Brake fluid leak

ukBp_Roy

Hello

I have a 2006 1.6 manual petrol Nissan Note

Over the last couple of months the brake fluid has gone from max to min a couple of times so I've had to top up a couple of times. I have checked and the only sign of a leak I can find is some fluid at the top of the brake pedal where it meets the servo in the drivers footwell, I have attached photos to show this. I believe the brake fluid is likely to be leaking from the brake master cylinder, through the servo and into where I can see it. I think the best remedy is to replace the master cylinder.

I have asked my local independent garage for a quote to replace the master cylinder. Main dealer quoted £523 to supply the part or £700 fitted! I am fairly competent mechanically so could replace it myself but sourcing a new part looks harder than I'd like. Big parts suppliers such as ECP show 1 but say not currently available. There are a few on eBay and some websites I've not used before so a bit unsure of them.

So my questions are does my admittedly amateur diagnosis sound correct? Any opinions/advice on rebuilding the old master cylinder, finding a used one, or finding a decent new one? Any advice should I go for a DIY fix, my biggest concern is bleeding the new cylinder but what I've read online looks fairly straightforward.

Thanks in advance

Goudy

It does look like the master cylinder is leaking. What does the view of the MC look like from the other (Servo) side, wet underneath?

Before you start it's still worth checking the rest of the braking system for more leaks.

You shouldn't have too much issue finding a replacement, I think this part is used on a few models.
Have you tried a Nissan parts specialist and the usual online suppliers like AutoDoc, Buycarparts, Bestpartstore etc.
Glyn Hopkins have a multi franchise parts site, nothing listed on there but you can ring them.

It shouldn't be two hard to replace, fiddly perhaps. 
First if you can, suck out all the old fluid in the reservoir, then clean off all the bleed nipples at the calipers/wheel cylinders with a small wire brush, a squirt of penertrating oil on them won't hurt either.

It's best to check if the nipples are all free now before you start, use a ring spanner just to check they aren't siezed up.
Don't use an open ended spanner as if the nipple is stuck it can slip and muller the nipple.

The MC is held on to the servo by two nuts/bolts, but first remove the pipes and be very careful not to kink them.

Once off, a small blob of grease on the end of the new MC's piston, where is connects will help stop some metal to metal graunching between the piston end and the brake rod from the pedal.

Refit as the same way old came off, again careful not to kink the pipes.

To bleed, fill the reservoir with clean fluid (new from a sealed container) the specs should be on the cap or in the handbook.

Start bleeding from the wheel cylinder/caliper furthest away from the MC then the next and so on.
So rear near side first, then rear off side, then front near side before lastly the front off side.
You'll need to continually top up the reservoir as you go, don't let the level drop too low or you'll introduce more air.

You can buy one person brake bleed kits and vacuum/pressure bleeding kits, but I always find it easier with two people a short length of clear pipe and a jar or container.
One person on the pedal and one on the wheel cylinder/caliper (A opens the bleed nipple, B pushed the pedal down, A closes the breed nipple, B lets the pedal up and so on).

When the new fluid comes through (it will look clean) without bubbles, lock off and move to the next wheel cylinder/caliper.

You will likely dribble a bit of fluid around the caliper/wheel cylinder nipples as you go about bleeding, so it's worth cleaning this off after you've locked the nipples off after bleeding with a spray of brake cleaner and a rag so it's easier to spot any further leaks later.

Grey_Critic

In the old days you could buy a kit and just replace the seals instead of replacing the cylinder.