Replacing Haas VF gearbox oil pump coupling on older VMC's?

Hi all you Haasheads,
My 2001 VF-5 threw the code for failure of gearbox oil cooling/circulation last night, and while it could be low oil, it's more likely a failed polymer coupling between the oil pump and motor. I haven't checked yet (didn't want to climb on the machine while tired), but will later today.

Does anyone know for sure if the pump on the larger head machines can be accessed by just removing the top sheetmetal panel and fan? I have a pretty compressive 80-20 enclosure around the head and top of the machine to help control mist, and if I have to remove the main sheetmetal off the head it's a chore. If anyone knows for sure that would be good (or bad) to hear.

I'll be away from the computer for a while, but if there's questions I'll answer them when I get back. I had to replace the coupling on my smaller VF-2 last year which did require significant enclosure removal. Hoping I don't have to do it on this one...

Edit - it was freeing up a stalled drive motor, not the couple for the VF-2 (had done the coupling only some years prior to the motor repair).

Hi Milland, Happy new year to ya! Betting you've already been in and done? When the son and I did a VF/6 gearbox rebuild not too long ago, I do recall more room with the top cover off. It was wide in Y so yeah.. I think I recall it being doable? We did take the 1 side panel off also just to get into the ports and connectors and gearbox. What a mess that project was! IT ran in the end. :-)

countryguy said:

Hi Milland, Happy new year to ya! Betting you've already been in and done? When the son and I did a VF/6 gearbox rebuild not too long ago, I do recall more room with the top cover off. It was wide in Y so yeah.. I think I recall it being doable? We did take the 1 side panel off also just to get into the ports and connectors and gearbox. What a mess that project was! IT ran in the end. :-)

Click to expand...

Hi Countryguy, back at you on the NY wishes and such.

Yeah, it's done, and I hope to find the time to do a proper write up of my approach (with only the top panel removed).

One current thought - I used replacement couplings I got from McMaster a while back, but was disappointed to see that they had damaged edges along both ends of the cylinder. A sort of irregular scalloping, likely from poor cutoff from a long extrusion.

So I made a reinforcement sleeve from aluminum, ID the barest press fit over the coupling, 1/16" wall, a touch longer than the coupling. My thought was the scallops could turn into stress points and initiate premature cracking down the road, with the sleeve I hope to gain a little more working life before I have to go back in there.

I left the internal parting burr in place, with that side "UP" when installed in the pump assembly. That was to prevent the sleeve from"walking down" the coupling while it flexes in use.