Bloody brake issues again

Adam Vinnicombe

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Hi all I’ve been have small issues with my new edge mustangs brakes for about 18 months now and today they have become big issues and here are the problems
The brake pedal is very slow to retune up from fully depressed (engine running)

when at idle and you depress the break pedal the rpm drops but will come back up not sure if this is normal?

when in neutral and engine running and you depress the brake pedal all you can hear is a hissing noise, is this normal ? I think not

when driving the brakes seem to be make of jelly and do nothing unless I put in a lot of effort and I mean a lot of effort.

the ABS is not working as well, I basically have to stand on the pedal to get the front wheels to lock up but no ABS is kicking in nor is there any ABS failed warning light coming on, the ABS light is working and does come on for its check when the ignition is turned on and then is goes out a few seconds later.

I have changed the pads and discs and fluid, check all brake lines, bleed them gif knows how many times and the master cylinder but still no bloody joy.
Please help me and throw me some ideas on what to try and do.
Is it the booster that’s broken ? If so how can I check it?
Many thank
Adam
 

white95

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Have you checked into the power steering side of the brake system? I know mine barely worked without a proper power steering fluid flow through the booster.

This is the process to bleed it:

1. NOTE: The Hydro-Boost power brake booster is generally self-bleeding, and the following procedure will normally bleed the air from the power brake booster. Normal operation of the vehicle will further remove any additional trapped air. Fill the power steering oil reservoir with MERCON (R) Multi-Purpose ATE XT-2-QDX or MERCON (R) equivalent.

2. Remove the Powertrain Control Module (PCM) fuse to prevent the engine from starting.

3. Crank the engine for several seconds.

4. Check the fluid level in the power steering oil reservoir and add if necessary. Install the Powertrain Control Module (PCM) fuse.

5. Start the engine.

6. With the engine running, turn the steering wheel from stop to stop twice. Turn the engine off.

7. Depress the brake pedal several times to discharge the accumulator.

8. Repeat Steps 5 and 6.

9. If foaming occurs, stop the engine and allow the foam to dissipate.

10. Repeat Steps 5 and 6 as required, until all the air is removed from the system (when the foaming stops).
 

SnakeBit!

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try pulling the fuse for the ABS and see what it does. you could have a stuck valve in the ABS block.
 

95opal

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You have a vac leak at the booster
 

Adam Vinnicombe

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Right so I’ve done the check that white95 mentioned and that is all good, I’ve also have tried running the engine then turning it off pumping the brake pedal which goes hard in about 4/5 pumps then holding it down and starting the engine. When the engine starts the pedals goes down a little bit more than instantly pushes back up so this is tell me that the booster is working, is this correct?
There are no leaks anywhere that I can see.
The ABS for some reason doesn’t work on this car although the ABS light does come on when the ignition is first turned on but will go back out a few seconds later so I take it that the ABS system is working?
I do not get an ABS warning light coming on when driving.
There is a lot of free play in the brake pedal before anything happens, now if you take up that free play first and then push the pedal down it moves smoothly then you can feel a second pressure increase if that makes sense? If not let me know and I will try and explain it a little better.
Also the pedal is very slow to come back up when fully depress and ideas why?
Is there a spring missing to help the pedal come back up?
 

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