[AlfaM]

All

Over the last few days (mornings and after work), when I've got in the car, the brake pedal is rock solid, i.e. as if I've pumped the pedal with the engine off. I have to then press fairly hard to enable the push start.

I've noticed no difference once engine started/driving about. Anyone had anything similar?

Cars - 335d, Blue Msport Brakes.

Cheers,

[snipnoob86]

a vacuum is part of the system and it is assisted by the cylinder when the engine is running but when it is not the air will escape, sometimes more due to atmospheric pressure, the weather and all that jazz. this is perfectly normal for you brake pedal to seem hard to press when sitting overnight. and as you start the car in the morning it feels like it sucks itself to the floor again.

my explanation is probably not the best.

if this happens within an hour or 2, or even minutes of the engine being turned off it could potentially be an air leak in the system. but if this is not the case o wouldnt worry atall

[AlfaM]

Originally Posted by snipnoob86

a vacuum is part of the system and it is assisted by the cylinder when the engine is running but when it is not the air will escape, sometimes more due to atmospheric pressure, the weather and all that jazz. this is perfectly normal for you brake pedal to seem hard to press when sitting overnight. and as you start the car in the morning it feels like it sucks itself to the floor again.

my explanation is probably not the best.

if this happens within an hour or 2, or even minutes of the engine being turned off it could potentially be an air leak in the system. but if this is not the case o wouldnt worry atall

Thanks for that - I'll test it over a few hours to see how quickly its dropping.

[Ss66]

Get the same thing with mine ,first thing in the morning

[335dMSport+]

Exact same problem, same car.

It's been back twice now and they've said there's. I thing wrong with it and it's normal. Coming from a previous F30 I know full well that it's not 'normal'.

If you find a solution/resolution then please let me know via PM.

[t5pilot]

This happens with mine also..... I assumed it was normal...

[AlfaM]

Just had a ratch around google and it seems it was a known issues on E60s and E90s, with a fix..

http://www.e90post.com/forums/showthread.php?t=589119

http://5series.net/forums/e60-discus...tarted-110628/

I'll give it a week to see if it changes with the weather, then I'll drop it in.

[t5pilot]

Will take a look, thanks for the info...

[Drek]

Same here, didn't realise it was being raised as a problem.

[Kal101]

Must be a 335d thing as mine does the same.

[PurpleTT]

Yup mine feels hard in the morning too.

Anyway, sort of a hijack - if I jump in the car in the morning, fire it up and try to drive off within say 5-10 secs of startup, I get what can only be described as clutch slip. My drive has bit of an incline exacerbating the problem.

Anyone else noticed this?

[snipnoob86]

Originally Posted by PurpleTT

Yup mine feels hard in the morning too.

Anyway, sort of a hijack - if I jump in the car in the morning, fire it up and try to drive off within say 5-10 secs of startup, I get what can only be described as clutch slip. My drive has bit of an incline exacerbating the problem.

Anyone else noticed this?

yup notice this in mine also, morning starts certainly arnet its strong point it always feels *broken* but is fine after a couple mins

[Jay1970]

Yes same on mine when cold, although it does seem fairly intermittent. Didn't really think anything of it since it feels spot on as soon as car starts. All cars have firm brake with ignition off so is it a problem at all?

[HighlandPete]

Originally Posted by Moonie

Thanks for that - I'll test it over a few hours to see how quickly its dropping.

Is it losing vacuum every day? Same for other users?

My E91 used to lose vacuum occasionally, no particular pattern, not a normal overnight loss.

A regular vacuum loss is not what I'd call normal. But it doesn't mean the braking is not safe, even if it does drop off over a few hours.

If you are testing it, remember each brake pump does use up some vacuum.

[HighlandPete]

Originally Posted by PurpleTT

Yup mine feels hard in the morning too.

Anyway, sort of a hijack - if I jump in the car in the morning, fire it up and try to drive off within say 5-10 secs of startup, I get what can only be described as clutch slip. My drive has bit of an incline exacerbating the problem.

Anyone else noticed this?

Sounds like a bit of torque converter drain back. Not typical, but your incline may be contributing to it. Takes a few seconds for pressure to build and fill the TC. There was a problem years back with the 5HP auto, where it was a common issue, due to a faulty one way valve, even affected cars parking on the flat.

[PurpleTT]

Originally Posted by HighlandPete

Sounds like a bit of torque converter drain back. Not typical, but your incline may be contributing to it. Takes a few seconds for pressure to build and fill the TC. There was a problem years back with the 5HP auto, where it was a common issue, due to a faulty one way valve, even affected cars parking on the flat.

Thank you sir, your posts are the most guru-like on this forum! Now you mention it yes it does feel like I'm waiting for some sort of pressure to build, rather than a clutch slip. Much obliged.

[John435D]

Originally Posted by PurpleTT

Thank you sir, your posts are the most guru-like on this forum! Now you mention it yes it does feel like I'm waiting for some sort of pressure to build, rather than a clutch slip. Much obliged.

I have this too driving up my drive, feels like the clutch slips a little before it gets going.

Also have a firm pedal when the cars been sat for the day at work, have to give it quite a bit of pressure to push down on it.

My car's in the garage on Monday anyway so I'll mention it when I drop it off and see what they say.

When parking up the other night I got a drivetrain fault on the idrive just as I switched the ignition off. The next morning when I started the car it felt like it was running on 2 cylinders only, then it cut out twice and had to be restarted as I tried to reverse it off the drive. It cleared up after leaving it idling for a minute after this and hasn't reappeared since but it's booked in for monday anyway, I'm thinking an EGR issue of some sort.

[Jay1970]

Just thought I'd update this thread...having been in the main dealers this morning I took the opportunity to ask them why so many of us feel hard in the morning

Their reply was this is all related to ambient temperature, how cold the car is mechanically, and the brake servo delay in bringing the vac pressure up to correct level. In other words they advised this is absolutely fine and nothing to worry about, since braking should be spot on almost as soon as the engine fires up.

[335dMSport+]

Originally Posted by Jay1970

Just thought I'd update this thread...having been in the main dealers this morning I took the opportunity to ask them why so many of us feel hard in the morning

Their reply was this is all related to ambient temperature, how cold the car is mechanically, and the brake servo delay in bringing the vac pressure up to correct level. In other words they advised this is absolutely fine and nothing to worry about, since braking should be spot on almost as soon as the engine fires up.

I've had mine for a year now, so a good range of temperatures and it's been hard at EVERY start up, not just the morning one. They really haven't got a clue and to be honest I'm not impressed with BMW in the slightest regarding this issue.

[AlfaM]

Now that the weathers picked up a couple of degrees, mines stop doing it.

[HighlandPete]

Originally Posted by 335dMSport+

I've had mine for a year now, so a good range of temperatures and it's been hard at EVERY start up, not just the morning one. They really haven't got a clue and to be honest I'm not impressed with BMW in the slightest regarding this issue.

If it is at every start up, that indicates a vacuum leak somewhere in the system. Could be as simple as the non return valve.

Temperatures could explain the odd vacuum issue, but not a regular vacuum bleed.