The threaded jack connection on the bottom of the casing, USE EXPANDO. Clean both sides with brake clean first then expando that connection before setting the casing. I mentioned the bad installs ended up having to be fixed...

- make sure to do roller guides and not slide guides (not sure if Canton changed to only provide roller guides yet or not but it does make a big difference)
- use a maxton valve - just my opinion but I think the adjustments on a maxton can really provide a better overall running car in the end in this situation
- be mindful of your trough/duct run in the shaft, specifically if the machine room is located in the back of the hatch - the bolster channel for the platform has the connection points for the hoist ropes which is located basically in between the main guide rail and the jacks and piston followers - this is where it can get tight with trough if the machine room is located in the back of the hoistway because the trough will need o run to the front of the shaft so it has to fit behind the jack, main guide rails and has to have the clearance for the bolster channel to pass by
- like someone above said - use expando on the threaded portion under the jacks.
- Typically the way Canton sets these up is pretty tight. there is basically one corner stuffed with your trough, limit switches, selector tape, etc. - Again just my opinion but I always like to pay close attention to the dimensions on their drawings as it is a tight fit.

I used to put in Canton units at this same time, and most are still running well. Controls have been modernized over the years, but the hydraulics have endure the test of time.
As someone mentioned, a good install goes a long way. Fortunately, I was taught by some of the best back in the beginning.

Why wouldn't you just replace the in ground casing and plunger? The purpose of the dual post jacks is to eliminate having to drill down but that doesn't seem to be an issue here. Also doesn't the existing elevator have a counterweight? Or is it cantilevered with a sheave?

In my experience dual post elevators are not as reliable, require more maintenance, are more time consuming to install and altogether just aren't as nice a product. I see them as a compromise when you can't drill or otherwise need the space below. I've installed 3 canton single stage roped hole-less and I don't like them and I have now maintain 2 that some hack company that went bust installed and they are a nightmare. I've never installed or seen a telescopic roped hole-less and would be very concerned about how it's stabilized and what maintenance is required. Is it like the inverted 330a jacks? Plastic pulleys and a special repack toolkit? No thank you I say.