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Large MPVs -- Ford Galaxy / VW Sharan / SEAT Alhambra: => Ford Galaxy / VW Sharan / SEAT Alhambra => Topic started by: Peter Burgess on May 14, 2020, 06:35:19 PM

Title: Firm brake pedal goes soft when engine started!
Post by: Peter Burgess on May 14, 2020, 06:35:19 PM
Hi,
I've just replaced the front discs & pads on my 2003 1.9 TDI.
I bled both front brakes twice.
Once with a vacume bleeder & then 2 handed with someone pressing the pedal for me.
The pedal is quite firm, but when the engine is started, the pedal moves slowly down to half way, under pressure.
The car stops ok & hands off drives in a straight line when braking.
The pedal travel though is too far & too soft for the first 2 - 3 inches.
Any ideas?
Thanks.
Peter.
Title: Re: Firm brake pedal goes soft when engine started!
Post by: johnnyroper on May 14, 2020, 10:35:17 PM
So long as you can stop safely then give the pads a bit of time to bed in,new brakes are always a bit spongy. All this is assuming when you bled them there was no air in the system.
Title: Re: Firm brake pedal goes soft when engine started!
Post by: Stevie t on May 15, 2020, 03:00:11 PM
I'm pretty sure this is sort of normal on all PD engines.The Passat I had before did exactly this, hard pedal when engine off and then slowly went downwards if you did the same when engine was idling.My present Alhambra does this and my old bosses Audi .Its not really something you normally do so you may just not have noticed it.
Title: Re: Firm brake pedal goes soft when engine started!
Post by: johnnyroper on May 15, 2020, 06:14:20 PM
Diesels are more prone to pedal creep due to vac pumps vice manifold vac, new brakes will make it seem worse aswell
Title: Re: Firm brake pedal goes soft when engine started!
Post by: Peter Burgess on May 15, 2020, 06:20:43 PM
Thank you guys.
I've only driven 5 miles since replacing them, so i'll give it a few more miles to settle down.
Regards,
Peter.
Title: Re: Firm brake pedal goes soft when engine started!
Post by: Stevie t on May 19, 2020, 02:52:30 PM
I think mine took about 50 miles to bed in properly
Title: Re: Firm brake pedal goes soft when engine started!
Post by: SirDavidAlhambra on June 07, 2020, 08:26:25 AM
Just be careful now, brakes are so important in this day and age.

That said, every car Iíve ever had has the brake pedal go rock solid after all the air has been pumped out of the power steering system by pressing it a few times with the engine off. Once I start the car and it pumps up again, it goes soft and springy again.

But just be careful with those brakes and if in any doubt take it to a garage or call the RAC for an opinion. Always think ďSafety FirstĒ, itís what they do in Formula 1 and if thatís a good enough approach for Ferrariís then itís good enough for me!
Title: Re: Firm brake pedal goes soft when engine started!
Post by: johnnyroper on June 07, 2020, 12:28:11 PM
Just be careful now, brakes are so important in this day and age.

That said, every car Iíve ever had has the brake pedal go rock solid after all the air has been pumped out of the power steering system by pressing it a few times with the engine off. Once I start the car and it pumps up again, it goes soft and springy again.

But just be careful with those brakes and if in any doubt take it to a garage or call the RAC for an opinion. Always think ďSafety FirstĒ, itís what they do in Formula 1 and if thatís a good enough approach for Ferrariís then itís good enough for me!

Air pumped out of power steering system??? Take it you mean the brakes?

Going solid with engine off is totally normal as you have used up the vac in the servo,once started up and vac has built again the pedal returns to normal feel.