Installing braided brake lines & master cylinder

[Casey]

Thanks for that James

It was something I wanted to add to this topic, but you've done a brilliant job and saved me the trouble. The only thing I'd add is this picture of the main two types of flare nuts - the correct one for the RX-7 nuts is on the right:

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The type with "shoulders" are intended for use wuth bubble flares. The one on the right has a 45 degree chamfer on the inner edge to correctly seal the inverted/double flare.

You can just about make out the chamfer on the nut on the righ:

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[Casey]

All hoses and hard lines now fitted. There is obviously still masses of air in the system, but I still had a full reservoir and will be changing the master cylinder next, so decided to give the pedal a few gentle pumps to see if it revealed any leaks. Yes, it did! Both rear hose-hard lines leaked (all the rest OK), so I tightened nipped them up a bit more (not wanting to over-tighten them when I first installed them). A few more pedal presses showed no further signs of leakage anywhere. I will check again when the master has been changed and the system bled.

Typical flare on new lines - looked OK to me.

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Passenger side hard line finished:

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I drilled and tapped a 4mm thread in the sway bar mount to add a new P-Clip as the old one was shot.

The rust is a job for another day!

[Casey]

For the master cylinder, before you put the new one on the car, make up a copper brake pipe (a good time to practice flaring and bending!) that goes from the outlets straight back into the reservoir and bench bleed the master, will save a lot of time doing it dry on the car.

That's a great idea! Yeah, a few people had mentioned it was much easier to bench bleed the master before installing, so I wish I thought of your idea before shelling out on an extortionately priced bench bleeding kit from Amazon

https://smile.amazon.co.uk/gp/product/B ... UTF8&psc=1

[Casey]

Installing the new brake master cylinder was very straightforward.

First task was to bench bleeding. I had the kit mentioned in a post above, which enabled two ports to be bled, so I made up a something (based on James' earlier post) to bleed the 3rd port:

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In practice, the nearest two ports bled fairly easily, but they then required to be blocked off to bleed the furthest port easily. I simply used some "Sealey" brake hose clamps, which I already had in my tool collection. Once bled, I used some bleed nipple caps to prevent fluid leaking everywhere.

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[Casey]

Next stage was to remove the old master cylinder. Messy, but very straightforward. I syringed out the fluid from the reservoir first - yuck, there was some horrid black sludge in the bottom of the tank!! The three pipe unions released easily, and the two nuts to the servo. The level sensor connector needs to be unclipped too, then remove.

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It's a doddle then to install the new master as quickly as possible to minimise the entry of air. I noted there was no gasket on fixing to the servo (I should have checked the parts list to see if there should have been one!), so gave a generous smear of white lithium grease to keep any water out. I replaced the two nuts and spring washers with s/steel.

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[Casey]

As expected, there was plenty of air in the system, having replaced the rear hard lines as well as the hoses.

I tried gravity bleeding the two rear calipers and couldn't get it to work.

I tried a vacuum brake bleeder on the rear and no luck either - I think air was coming in via the bleed nipple thread rather then the lines, despite usimg some red rubber grease on the threads.

So, Gwyn was around to use the tried and tested two person method, which worked a treat. Took a while, but no issues until I checked for leaks at the end. I found a very slight weep from one of the rear splitter outlets on the axle. nipping it up didn't seem to help, so decided to undo and refix. a small amount of re-bleeding and all was good

Without the servo, the pedal felt 100% better than prior to undertaking this overhaul.

Time for a test drive then.....

[Casey]

Wow, I'm sooooo glad I did this! The brakes feel so much better - no "softness", just a progressive bite and "solid" feel. No problem in stopping in a straight line with a heavy stamp either. I deliberately didn't go as far as locking up the brakes, but felt they were capable of doing so with a heaver foot.

After a test run I came back and immediately checked the disk temps with an IR gun. The temps across each axle were as near identical as they could be, with the front temps (as expected) being higher than the rear. I did a final visual check for any leaks (none ) and to confirm no fouling of the front hoses on anything, given the suspension was now fully compressed. All good too.

Another satisfying job with a great result. The stopping power may not be as good as my RX-8, but I'm so much more confident in the brakes now, knowing there is a good feel and adequate stopping power.

[Hobbawobba]

Nice work there aye bro. I also have a set of Hel lines I had made up from them a good few years ago now! I sent them my OEM hoses to use as a template - unsure if that's where this kit came from in the end

Good to hear your pedal is feeling good now aye!

[TOOL]

And invest in some brake pipe spanners #just saying

[Casey]

And invest in some brake pipe spanners #just saying

Yep, I have a set of those that I used on this task