Brakes going soft suddenly but still work?

[JordK]

Hi all
The other day when driving my pulsar I noticed my brake pedal had to go a lot closet to the floor before it would have any stopping power. I checked the fluid and it was a tad low so topped it up (yet to bleed it). There's no obvious signs of a leak either. They were working perfectly fine (as well as the stock system works) before but now the pedal is nearly on the floor before I get any feel from it. What could cause this? Faulty line/servo? If I bleed it will I need to do all 4 calipers and if so what order? Or can I just bleed the front two?

 

[PobodY]

How old is the fluid?

At a guess I'd say there's air and/or moisture in it and you need to flush and refill. - Could also be that there's a leak somewhere because it doesn't tend to just disappear.

Do any of your lines look rusty?

When the brakes started getting soft on mine it was because the rear callipers needed to be rebuilt.

 

[Fusion Ed]

I'm in two minds on this, firstly how low did the fluid go?

Secondly, what you have experienced is NOT normal and you need to get the car in the air and check the condition of ALL the brake lines just to be on the safe side.

 

[Fast Guy]

Fluid could be low due to all pads being worn, or a leaky master cylinder (check around the pedal in the car) if there's no other signs of a leak.

I'm thinking more likely the master cylinder.

 

[PobodY]

That's a good observation; it's hard to spot a leaking master cylinder unless you're looking for it.

It's easier to spot a leak under the car as the fluid tends to give it away by dripping.

The brake system is crossed-over, so the front left and rear right are a pair, as are the front right and rear left. - I think the prescribed order is: RL, FR, RR, FL.

 

[JordK]

Thanks for all the replies guys! Had a closer look around the lines and calipers today and did find traces of fluid on the drivers side caliper (near the banjo) so looks like it could be a poor sealing washer or split in the line. Have braided lines on the way and getting the car up on a ramp later in the week to give it a good looking over. Will check the master cylinder then too. The clutch MC is leaking slightly and left some fluid on the pedal assembly but as far as I can see they are separate systems?