ive got a mk3 2.0 jetta and ive redone the whole brake system: new calipers front and rear, pads front and rear, stainless braided hoses, new master cylinder, and a new prop. valve. im using the motive power bleeder (pressure bleeder) and have followed the specific instructions stated in my bentley manual, but im still getting a low pedal. at one point it was stiff as hell and right up top, just how cars with stainless lines should be, but after i took the bleeder off, it lost the firmness. any ideas? no more air is coming out of the bleeder screws. thanks in advance. also, not sure if it matters or not, but im using ate typ-200 brake fluid.
pressure bled brake system on mk3 2.0, still low pedal
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bump.
as long as the pedal is not dangerously low. It may just need driven.
The pistons in the caliper need a few miles to seat perfectly to the brake pad. The brake pad to the rotor, ect
The pistons in the caliper need a few miles to seat perfectly to the brake pad. The brake pad to the rotor, ect
No!as long as the pedal is not dangerously low. It may just need driven.
The pistons in the caliper need a few miles to seat perfectly to the brake pad. The brake pad to the rotor, ect
Do not drive your car with damaged brake system... seriously?
Look for leaks first
Get a new master cylinder if there are none.
Hence the reason why I said "as long as it is not dangerously low"No!
Do not drive your car with damaged brake system... seriously?
Look for leaks first
Get a new master cylinder if there are none.
If you just replaced every component of your braking system you can expect the brake pedal to not feel as firm as it will after a couple miles of driving
And telling him to start replacing brand new parts without diagnosing them ? Seriously?
Bogus new parts are entirely possible. I just bought a new master cylinder and it was non-functional out of the box. The piston wouldn't return by itself. To the thread-starter, can you mount the master cylinder in a vise and make sure the piston goes in and out all the way?
Yes. It is completely possible. That is why you would want to TEST the part. Not just start randomly condemning new partsBogus new parts are entirely possible. I just bought a new master cylinder and it was non-functional out of the box. The piston wouldn't return by itself. To the thread-starter, can you mount the master cylinder in a vise and make sure the piston goes in and out all the way?
There arent that many parts to the brake system... Check for leaks, if there are no leaks im pretty sure its your master cylinder.
When i replaced my pads somehow my pressure was lost. I drove it for a little while and having ****ty brakes is not a good feeling. Id never advise someone to drive on a half functional brake system...
What ever it is, fix it first.
When i replaced my pads somehow my pressure was lost. I drove it for a little while and having ****ty brakes is not a good feeling. Id never advise someone to drive on a half functional brake system...
What ever it is, fix it first.
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Did you bleed the brakes with the rear wheels on the ground, or support the rear wheels with the jackstands on the rear beam while bleeding the rear brakes to hold the rear wheels in the same position they have when they are on the ground, or position the load level on the proportioning valve in the "rear wheels on the ground position"?
If you didn't, then the proportioning valve would have restricted fluid flow to the rear brakes, and the rear brake lines will not have been bled properly. Since the rear brakes are connected diagonally to the front brake calipers, when the rear brakes do not work, the front brakes do not work.
How much fluid did you use while bleeding the brake system? Typically, it takes me almost two quarts to fill and properly bled a MKIII brake system after I have it opened up and replace parts in both the front and rear brake systems. Even with a pressure or vacuum bleeder you have to run enough fluid through the system to force the air to come out.
If you didn't, then the proportioning valve would have restricted fluid flow to the rear brakes, and the rear brake lines will not have been bled properly. Since the rear brakes are connected diagonally to the front brake calipers, when the rear brakes do not work, the front brakes do not work.
How much fluid did you use while bleeding the brake system? Typically, it takes me almost two quarts to fill and properly bled a MKIII brake system after I have it opened up and replace parts in both the front and rear brake systems. Even with a pressure or vacuum bleeder you have to run enough fluid through the system to force the air to come out.
Seriously? Brake components don't "firm up" with wear.Hence the reason why I said "as long as it is not dangerously low"
If you just replaced every component of your braking system you can expect the brake pedal to not feel as firm as it will after a couple miles of driving
And telling him to start replacing brand new parts without diagnosing them ? Seriously?
Fix it before you drive it. You know how it should feel, it felt like that before you disconnected the bleeder. What was the bleeder providing? Additional pressure? If you have clean, bubble free fluid coming from all four corners it is bled properly. I use a vacuum bleeder, I've read that pressure bleeders can force micro air bubbles into the fluid. Now that you have all the fluid replaced try the old fashioned "helper pressing the pedal" type bleeding and see if you get to where you need to.
everything is new in the brake system. yes, i bench bled the master, but it sat for 2 months before getting installed. it works 100% rear brakes are grabbing hence why i cant rotate the rotors with a helper holding the pedal, and the front work as well. i have the entire car up on stands so all wheels are off while bleeding. i used a little less than 2 litres of fluid, and its all coming out clean, and bubble free. no leaks at all. my dad and i are thinkin of bleeding the master cylinder again once i get more ate brake fluid. i followed the procedure from the bentley manual for bleeding with a pressure bleeder and i had a solid pedal at one point, but got soft after i cracked one of the front bleeders open to purge.
If you figure it out, post your findings. My brakes work great, but the pedal engages lower then what seems "normal" to me as well. I've been through the whole system and couldn't find it.
try a new master ive put some on that are **** right out of the box
i followed the procedure from the bentley manual for bleeding with a pressure bleeder and i had a solid pedal at one point, but got soft after i cracked one of the front bleeders open to purge.
Its supposed to do that. How many times did you bleed the system though? I didnt really bench bleed mine, just had some rubber hose feeding back into the res and pressed the pedal about 15 times. Then connected the lines to the MC and bled the brakes with a hand pump bleeder about 5 times per wheel, then again with a helper on the pedal to ensure the pedal was stiff.
I knew they were back to 100% when I finished, you have more control over the car with less work from the brake pedal.
Id bleed again, and look for leaks while bleeding. Maybe one of the bleeder screws are lose?
If not, MC replace. If you got it two months ago, see if you can return it and get a new one.
Half of you must be remedial.Seriously? Brake components don't "firm up" with wear.
Fix it before you drive it. You know how it should feel, it felt like that before you disconnected the bleeder. What was the bleeder providing? Additional pressure? If you have clean, bubble free fluid coming from all four corners it is bled properly. I use a vacuum bleeder, I've read that pressure bleeders can force micro air bubbles into the fluid. Now that you have all the fluid replaced try the old fashioned "helper pressing the pedal" type bleeding and see if you get to where you need to.
It's not "firming up with wear" it is the pistons fully seating against the pad. Especially in the rear. The caliper piston needs some time to fully adjust. Ever hear how your e brake helps adjust the rear calipers? all of this is related and can have effect on brake pedal feel.
Seriously? Brake components don't "firm up" with wear.
Fix it before you drive it. You know how it should feel, it felt like that before you disconnected the bleeder. What was the bleeder providing? Additional pressure? If you have clean, bubble free fluid coming from all four corners it is bled properly. I use a vacuum bleeder, I've read that pressure bleeders can force micro air bubbles into the fluid. Now that you have all the fluid replaced try the old fashioned "helper pressing the pedal" type bleeding and see if you get to where you need to.
Half of you must be remedial.
It's not "firming up with wear" it is the pistons fully seating against the pad. Especially in the rear. The caliper piston needs some time to fully adjust. Ever hear how your e brake helps adjust the rear calipers? all of this is related and can have effect on brake pedal feel.
The brakes should be adjusted before driving the car.
Op: pull the e brake up, step on the pedal, then let the e brake down. Do this several times. If it doesnt help, dont worry about them not being adjusted...
-David
i went around 3 times before i saw the little side note i overlooked in the bentley about adjusting the prop valve all the way down. after that, i got a hard pedal after doing the rears once. but once i got to the passenger front caliper, it got soft again. i hadnt gone around and bled it again since i only have half a litre of fluid left, which i dont think is enough to go around 3 or 4 more times. im waiting till tomorrow or tuesday when i get more fluid from germanautoparts.com. think if i go aound a few more times itll help?
fyi, i havnt hooked up the park brake cables to the handle yet. im gonna put it on once it cools down outside. this heat wave is killer.
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i went around 3 times before i saw the little side note i overlooked in the bentley about adjusting the prop valve all the way down. after that, i got a hard pedal after doing the rears once. but once i got to the passenger front caliper, it got soft again. i hadnt gone around and bled it again since i only have half a litre of fluid left, which i dont think is enough to go around 3 or 4 more times. im waiting till tomorrow or tuesday when i get more fluid from germanautoparts.com. think if i go aound a few more times itll help?
You got it backwards.
I wrote about this in POST #9 yesterday. The proportioning valve has to be positioned like the wheels are on the ground (lift and support axle beam, not on the rear chassis), with the Proportioning Valve Lever Positioned UP, NOT DOWN. Lever down restricts fluid flow to the rear brakes.
gottcha. so, get under the car, loosen the nut and bolt and pull the lever towards the ground, and jack the axle up as if its sitting on the ground. correct?
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