Thread: '91 Haas VF-1 Rebuild

Originally Posted by ChuckMTB

I just wanted to add one suggestion while you are up by the draw bar... There is a cast aluminum valve where the air comes in and heads down to the drawbar, it has an exhaust opposite the inlet. I think it says Humphrey SQE on it. There is a rubber diaphragm in there that wears out/shreds up and then the draw bar will not release. Check it out to see what shape it is in, you can unscrew the side with the exhaust and see the black valve in there. you can kind of pick it out of there. You can just replace the diaphragm and o-ring, sourced on line or get the whole valve from Haas. Since the other o-rings are worn out it is probably close to dead.

Do you have the numbers that I need to order the diaphragm?

I bought valves at Grainger in a pinch and paid way too much. Not sure who these guys are but they have the valve and o-ring kit:

Cleaner's Supply - Catalog

and I think this is the same part on Ebay:
HUMPHREY SRKQE SEAL REPAIR KIT FOR SUPER QUICK EXHAUST VALVE QE1 QE2 QE3 | eBay

Anything worth doing is worth doing right! I got the Humphrey seal repair kit in. It should be a simple install. I'll update with pics when I get a chance.

Originally Posted by moparmuscl

Thank you Mike! Just changed the setting to 100,000 and it ran 3 times longer than it has before without throwing a code! Hopefully this will drastically cut back on the way lube usage.

Just so you know if you are still getting an alarm: You may need a new pressure switch---I did. Simple and easy and cheap to replace, right behind the pump. NAPA has the part "Napa Echlin OP6616 Oil Pressure Sender Unit." I replaced mine and all is well now.

If you sit and watch the pressure pump for about 30 minutes while the spindle is running, you can see if it cycles or not. Or, you can cheat like I did and set a video camera to watch it for you. Once I verified that it was pumping, I jumpered the switch and the alarm went away, so I knew it was the switch.

Mike

Already replaced the pressure switch. I guess I didn't document that. I wish I would have had that part number, because the Haas switch wasn't cheap!

Mine cost $7.00 with free shipping from eBay!

So, I've found two more issues that I need help with. One is the old issue of the lube pressure alarm. It looks like the lube pressure is too high and does not bleed off fast enough. I assume a line has a kink or clog. Any was to easily diagnose the issue other than start taking the machine apart again and replacing all the lines like I was originally planning on doing?

The other issues, after milling for awhile, the screen goes blank. The green power light is still on, the keypad still works and machine still functions, but the screen is blank/dark. Any suggestions?

Originally Posted by moparmuscl

So, I've found two more issues that I need help with. One is the old issue of the lube pressure alarm. It looks like the lube pressure is too high and does not bleed off fast enough. I assume a line has a kink or clog. Any was to easily diagnose the issue other than start taking the machine apart again and replacing all the lines like I was originally planning on doing?

The other issues, after milling for awhile, the screen goes blank. The green power light is still on, the keypad still works and machine still functions, but the screen is blank/dark. Any suggestions?

Check for supply voltage at the video PCB. If video board looks good, it could just be a bad monitor. Anything else you can plug the monitor into to check for display like old computer? Or an old computer monitor to plug in at machine? Others may be able to help troubleshoot components of the monitor if needed.

Check the filter bowl at the lube pump, it could be full of sludge. Not sure on your vintage, but most will have a stone type filter that could be clogged also. If those are good, start by disconnecting the main feed at each axis. Best access for X axis should be under the right cover, Y under the front cover and Z behind Z covers. Disconnect the main feed line before it brances off, pump manually and check for flow. Should help narrow it down, but if a couple metering units are clogged then many more probably will be also. Sorry!

I have a 1993 VF3 and just had to replace all of the Bijur metering units because they were clogged.
15 of them total I think. The best price was direct from Haas and it took about 6 or 8 hours all said and done.
So like Haastec points out it might be time to replace them all.

Originally Posted by moparmuscl

I got all the o-rings changed out tonight on the shot pin piston assembly, gear shifter piston assembly, and the tools release piston assembly. Everything went really smoothly in general until the tool release piston. All o-rings fit great and were the correct size. Everything seemed to be in good shape except for the o-rings that I pulled off. They were mostly all flattened and semi-hard. A couple were even brittle. I'm glad I went the extra step and switched these out. I used air tool oil to lube everything when it went back together, so hopefully that will work fine. The last thing was the tool release piston. I got it apart, cleaned up, and almost back together when I slipped putting the snap ring in. I overshot the groove and nicked the piston bore. I would estimate it was .008-.010" deep. I started with 400 grit sandpaper and worked my was up to 2000 until I had worked the nick out. I'm glad I bought extra o-rings for everything, because I didn't want to take a chance of the first one being slightly cut. I tested to piston with ~50 psi and it didn't leak, so I'm happy with the repair.

I am having problems with my orientation piston so I am going through the same O-ring process you did. Do you know what size the O-rings are for the piston? As far as I can tell there are 2 different sizes and 2 or each size. Thanks

Steve