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Best ways to blank hydraulic brake lines
jps - 27/7/23 at 06:43 PM

It looks like I’m going to be left with one or possibly two ports to blank off in my brake system.
1 - an outlet from my brake master cylinder. I have 4 but am only using 3, leaving a 10mm outlet that needs blanking off.
2 - one of the outlets from a brass t-piece on the bulkhead. I *might* use this to fit a pressure switch but if not the t-piece is still a very useful way to break up a long run of brake pipe so I will install it regardless. If I don’t use the third port on the t-piece it’ll need blanking off.

These are both female ports which take m10 threaded unions with concave seats in the port. To blank off do I use a suitably short m10 bolt with a copper washer so it seals on the outer shoulders of the ports? Are there specific blanking unions I should use? Should I be putting bleed nipples into these ports? Or is there a mystery 4th solution…?

[Edited on 27/7/2023 by jps]

rusty nuts - 27/7/23 at 06:49 PM

Once upon a time some master cylinders came with blanking pugs made for the job . I had a couple I used to blank off pipes when making up new metal brake pipes

JAG - 27/7/23 at 07:47 PM

I've used a male fitting and a suitable ball bearing in the past.

Find a ball bearing that fits in the port. It should sit low in the port so that you can then screw the male fitting in, on top of the ball bearing.

Works a treat

theconrodkid - 28/7/23 at 06:15 AM

bleed nipple , why make life more complicated and therefore prome to failure ?

Mr Whippy - 28/7/23 at 08:15 AM

Use the spare line it to add a pressure gauge to the dash and say its a race thing

jps - 28/7/23 at 12:38 PM

quote:
Originally posted by theconrodkid
bleed nipple , why make life more complicated and therefore prome to failure ?

I guess my concern on this is whether it will seat sufficiently well to seal. Maybe I’m overthinking the DIN/SAE issue but thought the concave seats were different angles - I understand it’s negligible when there’s a brake pipe being crimped up in the join, wasn’t sure whether it might be problematic when it’s steel bleed nipple onto brass t-piece…

JAG - 28/7/23 at 01:20 PM

Bleed Nipple will work perfectly well - if you have a spare it's probably the best solution

But a brake pressure guage would be a cool addition to the dashboard. It needs to read 0-80 bar or 0-1200 psi.

[Edited on 28/7/23 by JAG]

adithorp - 29/7/23 at 07:13 PM

Bleed nipple. Designed for the job.

Some slave cylinders have 2 identical outlets and just use different holes for pipe and bleed on opposite sides of the car.

gremlin1234 - 30/7/23 at 05:53 PM

quote:
Originally posted by jps
wasn’t sure whether it might be problematic when it’s steel bleed nipple onto brass t-piece…

it certainly used to be possible to get brass bleed screws

pigeondave - 31/7/23 at 12:37 PM

Yep another vote for nipples (again)

adithorp - 31/7/23 at 06:27 PM

quote:
Originally posted by pigeondave
Yep another vote for nipples (again)