Okay, first a reminder that I am NOT mechanically inclined. I have searched the site for some possible help, but did not come up with any. Sorry for the long post to follow. Now, onto my problem...
I am attempting to replace the faucet on our Breakaway kitchen sink. I have now realized this is NOT going to be as easy a project as replacing my home kitchen faucet. It is a single hole/single lever type Moen faucet mounted directly to the rear sink flange with no escutcheon (where did they come up with that name? I can't even say it correctly). We are having problems with it and my wife would like a faucet with a higher arch anyway. She does not need, nor really want, a new one with the pull out head.
I removed the water feeds from the copper tubes feeding the old faucet. Okay, that went smooth. After doing this is when I started to realize I was going to get in trouble. I check it out and ask myself...How do I get to the shank and mounting nut on the bottom of the old faucet? I have come to believe that I either have to remove the shelf in the cabinet below the sink so I can try to fit under there to get to it or remove the sink itself to get to them. Upon further investigating I realize there is a vertical "board" running along the back of the sink opening in the counter top that the faucet shank runs right next to. I mean to say, there does not seem to be a 1/16" between the shank and this board. It actually feels like the mounting nut is right up against this board! So now I have also come to believe that the faucet was installed in the double basin sink BEFORE the sink was actually installed in the opening of the corian counter top. Can't imagine they would have done it differently at the factory. So I am going to attempt one solution or the other today so that I can actually try to remove and replace this faucet. But it looks like the sink might have to come out? If anybody has any experience with this or suggestions, I'm listening...
After getting frustrated at this point of time, I decide to take a breather and look at the new faucet and mounting instructions. Uh-oh, another problem. I purchased a Moen Camerist faucet as a replacement. Even spoke with the tech folks at Moen to confirm it will work. Here is a lesson for anyone doing this replacement: Measure, measure and then measure AGAIN! I had originally got a tape measure and "eyed up" the width of the base of the exisitng faucet. Looked to be I had about 2" of working room. I confirmed with the Moen tech that the base of this new faucet was within .07 of that. Now that I had been working with the old faucet in trying to figure how to remove it, I started to think this new one seems a lot bigger. I now had access to a dial indicator so I start doing precise measurements. Yep, Houston we have a problem... The existing base mounting on the sink surface is 1.75" in diameter. The new base is 2.125". That's a 3/8" difference! Normally this would not be a problem, but it seems that the flange on the rear of the sink is not very wide for mounting a faucet there. It seems to me that I do not have the 3/16" extra space (1/2 of the 3/8" size difference) on that flange for this larger base to fit in place of the existing. It seems to me that I will not have a flat surface under the entire base of the new faucet to mount this properly.
As I saw that quite a few folks have replaced their faucets with ones from Home Depot and Lowes, has anybody else run into this? Am I not seeing this correctly? Is there a way around this? Do I need to find a faucet with a 1.75" base like the one that is in there presently?

This isn't an answer to your question but perhaps it will help. I have found my digital camera to be a great assistant for those projects where eyeballs don't go. If needed you can mark dimensions on duct tape and put it in place so you can measure. Usually if you let the camera have a second it will macro focus and give the right flash level. Don't forget to use the lanyard around the wrist, some locations are not forgiving when it comes to retrieving the camera.
Good luck, I've been close to that condition and I did survive.

Bruce,

First of all, a plumber's sink wrench might be the solution to get up to the nut. It is designed to fit into those tight spaces and self tightens.

To deal with the dimensional problem, you might find that bathroom fixtures are a better fit. Some, like in the Grohe line mount without a flange and have a nice high arch.

Another thought would be to make a spacer out of a piece of Corian.

I replaced the faucet in our Barth. Took a good long look and removed the sink. This was easy to do and also allowed me to really tighten the new one down. We have a stainless sink and there were only 4 (maybe more) screws to remove. Then just take a case cutter and cut thru the caulk holding the sink in place and it should lift up.

Oh yes, you do have remove the plumbing.

Thanks for the replies folks!
Corey---I have one of those tools but did the same thing Gary did, took a long hard look at the situation. I have come to the conclusion that because of the close proximities of the shank to that vertical board, I'm going to remove the sink.
As far as the dimension differences in the base of the new and old faucets, I figure since I'll have the sink out I'll take the old one out and actually see how the new one will fit. Hopefully at worst case scenario I might have to put a plate under the new base so that I have a complete "seal" under it.
Anybody else do this chore and want to share their experience?

Had a leaking Moden kicthen faucet took it apart and got a kit from a pluming store and no more leaks. Don't rember cost but was around 20bucks . the repair cartage is comon item though.

Removing the sink and changing the faucet today. I'll report back on my venture....

First, I am going to request Bill, Rusty or Bill to move this posting to Barth Upgrades and Improvements.
Second, this project involved removing a Moen faucet that was mounted in a Moen double bowl sink and replacing it with a newer style Moen Camerist CA7825CSL faucet. Both the new and old faucets mount in a single hole on the flange of the sink.
Third, I apologize for my following long post on the faucet replacement...
I meant to take photos of this project, but forgot the camera and didn't have the time to go back to get it. After finishing the job I realized that if I just told you what took place you would understand everything as you went along with this if you did it yourself.
Removing the sink: Disconnect your water lines. Make sure you mark hot and cold lines for proper re-attachment. Disconnect your drain lines from the sink bowls. Now for the fun part. You have channels mounted around the perimeter of the sink under the counter top. You can see these by looking up to the bottom of the sink from the cabinet under the sink. These channels should have 10-12 clips that are in the rails at different points under the sink. There should be at least two at 90 degress at each corner and then one each at half way down each side. These clips have small screws that thread through the middle of the clips and are used to tighen down the sink to the counter top. This is where it gets a little tricky because you need to loosen all those clips and slide them out of the channels at either end of the channel. Patience is needed here, as some are a bit tricky to get to. Once all the clips are removed you can now lift the sink out of the counter.
NOTE: I will say here that I now understand how the plumbers sink wrench that Corey spoke of (and I had) would work. The back edge of the sink opening in the corian counter top has a "cut out" in it where the faucet mounts in the sink flange. This gives you room to get that wrench up there to take off the mounting nut from the faucet shank. This would work if you can get all the way under your sink to get to the nut, can get the nut off with that wrench AND if you are replacing the faucet with an exact replacement. If you are going to be using a newer style replacement faucet, you need to keep doing what I did. Here is why.....
After removing the sink we found it to be MUCH easier to remove the nut from the shank of the old faucet. You can easily get wrenches on it now. Ours had some thread damage on the shank along with some corrosion issues that made it basically impossible to get the nut off the shank. We ended up cutting it off. Here is where the new faucet compared to the old faucet meant making alterations. When we pulled the old faucet from the sink we found that the faucet had been matched up to the sink by way of two flat edges on both the shank and the hole in the flange. The new faucet has a 360 degree round shank. Add to that, the hole in the sink flange was about 1/8" too small for the new shank. And I already knew that when the new faucet was mounted in the hole that was there, it was possible there was going to be about an 1/8" overhang on the rear sink flange. So we planned to kill two birds with one stone. We decided we would "round out" the flat sides of the opening and at the same time move the hole opening closer to the bowls of the sink. So with files, grinding stones and lots of trial "fittings" of the new faucet, we did this. Once we got the hole opening larger and closer, we then mounted the new faucet, per the directions, into the sink flange. Looked good at that point. We then went to drop the sink back into the opening to make sure everything fits and found that because of the new location of the hole along with the larger nut on the larger shank, it hit on the back edge of the opening and the flange would not lay flat on the counter top. Pulled the sink and enlarged the "cut out" on the back edge of the counter top. Now the sink fit properly. We penciled the outline of the sink flange all the way around the sink while it was sitting in the opening. We removed the sink and then took some clear silicone and put a large bead around the inside of the line and did the same all the way around the flange of the sink. We then put the sink back into the opening and then proceded to reinstall the 12 clips we had removed by sliding them back into the channels and tighening them in place. The sink was now reinstalled. We had to get adapters to hook up the water feeds, as we had female connections on both the water feeds and faucet flex hose connections. You can pick them up at Home Depot or Lowes. Then we re-attached the drains and we were done. Oh, and another NOTE: It was much easier doing this with at least two people.
It looks real good and Kathleen likes the new faucet much better than the old one. And since the previous owners had decided to put a water filter on the incoming water feed under the sink and disconnect the old small bar type faucet/water filter, she has now decided to replace that with a soap dispenser. So we removed that faucet and found a hole that is not big enough for a soap dispenser. Okay, another job for another time as I have to figure out how to make the hole larger with out destoying the counter. A hole saw will not work. I'm thinking a step bit might be the way....

Thanks for the clear and comprehensive directions!

I'm inclined to leave it here in Tech Talk because it's a repair using replacements for out-of-production fittings (and some imaginative thinking!).

Nice work! You can use a hole saw if you cut a hole to fit in the hole. Also if you can glue scrap to the bottom of the counter and glue the plug to the scrap you should be good to go. You only need to get the first 1/8 inch or so started.
Good luck.