the gear section and take pics of the location of the shift forks. Tape the shift knob in place and witness the gear it turns, disconnect the line from the pressure regulator and the dist. Remove the the 4 allen head bolts, tap slightly wiggle it out.
Do a little fishing with a flex magnet in the bottom of the case, you may come up with a mangled cclip or possibly a key. If you decide to drain the oil put a 5 gal bucket under the filter before you take it off.
Let us know what you find.

Guy apparently has flaked out on me. He came into our shop to work on one of our guys' trucks and I told him about the manual and we set up last Sat to work on it. I called him Friday and left a message to holler so we could set the time up and never heard back... a week later, still not a peep.

Mike C. said:

Guy apparently has flaked out on me. He came into our shop to work on one of our guys' trucks and I told him about the manual and we set up last Sat to work on it. I called him Friday and left a message to holler so we could set the time up and never heard back... a week later, still not a peep.

Click to expand...

Rats, I was looking forward to this one...

Yeah, me too.

Hey, the guy got with me last week and we tore the lathe down today. Bad news, I had to pull the spindle and TWO shafts out of it. Good news, nothing is really very bad wrong.

The issue was with the "backgear shaft". The bearing retainer nut on the headstock end of the shaft backed OFF. The nut fell off and the bearing fell out of the housing. The bearing ended up harmlessly back near the governor pump strainer. The nut was the issue. It fell right under the helical gear on the bottom most shaft and was drawn into the gear by the flow of oil cause by the rotating gear. It sat there and let the gear chew on it until it hit a magical thickness and was sucked into the space between the gear and the bottom of the headstock. It was stuck horribly solid. Had to remove the governor pump (thought it might have been locked until I found the nut jammed in there), then took the same type retainer nut off the tapered bearing on the end of the helical gear shaft. Still had to do some serious prying and banging to get the bearing to totally release and come out, but once it came out, I just picked the shaft up and pulled the jammed nut out. Also had a broken finger on the shifter fork, but not sure if that was the jam or the owner and his monkeys trying to pry the helical gear into moving. Going to pin and braze that back and it'll be fine.

Going to replace all the bearings we have removed and the ones on the opposite ends of the shafts. Those were the ones most stressed. Spindle bearings are OK and machine seems otherwise still fine. Can't believe it didn't break the insides of the headstock, but that is one stout little machine. Having been inside one now, I am far less skeptical of the hydrashift mechanism. Really not much to go wrong on them, and just as I figured, once the hydraulic shift mechanism is removed, it's just a typical manual gear head lathe headstock.

Here's a pic of the mauled retainer nut...