Spongy brakes

[Britj]

Hello all
Having a problem with my bakes
About a week ago my brakes felt a bit spongy
The first 10% of the pedal felt OK but then goes spongy for about 40% of the pedal then feels OK again
I've changed the brake fluid bled the brakes I could see the odd bubbles while bleeding and old fluid seemed clean
The brakes felt loads better but this last day or 2 the pedal has gone back to how it was
I couldn't see any leaks and used a pump with a pressure gauge to bleed them and this held pressure for a good 30 mins
Could this be a master cylinder fault
thanks in advance for any help

[lizzard-t]

How old are your pads ?
Also check the brake booster for oil leaking.

[Britj]

Booster looks dry as far as I can see
The pads were done last year and still have a fair bit of meat on them

[lizzard-t]

How long has this been going on for?
What does the pedal do if you pump it a couple of times with the engine off .then hold the pressure with your foot then start the car?
DId you vacuum bleed the brakes or did you put the system under pressure to change the fluid?
Are your discs in good shape
Ie no lipping .
There is a rubber seal behind the shaft of the brake booster that deteriorates.

[Britj]

I first noticed it Thursday last week that's when I changed the brake fluid
This morning I thought it was slightly spongy and over the day it's got worse I've done about 40 mile today
I had a hospital appointment so pumped pedal up when I parked up I came out an hour later and pedal was still solid when I started car pedal dropped
I put system under pressure with a little pump when bleeding
Discs were changed last year same time as the pads

[lizzard-t]

So this has happened since you replaced the brake fluid?
If so re-bleed the brakes again.

[Britj]

It was doing exactly the same before i changed the fluid last week so it's been fine for about a week
I'll bleed them again in the morning I'll have to get some more fluid hopefully it is just a bit of air

[Britj]

Just a quick update
Bled the brakes this morning and found rear passenger caliper was leaking
Don't no how I didn't see it last week it seemed to be coming from at the back somewhere near where the handbrake cables connect
Anyway put a new one on and seems perfect now
Cheers for the help guys

[lizzard-t]

Glad you found it and updated the thread something like that can be missed by any of us .but always check.check and triple check.i had it once when fitting some braided hoses . renewed the crush washers . and everything was fine.so I thought.
Put it in for MOT and it failed on brake fluid leak from caliper.one of the crush washers had decided it didn't want to be a crush washer anymore.
But a little pointer .
for future reference.when you ask for advice please give us all the information to start with.it helps with the answers we will provide.and speeds up the diagnosis.
It's like going to the doctor's and just saying "I've got a pain"

[Britj]

I only really noticed it because fluid had dripped on to the inside of the wheel
I'd filled the fluid up to the little hole in the reservoir and level had only dropped a couple of mm so wasn't leaking too bad