Having problems with my LT40 carriage head moving along the rail

[CalebL]

I paid to have my mill (2005 LT40HDD34 w/525hrs) go through the gold service plan with an authorized dealer before I purchased the mill.  While going through the training I noticed the carriage would stick and slow/stop at certain points on the rail.  When doing this it also gives a rubbing/vibrating deep sound.  You can power through them by turning up the speed or pushing the carriage forward.  I talked to the service guy about it and he told me it was probably because the mill sat for a long period of time without use and would "loosen up" after some use. 

Well, it's 5 months later and it still does it.  I have checked the upper and lower track rollers and can't find anything wrong.  I thought it was the plastic wipers binding up and vibrating causing the noise but i took them off and moved the carriage and it still does it.  All of the cam followers turn when the carriage is moving.  Anyone have any advice on what is causing this? 

[cypresskayaksllc]

Does it always slow/stop at the same spot on the rail? How many points on the rail does it slow/stop?

[CalebL]

Does it always slow/stop at the same spot on the rail? How many points on the rail does it slow/stop?

Yes, it seems to always stop in about 3 or 4 same places on the rail.  All of which is on the front part of the rail before the tire. 

[CalebL]

I asked my wife how she would best describe the sound it makes when it hits those spots and she said it sounded like a heavy chair being dragged on the floor.  I don't know if this will help describe it or not but it was better than I could come up with.

[MartyParsons]

Hello,
Sounds like a bad cam bearing, I know you said you checked them. Check again. You will need to remove the weight off the bearings. The bearing will have a flat spot where it stops. If you are sure they are all ok. Check bearings in the power feed. Remove the belt for the power feed and push the saw head forward see if you can hear and see what is binding. 
I would guess it would be the lower bearing. Lower the saw head at the rest pin location on a block about 4' long this will push the saw head up and remove the weight on the lower bearings.
Hope this helps.
Marty

[CalebL]

Hello,
Sounds like a bad cam bearing, I know you said you checked them. Check again. You will need to remove the weight off the bearings. The bearing will have a flat spot where it stops. If you are sure they are all ok. Check bearings in the power feed. Remove the belt for the power feed and push the saw head forward see if you can hear and see what is binding. 
I would guess it would be the lower bearing. Lower the saw head at the rest pin location on a block about 4' long this will push the saw head up and remove the weight on the lower bearings.
Hope this helps.
Marty

Thanks Marty, I will try this tomorrow. 

[Peter Drouin]

there are some stops opposite the bottom rollers ,bolts that stop the head from rocken, there rubbing on the out side of the rail , there should be I think a 1/4" from the rail .

[Slingshot]

  As Marty said you may have a bad lower cam bearing but if they are OK, check the
clearance of the lower stop blocks pointed out by Peter Drouin. When I built the extension
for an LT30 I had a binding on the very end that did as you describe, caused by a slight
unevenness in the lower rail.(my fault) A little adjustment took care of it but was still within the recommended
clearance overall.

Here is a picture you should have in your parts list and maintenance







__________________________

[jc]

I had the exact same problem with my LT40 hydraulic.  It was one of the bearings on the underside.  I call it a traveler bearing but I don't know if that's the right nomenclature.  

[VictorH]

I have a similar issue on my Lt40.  Mine is caused by a link in the travel chain that is stiff - I believe rust on the chain is the issue with mine.  I too have to either push the saw head a little or turn up the speed control.  I have not heard a noise associated with mine though.  You might take a close look at your chain.

[terrifictimbersllc]

Might want to check if your forward/reverse belt is tensioned right, if it's slipping lots of things will make the mill stop.

[SAW MILLER]

My Lt 40 had a few spots along its travel that it didn't want to pass and it would slow down or jerk through the bad spots .I found out that the chain that the feed drive run on was rusted tight in a few spots and wouldn't flex .Several coats of penetrant fixed it .

[CalebL]

Hello,
Sounds like a bad cam bearing, I know you said you checked them. Check again. You will need to remove the weight off the bearings. The bearing will have a flat spot where it stops. If you are sure they are all ok. Check bearings in the power feed. Remove the belt for the power feed and push the saw head forward see if you can hear and see what is binding. 
I would guess it would be the lower bearing. Lower the saw head at the rest pin location on a block about 4' long this will push the saw head up and remove the weight on the lower bearings.
Hope this helps.
Marty

Yep.  It was a lower cam bearing.  I finally noticed it would slide instead of turning at a certain places.  I squirted a lot of ATF on it and it freed up and the shutter went away.  My mill will travel with the speed dial turned to the lowest setting now.  That has never happened since I have had it.  You would have thought this would have been caught during the gold service plan but oh well.  Ordering a new cam bearing  (and a spare) as I type this.  Thanks again guys, I love this place.

[Bibbyman]

Here is an old topic where I show how I changed out the upper cam bearings on our mill.

https://forestryforum.com/board/index.php/topic,19439.0.html

There may be some other tips further on for changing out the lower ones.