What makes your brake pedal go soft?

[Morat]

My brake pedal seems to have developed a lazy streak since the car had a quiet couple of months during the snow/ice.

The pedal doesn't even want to come all the way back to the top of its travel enough to switch the brake lights off so they are now permanently on unless I lift the pedal up by sticking my foot underneath the pedal and lifting it.

When driving there is a really soggy feel and it is very hard to get much braking. I can just trigger the ABS on a wet road with a really hard boot on the brake (probably 100kg of effort) but its not exactly confidence inspiring and the zone roam is coming up!

I've tried cleaning up the disks with some medium stops from about 60 then some hard ones. The brakes didn't fade, but they didn't seem to improve much either. The pedal refuses to pump up as they usually do when they need bleeding.

I'm stumped - what should I try?

[e301988325i]

Spongy pedal is flex somewhere in the system, failed rubber hoses or air in the system, or contaminated fluid.

Get the Mrs to press the brake pedal with the engine running and check the hoses for bulges.

[jmc330i]

Master cylinder, knackered flexi hoses??

[Morat]

Hmm, I was hoping no one would mention the M/C. I'll check the flexis in tommorow and report back.
Thanks guys!

[town325i]

Hmm, I was hoping no one would mention the M/C. I'll check the flexis in tommorow and report back.
Thanks guys!

If the master cylinder has gone you can normally pump the pedal so much and get the brakes to work this sounds more like tired flexi hoses.

[daimlerman]

Be worth running your brake pipe spanner round the pipes entering and exiting the ABS pump.
I traced a soggy pedal to a tiny leak there the other week...there's a grope buy on for stainless steel flexi's at the moment,as well!

[Kos]

gareth experience a similar probelem recently albeit after a track day !

iirc he's re bleed the brakes and it was still spongy so he was going to bereplacing the flexi line with braided ones and do the MS. my sudgestion would the be MS, logic says that its over 20 years old and not functioning quite as well as it should do.

i recently replaced all the braking components on my compact, and used ATE superblue brake fluid but after a track day its now a little spongy again. so i'll re bleed it and replace the MS and its should be just fine.

[Bewdley320T]

Hmm, I was hoping no one would mention the M/C. I'll check the flexis in tommorow and report back.
Thanks guys!

If the master cylinder has gone you can normally pump the pedal so much and get the brakes to work this sounds more like tired flexi hoses.

If its taking more pressure to get the same effect as before, I'd check the servo first, after all, that supplies the power. Try braking with a healthy system without the engine running and you'll see what I mean.

[Morat]

It is taking more pressure but also more travel. I need to push the pedal all the way down to get half* the braking I would expect! The flexi hoses are the favorites right now and if I find a bulging one then the Goodridge GB beckons...


*this figure determined during the not wholly scientific "Jesus, that Range Rover with dazzling eye level HIDs is turning right across me on this mini roundabout" test.

[daimlerman]

As the thing has been standing a while,this could just be condesention in the fluid....try a flush through with new fluid.

[Morat]

OK, I'm feeling a bit dense now. She's just been up on a ramp and the pads are shot. I couldn't really see from the outside, it looks like the inner ones have really died - and pretty much taken the disks with them. Hey ho, it could have been worse.

[daimlerman]

OK, I'm feeling a bit dense now. She's just been up on a ramp and the pads are shot. I couldn't really see from the outside, it looks like the inner ones have really died - and pretty much taken the disks with them. Hey ho, it could have been worse.

Could be sticky calipers as well,then,I am halfway through the front brakes on the touring,everything has arrived except for the new s/s braided hoses,ordered last Friday
Even the new Greenstuff pads ordered at 1.44am on Wednesday have arrived....
Re-built calipers came via Unipart,BTW, at just short of £120 for the pair,discs from GSF at £45,the bloody thing had better stop right now!

[Morat]

Better not be, they're only two years old :/

[aceifty]

I HAD THE SAME PROBLEM, MY PEDAL WAS SPUNGY AND THE BREAK LIGHT WOULDN'T GO OFF TRACED IT DOWN TO THE SERVO. NOW THEY ARE 100%