Mazak VCU Y axis squeak?

Hello.

We have a 2014 Mazak VCU 400, ours is a 5 axis but I think all the VCU mills are set up the same way, the Y axis travel is the head traveling on liner guides about 6' off the ground.
We do mostly pretty light work in the machine and keep it clean. The machine is really accurate.
Moving in Y minus direction, to the operator, we get a squeak in travels, it does not sound like thrust bearings and is mostly from the Y plus limit to about 6" to 10" in the Y minus. We rarely go too far in the Y minus past the table centerline, that is where there is a lot of weight on the slides, it never squeaks there?
We almost never machine anything in that area(6" to 10" in the Y minus) most of that area is traversing over the far side of the trunnion?
I cleaned out the lube meters on head and it looks like everything is being greased, all the meters put out equal grease with the lines off and the liner guides look good.
The only sign of any kind of wear is on the brass caps covering the bolts that hold the linear guides in place? If I put grease on top of the guides where I am seeing some wear on those blot caps it will squeak less or not at all.
It does not squeak all of the time but it seems to be getting worse, those caps with the wear on them may be dragging in the linear guide housing, I guess I will try and seat those tomorrow but they are just caps, not really sure why they would create a light squeal for about 4-6" of travels.
Mazak made a lot of these machines, other than the funky trunnion casting the iron on these machines is way over built, pretty much a brick sh?? house, probably due to the weight of the head traversing out.
There is a lot of funky sheet metal moving around up on the head but no signs or rubbing up there, hopefully some of you people have some ideas?

Have a Happy Holiday Season!

putting grease on the top of the rail is nothing but reinforcing a placebo effect. rollers not even run there, assuming you are helping to lubricate linear guides. Very strange noise. Is it high pitch of low pitch? IS it possible to record it as audio?

It is pretty high pitch, The fact that the brass covers on top of the bolts holding the linear guides down have clear signs of ware on them in the same area where the sound is coming from is alarming. There are high points on the covers, they are not set flat in the c-bore, not even sure how they are secured but if they came loose they at the very least trash the wipers. I tried re-seating them with a 1.2.3. block and a mallet, no luck. If I damage them it will kill the wipers as well, I guess I will call Mazak next week.
I am thinking the high points on the covers are dragging on the moving linear guide housings, just enough to make a little noise, still metal on metal. I am really worried about putting to much pressure on the covers or grinding them flat, if it grabs chips and they get dragged under the wipers really bad things can happen. I think I will google Mazak linear guide rail brass covers, I doubt I am the only one having issues with these?

Here is a link to see the brass covers, scroll down about halfway, it looks like they are just brass pucks, not really sure what is causing them to randomly protrude unless they were assembled that way?

https://stevenengineering.com/wp-content/uploads/2019/02/NSK_LINEAR-GUIDE-INSTALL.pdf

I think you are overthinking the whole issue. Google places which sell rail guides caps ( plastic ones) and get two sets. Remove old ones and install new ones. Old ones - you drill a hole in it, after..... you use a TAP to tap it and just pulled them out with your hand drill. Easy.

You know what interesting is, if you google your particular machine you will see that this particular model is made in Singapore. At least ( .co.id) domain advertises it. May be was created for specific market. Who knows. May be that is the reason why no one here giving his feedback when it comes to this particular model. Not sure. I am guessing here.