My brake pedal is right up the top with handbrake off and engine not running. When I start the engine the pedal goes half way down and does not seem to come up after a pump.

I was going to bleed them this morning with my new pressurised all singing and dancing kit, but on reflection they are only going down when engine is running so not probably air in the lines and no work to brakes has been carried out apart from the odd dust removal some time ago.

Any thoughts welcome.

Do you mean that under normal running conditions, the brake pedal is MUCH further down than usual and you're sure nothing has been worked on or changed and nothing strange as happened and when did this start (I can't believe, at the moment, this came from nowhere)?
AND, are the brakes working normally with assistance whilst the pedal is still further down but still well above the floor, giving enough reserve travel for emergency braking, or not?

Also assume all pads/shoes are fine and adjusted correctly and nothing seized.

Just trying to really get some depth and history into your explanation.

About half way down after starting the engine. at the top before starting. Brake hardware in good condition no visible leaks. I realise there is more pressure after start up with the booster now helping. Could it be air drawn in via rear cylinders.

After posting my problem I watched a video on YouTube, I have put the link below, in which air entered through rear wheel cylinder and could not be removed and cylinder was replaced. I had never thought it possible but maybe this is what I have.

Hope admin allows below if not please remove.

 

I'll need to look at that later.
You haven't answered a lot of my questions and my understanding is that the booster should not give/make any assistance unless the pedal is pressed.
The starting point to me would be to ensure that there is no air in the hydraulic side as this would make the pedal spongy with or without servo assistance..
The reason for any air ingress is still a mystery but that definitely needs checking/ruling out and checking that the brakes work without any sponginess before starting to look at the servo?

I'll need to look at that later.
You haven't answered a lot of my questions and my understanding is that the booster should not give/make any assistance unless the pedal is pressed.
The starting point to me would be to ensure that there is no air in the hydraulic side as this would make the pedal spongy with or without servo assistance..
The reason for any air ingress is still a mystery but that definitely needs checking/ruling out and checking that the brakes work without any sponginess before starting to look at the servo?

 

Edit: My next thought would be to carefully clamp the flexibles  in turn or together, using  proper tools or protected Mole grips (locking pliers) which may tell you if there's air and where it i or change the symptoms.

On 8/1/2025 at 11:41 AM, frund said:

My brake pedal is right up the top with handbrake off and engine not running. When I start the engine the pedal goes half way down and does not seem to come up after a pump.

I was going to bleed them this morning with my new pressurised all singing and dancing kit, but on reflection they are only going down when engine is running so not probably air in the lines and no work to brakes has been carried out apart from the odd dust removal some time ago.

Any thoughts welcome.

Assuming the brakes are working normally when driving, then that sounds as if there is a vacuum leak somewhere that is depleting the vacuum in the servo when the engine is off. A thorough check of the vacuum system would be where I would start.

As the brake pedal is right at the top when the engine is not running, I would not expect there to be air in the brake system.

Well Alan you may be correct (I call it a Booster) The pedal is half way only when engine running, and Shearers, foot on the brake of coarse.

Sounds like you may be on the right track but you still haven't answered my questions or given  history of the "issue", especially if the pedal is solid at an acceptable height i.e long travel remaining with engine off.

However I'll let you get on with that (servo/booster SHOULD give more travel with same pedal pressure so this isn't necessarily a fault - back to the history and your previous experience of this car - what has changed and are the brakes effective?)

The Pedal does not ever go to the floor. I tried pressing the pedal hard down, eng running, and it does not go past half way. the brakes are excellent.  I will try a pressure bleed later this week but taking all into account I have very good brakes.

When I bought the car, 2 months old from new, the brake pedal was up the top.

Our 17 year old fiesta with new calipers, discs and pads 80K genuine mileage has better pedal. I fitted the new parts. Bled with wife pressing pedal and topping up. 

I will report back after pressure bleed. 

Thanks for helpful comments.

 

Well, there has obviously been a change if it was very good 2 months ago and that needs thinking about.
If you do the bleed (you must have a reason for that, as it usually causes sponginess) and you check all calipers/cylinders for seizing and proper adjustment plus are getting a good amount of servo assistance, the mystery remains and needs monitoring.

The all singing brake pressure kit came with only one pressure cap which did not fit my Mk7 so I've sent it back to Seller on eBay. Through the parts missing and not a proper Sealey but a copy. The genuine one has 4 cap types. Which I will order if seller replies to my 'will it fit the very popular mk7 ?' question.

If it's not as described then supplier should send you a label for return, or agree some other solution, if they don't, get eBay involved?

I do not accept returns. But after a few days eBay stepped in and I got a label to print and take to Post Office. Then message from eBay saying return posted, money returned to account. Good outcome. Glutton for punishment ! I orderd another one, not same supplier obviously, with 4 pressurised coupling caps and one fits my Mk 7 1.5 tdci. yea come on Shrewsbury.

Outcome.  rear wheels off easy with 'rattle gun' and trolley jack. pumped up new pressure bottle with Dot 4 inside and bled rear brakes using collection bottle and pipe supplied with kit so easy the circuit with 12 lbs pressure which hardly moved during bleeding.  Massive modification to kit. The collection bottle builds up pressure so I drilled a 1/8 " hole in cap.

I did not notice an enormous improvement just sitting in the car but today I will drive 40 miles into Shrewsbury, with Wife = lunch out, to collect my book called Entitled  then few yards away coffe in Neros.

The brakes were always very good  and still are. The pedal movement is not excessive perhaps I'm being a bit too fussy.

 

I'd recommend using Forscan's bleeding service function to help rule out any issues that might be attributable to air in the system. It can do a complete flush, including normally-isolated channels in the ABS, too. It is pretty much hands-off apart from connecting up a couple of pipes to the bleed nipples of course.

1 hour ago, MJNewton said:

I'd recommend using Forscan's bleeding service function to help rule out any issues that might be attributable to air in the system.

I would agree 👍

Yes. Modern cars use a clever little program to purge any air that works the abs pump instead. It works well. Before going in mob handed, observe the brake fluid level. Brake master cylinders can fail in such a way that they allow brake fluid to be sucked into the servo, resulting in a low pedal which is often the only other symptom until the reservoir is nearly exhausted.

I pressure bled brakes. The fluid was already up to where it should be so no leaks. Picked up book 80 ish miles later, pedal down about one and half inches and solid there. I will keep an eye on things.

I have Forscan on my old Acer Win 10 laptop also the correct OBD connecting to USB but have not looked at the Brake bleeding yet.

ta for input