Hi all group members,
My name is Adam and I would like to ask the experts on this forum for a help with my brakes.
The problem is that the brake pedal is very soft and the braking is inefficient (especially when I drive slowly), actually I can easily press the pedal to the floor without blocking the wheels (I do not have ABS).
I went to Break Team, they checked everything and said that the rotors were o.k., pads were o.k., no leakages, so they just changed the brake fluid and said that the brakes were in a perfect condition...
But I am afraid that is not true! I thing that is abnormal when you can press the brake pedal to the floor without blocking the wheels...
Dou you have any idea what should I check?
When the engine is turned off the pedal is hard. There are no leakages from the main pump or calipers.
What can be wrong??
Thanks for help
Adam
Brake problem in Leganza 2001 w/o ABS, expert's help needed
Moderators: daewoomofo, Moderators Group
Welcome Adam,
There is indeed a problem if you can floor the brake pedal.
That could be a leak inside the master cylinder or a bad purging procedure.
First try purging the brakes without flooring the brake pedal. Only half way. Take attention not running low on brake fluid level during purge.
Daniel
There is indeed a problem if you can floor the brake pedal.
That could be a leak inside the master cylinder or a bad purging procedure.
First try purging the brakes without flooring the brake pedal. Only half way. Take attention not running low on brake fluid level during purge.
Daniel
regardless of what Break Team said you got issues with your braking system (beeing called "breaking" could mena they made your problem worse).
lacking friction in brakes could be due to:
1- worn or wrapped rotors: with the simptoms you discribed the rotors should be very badly worn and have uneven surfaces that you can visually see that... if they "look" OK then they are OK as minor surface deformation can not cause sevear problems as you have.
2- worn pads: if the pads are all eaten up you can have lack or absence of friction, check the pads and see how much esbestos is left... if the pads are too worn then you will lose all your braking power and you might even mess up your rotors.
3- contaminated friction surfaces: if the pads and/or rotros are contaminated by oil or greas or any kind of lubricant then you will have very weak friction and the pads will just slip over the rotor, check for contamination or brakes fluid leaks arround your pads and rotors. if you find any then you can remove the oil easly off rotors but if the pads are contaminated you have to replace them as the oil will be soaking them to the bones and their is n way to clean them.
4- leaking brakes fluid: if their is a break in brakes line then the pressure applied by the brakes pedal will be leaked through that breaking point. check all brakes lines, hoses and most important master cylender and pistons seals, usualy this will be associated with subistantial brake fluid loss.
5- air in the braking system: if you got an air leak into the system it will act as a "pressure absorber" as the air consumes part of the pressure in the system to contract so you are constantly losing some of your braking pressure and hince braking power. you can bleed the brakes at all 4 wheels pistons and the master cylender too but it is kinda tricky to do so and i would leave that to an expert.
that covers about most of the reasons why you have weak brakes, check those points and get back to us with what you found and we will see what to do next.
MMamdouh
lacking friction in brakes could be due to:
1- worn or wrapped rotors: with the simptoms you discribed the rotors should be very badly worn and have uneven surfaces that you can visually see that... if they "look" OK then they are OK as minor surface deformation can not cause sevear problems as you have.
2- worn pads: if the pads are all eaten up you can have lack or absence of friction, check the pads and see how much esbestos is left... if the pads are too worn then you will lose all your braking power and you might even mess up your rotors.
3- contaminated friction surfaces: if the pads and/or rotros are contaminated by oil or greas or any kind of lubricant then you will have very weak friction and the pads will just slip over the rotor, check for contamination or brakes fluid leaks arround your pads and rotors. if you find any then you can remove the oil easly off rotors but if the pads are contaminated you have to replace them as the oil will be soaking them to the bones and their is n way to clean them.
4- leaking brakes fluid: if their is a break in brakes line then the pressure applied by the brakes pedal will be leaked through that breaking point. check all brakes lines, hoses and most important master cylender and pistons seals, usualy this will be associated with subistantial brake fluid loss.
5- air in the braking system: if you got an air leak into the system it will act as a "pressure absorber" as the air consumes part of the pressure in the system to contract so you are constantly losing some of your braking pressure and hince braking power. you can bleed the brakes at all 4 wheels pistons and the master cylender too but it is kinda tricky to do so and i would leave that to an expert.
that covers about most of the reasons why you have weak brakes, check those points and get back to us with what you found and we will see what to do next.
MMamdouh
Driving is the utmost fun you can have with your pants on!
Check out my ride: http://www.cardomain.com/ride/567267
Check out my ride: http://www.cardomain.com/ride/567267
I did a homework: brake problem in Leganza, help needed
Hi,
First of all big thanks for MMamdouh and Daniel. It took me a while to check all things that you mentioned but I did it. Now is a time for my report:
>1- worn or wrapped rotors...
I checked all four discs and they look practically like new. No deep scratches on any side.
>2- worn pads:
Front pads - used in 50% (9-10 mm left), rear in 35% (12-13 mm left) so I think it is not a case
3- contaminated friction surfaces:
I bought a special brake cleaning spry and I dismounted calipers pads and then cleaned everything, including pads and rotors.
4- leaking brakes fluid:
No wet places, no leakages. Everything is completely dry. The calipers, brake lines and the main pump are dry. The level of the break fluid: max, it has not changed since last 4 months.
5- air in the braking system:
Brake Team exchanged the brake fluid (after I did it by myself) because I was afraid I did something wrong. But the result was exactly the same. Furthermore, as far as I remember if there is an air in the system the pedal raises up (becomes harder) after you press it couple times. In this case I can "pump" forever and it does not change the situation at all.
To sum up I am afraid that the problem is somewhere else.
Is it possible that due to the high air temperature the front brake lines become too elastic, they expand and that is why the pedal is soft?
Is there any other element that can expand in the break system?
What about the booster? Can it have something to do with my problem?
I noticed that when the rear of the car is loaded (a lot of stuff in a trunk and passengers on the rear sit) the pedal seems to be harder. It is probably related to the brake pressure distributor that changes the pressure directed toward front and rear axle depending on the weight distribution. Does it mean that the problem exist in the front brakes, and therefore when the rear axle intercepts more of the pressure the break pedal ?behave? better?
Thanks
Adam
First of all big thanks for MMamdouh and Daniel. It took me a while to check all things that you mentioned but I did it. Now is a time for my report:
>1- worn or wrapped rotors...
I checked all four discs and they look practically like new. No deep scratches on any side.
>2- worn pads:
Front pads - used in 50% (9-10 mm left), rear in 35% (12-13 mm left) so I think it is not a case
3- contaminated friction surfaces:
I bought a special brake cleaning spry and I dismounted calipers pads and then cleaned everything, including pads and rotors.
4- leaking brakes fluid:
No wet places, no leakages. Everything is completely dry. The calipers, brake lines and the main pump are dry. The level of the break fluid: max, it has not changed since last 4 months.
5- air in the braking system:
Brake Team exchanged the brake fluid (after I did it by myself) because I was afraid I did something wrong. But the result was exactly the same. Furthermore, as far as I remember if there is an air in the system the pedal raises up (becomes harder) after you press it couple times. In this case I can "pump" forever and it does not change the situation at all.
To sum up I am afraid that the problem is somewhere else.
Is it possible that due to the high air temperature the front brake lines become too elastic, they expand and that is why the pedal is soft?
Is there any other element that can expand in the break system?
What about the booster? Can it have something to do with my problem?
I noticed that when the rear of the car is loaded (a lot of stuff in a trunk and passengers on the rear sit) the pedal seems to be harder. It is probably related to the brake pressure distributor that changes the pressure directed toward front and rear axle depending on the weight distribution. Does it mean that the problem exist in the front brakes, and therefore when the rear axle intercepts more of the pressure the break pedal ?behave? better?
Thanks
Adam
-
GsiTurbo
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Well....there is one or two more possibilities. You brake boosted, and or a vacuum hose going into, or the check valve in between might be faulty. Also, you might have a 'flexible brake line somewhere, that lost its tension. As a result, when you press the brakes, it blows like a balloon, thus efficiently making you brakes feel 'spongy' and soft.
Tom
Tom
__________________________
2002 Lanos 1.5 SOHC... stock!!!
Hi Adam,
I still think at a leak inside your master cylinder if you can floor the brake pedal even with engine (and brake assistance) off. Such leak can be unperceived as it occurs between front and rear sides of master cylinder's piston(s). It's then like a syringe with a pinhole in the seal. Hope it helps.
Daniel
I still think at a leak inside your master cylinder if you can floor the brake pedal even with engine (and brake assistance) off. Such leak can be unperceived as it occurs between front and rear sides of master cylinder's piston(s). It's then like a syringe with a pinhole in the seal. Hope it helps.
Daniel
brake line: check your rubber brake hoses, preferably with someone pumping the berakes... look for a ballon inflation on the surface of the hose, replace the faulty hose.
booster: pump the brakes with the engine off till the pedal is rock solid (all boost consumed) then with your foot firmly pushing the brakes pedal start the engine... the pedal should go down subistantially due to the booster assistant... if you got other feedback then your booster got problems.
as fas as i know our daewoos has no brake distribution according to weight gadgets so what you explaned is due to something else.
also if you have bad master cylender it will be associated with an oil leak from it so make sure it is not leaking.
what kind of pads you are using? could be low grade pads with low friction making you do extra efort to brake and thus give you the feel that the pedal travels too much.
MMamdouh
booster: pump the brakes with the engine off till the pedal is rock solid (all boost consumed) then with your foot firmly pushing the brakes pedal start the engine... the pedal should go down subistantially due to the booster assistant... if you got other feedback then your booster got problems.
as fas as i know our daewoos has no brake distribution according to weight gadgets so what you explaned is due to something else.
also if you have bad master cylender it will be associated with an oil leak from it so make sure it is not leaking.
what kind of pads you are using? could be low grade pads with low friction making you do extra efort to brake and thus give you the feel that the pedal travels too much.
MMamdouh
Driving is the utmost fun you can have with your pants on!
Check out my ride: http://www.cardomain.com/ride/567267
Check out my ride: http://www.cardomain.com/ride/567267