Fiesta mk6 1.25 brake pedal stiff no brakes, waited 5 mins and brake pedal came back

[Prophet254]

Hi guys i was driving my fiesta home today and pulled over for a moment to check my phone, the car was stopped for a moment and then i went to pull away but the brake pedal was stiff and didnt work, i turned the car off and left it for 5 mins and now it is back to normal. are there any common faults that may point to this? common vacuum leak points etc? any help would be really appreciated thanks guys

[isetta]

Sounds like servo wasn’t working. Which would normally be a vacuum leak between engine and servo.  Servo is between the brake pedal and master cylinder.  But a vacuum leak wouldn’t normally come and go

[isetta]

I do recall a few months ago someone on this forum where the vacuum pipe had worn through along the back of the engine from rubbing on something. 

[Prophet254]

Thanks, i will have a look at all the vaccum piping tomorrow and hopefully find something amiss. Car brakes fine at the moment so i am very puzzled

[Prophet254]

Checked the vacuum line to the servo all fine :/, not sure where else to look. or perhaps it was a one off and just to ignore it

[TomsFocus]

Can you recreate the event again?  I'm not really understanding why you pressed the brake to pull away.  Is it an auto?

[Prophet254]

Can’t recreate it no matter how hard I try, the car is a manual, the car was pulled over on a hill with the handbrake on, so when I went to pull away I put my foot on the brake and took the handbrake off, ready to pull away, but instead of staying where I was I started to roll backwards down the hill because the brakes weren’t working haha

[Prophet254]

Other info after inspecting the car over:

I found some very very corroded hard brake line on the drivers rear which I am going to replace

car doesn’t pull in any direction when braking

rear drivers drum brake squeals a lot

brake fluid is full but looks nasty

car has 105k so plenty of things to go wrong

[TomsFocus]

3 hours ago, Prophet254 said:

Can’t recreate it no matter how hard I try, the car is a manual, the car was pulled over on a hill with the handbrake on, so when I went to pull away I put my foot on the brake and took the handbrake off, ready to pull away, but instead of staying where I was I started to roll backwards down the hill because the brakes weren’t working haha

That's the strangest way I've heard anyone do a manual petrol hill start.  Most of us don't have 3 feet though.   

Couple of suggestions can be made from that.  The handbrake being on tight means the shoes are already pressed hard into the drum by the cable so there's no movement possible in the pedal hydraulic system.  Without pedal movement, the servo won't operate. 

Also worth noting that servo power is directly linked to engine revs/load.  Brakes will be poor if the engine's about to stall because you're not upping the revs.  Or because it's been idling for a while only creating low vacuum.  

That's not to say there isn't a fault as well though.

[unofix]

1 hour ago, TomsFocus said:

Most of us don't have 3 feet though.   

He is from Sussex 🤣

[Prophet254]

Is it weird to be able to pull away using the brake instead of the handbrake?🤣  both ways feel natural to me, just jumó quickly from the brake to the throttle 

what your saying is what I was sort of hoping to hear, as I haven’t experienced any more issues I will change out that brake line and flush the brake fluid and leave it for now and hopefully it won’t come back, thanks

[TomsFocus]

Pulling away from the foot-brake is fine in stop start traffic. 

But in this scenario the handbrake is already holding the car perfectly well on the hill.  You're then wasting time and effort replacing one perfectly good brake with another brake, which then requires extra foot precision for really no reason at all.

If you ever drive a petrol supermini with no torque and very little clutch feel, it'll be pretty much impossible to hill start without the handbrake.  Something like an Aygo or Fiat 500.

[YBTURBO]

On 10/2/2022 at 7:59 PM, isetta said:

I do recall a few months ago someone on this forum where the vacuum pipe had worn through along the back of the engine from rubbing on something. 

That was me with my fiesta 1.4tdci 2007. stiff plastic pipe running from the servo along the back of the firewall, on mine the clips had come undone and it had rubbed through.

Wasn't hard to find and not that I would recommend it but I fixed it with 3 layers of tape. PTFE to seal it, electrical tape to hold the PTFE in place then a wrap of loom tape for protection. I did and still do intend to get around to changing it but in honesty I haven't done anything with it since putting the tape on it and putting it back in the clips on the firewall.