MK4 - Brake pedal long travel when is raining

[Turbo_Boss]

Hey guys,

I have a 2002 1.8T with 62,000kms

It has new brake pads in the 4 corners installed at 61,200kms.

In normal days, the brake pedal travel is normal but as soon is raining the brake pedal travel is more.  I will say its almost the double.......... Its look like the brake system knows is a little colder/raining and the brake pedal behave that way

In none of the cases, the brake pedal is spongy.  There is no brake oil leaking

Car is breaking OK just the brake pedal travels more until I feel resistance.

I try it breaking very hard and the ABS activate as normal

The brake fluid reservoir is full and the color looks OK

The brake booster vacuum plastic pipe is all new. I replaced a few month ago.

What can be the problem?

THX,

Isaac

[Nino]

Sounds like mosture in the lines to me. It happens when the hydraulic fluid has been in for awhile. Brake fluid is advised to be changed every 3 years. If it has not been done in a long time id suggest you start there.

[Turbo_Boss]

Sounds like moisture in the lines to me. It happens when the hydraulic fluid has been in for awhile. Brake fluid is advised to be changed every 3 years. If it has not been done in a long time id suggest you start there.

Hey Nino,

Well, I have never flush the brake fluid but the pedal also does not feel spongy. Its my understanding that is there air in the lines the pedal will feel spongy..............

Any advise?

THX,

Isaac

[Dean_W]

As said above, I would start with bleeding the brakes and replacing the brake reservoir cap and seal.

Are the discs in good condition?

[Turbo_Boss]

As said above, I would start with bleeding the brakes and replacing the brake reservoir cap and seal.

Are the discs in good condition?

The rear rotor disc does not look completely flat............... They are not worn but they dont look flat.

I know how to mechanic/fix my car. Sometimes I do my own fixes. I was there when the mechanic change the brake pads. The old pads was not completely worn out when I change them. I just saw that they was more thin and decide to put them all new as regular maintenance.

I saw the calipers, hoses, master cylinder and all of them are OK and not leaks.

Today I drive with the hand brake one notch up and the brake pedal travel is the same...............I will do the same test when is raining to see what I find.

THX,

Isaac

[Nino]

It wont always feel spongey but does sound like air in the lines to me. Also when you have it done enaure a garage does it and that they also bleed the ABS pump. And that its done on a computer that controls the bleed because if you dont and bleed is done wrong you will go to brake one day and your pedal will hit the floor.

[james2]

I would have put new discs on when changing the pads. My car felt like it hardly had any brakes, so i got new discs.

[Turbo_Boss]

I would have put new discs on when changing the pads. My car felt like it hardly had any brakes, so i got new discs.

Hey James, do you put pads and rotor disc at the same time?

My car is braking OK............... I will keep checking them when its raining............. But if I still fill the same problem, my next thing would be changing the rotor disc.

THX,

Isaac

[james2]

I would have put new discs on when changing the pads. My car felt like it hardly had any brakes, so i got new discs.

Hey James, do you put pads and rotor disc at the same time?

My car is braking OK............... I will keep checking them when its raining............. But if I still fill the same problem, my next thing would be changing the rotor disc.

THX,

Isaac

I put new grooved and drilled discs on and used the old pads because they looked fine. The Pads had worn uneven on the old discs. You want new discs and pads so they wear perfectly with each other. My car was unsafe for me to trust them and I got new pads 2 days later. I will always change them both at the same time when i need new pads.

[Nino]

Choose to take my advise or not. But discs will not be the cause of "longer travel on brake pedal"