Apologies for the following mess, may be
a pretty tough and tedious read, so
in summary, I need a source/link for the exact
OEM match in Banjo-Bolt Washers.

I replaced my front brake cables (2013 ZX145R)
with aftermarket cables, and thought I had lost
one washer, I've bought two different packs of
washers and still have drippage.
It has been super difficult to actually find
the correct washers, the specs listed are not
the specs I'm receiving and now I'm finding
that there seems to be some 'weeping' out of
the upper double banjo bolt assembly as well
as one lower bolt where I'd replaced
that washer.
What are the best washers to use?
The ones I've gotten so far measure
9.75 ~ mm id
13.76 ~mm OD,
I think they should be 10 and 14mm exactly and
2mm thick, but what material; copper, alum or?
--
The thickness on the first set was 1mm (way too thin,
did not work) , and 1.35mm second set, was
better, but not great and as mentioned these
are all measuring about 9.74 id and only 13.75 od. "
--
The more I consider everything related to my initial
brake problem, the more I'm thinking the front lines
or one of them had a total clogging issue as I think
was suggested by @rook or @hub, someone else mentioned
a valve somewhere.
Should I soak the possibly clogged cable/s in brake
cleaner and try them again?
Either way I definitely need to replace at least
1 OEM banjo bolt washer with an equal, I have yet
another set of banjo bolts on the way and if the
included washers still suck, I figure on taking
a banjo bold to O'Reilly's and see if I can't come
up with a 'proper' washer match.

What are the best washers to use?

I've used Goodridge lines, Galfer and Spiegler. I always used the gaskets that came with the brake line kit and the banjo bolts too. I've always gone with aluminum banjo bolts and I've always under-torqued them as I do with any aluminum fastener. Go about 60% of specced torque with aluminum as a general rule. In my brake line tutorial, I stated that 18ft lb seemed too much for an aluminum banjo bolt so I went with 12 ft lb. The rear needed to be tightened just a crick more (maybe two cricks) to stop the leak at the caliper.

Are you using aluminum banjo bolts? If you went with stock torque spec, the threads might possibly have stretched and that could be the source of the problem.

A) buy new banjo bolts with new gaskets supplied from the same company and probably the same manufacturer as the brake lines. Don't over-torque, if aluminum, under-torque and watch for leaks, tighten a bit more if leak appears.

B) Wait it out. Brake fluid is oil. Once oil finds a path to seep between surfaces, it tends to continue to seep. Often, the seepage stops on its own. Microscopic deposits of crud, a light film of corrosion fills gaps?....IDK but it will often stop on its own assuming there's no actual damage to the surfaces the leak is getting through. I've seen this with bleeder valves a number of times. Reservoir caps too (that's why they make reservoir socks). They weep and one day, they weep no more.

C) If all else fails, you might consider craftily using some teflon tape. I'd really do my research on that. If brake fluid doesn't damage the plastic bottle it's in, teflon tape might be impervious as well. I can tell you ABS type plastics are not. Also, you'd want to make sure no bits of the tape could enter the brake system. I used a quality teflon tape on my oil pressure sensor adapter and it worked. No problems I'm aware of. ...this is a little drastic though. People don't normally use teflon tape to install brake lines.

Should I soak the possibly clogged cable/s in brake
cleaner and try them again?

Keep that idea as a backup but I don't believe there could be anything wrong with your new lines and banjo fittings assuming they are from a reputable manufacturer. As far as cleaning old lines, brake parts cleaner sounds like a good thing but you'd want to make sure somehow there was absolutely zero left in the line before installing it. Nothing should be in the hydraulic system except brake fluid. I'd favor forcing brake fluid through the old line instead of brake parts cleaner. However, I'd really just replace the lines which you've already done.

I have yet
another set of banjo bolts on the way and if the
included washers still suck, I figure on taking
a banjo bold to O'Reilly's and see if I can't come
up with a 'proper' washer match.

See A) above.

* Last updated by: Rook on 9/30/2026 @ 5:16 PM *

Thanks @Rook , lots of great ideas and I was also
thinking that alum might crush better and yield a
better seal, I tried cu, but both kits were woefully
under specked.
The brake cleaning idea was about my old lines, thinking
I might be able to clear them if they were in fact
the actual problem, I should have mentioned that.
I got another package today of a random 35'' brake line
cause it comes with banjo bolts and washers,
I didn't open the package yet, but the washers were
visible and look much better, they look to be 2mm,
which is something I hadn't been able to find, 2mm thick
not 1mm or 1.35mm like the previous washers.
I'll keep the 12ft lbs in mind.
I've checked for leaks a few mins ago having wiped
everything down pretty good this am, right now
as you mentioned, they may well have sealed.
Either way, now I think I have better materials and
a better chance at success.
Thanks....

Pass on the tape. More like crush a higher torque value. If you are using 2 lines with a longer banjo bolt, there is a crush washer between the lines, meaning 3 are the total washers used.

Copper washers work as well as aluminum. Might want to try different dealers and order new OEM type washers. Dimensionally speaking, size hole and outer diameter meeting or exceeding the round of the hose ends will seal

Pass on the tape. More like crush a higher torque value. If you are using 2 lines with a longer banjo bolt, there is a crush washer between the lines, meaning 3 are the total washers used.

Thanks...