Brakes Faulty? Or is this normal?

[Phandy]

Background: I had a new brake servo fitted about six weeks ago on the advice of this forum, as my brakes were making a hissing noise.

About 3 week's ago, I had just turned over the car and was slowly pulling away (5 mph) when I pressed the brake pedal, and it was hard as a rock; the pedal would not move down, and I hard to put a lot of pressure on it for the car to stop. I drove and reversed a few times and the same thing happened. All of this was done on a drive way. I pulled out into the road (very quiet road) and tested them again, at say 10mph, and they came back to life (the pedal moved downwards as I put pressure on it); all was OK until this morning when exactly the same thing happened.

I started to pull out of my drive and the brake pedal was rock hard. It took a few minutes of moving backwards and forwards until the brake pedal move down and I was confident the brakes were OK. I drove for 15 miles and they were fine.

My concern, is that if I am in a car park (surrounded by pedestrian) and it happens again. You need to use a serious amount of pressure on the brake pedal at 5mph to stop the car, if it stops at all.

Advice?

[Brendan W]

Doesn't sound right. Motor off, repeatedly push the pedal to exhaust any vacuum. Start the car with the foot hard on the pedal and it should travel down as the motor fires up. Stop the motor and repeatedly push the pedal, it should get progressively harder to push and rise to meet your foot.
Wondering if the electric assist pump is on strike.

[4candles]

Non-return valve in vac line?

[Clan]

Originally Posted by Phandy

Background: I had a new brake servo fitted about six weeks ago on the advice of this forum, as my brakes were making a hissing noise.

About 3 week's ago, I had just turned over the car and was slowly pulling away (5 mph) when I pressed the brake pedal, and it was hard as a rock; the pedal would not move down, and I hard to put a lot of pressure on it for the car to stop. I drove and reversed a few times and the same thing happened. All of this was done on a drive way. I pulled out into the road (very quiet road) and tested them again, at say 10mph, and they came back to life (the pedal moved downwards as I put pressure on it); all was OK until this morning when exactly the same thing happened.

I started to pull out of my drive and the brake pedal was rock hard. It took a few minutes of moving backwards and forwards until the brake pedal move down and I was confident the brakes were OK. I drove for 15 miles and they were fine.

My concern, is that if I am in a car park (surrounded by pedestrian) and it happens again. You need to use a serious amount of pressure on the brake pedal at 5mph to stop the car, if it stops at all.

Advice?

Is it an automatic gearbox and petrol engine ? There may be an electric vaccum pump , either at the side or underneath the air filter .which supplies the vacuum for the first few minutes , as the engine will be reving higher when cold for the first minute or so , hence very little vacuum . Do you have one?

[Phandy]

[QUOTE=Clan;1938368]Is it an automatic gearbox and petrol engine?]

Hi, yes, it is a petrol engine with an Automatic gearbox.

[Phandy]

Sorry, I am not sure if I have a vacuum
pump. It is an s60 2003 T SE automatic.

It is a difficult fault to replicate. As Branding stated, the pedal should travel down, and it does 99% of the time. It is the 1% that worries me.

Have to nip out now but will be back online later. Thanks for the replies.

[Clan]

Originally Posted by Phandy

Sorry, I am not sure if I have a vacuum
pump. It is an s60 2003 T SE automatic.

It is a difficult fault to replicate. As Branding stated, the pedal should travel down, and it does 99% of the time. It is the 1% that worries me.

Have to nip out now but will be back online later. Thanks for the replies.

Yes there should be a vacuum pump . if you sit with ignition on you should hear it run when you pump the brake pedal . then it shuts off when it has built up the vacuum .
There could be an air leak which keeps the vacuum pump running all the time youa re driving which burns it out . Or the pump could just be faulty . or the pressure switch which controls the pump might be faulty . It's a fairly simple circuit if you are used to car electrics .

[Phandy]

Thank you Clan. I am not that clued up with circuits, but I am now armed with some useful information I can use when I book it into a garage next week.