Just put a thread in the steel plate and screw your fitting into it with a lock nut on top if you really think it needs it

At that od and on a pipe fitting I’d guess most likely 1/4inch bsp!

Pull a (tubeless) Schrader valve through a bit of thinner plate..

The coupling you are showing looks like a Euro Style air line connector. the thread for these is 1/4 BSP Taper. It does not look like a standard PCL connector.

A vacuum bleeder might be an easier solution – not expensive.

@Clive

I know this is not really an answer to your question, but if the pressure-method fails, try the reverse. Use one of these oil extractors where you pump up a vacuum in a plastic container. Connect the extractor tube to the brake nipple and suck the brake fluid out.

This is also perfect when you replace the fluid. Suck the fluid from the reservoir, top up with new fluid and suck the remaining old fluid from each brake nipple.

I have been using this method for many years, and it is very pleasant to use. No problems with pressurized master cylinder reservoirs.

Hi, I know I’m not answering your question , sorry.

Why not do it with another person pumping the brake pedal.

Maurice

It’s a standard Euro fitting by the looks of it, which comes with most of the cheap Lidl/Aldi air tools.
They seem to come with two different threads ¼”BSP and also a fine metric; most, but not all, of the metric ones I have are parallel thread with a small O ring.
Personally I’ve used a Gunsons Easybleed for years as the best method for the Landrover brakes, but I only use a low pressure; rather than the oft recommended tyre, I just use an inflated inner tube.

Maybe look to pick up a spare cap, new or from a scrapyard.
I’ve just had a heater leak on the Disco and wanted to pressure test the cooling system.
I used a spare cap for the header tank, a few brass fittings, a pressure gauge off an old footpump, a spare Schrader valve from an inner tube, with the rubber cut off and soldered to a bit of brass, and pressurised with a bicycle hand pump.

For modern cars with anti-lock brakes, I’d check that pressure bleeding is OK.
Some even need a laptop to tell the ABS to open internal valves.

An alternative is some sort of self bleeding nipples; I have some of the old two piece ones with a plunger and loose spring, but it looks like this is a modern alternative.
https://www.merlinmotorsport.co.uk/p/goodridge-speed-bleeder-bleed-nipple-g-bn

Bill

Just reread your OP and it looks like you dont actually have the universal cap/plate in your pic?

So if persevering with making your own from flat plate, just take that fitting you already have,drill a hole in the plate and glue the fitting in with epoxy glue. It only needs to withstand low air pressure. No big deal.

Vacuum bleeding is a cleaner and less risky method, BUT, pressure bleeders also supply new fresh fluid into the brake reservoir, so it will not run dry while you are bleeding the brakes.

As some have said you don’t need a lot of pressure, and in fact brakes can slowly  gravity bleed to a certain extent, just by opening the bleed and letting it drip into a container – although this might not move all the air bubbles out if they are trapped further up the system.

It is also a lot more convenient and much easier to be able to bleed each brake yourself, rather than having to have someone in the car pumping the pedal – “down”…….”up”……..”down”…… etc., for all four corners, especially if you are completely changing the fluid as well.

I am sure that you will be able to reinforce or remake your pressure fitting lid.

On 30 August 2024 at 09:19 John Doe 2 Said:

Vacuum bleeding is a cleaner and less risky method, BUT, pressure bleeders also supply new fresh fluid into the brake reservoir, so it will not run dry while you are bleeding the brakes.

I thought this one consisted only of air pressure supplied to a lid that goes on the existing reservoir containing the brake fluid?

Pumping pressurised  brake fluid into the reservoir through a dodgy seal on a universal lid sounds like a recipe for disaster.

The standard reservoir on most cars contains enough to bleed two calipers in most cases without needing fresh fluid. Then top it up and do the other two. I just did a total flush on my Toyota Corolla 4-cyl hatchback — with a vacuum hand-pump — and used less than a 500ml container of new fluid. The reservoir holds probably 200 or 250ml. I use a turkey baster to suck the old fluid out of the reservoir before starting so all the bleeding is done with fresh fluid.

Living in a wet tropical environment with 8 feet of rain a year and 85 to 100 per cent humidity year-round, I have  become a bit of a dab hand at the brake bleeding thing. All my bikes and the car need a total brake fluid change every 12 months according to the test meter. Failure to do so, in my painful experience, results in rotted out calipers and master cylinders.

The solution on non-ABS bikes for me has been to convert them to DOT5 silicon brake fluid. Non-hygroscopic so it does not suck in the moisture through the pores of the hoses etc. As used by the US military and Harley Davidson since the 1970s so it is tried and true. But not compatible with ABS unfortunately, due to its thicker viscosity.

Yes DOT5 is very viscous and so does not respond well to the pulses of ABS. It also entrains air bubbles very badly that take a long time to float up through the thick soup and form into larger bubbles that can be bled out.

Plus, if converting from DOT4 to DOT5, you have to clean the whole system very thoroughly by complete strip down and flush with methylated spirits because if any residual DOT4 mixes with the new DOT5 it can form a sludge that does no good at all.