Vacume/boost guage prob. slugish ?

[Bills R2]

I could use some thoughts on my Avanti guage.
I am most interested in first hand experiance, not so much in opinions.
The guage is very slow to respond, though I have cleaned the small orifice in the back. This hole is very small and a .015 cleaning file will not come close to fitting it. I have considered drilling a small hole into the side of the fitting in order to clean out the guage internals with carb cleaner and then just soldering the hole shut. I have also thought about simply enlarging the hole in hopes that it would result in a faster responding guage.Would there be a risk in this? Perhaps damage to the guage in the event of a backfire? SW clearly designed this guage carefully, it's kind of hard to guess their concerns.
Has anyone been there-done that?

'64 R2 back on da road again
POCI,SCCA,SIMTA

[Bud]

I've seen vaccum gauges become sluggish over the years. I believe the cause is the mechanism sticking inside of the gauge and not a restricted vacuum port. Bud

[PackardV8]

Without the tiny orifice, a vacuum gauge flutters as vacuum varies between intake strokes at idle. The sluggish reaction is caused by the original lubricant drying up and becoming gummy. There is no easy fix. One thing which helps is to use a Mighty-Vac vacuum/pressure pump to move the gauge through its full range of motion rapidly several times. This often frees it up a bit.

thnx, jack vines

PackardV8

[WCP]

The only permanent solution is to take it apart by removing the front bezel, and then freeing up the mechanism and lubing the various pivot points with clock oil or sewing machine oil. I had to do an NOS '64 gauge a couple of years back that was completely frozen. The front bezel can be removed by carefully prying up the back over several passes around the gauge. That is best done with the bezel face down in a tightly fitting plywood template so the the flat portion of the bezel front isn't distorted during the prying and later tapping back down with a suitable pin punch. With a little patience, the job can be done with no visible evidence that it was ever taken apart.

[64studeavanti]

In his book "What the shop manual won't tell you", Stan Gundry has a proceedure for addressing this on page 61. He says to use something called Tri-Flow teflon lubricant. Inject it into the nipple and let is sit overnight. Shake it out and repeat several times. When this is done, direct compressed air (50psi) at a right angle to the nipple (NOT into the nipple) to create a vacuum. Do this several times to free it up. If you don't have it, the book would be a good thing to get.

[Bills R2]

Thank you all for the gret replies! Packard, the fluttering idea occured to me just a couple of hours ago & is a very logical explanation. I do think I will pull the bezel and try a bit of lube.
Once I get this dash back in,I will never pull it again!!

'64 R2 back on da road again
POCI,SCCA,SIMTA