Odd brakes

[Jim Haseltine]

When I leave for work in the morning, I start the car, move off immediately and stop at the end of my drive (a distance of a couple of yards maximum) to check the road is clear. 2-3 times a week it takes an unusual amount of leg pressure to stop the car but just that once - every time I use the brakes after that they perform normally. Today, it didn't happen first thing, went out then parked nose in when I got back and changed the front drop links. When I reversed the car out later it stopped ok at the end of the drive but then despite moving slowly I pretty near ended up in the driveway across the road.
Doesn't feel like the ABS releasing pressure as the brakes work but need a lot of pressure - almost as if there's no servo assistance.

[longman h]

So do the brakes perform as they should after this happens??

[Jim Haseltine]

Yes, after that everything seems normal - it's just the first application which requires a lot of effort. I live only 20 yards or so from a T junction where I turn left and if I have to slow or stop for other traffic the brakes are fine.
It doesn't happen every day though.

[IanH755]

Hi Jim,

Are these OEM steel or Ceramic brakes? If they are steel do you know what pads are fitted (OEM or aftermarket)? Also, have you had the fluid changed recently?

If you pump the brakes with the engine running how many pumps does it take for the pedal to go firm, 2-3 or more?

[Jim Haseltine]

OE steel. Rear disc & pads were replaced as part of the deal when I bought the car - disc are OE, don't know about the pads.
Front discs are approx 20% worn, pads are about 50%. Again can't comment on pad make.
Same with the fluid - last time (or if) the fluid was changed it'll have been in a service.
Can't say that I've noticed the pedal firming up, I'll have a play when I get home tonight.

[Jim Haseltine]

Car in park, engine running, the pedal doesn't change no matter how many times I press it (OK, I gave up after 15).
Stop engine and the pedal is hard part way through the second press.
Start the engine again and the pedal sinks under my foot - back to a 'normal' feel.
Usual or not?
If not I'm thinking a duff servo line non-return valve - assuming such a thing exists on the car.

[IanH755]

Thanks for the update Jim, that sounds like normal operation for the brakes compared to a test of mine this morning. They may just need a bleed as a servo or NRV issue would be there all the time, not just on the first press.

[Jim Haseltine]

I've been thinking about this. This might be down to my starting procedure - my neighbours are mostly retired or elderly and have in the past remarked* on the noise made by some of the cars I've driven so to reduce any disturbance to them in what is (to them) the early hours, as soon as the engine is running I move off. It might be that sometimes I'm moving before the servo has enough vacuum.
This morning I waited until I felt the pedal drop fully and didn't have the issue.
* Only remarked - none of them have ever complained. Well, not to me anyway...

[IanH755]

Sound plausible, mine only sits at idle for about 5-10 seconds before moving off (neighbours again) and I then have to stop within 4m for the T-Junction at the end of my drive and I don't get any issues.

[Ian_C]

I've been thinking about this. This might be down to my starting procedure - my neighbours are mostly retired or elderly and have in the past remarked* on the noise made by some of the cars I've driven so to reduce any disturbance to them in what is (to them) the early hours, as soon as the engine is running I move off. It might be that sometimes I'm moving before the servo has enough vacuum.
This morning I waited until I felt the pedal drop fully and didn't have the issue.
* Only remarked - none of them have ever complained. Well, not to me anyway...

This. I drive manual Audis and always leave the car in gear with the handbrake off, and when I get into the car I put 'both feet down' to start the car. You can feel the brake pedal move a few seconds after you start the car. If you start on a slope, you've got to nip the handbrake on, because no matter how hard you stand on the brake pedal, you have no brake servo to help you for the first few seconds