How to improve braking performance (semi-DIY)

Izso

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Hi bro, my wife myvi brake is operate abnormally. I have to pump the brake until felt the brake bit. Then, when I put my feet on the pedal for a long time, the pedal start to go floor, same as when sudden braking. The pedal will straightly went to floor.

What wrong with the brake? I've bed-in the brake before but problem still occurred.
Please advice
For this sort of problem i'd check two things.

1. Is your oil level consistent or does it drop? If drop means you have a leak in your system somewhere.
If not it's probably time to bleed the air out of the system.

2. How old is your brake hoses? If old and cracking you should change them. What mods have you done to the brakes? Did you change the servo?

All really depends on the condition of the above.


I just remembered something. Did you take out the calipers like I have? Did you ensure left and right positions are correctly installed? Make sure the bleed nipple valve is facing upwards not downwards. If downwards the problem is with your caliper install - it's reversed
 
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me2kimi

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For this sort of problem i'd check two things.

1. Is your oil level consistent or does it drop? If drop means you have a leak in your system somewhere.
If not it's probably time to bleed the air out of the system.

2. How old is your brake hoses? If old and cracking you should change them. What mods have you done to the brakes? Did you change the servo?

All really depends on the condition of the above.


I just remembered something. Did you take out the calipers like I have? Did you ensure left and right positions are correctly installed? Make sure the bleed nipple valve is facing upwards not downwards. If downwards the problem is with your caliper install - it's reversed
1- The oil level is steady and I already bleed it out without taking out caliper. Problem is still there.
2- everything is in stock condition and that myvi is 2006. So I think is 5 years already. Servo also original from P2.

He need to get his master pump cylinder serviced with compatible parts, not something from halfcut.
Bro, I only get the cap from chop shop coz spare part did not sell cap only. After replace the cap, the bleeded the brake.

p/s: only cap from chop shop, not entire servo assy
 
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Izso

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1- The oil level is steady and I already bleed it out without taking out caliper. Problem is still there.
2- everything is in stock condition and that myvi is 2006. So I think is 5 years already. Servo also original from P2.



Bro, I only get the cap from chop shop coz spare part did not sell cap only. After replace the cap, the bleeded the brake.

p/s: only cap from chop shop, not entire servo assy
I still think there's a leak somwhere. Should consider getting the original cap from Perodua as it's not expensive mah. For the pedal to sink all the way in like that either your servo is completely kaput or you're running a leak. Since the oil level is steady it sounds like the weakspot is cap. Or do you have a jammed rear drum? My wira had a jammed drum at one time and the pedal did exactly that.
 

me2kimi

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Servo is the black round part right?
I think drum is still in good condition coz it operate perfectly by using handbrake.
(no problem while park at my house with ramp ground)
I'll try source new oil cap first.

BTW, while bleeding the brake fluid, why there is a constant bubble coming out from nipple?
Is is normal? Or got leak somewhere?
 

me2kimi

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One more thing forgot to mention, it's got an ABS. And during bleeding, once press the pedal has to wait few seconds to pedal rise up the can push it back. Cannot continuous pumping the pedal.
 

Izso

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One more thing forgot to mention, it's got an ABS. And during bleeding, once press the pedal has to wait few seconds to pedal rise up the can push it back. Cannot continuous pumping the pedal.
Wow.. I'm thinking you might need to service your servo. Perhaps the seals there are spoilt.

Best you bring it to a mech to diagnose. Don't delay the brake repairs! It's the difference between stopping in time and smashing into a car!
 

nismoskyline87

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Superb write up! Now I understand better about braking performance. BTW, I would like to ask you where did you get the Yoko AD07? I went around to look for these tyres and found nothing. My tyres are nearly worn out!

Again, excellent job!
 

Izso

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Superb write up! Now I understand better about braking performance. BTW, I would like to ask you where did you get the Yoko AD07? I went around to look for these tyres and found nothing. My tyres are nearly worn out!

Again, excellent job!
A friend recommended a shop in Subang who just so happened to have the AD07s. You won't be able to find anymore as I took one of the last sets.
 

me2kimi

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Wow.. I'm thinking you might need to service your servo. Perhaps the seals there are spoilt.

Best you bring it to a mech to diagnose. Don't delay the brake repairs! It's the difference between stopping in time and smashing into a car!
Thanks bro. Lucky my wife is in meternity leave. so that myvi not been driven for few weeks already
 

TitanRev

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Bro TitanRev, I just check with vacuum gauge. I got 18 in.Hg at idle. I think it is good reading for vacuum.
And the brake can function perfectly at park position.
When this problem occured, I notice that cap oil seal for brake fluid putus already. Then changed it from hulf cut shop but with fifferent type seal. Does this cap play major role in brake operation?
The cap seal is also important as it keeps dirt from contaminating the fluids. Since your vacuum is good you need to replace your master cylinder piston's O ring....Like Drex said. is your master cylinder. From your post the MyVi already had some age in it so have the master cylinder repair.
 
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Thanks bro iszo for the guide. i successfully change my myvi disc to brembo disc thanks to this guide. it actually very easy job just depend on either you willing to do it or not. Bro iszo can I add some point here? If let say your disc cannot be remove easily due to already rust, u can use 2 fixing hole at your disc. just use 12mm screw and turn it until the disc is separated from the hub (make sure put your car in 1st gear for manual and D gear for auto). if u plan to change to new brake pad and don't have tools to press the piston back to the position, u can use G clamp and your old brake pad to press it. please correct me if my point got error.
 

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