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Old 13th July 2016, 19:39   #31
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Quote:
Originally Posted by IndigoXLGrandDi View Post
In our Xylo E8 ABS Nov 2009 that has covered 2,68,700+kms, I was draining the old brake fluid at wheel end and by mistake I injected air in the brake system.



Now the brake pedal is sinking down when I press the brake pedal. But it returns to its default position after its released. The braking power has reduced drastically. I got the brake system bleeding done but no improvement.



If I pump the brake pedal 3-4 times during brake application (car in motion), the brakes get applied. Even at speed of 90-100kph, 3-4 Times pumping does the trick.

Has the master Cylinder conked off?

I have got the Master Cylinder replaced around 2-2.5 years and 50-60000kms ago.

Mods please move to appropriate thread If need be.

It sounds like you still have air in the system and you need to bleed it properly before taking any further steps.
I should not drive the car in this state at all. Fix the brakes properly first thing.

Jeroen
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Old 13th July 2016, 20:19   #32
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Default Re: DIY: Flush / Bleed the clutch & brake fluids

^ Or there is a leak in the system. The brake pedal sinking when pressed and held is a classic symptom of leakage in the brake circuit. Advise to get it fixed as soon as possible.
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Old 13th July 2016, 23:56   #33
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Default Re: DIY: Flush / Bleed the clutch & brake fluids

Quote:
Originally Posted by Jeroen
It sounds like you still have air in the system and you need to bleed it properly before taking any further steps.
How to conclude that the air got removed completely after bleeding the brake system?

Quote:
Originally Posted by saket77
^ Or there is a leak in the system. The brake pedal sinking when pressed and held is a classic symptom of leakage in the brake circuit.
But the brake fluid level does not drop. I did a 320km trip (Sorry the Trip was unavoidable and I had to take Xylo itself in that condition). But still the Low Brake Fluid Warning was not triggered. I did not visually check the level.

The Handbrake is working Fine. The car does not move on an incline with handbrake applied.

Edit:-
Google Baba says that If the Brake Pedal is sinking down that means Master Cylinder is not able to develop and maintain Pressure.
Any idea?

Last edited by IndigoXLGrandDi : 14th July 2016 at 00:01.
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Old 14th July 2016, 00:58   #34
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Default Re: DIY: Flush / Bleed the clutch & brake fluids

Quote:
Originally Posted by IndigoXLGrandDi View Post
In our Xylo E8 ABS Nov 2009 that has covered 2,68,700+kms, I was draining the old brake fluid at wheel end and by mistake I injected air in the brake system.
Quote:
Originally Posted by IndigoXLGrandDi View Post
How to conclude that the air got removed completely after bleeding the brake system?.
When I was bleeding my Cedia, air always crept up in the system despite my best efforts. It seemed that air was sneaking in through the threads of the bleed nipple. The solution was to remove the bleed nipple, wrap it in 3-4 layers of Yellow Teflon tape ( Yellow is important, it is meant for uses involving oil - Avoid white tape, its meant for use with water only) like so. Replace the nipple and the leaks disappeared. Do not cover the hole in the bottom with tape - restrict it strictly to the threaded area!

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Slave Cylinder with teflon taped nipple

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I later realised that even though my system was bled, I would see air coming anyway. I realised even when I was pumping, air would get sucked in through threads and come out of the pipe, giving me the impression that the system still had air.

So I'd suggest you give the same treatment to all the bleed nipples of your vehicles first and bleed again.

Get a second person to help you, watch this video and make your helper watch it too so that both understand the process. One man bleeding like I mentioned in this thread is difficult to get right first time and if you're facing problems, this is perhaps the best way to tackle it.



Instead of using a tube and putting it into a bottle, hook it upto a 40cm long transparent line and a 50ml syringe. Fill the pipe (syringe must be empty, press syringe all the way, dip the pipe into brake fluid and pull back the syringe so that the pipe is fill, but the syringe is still empty) then fix it to the bleed nipple.

Start the bleed process as per the video. With every press, the fluid moves ~ 30cm in the pipe. Observe the pipe if any tiny air bubbles are present. If yes, keep bleeding till you don't observe any air. When the syringe is almost full, remove it from the pipe, dump the fluid into the spent fluid bottle fix it back and continue to bleed.

You can see tiny air bubbles in the pipe

DIY: Flush / Bleed the clutch & brake fluids-img_20160227_084919001.jpg

Bleeding by using these tips should help you get an air-free system. If the problem still persists, either some seal in your system is bust and is taking air - this can be piston seals in any caliper/wheel cylinders or master cylinder or ABS unit.

I made the mistake of not filling the reservoir while bleeding and managed to fill the whole system with air. With the two person bleeding, it took me 10 minutes to remove all the air and return it back to normal.

Quote:
Originally Posted by IndigoXLGrandDi View Post
The Handbrake is working Fine. The car does not move on an incline with handbrake applied.
Handbrake is independent of brake hydraulics, that is why its called emergency brakes. They work using cables and will work even if primary hydraulic brakes fail completely.

All the best!
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Old 14th July 2016, 02:14   #35
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Default Re: DIY: Flush / Bleed the clutch & brake fluids

Quote:
Originally Posted by IndigoXLGrandDi View Post
How to conclude that the air got removed completely after bleeding the brake system?
You have to make sure that only brake fluid comes out of each bleed valve no air bubbles.

As you seem to have let air in the system, you have to pump a lot of fluid through. Bit of pain, but follow the instructions in the video and you should be good to go.

I don’t know if you can get these sort of “easy bleed” sets in India. I use them all the time. Much saver, easier and quicker then pumping the brake pedal.



Quote:
Originally Posted by IndigoXLGrandDi View Post
But the brake fluid level does not drop. I did a 320km trip (Sorry the Trip was unavoidable and I had to take Xylo itself in that condition). But still the Low Brake Fluid Warning was not triggered. I did not visually check the level.
If the master cilinder has developed an internal leak the brake fluid level remains steady. The best way to test is to pump the brake pedal a few times and then press on it with all your might and hold for thirty seconds or so. If it doesn’t budge you should be ok, if it slowly but surely drops you have a problem with the master cilinder, most likely a seal is broken.

Quote:
Originally Posted by IndigoXLGrandDi View Post
The Handbrake is working Fine. The car does not move on an incline with handbrake applied.
As pointed out, handbrake works mechanically and is completely independent of the hydraulic system


Quote:
Originally Posted by IndigoXLGrandDi View Post
Google Baba says that If the Brake Pedal is sinking down that means Master Cylinder is not able to develop and maintain Pressure.
Any idea?
See above. You need to distinguish between it dropping because of air or dropping because of a problem with the master cilinder

Good luck
Jeroen
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Old 16th July 2016, 07:32   #36
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Default Re: DIY: Flush / Bleed the clutch & brake fluids

I got the Master Cylinder replaced with New one and bleed the brake system. Now the brakes are normal.

Thank you for helping me.
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