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Brake "spongy" feeling

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Dear all,

 

I am driving a Chevrolet Optra 1.6 (A),

 

i this "spongy" feeling of the brakes... whereby i have to depress the brakes pedal alot before the pad will bite. This casue me difficult to control light braking and sometime even dangerous in some situation.

(i had done bleeding and changing to aftermarket pads already.. the "spongy" feeling still comes back after a month of usage)

 

As disscussion with my mechanic, conclusion is that the master brake booster cannot build up adequate pressure to allow effective braking feel on the brakes.

 

 

Q: Other then changing the master brake booster, is there other ways to reduce this "spongy" feeling or to build up the master brake booster pressure?

 

Comments?

 

thank you flowerface.gif

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My previous COE car also had this problem b4.

 

When at traffic light, I step on the brake, it will hold and then slowly sink to the end. If at a slope, the car would then start moving on its own!!! I have to pull hand brake or let go n step on the brake again to stop it from moving!!!

 

I send my car immediately to my next door mechanic and he immediately told me its the master valve spoilt, unable to hold the hydraulic pressure. As a newbie then, I told him to rectify it immediately as it is dangerous.

 

It cost me abt S$200 plus. Dont know if got kena carrot head or not.

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If your mechanics is still using the "1950s leg-power" way of bleeding your hydraulic brake sytem, the chances of getting rid of all the air bubbles in the system is very slim for this generation of cars.

The best way is to use pressure bleeding and the next alternative is to use vacuum bleeding.

 

Ps attached is a vaccum bleeder with a automatic brake fluid refiller.

post-6-1126782384_thumb.jpg

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Yes, i thinking he his using a vacuum bleeder.. as he mentioned to me it costed him 3~4K to get it and not many workshop has it..

 

Hmmm... thought steel braided hose more effective for harder braking as it reduce hose flexing under hugh pressure...

 

But mine hard braking no problem... just doing light braking, difficult to control braking as hav to depress quite abit of pedal to bite..

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bro... from wat i knw is that the steel brake hose will eliminate that spongy feel sometime the rubber hose swell u will get this kind of spongy feel and steel brake hose does not expand that easily....have it check by yr ws first .,, b,t,w steel brake hose does not improve yr braking distance only improve in feel, giving u more confidence in the brakes....hope it helps [:)]

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Dear all,

 

I am driving a Chevrolet Optra 1.6 (A),

 

i this "spongy" feeling of the brakes... whereby i have to depress the brakes pedal alot before the pad will bite. This casue me difficult to control light braking and sometime even dangerous in some situation.

(i had done bleeding and changing to aftermarket pads already.. the "spongy" feeling still comes back after a month of usage)

 

As disscussion with my mechanic, conclusion is that the master brake booster cannot build up adequate pressure to allow effective braking feel on the brakes.

 

 

Q: Other then changing the master brake booster, is there other ways to reduce this "spongy" feeling or to build up the master brake booster pressure?

 

Comments?

 

thank you flowerface.gif

 

Bro, I'm driving the same car as u & I experience the same problem as u do. I took a drive in my fren's Pre-FL G9 which is the same as our ride, all round 4 disc brakes & the brakes in the G9 is performs well with good braking feel [thumbsup]

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Hand held air powered vacuum brake bleeder is the most economical, and profitable generating service tools.They are deisgned maily for workshop used so for DIYers the prices are on the high side. They are available on-line auction in ebay & Yahoo Spore.

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Ok then it looks like there is air being suck into the system either via the brake hoses, or connection at the brake fluid reservoir. The other possisblities , may one or more slave cylinders rubber cup seals are not able to hold the hydraulic pressure for a perlong period.

Try to completely flush the system, maybe the old brake fluid maybe heavily diluted with water vapour. Most of the brake failure at high speed braking is due to presence of water vapour in the system thereby reducing the brake fluid max boiling point

 

PS. Frnakly have not come across any shop in Spore even car importers using a 3 to 4k high performance , high volume brake bleeder ( normally they are pressure bleeders)

Edited by Yeobh

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1st- when the last time u changed ur brake fluid? if it is more then a year old, you need to get rid of them cos they r hydroscopic and tat affects the effectiveness of braking, probably formation of bubbles in the brake line as well.

 

Once u changed them, it should work better. stainless steel briad line is not impt. just drive carefully and u r safe.

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i think stamford tires (jurong branch) has a proper vacuum bleed device for draining the brake fluid. it's a tall acrylic plastic cylinder with a few tubes, one of which i remember is connected to a pump of some sort

 

btw, is it normal to hear gas, hissing sound when the brake pedal is depressed?

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From your description it looks like the unit is a coolant exhange unit from USA.No much of a use in Spore where used coolant by law is not reauire to undergo any recycling.

No gas is being used in car brake system unless you are driving a heavy truck that uses air assist brake system.What you hear may be noise from the brake assist vacuum unit that allows atmpheric air to go into another chamber in the vaccum unit and thereby allowing you to apply the brak pedal with ease.

Hope this helps

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Dear all,

 

I am driving a Chevrolet Optra 1.6 (A),

 

i this "spongy" feeling of the brakes... whereby i have to depress the brakes pedal alot before the pad will bite. This casue me difficult to control light braking and sometime even dangerous in some situation.

(i had done bleeding and changing to aftermarket pads already.. the "spongy" feeling still comes back after a month of usage)

 

As disscussion with my mechanic, conclusion is that the master brake booster cannot build up adequate pressure to allow effective braking feel on the brakes.

 

 

Q: Other then changing the master brake booster, is there other ways to reduce this "spongy" feeling or to build up the master brake booster pressure?

 

Comments?

 

thank you flowerface.gif

 

 

hi bro....pretty coincidental that ur car had the same problem as mine.im driving an old coe honda.just had the same problem rectified in a workshop in JB.i also had to depress my brake pedal a few times just to brake effectively.at traffic lights need to pump brake pedal.worst still,press ok then the pedal will go all the down on its own.my mechanic changed the master brake pump and everything sui oredi.cost = RM120 for it but i did other repairs so it all came up to RM259....hehe!cheap!

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Actually the sponginess can be done just by bleeding of the brakes. Get rid of the air bubbles that is causing it.

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If your mechanics is still using the "1950s leg-power" way of bleeding your hydraulic brake sytem, the chances of getting rid of all the air bubbles in the system is very slim for this generation of cars.

The best way is to use pressure bleeding and the next alternative is to use vacuum bleeding.

 

Ps attached is a vaccum bleeder with a automatic brake fluid refiller.

Which workshop uses the vacuum method?
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