First VW, Brake question.

[Gotrek]

Ok it's my second VW we had a VW Vanagon when I was a kid..

Just want to know if my brakes are "normal"

I have a 2004 Jetta Wagon, bought it recently used with 140 000km on it.

Love it so far except the transmission (auto) (anemic and hate how it shifts but it works)

And the brakes.

I want to know if this is how the brakes are. At highway and regular driving speeds the brakes are great, panic breaking is great, regular slowing down is great, decent pedal feel, brakes don't grab all in all great.

When I'm under 20kph or creeping along in traffic it always feels like the motor wants to overpower the brakes, it feels like I have to apply more pressure then I really should. Like a car with the idle speed set to high. But if I apply faster pedal pressure then they feel better. It's if I'm dragging along with light pressure it seems like I need way more pressure then I would in anyother car to feel them grab.

Is that just how they are? I replaced the rotors and pads, lubricated the sliders on the weekend all around in hopes it would feel better but it's the same. the braking system looks in good shape. Maybe time to bleed the brakes/change fluid?

 

[JETaah]

Check the vacuum line to the booster. At higher engine speeds it is possible that the vacuum pump can overcome a vacuum leak better than if just drifting forward at idle speed.
The stiff plastic tube between the vac pump check valve (external w/ the small nipple for the other vacuum operated devices) and booster tend to crack at the barb fittings on either end with age.

Push the brake pedal down then turn the engine off. Does the brake pedal want to raise abruptly? If so it is losing the vacuum too quickly...perhaps because of a leak in the pipe or booster/grommet.

Fluid should be changed every 2 years per VWs maintenance schedule anyway so what could it hurt?

 

[BobnOH]

Most modern cars benefit from frequent brake fluid changes, but I think you may be loosing vacuum at lower speeds. Check all the vacuum piping for leaks, especially the piece to the brake booster.

 

[Gotrek]

Awesome thanks guys I'll check it!

 

[Gotrek]

So the pedal does not push back when the car is turned off. Didn't seem to have a vaccum leak.

I also tested the Master cylinder holds pressure with the car off by pumping the pedal a few times and making sure it gets hard and stays hard. It does.

Somehow while doing that I must of worked some air out of somewhere because this morning the brakes were what I'd consider normal. so that's great but definitely a sign I should bleed them

Thanks for all your help guys

 

[JB05]

You may want to bleed the ABS also, but that requires the VCDS diagnostics by Ross-Tech.

 

[Gotrek]

Ok good to know. That shouldn't be a problem.

 

[02Blue]

also check the output "nipple" on the vac pump. Mine was loose there and I had to re-seat it carefully with a hammer and some patience. i simply held it in tight, and reformed the outer edge of the retainer around it. works like a champ now.

 

[Gotrek]

I bled the brakes this weekend after activating the ABS pump a few times by locking on gravel. Fluid didn't look dirty but still pumped about 1 L of new fluid around the lines.

It's probably in my head but i'd say it's marginally better. There still a definite lack of pedal feel. The brakes feel like the engage in the first 1/2" of travel but there is no real pedal feedback until the pedal is a few inches from the floor. Pedal is firm when it get's there though.

Found a bunch of posts on here and other forum saying it's nor abnormal for this model Jetta. And many were this way from the factory so for now I'll let it be.

I guess the booster is just really strong on these cars.

 

[Gotrek]

So it turns out I think it was my transmission...

After changing all my solenoids a few weeks ago I find the brakes are way better as well. I'm guessing it's downshifting more correctly now, or the RPM of the motor now is better and the vacuum canister is working better.

Something or maybe I bumped something while working on the trans. Either way they are a lot better,

 

[JB05]

Thankyou for the update. A VCDS cable would let you know if there are any stored DTC's in the TCU and what solenoids were at fault.

 

[Gotrek]

There were none I had checked. I changed the solenoids because 2-3 shift was flaring... Although it's possible that when I got my tune they erased the codes.