NA6 Clutch Master Cyclinder Kit

[davamb]

Hey all,

Clutch is getting pretty soggy, slowly engages if you hold the pedal down. Slave was overhauled a year ago and isn't leaking, so that leaves the main cup seal in the master cylinder.
Dropped by my spanner last night and he confirmed my suspicions, but thought it's not going to fail bigtime over the next couple of days and to just keep driving (better than riding the lil Duke in this weather). Anyways, he wanted to make sure of the cylinder bore size before buying an overhaul kit. Taking a guess from under the dash he estimated about 18mm and BHA lists it as being 15.87mm
Can anyone advise / confirm for a 1990 NA6 (small nose - if it makes a diff)?

Thanks in advance.

[Uncle Arthur]

You should be able to buy a standard kit for whatever model MX5 you have...

I got mine through a clutch and brake hydraulics supplier up here in BrisVegas..... was pretty cheap too, and fixed any problems I had (especially seeing as I had installed a heavier clutch).

[davamb]

Thanks Unc,

only trouble is when he did the slave, Maz gave him the wrong kit. Not much use on a Saturday arvo when it's all in bits and the shop's shut. Might whip out the master cylinder and measure the bore to be sure, to be sure.

[john!]

Mx5 rebuild kits tend to be a bit thin on the ground, however, when hunting for one a month or two ago to do my clutch master cylinder, cross referencing the part numbers revealed that the rebuild kit for the same year 626 was the same. A new master cylinder was 110 and a 3 day wait, while the rebuild kit was 20 bucks and available there and then in my case. I gave the rebuild kit a go and it went together fine, and is indeed still working good 2 months later.

The main things I noted from the experience:

1. Getting the master cylinder out is a painful experience, the only more painful job is putting it back in. If you have someone guiding it in while you keep the pushrod on the clutch pedal lined up with the piston bore (you will see what I mean when you do it), it really helps. It is even better if you can hold the cylinder from the engine bay and let some other unfortunate (preferably midget contortionist) stand on their head in the drivers foot well to guide the cylinder home and tighten the nut on the inside of the firewall.

2. If the cylinder hasn't been out in a long time there will be a lot of black gunk in it, you heart will be filled with joy when you clean it all out and start filling your reservoir with clean fluid.

3. Keep your long-suffering friend handy to help you repressurize and bleed the system, it may take a fair bit of pumping to get fluid moving through the system.

Hope this helps.


john

[davamb]

Thanks John, looks like I get to play the midget contortionist this weekend, wouldn't put my spanner through it, he'd be sure to pump the bill in return!

[Uncle Arthur]

A brake and clutch bleed kit is one of the most useful bits of gear you could ever get for yourself....

JBT helped me with both the slave and master rebuild projects - it's actually a pretty easy job.

[davamb]

Thanks John and Uncle Arfur,

it all went smoothly this morning, about an hour from go to whoa, including honing the bore and bleeding afterwards - no skinned nuckles though!

Clutch is now much firmer and doesn't bleed away. Think it had been dodgy for some time.