NB Master Brake Cylinder

Donovan · Post by **Donovan** » Wed Aug 01, 2012 8:28 pm

Going to ask my usual Noob question, and does the NB MBC fit on an NA, and if it does, is it larger fluid capacity and handle larger brakes better?

Euen · Post by **Euen** » Wed Aug 01, 2012 9:02 pm

All the info you may need should be here

http://forum.miata.net/vb/showthread.php?t=363284

Enjoy!

brownie · Post by **brownie** » Wed Aug 01, 2012 9:23 pm

i'm fairly sure they are the same unit,The only piece different between early 1600's and NA 1800 and later is the BPV (Brake Proportioning Valve),Di you change that with doing the bigger brakes?.
If not,let me know at work and i will get you the one off the VVT-I front half we have,Should suit your bigger brakes better.Might help

Donovan · Post by **Donovan** » Wed Aug 01, 2012 9:44 pm

No, haven't done the BPV, don't even know where that is, all I've done is slapped the 6pots on the front, haven't even put the bigger NB calipers on the back as yet, but they look the same piston size anyway as the 1600 brakes, just a different mounting and larger pads.

Anyway, my thoughts was to do a rebuild kit on the MBC, and since never having done it before, do it it on the one I have here from the NB, and that way if I balls it up, won't make too much difference, and if it improves the brake performance with the NB unit, then even better, as I may put 2pots on the back at some stage.

I figure, the speed my car is capable of, I want to make damn sure I can pull it up from any speed it can do, so quite happy to overdo the brakes suspension. Especially if I get this daft idea that I need to start getting more HP out of the engine.

Donovan · Post by **Donovan** » Wed Aug 01, 2012 9:45 pm

Euen wrote:All the info you may need should be here

http://forum.miata.net/vb/showthread.php?t=363284

Enjoy!

Thanks, will have a read thru

Born_disturbed · Post by **Born_disturbed** » Thu Aug 02, 2012 7:35 am

Ahh i forgot to grab the BPV off you when i got the other bits.. whoops

Still got the NB? otherwise i might have to have a word with you brownie

Kieran · Post by **Kieran** » Thu Aug 02, 2012 12:22 pm

Just get a adjustable proportioning valve the balance of your brakes is probably way off if you put 6 pots on the front and have stocks on the back the brake bias will be almost entirely in the front

Its cheap and if it works will save you alot of time and money!!

Also the vvt bp brake proportioning valve is electronic and will be a pain to setup

http://www.flyinmiata.com/index.php?dep ... r=14-76240

Donovan · Post by **Donovan** » Thu Aug 02, 2012 4:01 pm

Brake balance doesn't seem that bad at the moment, just started the cert process, and in the brake test, all 4 wheels locked up, but I am guessing it is more to do with the pads I am running, and they weren't up to temp, so not biting as hard as they would on the track.

Might be all a mute point at this stage anyway, while checking over things for the cert, the rotors are already starting to crack on the front, so looks like a new set of rotors are next on the list.

Donovan · Post by **Donovan** » Tue Aug 07, 2012 9:26 pm

Is it worth swapping over the booster as well from the NB, or just the BMC.

My existing brake level seems to be dropping down about 1/4 after a track session, not seeing any fluid leaking out of the calipers, so might be something to do with the BMC?

Euen · Post by **Euen** » Tue Aug 07, 2012 10:10 pm

Do you mean the fluid level? If so, could be pad wear if you've been working them hard and there are no leaks.

That thread I sent you on the master cylinders also discusses the various options for servos.

Donovan · Post by **Donovan** » Mon Aug 20, 2012 3:10 pm

Right, have finally had a chance to sit down and read over Euen's link fully.

So the plan at this stage is to rebuild the 98 NB BMC that I have here as it is the same as the one in my car, and shove that in, rebuild my 6 pot calipers (larger of the pistons on it were pretty siezed, and making sure they go on the correct sides, since these things are side dependant) so just waiting on that to arrive from the US, put the 02 sport NB calipers on the back, slap it all back together and see how we go.

From what I have read, I should still get even pressure with the 6pots, just a lot more travel and spongyness than I might want at the moment, but if I am not getting uneven wear on the pads, then I am halfway there.

After that and I have that part of the system settled, will look around for a larger BMC and booster, to firm up the pedal feel and travel, but that will be a little later on, as there are other things I need to get sorted once I have it stopping semi ok.

Donovan · Post by **Donovan** » Wed Sep 12, 2012 8:33 am

I have done the rebuild on the BMC on the NB unit that I had and put it on, but it has started to squirt out brake fluid out the back. I haven't had a chance to pull it off and have a look what is going on, but to be honest I have no idea where I could have gone wrong with this, it's seemed to be a pretty simple job. Take the unit off, take the holding clip and screw out, get the two old pistons out, make sure the cylinder is clean and free of debri, carefully put the two new pistons back in, put the screw and holding clip back in and put it back on the booster.

Anybody got any ideas how I could have stuffed this up?

WideOpenThrottle · Post by **WideOpenThrottle** » Wed Sep 12, 2012 9:40 am

You have either got the pressure cups the wrong way around or you have a small hole/split in the cup [or a bit of diirt] at the point where the fluid is sucked into the piston.

And did you coat with fluid on re-installation?

Donovan · Post by **Donovan** » Wed Sep 12, 2012 9:45 am

When you say the pressure cups you mean the rubber seal around the piston. The rebuild kit contains the pistons with the seals on them, I just pulled out the old pistons and put the new ones in the same way the old ones came out, so don't think I could have stuffed that up, but I am not exactly the brightest when it comes to these sorts of things.

I was pretty careful in checking for dirt and such when putting it together, but I guess I can check again.

2low2c · Post by **2low2c** » Wed Sep 12, 2012 9:57 am

did you push the first piston all the way down and hold with an screwdriver or some thing before you put the screw in ?

Donovan · Post by **Donovan** » Wed Sep 12, 2012 9:58 am

Er, no. Instructions that cam with the kit were pretty brief, and didn't mention anything like that.

WideOpenThrottle · Post by **WideOpenThrottle** » Wed Sep 12, 2012 10:01 am

when i took the piston out again and had a close look at the most rearward cup it had little holes on the outside and it was causing the fluid to be pushed back up the hole into the reservoir and i could see it hitting the top.[was on a mazda capella].

2low2c · Post by **2low2c** » Wed Sep 12, 2012 10:07 am

give me ring you have my number

NB Master Brake Cylinder

NB Master Brake Cylinder

Who is online