A special tool to hold the camshafts in place is required if doing the water pump and special tools are highly recommended if replacing the seals. The tool are all available online. Honestly if labor is being saved and you want factory parts, buy one of these kits and do everything (timing belt, water pump, front seals, drive belts, and thermostat):

https://www.m.ebay.com/itm/NEW-LEXU...X330-TOYOTA-CAMRY-SIENNA-OEM-TIMING-BELT-KIT-3-0-3-3-L-/370799217514?nav=SEARCH

No thermostat:

https://www.m.ebay.com/itm/Genuine-...and-Water-Pump-Kit-with-Seals-Belts-Tensioner-NTN-KOYO-/180747911575?nav=SEARCH

Tools needed

Camshaft tool:

https://www.amazon.com/Performance-...236_SY340_QL65&keywords=toyota+camshaft+tool&dpPl=1&dpID=31AwcNXDtYL&ref=plSrch

Seal puller/installer:

https://www.amazon.com/dp/B0080IG53A/ref=cm_sw_r_cp_awdb_t1_jY7dBbFS8SJ15

Seal puller only:

https://www.amazon.com/dp/B000FPYW4K/ref=cm_sw_r_cp_awdb_t1_107dBbQAQKYAT

Seal installer only:

https://www.amazon.com/dp/B007SY9KAW/ref=cm_sw_r_cp_awdb_t1_4Y7dBbAW7DK3J

 

I got the cam shaft pully thingy. But it's a universal one. It's a bit clunky at best but does work. Might get that one specific since I work a LOT on the 1MZ.

I got the seal installer and seal puller. Those are IMO are necessity to doing this job correctly.

I plan to do my 1MZ 04 V6 soon. Just i'm dreading it a tiny bit since working in the Gen5 engine is overall a bit of a PITA due to the tigher space between the rear and front of the engine compared to the Gen3/4.

 

I just did the water pump and timing belt on a 2006 3.3L Solara and did not need a camshaft tool. However, that does not mean you do not nor is it simple or easy. You will have to take the rear dust shields loose and pry them out a little bit to get the water pump out from behind the dust shields. Really did not make sense to me why Toyota did it this way, but oh well. Plan for a weekend to do the job if not experienced in doing this type of work. If you are experienced I still say it takes 4-8 hours...I bought this kit, which is factory, for mine yours may be different so please check.

https://www.amazon.com/gp/product/B008EEYWX0/ref=oh_aui_detailpage_o06_s00?ie=UTF8&psc=1


Note:
I am not advocating not using all of the specified tools, purely stating that it may be possible to do the work without certain tools.

Best of Luck...