Crash...bang....5900 variable speed master cylinder

I have a 5900 , reading your post but for the life of me can't figure out why you master cylinder cracked ?
 
Alcap said:
I have a 5900 , reading your post but for the life of me can't figure out why you master cylinder cracked ?
Click to expand...
The original problem is when I would crank up the speed, the cam which contacts the roller would go just a little past it’s end.... and after it’s at its highest cam position , then the roller just falls off into a recessed area of the cam. And now the roller is stuck in that recessed part of the cam.
Then it got stuck there. Can’t back it up. Can’t move forward. I really wish I would have taken more pictures Alcap.
Anyway when it would lock up the speed control at the master cylinder. I had to take all of that off. I’m guessing it was at that point..... the hydraulic hose at the slave cylinder .... then unclamped From that bracket ( part # 002-050) which holds the cylinder hose in the middle of the lower belt. The part break down calls it a “hose arm”. There is a two part clap which holds the hose in place and it screws to the end of the hose arm. Because the slave cylinder is constantly moving in and out with the outer pulley sheave...there can not be a ridgid bracket. The hose arm allows the clamped hose to swing in and out but secured between the lower belt. Remember, the lower hydraulic hose is literally inches away from the pulley and it runs between the bottom belt.....about 3 inches from each side of the spinning belt. The belt itself is constantly changing positions.
After that happened, because I had not removed the lower housing cover panel..... I didn’t see the loose hose. When I turned on the machine after fixing the cam roller and reconnecting the Master cylinder ....the hose got caught in the lower pulley and the hose and slave cylinder spun around a full turn. It just ripped the aluminum master cylinder downward and shattered the housing which has the speed control spring and cam roller.
I’m having trouble explaining it....but let me know if this doesn’t make sense. I’ll go back...take some pictures and show you what I mean.

by the way... I think I fixed the cam roller by putting a little 3/8” round....on the roll pin which prevents the cam from turning too far.
I inspected and inspected the mechanism to see the wear patterns on the collars, roller cam assembly, and cylinder bracket Assy. I’m pretty sure it’s all connected and assembled properly.
In the parts break down....on 5900-72, you can see the parts I’m talking about. The cam assy is 5900-71. Then there’s a couple of collars with 2 dowel pins and a roll pin. These items prevent the cam from turning too far. I’m at a loss as to why this happened. But my shaft does look a little wonky. It was bent pretty bad. Like I could slide A Nickel under the center of the shaft when I would put the shaft on the surface plate. So I did heat it and pressed it in the press....pressing against the center with each end in v-blocks.
But, it looked to me like someone made this shaft to replace a damaged shaft at some point in the lathes life.
So the shaft is straight now. But the lower collar has an obvious drilled recess for one of its two set screws to go into. I tried my collar in both positions and am pretty sure I’ve got it right now.
So what I did....is drill an aluminum spacer which now fits tightly over that 3/16” x 1” dowel pin which acts as a stop. The spacer is only adding about 1/8” additional space which contacts the stop pin a bit earlier now.
I think I‘ve got it fixed now.
 
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If you should have other issues with it, see if a 6913 has the same part number. Mine was on the machine but never hooked up. The Reeves drive was absolutely trashed as well. Right or wrong I made a belt pulley and have been fine with my lack of knowledge on this stuff so I'll never probably fix all of it. It works good for the little I do. If it is the same and you need it, maybe we can figure something out.
 
It’s good now. Thanks for the offer Dhector. The real culprit was that silly two piece hose clamp. It just barely holds the hose to the swing arm bracket.
So I just made a strap to wrap around it so it will always keep the hose attached to the swing arm and that way the hose shouldn’t get caught in the pulley again.
 
Thanks now I get it , the hydraulic hose ripped the master cylinder off .
 
Yes. I guess it was confusing because I was explaining my thought patterns at first. Bottom line of my advice....if your lathe has that same two piece clamp holding your hose, it wouldn’t hurt to wrap it in a steel strap to securely guarantee it doesn’t slip out of the clamp.
 
I'm going to double check mine , I did have that line off to replace the belt a few months ago , I still don't the it bleed correctly though I didn't use it much before changing the belt so I assuming I caused the issue
 
One more thing I want to clear up. I didn’t replace the original 2-piece clamp. It’s still on the hose. I don’t like modifying stuff too much.
I did wrap the hose and original clamp with plumbers strapping. It was pretty much a perfect fit in that I used a longer socket head screw and the strapping is just in addition to the original clamp. That way, if the hose slips out of the two piece clamp then the strap still keeps the hose out of the way of the belt.
 
Terrible design having a hydro hose go through a variable belt setup like that. Nothing should ever be routed through a belt assembly. Good job on the repair, though!
 
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