Broken springs

paul case · September 15, 2012, 12:21:52 AM

I had a spring break on my mill today. It was one of 4 that center the hydraulic valves. 1 had broken before I bought the mill and it had a heavy rubber band around the lever and some hose fittings that stick out just right so the band will center the valve. I ''fixed'' the other one the same way.

The spring is coiled with the ends sticking out to contact the stops. The trouble is it is on the valve handle so thatt it looks like you would have to dismantle the whole hydraulic valve to replace it.

Anyone else had this on an older LT 40 hd like mine?

Jim_Rogers · September 15, 2012, 09:04:12 AM

I have a 94 LT30 (four handle hydraulic system) and I have replaced the self centering springs a couple of times.

Is yours a four handle system?

It isn't too hard once you've done it once.

I can talk you through it if you have a replacement spring on hand.

Jim Rogers

paul case · September 15, 2012, 06:30:19 PM

Mine is the 4 handle system.
Do you have to pulll the hydraulic valves off to change the spring? PC

paul case · September 15, 2012, 09:40:34 PM

Our own Electric Al( i think) beat ya to it.
http://www.youtube.com/watch?v=yQcXrP8ehTE&feature=relmfu

PC

Jim_Rogers · September 16, 2012, 08:49:51 AM

That was a good video.

But I may caution you to try the handle before you put the big cover back on.

One of the first times I did that, the shaft the handle is on was rotated out of line with the handle and when I backed up the saw carriage head the hydraulics started working with the handle in the center position.

I had to rotate the shaft a little to get it back to being centered. That is between the up and down position.

A WM tech suggested that I scribe a line onto the end of the shaft so that it lines up wit the handle. Which I did on each handle body before I loosen the allen wrench set screw.

Sometimes when I change my spring I remove all three outgoing hydraulic lines and remove the valve body from the lower box and hold it in my hand while I scribe the line on the end so that the line goes across the end of the shaft and across the handle body.

The last time I did this, I dropped the valve body and broke the grounding wire. I simple wire connector was needed to put it all back together again.

Al's method is good and fast, but you have to also understand what to do if it doesn't work right afterwards.

Good luck with your repairs.

Jim Rogers

paul case · September 16, 2012, 09:03:25 AM

Thanks for the pointers Jim.

I thought that it probably had some type of flat spot or keyway to keep them lined up, but they both are completely round? I will keep my eye on that. PC

Jim_Rogers · September 16, 2012, 09:08:48 AM

As I remember it, yes the shaft and handle hole are completely round and no keyway, at least on mine there isn't.

Jim Rogers

paul case · September 17, 2012, 09:10:53 AM

I about had a little fit when I saw that these springs ONLY cost $6.38 each? PC

Jim_Rogers · March 30, 2013, 01:14:47 PM

Yesterday, I had to opportunity to revisit this thread topic.

I broke another self centering spring on my sawmill. This time it was the second level from the end the one that make the log turner move:

After gathering all the tools I would need and taking everything apart, I noticed that the shaft of the valve unit had a hole through it.

And that the set screw had a long point on it:

To help align everything back up I took the set screw out and used my ice pick to the the shaft aligned with the hole:

After the handle was aligned with the hole in the shaft the set screw tip went right down into the hole and everything lined up right.

I just thought I'd add a few pictures to this story for the next sawyer who had to change his self centering spring.

Jim Rogers

beenthere · March 30, 2013, 03:39:34 PM

Would bug me to have all that oily sawdust around when the hyd. fittings are open and exposed that way. Won't take much to plug up some lines and valves with just a small amount of wood particles getting into your lines. Just worryin for ya here. ;)

Maybe follow that set screw with another to keep it secure.

Jim_Rogers · March 30, 2013, 07:05:50 PM

I am always concerned as well.
I was most worried about the out flow port on the pump body below the valve bank.
I put a cover over the outflow port, you can see it in the picture just below and to the right of the blue wire connector.

I don't know if these fittings need it or not, but I put tread tape on all of them before I put them back together to try and cut down on any oil weep.

I've been trying to do that to everyone every time I take it apart.

Maybe it will help, maybe not.

Jim Rogers

bama20a · March 30, 2013, 07:21:58 PM

That is what I love about this place someone always willing to help. smiley_clapping

Jim_Rogers · June 14, 2019, 04:22:00 PM

Same thing again today:

All better now.

Jim Rogers

luap · June 14, 2019, 06:15:37 PM

Quote from: beenthere on March 30, 2013, 03:39:34 PM
Would bug me to have all that oily sawdust around when the hyd. fittings are open and exposed that way. Won't take much to plug up some lines and valves with just a small amount of wood particles getting into your lines. Just worryin for ya here. ;)

Maybe follow that set screw with another to keep it secure.

Some mechanics will take a balloon and pull it over the end of a hose. I have even seen guys take a latex glove and cut fingers off the glove and pull them over the hose end and put a zip tie on it.

barbender · June 15, 2019, 12:24:09 AM

I've also seen guys NOT take those precautions and get dirt in a line, and take out the hydraulic pump on a brand new machine causing untold thousands of dollars of damage, and several weeks of downtime.

RAYAR · June 15, 2019, 12:45:33 PM

Quote from: Jim_Rogers on March 30, 2013, 07:05:50 PM
I don't know if these fittings need it or not, but I put tread tape on all of them before I put them back together to try and cut down on any oil weep.

I've been trying to do that to everyone every time I take it apart.

Maybe it will help, maybe not.

Jim Rogers

It's the tapered seats that seal together. They must be absolutely clean and smooth to make a leak free seal. Any spec of dirt or scratch on those tapered surfaces can be cause for a leak or seep.
Ray

Ben Cut-wright · June 16, 2019, 08:44:22 AM

Quote from: RAYAR on June 15, 2019, 12:45:33 PM
Quote from: Jim_Rogers on March 30, 2013, 07:05:50 PM
I don't know if these fittings need it or not, but I put tread tape on all of them before I put them back together to try and cut down on any oil weep.

I've been trying to do that to everyone every time I take it apart.

Maybe it will help, maybe not.

Jim Rogers
It's the tapered seats that seal together. They must be absolutely clean and smooth to make a leak free seal. Any spec of dirt or scratch on those tapered surfaces can be cause for a leak or seep.
Ray

You are correct RAYAR. PTFE tape as a thread sealant is generally not considered appropriate in fluid power (hydraulic) systems.