On Sun, 25 Oct 2020 22:29:55 +0000, newshound
wrote:

snip

I think the pumps come with a 1/2" male (looks tapered) outlet and so
I'd need a mating female to whatever I was working on, in the case of
most motorbikes, a 'banjo' connection of some sort.


Given that you already have a hydraulic pump with all the right fittings
and fluid to hand this seems like a lot of work.

Well true, it's just that I'll have to do that with the caliper
dangling on the bike and with risk of spraying brake fluid everywhere
rather than on the bench in the workshop. ;-)

If you are going to make a general purpose system you have a choice
between using mineral oil and "brake fluid". (When you say "hydraulic
fluid" earlier it is not quite clear what you mean).

Jack oil? I saw a litre of something like that when looking for fork
oil yesterday but will have a closer look at it today.

I would generally
use mineral oil (absorbs less water, gives better lubrication for a
stuck or rusted system, and less likely to strip paint).

Yup, they seem to be the properties I'm looking for.

But, you might
then worry about compatibility with seals specified for brake fluid. No
problem if you are going to replace them once you get the thing apart.

Good point and true.

In fact in general people worry more than is necessary about
compatibility of mineral oil with rubbers other than nitrile and viton.
Provided the exposure is short and it is cleaned off well with suitable
solvents there should not be a problem.

As would be the case (brake cleaner).

Although mineral oil will cause
natural and many other rubbers to swell and become soft the effect is
generally reversible.

OK, thanks.

I appreciate Tribology is your thing g but do you have any
experience of any diy-able fittings that can takes the sorts of
pressure you might find in such a system?

Cheers, T i m