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Old 1st July 2008, 22:48   #1
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Default problematic brakes!

hi guys,
i have e problem in my chevrolet optra. i had changed all my brake pads on 25000kms, resurfaced the drums and disc too. now at 28000kms i am having trouble in the brakes. the distance of brake pedal has increased;(
the manual says the playof the pedal should be around 1mm~8mm but it is generally more than 1 inch~2 inches!)
if i'm drving at a high speed around 100kms+ i have to press the brake pedal deep and it brakes. there is no leak as even if i pump the pedal remains at the same level. it doesnt come up, neither i feel loss in braking power. they are as sharp as they should be. what can be the posible reason.
the manual says the playof the pedal should be around 1mm~8mm but it is generally more than 1inch~2Inches!
pls advice thnx
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Old 2nd July 2008, 00:08   #2
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If the brakes were checked recently and serviced it could just be that the mechanic may have not adjusted the play of the pedals properly. Since we are talking brakes here you should get your master cylinder rechecked and the play readjusted. Safety first
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Old 4th July 2008, 15:52   #3
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Are you talking about play (1-2 Inches is not possible usually) or pedal travel while braking?

I hope your pedal travel has increased.

Play: Play is the free travel of effort side of mechanism, after which the mechanism actually start to transmit effort to linkages(mechanical hydraulic or others).

Pedal travel: It is the distance by which brake pedal travels at which expected brake force is felt.

Reasons of increased pedal travel: Ofcourse play (but 1-2 inches is too much to be the play only).
air in hydraulic circuit(remedy=bleed the system).
Less level of brake fluid(check & top up)
too much wear of brake lining material(change pads/liners)
Disintegration of brake fluid ( change brake oil)
water in sytem( change brake oil).
Disintegration of rubber components(ususally dont occur at 25000KMS)


Things probably wrong with your car-in order of diagnosis:
1 Air in system (bleed)
2 low level of fluid(check & top up)
3 condensation in fluid (check & replace brake oil)
4 worst: since you mentioned you resurfaced the discs/drums the job was not done properly. Either uneven surface was left, which has eaten away your new pads as well.

or disc/drums were thinned too much due to machining, hence you have to live up with more pedal travel(unless you replace with new disc/drums)

My advice would be to change disc/drums rather than machning them if you need.

Note: 25000kms was too early for a disc to be resurfaced/machined unless it was damaged/burred.

Last edited by arunforu1 : 4th July 2008 at 15:55.
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Old 4th July 2008, 16:11   #4
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[quote=mdesai_1981;887535]hi guys,
if i pump the pedal remains at the same level. it doesnt come up, [quote]

symptoms that something could wrong with the master cylinder. pls get it checked thoroughly.

moreover, as Arun mentioned, 25K on the odo is way too less for the rotor disc to get disrupted and needed re-surfacing
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Old 4th July 2008, 16:21   #5
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Quote:
Originally Posted by mdesai_1981 View Post
if i'm drving at a high speed around 100kms+ i have to press the brake pedal deep and it brakes. there is no leak as even if i pump the pedal remains at the same level. it doesnt come up, neither i feel loss in braking power. they are as sharp as they should be. what can be the posible reason.
I think he means that, he pumps the pedal several times up & down. Still pedal travel remains same(doesnt come up). There should not be anything wrong with a critical component like master cylinder at 25k.

Most probably too much material was machined away from discs & now they are too thin. as only pedal travel has increased there is no loss in braking power as he mentioned.

go to an authorised work shop, remove wheel, clean disc of dust. Measure the disc with the caliper or similar intrument & compare the reading with workshop mannual. A new pair of disc is not too much costly, always replace them. A wrong machined pair of discs can eat away new pads in one week flat & proves more costly.
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Old 5th July 2008, 02:23   #6
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guys i had gone to e chevy a.s.s. they cleaned the thing and told me that the brakes and the rotors are perfect and they cleaned the same. he says the distance to brake will decrease with time as thay have just cleaned it.
also i had replaced the brake pads as at 25000kms they were 80% done so instead of resurfacing i replaced them. thought its like e preventive maintainence. i was a big fool though!
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