[Nasher]

I worried that My Mityvac was going to struggle with bigger jobs but it hasn't.

It handled changing the Brake fluid in My Discovery really well, despite the system being huge with ABS etc, all I had to do was a couple of additional pumps on the handle to top up the vacuum part way through.
I've also used it a couple of times to prime the 2T Oil hoses from the remote reservoir to my outboard.

The kit has many other test and maintenance uses in both Vacuum and pressure modes that I used in my 'Man-Maths' justification for spending what is a reasonable sum of money on a good piece of kit rather than an adequate one.
But as you can imagine I've only actually used it as above.

I do however have a big compressor powered Vacuum pump for changing the Oil in our cars.