Break servo booster

[Martin Wilshire]

Just now, Martin Wilshire said:

I have had the whole brake system replaced pads discs master cylinder and hoses ..ford have blead the abs system ..but still keep getting a soft pedal  

And no fluid leaks 

[Paulkp]

Martin, there is a test procedure in the Haynes Manual for Fiesta and the Fusion, Have you tried that ?

[Martin Wilshire]

1 minute ago, anon said:

Again, ARE YOU LOSING FLUID?

No not losing fluid 

[Paulkp]

There is also apparently a non-return valve in the Vacuum line ?

[Martin Wilshire]

2 minutes ago, Paulkp said:

Martin, there is a test procedure in the Haynes Manual for Fiesta and the Fusion, Have you tried that ?

No i have know manual did not think they made one for the ST150 facelift model

[Martin Wilshire]

2 minutes ago, Paulkp said:

There is also apparently a non-return valve in the Vacuum line ?

Did not know this ..i have just looked can,t see a valve on the pipe which runs from servo 

[Martin Wilshire]

Just now, Martin Wilshire said:

Did not know this ..i have just looked can,t see a valve on the pipe which runs from servo 

Replace this vacuum pipe ?

[anon]

No loss of fluid. That means it is not leaking into the Servo. Does the engine idle properly?

[Paulkp]

Getting back to the original post about what servo might fit, there are a number listed in CatCar for Fiestas and Fusion, and it looks likethe vacuum pipe is unique to the ST.  Type your VIN into Ford Catcar, and see what is listed for your car, and that will give you a FINIS code which you can then search.

As for Haynes not producing a specific handbook for the ST, most of the car will be similar to a 2 door Fiesta of that ilk, and Standard Fiesta Haynes will come in useful.

As Anon states - rough idle can be caused by leaky vacuum.

 

[Martin Wilshire]

30 minutes ago, anon said:

No loss of fluid. That means it is not leaking into the Servo. Does the engine idle properly?

Yes engine runs great 

[anon]

Or good idle can rule it out. My Fiesta will behave differently with gentle pedal pressure. It drops about two inches before engaging brakes. Stamp on the pedal and it will react immediately. This is no surprise in a modern over servoed car, particularly one with uprated brakes or harder pads as you will find on the ST150. The only car that has instantaneous brake action (and no need for a servo) is a hydropneumatic Citroen which responds to pedal pressure and not movement.

[Martin Wilshire]

22 minutes ago, Paulkp said:

Getting back to the original post about what servo might fit, there are a number listed in CatCar for Fiestas and Fusion, and it looks likethe vacuum pipe is unique to the ST.  Type your VIN into Ford Catcar, and see what is listed for your car, and that will give you a FINIS code which you can then search.

As for Haynes not producing a specific handbook for the ST, most of the car will be similar to a 2 door Fiesta of that ilk, and Standard Fiesta Haynes will come in useful.

As Anon states - rough idle can be caused by leaky vacuum.

 

Thanks i will take or advice and look at catcar ..as for the 2.0 duratec engine will i need to look at a mondeo manual i think that car had the same engine 

 

[Martin Wilshire]

21 minutes ago, anon said:

Or good idle can rule it out. My Fiesta will behave differently with gentle pedal pressure. It drops about two inches before engaging brakes. Stamp on the pedal and it will react immediately. This is no surprise in a modern over servoed car, particularly one with uprated brakes or harder pads as you will find on the ST150. The only car that has instantaneous brake action (and no need for a servo) is a hydropneumatic Citroen which responds to pedal pressure and not movement.

Ok thanks that sounds like my st the same pedal effect ..its just i never had this before the pedal was allways good did not sink felt good then oneday the pedal sank almost to the floor and i have this soft pedal this is why i upgraded the breaks and parts but now can,t get the pedal i remember ..this i why i think the servo  is leaking ..but now are you right and i am wrong but you have give me more confidence that the brakes will not fail me 

[anon]

Have you upgraded the brakes with harder pads or different calipers to standard?

[unofix]

Hello Martin, firstly I'd just like to say that my comment about your name was not ment in any bad way. I thought (wrongly as everyone is very quick to point out) that your name was very much like a place in Somerset. It was only an observation which seems to have become far more important to some than your original question.

So back to the original question - you feel that the brake pedal is softer than it ought to be. With out starting world war 3 on here, can i ask if you have been able to test drive another car of the same type to be able to compare ?

If the servo has a vacuum leak the pedal would be soft all of the time, and it is very likely you will loose brake fluid over a few days.

[anon]

Harder pads will give a softer pedal paradoxically becaause they don't stop the car until they warm up. Different calipers can cause different pedal movement, Bigger ones will cause a lower pedal as more fluid needs to be pumped to make them work.

[Martin Wilshire]

36 minutes ago, unofix said:

Hello Martin, firstly I'd just like to say that my comment about your name was not ment in any bad way. I thought (wrongly as everyone is very quick to point out) that your name was very much like a place in Somerset. It was only an observation which seems to have become far more important to some than your original question.

So back to the original question - you feel that the brake pedal is softer than it ought to be. With out starting world war 3 on here, can i ask if you have been able to test drive another car of the same type to be able to compare ?

If the servo has a vacuum leak the pedal would be soft all of the time, and it is very likely you will loose brake fluid over a few days.

No i have not been able to test drive another st not a bad idear thou ...yes padal feels soft not confident in brakes when in traffic pedal is to low before the brakes work ..will keep a eye on my fluid to see if i am losing any