Need Help!- VF-1 no low gear

[GITRDUN]

Have a 98 VF-1 that will not go into low gear. On power up restart it will try to switch to low gear but alarms out after 2 attempts. It will go into high gear and the spindle runs fine, no gear noise or anything while running. I have bored out the two brass regulator valves in the gear change air lines, didnt help. I replaced the MAC solenoid valve that controls the gears, didnt help. I checked that air blows through the high gear air line after the mac valve and also the low gear air line when M41 or M42 is commanded, so in my mind that elminates the electric and air issues. Im pretty sure the gear changer arm or whatever is just stuck in high gear position.

So how do i get the changer unstuck?

[Bryan33]

There are a few things you can try.\
1. I would put some pneumatic air gun oil in to the piston (shot it down the bras lines)
2. While trying to **** tap on the side of your gearbox to help break it loose.

If you get it running then you will need to run your gearbox in high and low gear for a while at different RPM to help get everything lubricated.

Please let me know if this works. If not I will come up with some more stuff to try

[fastfrank]

Greetings

I have a machine that did the same thing. I probably caused the problem because my air was not as dry as it should have been. If you can visually see any moisture coming out of the air line when blowing parts off, it's asking for trouble…anyway... Taking the air line off after the main regulator and adding some oil helped for me. Air tool oil worked for a little bit. WD-40 also worked for a little while. I think PB Blaster is the way to go. I gave it a 2 second shot and repeated it about a week later and have been running ever since (more than a year).

The oil in the air line is kind of a “What came first, the chicken or the egg” thing. You have to put oil in the line to get the trans to shift but you have to shift the trans to have the oil get worked into the shift mechanism. When I was using air tool oil and WD-40 the trans would not shift without help a couple of times. If you take the sheet metal off the Z axis and remove the tool release piston assy (4 bolts and it lifts right off and no need for any adjustment on reinstall) you can just barely see the shift pin coming out of the bottom of the tranny that activates the high gear/ low gear switches. You also have just enough room to get a pry bar in there and push the pin back into the tranny (shifting it by hand in other words). Mine seemed to be a little tight only when the pin was all the way out. Once I got it started, it moved free. Just keep working your M41 and M42 to get that PB Blaster worked in good and help it shift by lifting the pin if needed and I bet you will be good to go.

By the way, my tool release piston was weak and was giving me trouble not having enough power to break the taper in order to change tools and since the Blaster in the air line, no more problems with that either.

I don't know but I assume the Blaster swells the o-rings giving them new life.

Hope this helps

Fastfrank

[haastec]

If the oil in the line doesn't immediately help, using a quick connect on the air supply, quickly disconnect and reconnect the air. Sometimes the surge of air when reconnecting will allow the shift. You may have to do this several times.

Another thing to try is if you can get it in high or low, run the spindle for a while to warm everything up and add the air tool oil again. Then shift high/low several times to work it in.

Good luck!

[Machineit]

Just a warning, WD-40 was developed as a solvent to loosen stuck parts and displace water, "WD= Water Displacement, 40= 40th try!" It dries to a sticky paste after time. It should not be used as a lubricant, only to break loose stuck parts, then add a real oil for lubrication.

Air tool oil is a a good light weight lubricant and should do the job, just don't over do it. In air tools the oil passes through as the tool is used. In a piston type cylinder it may not escape and may build up inside.

Cheers---Mike