Marcel, Macs autoparts are selling complete pumps for good price. Single pulleys but you can exchange them for your doubles I guess.
They are working on my carrier just fine.
Consider this as an option.

Hi Marcel,

Try some of these suppliers in The Netherlands:

https://www.lilypadspeedshop.nl/c-495641/water-pumps/
https://www.adamscc.nl
and see Oldtimer part suppliers in The Netherlands

Hanno and Petr thanks for the information.
I will go to try tto find overhaul sets for the double pulley waterpump other wise it will be new ones with single pulleys.

I had find out that the diameter of the shaft of the single pulleys are 12mm and the diameter of the double pulley will be 16mm.

Is this correct? So cannot exchange shaft of a double pulley for a single pulley

Bearings for the water pumps on mine where the same as MB GPW Jeep ones

Hi Marcel, unfortunately cant measure now the diameter of the shaft on Macs pump however I checked my double pulleys and interestingly there are two types. One for 12mm shaft and another for 16mm shaft. I believe that 16mm is more common for heavy use - trucks etc.
Confusing? :)

Marcel,
I have been down this road over the past years with my carrier and there was a thread on here all about the water pumps though I can't find it now. I have now tried both the single pulley modern pumps and rebuilding the originals, have had the pumps off and on 4 times so for what it is worth here are my findings. The Jeep pump bearings are the same size but the shafts are not so would need grinding down to fit the Carrier pulleys/impellor. I have fitted the modern single pulley pumps which are excellent and water tight if you are happy to run a single pulley which is of course not original, it does depend on how original you want the engine bay to look, if you are not too worried I would go that route for both cost and peace of mind. I have also had my original pumps rebuilt 3 times now, twice by a cowboy outfit who used Chinese bearings which lasted a few minutes running and lastly by a decent engineer using new rebuild kits from the USA. These have done well so far though I have just had a small leak from one probably due to not having run the Carrier for the past year. I bought the pump kits from Gotham Autoparts in New York sales@gothamautoparts.com You want the 1937-1948 Truck Dual-Belt Water Pump kit Looking at the invoice I think the part number is 79-8591. When rebuilding the pumps you need to find an engineer with the ability to reface the inside of the pump body casting against which the carbon disc sits, if this is scored the pump will never be water tight.
Hope this helps.

Interesting Mike, I gave Marcel some of that info on FB. I have dealt with James at Gotham and he has been great to deal with. The Double pulley pump has a bearing, while the single pulley pump is bushed so they are different. The carrier fan is a big one and Ford decided that they need two belts to drive them. (keeping in mind that the belts cant be very tight)
I have done a couple of pumps with James's kits and they are good.
As you say the Jeep bearing is not the same it has a bigger dia. and longer shaft than the double pulley truck pump.

I have added a picture of pump parts (James's photo)