[almir]

Hi all, before I remove wheels and start inspecting suspension of my jetta, maybe some of you had this particular problem where steering wheel shakes on braking. Rotors are two months old, and I know that they are OK since brake pedal is not pulsating at the same time. Maybe some bushing problem?

let me know what you people think.
Al

 

[Seatman]

Check the sliders for the calipers are nice and free, mine gets vibration if one is sticking.

 

[chittychittybangbang]

Also check the control arm bushings. No pulsing in pedal means something else. Probably these: http://www.myturbodiesel.com/1000q/a4/LCA-bushing-Jetta.htm

 

[stroud2010]

If all of those things are ok, maybe check your tires?
you could have a broken strand that can cause the wheel to shake
its happened to my mom before
my two cents

 

[almir]

I will check all your suggestions. Thank you!
Here is little more info.
Steering wheel doesn't pull left or right nor there is any play. There are no clunking or any type of noises when going over bumps. Steering is tight and responsive in sharp turns. No pulling left or right during braking. No bearing noises.

 

[almir]

update - so steering wheel is vibrating when braking (steering wheel moves about 5mm (less than 1/4") to the right and back. I was thinking it has to be something on the front right side, but today when I was installing new wheels, I noticed that the front left caliper can be moved by hand. Caliper's sliding pin allen bolts are tight. I tried to move caliper on the right side by hand and it was normal (no movement at all). I know that there should be some pressure by caliper cylinder against the brake pads, but the one on the front left acts like there is no pressure against the brake pads at all. I can move brake pads by hand. To me this looks like air in the front left brake lines, I will try bleeding air tomorrow. If that does not solve the problem I am thinking it could be worn steering knuckle or caliper. What are your opinions?

 

[Seatman]

It might be a good idea to check both callipers are nice and free and the pistons aren't sticking at all, pop the pads out and just have someone pump the pedal while you watch to make sure they don't pump to much and pop the piston out, that wouldn't be so handy. Then pull back the dust cover and give the piston a good spray with WD40 or something similar and clean off any crud there, I often find muck where the pistons been sitting. For checking the steering knuckle leave the wheel on and jack it up, you should feel it if there's a little bit of play but I think it'll be the callipers themselves that are probably causing the vibration. As for the wishbone bushes, I try and move the wheel back and forth with the handbrake on, it should be nice and tight.

 

[bigochief]

It really sounds like you have a seized caliper. The pads should have some pressure as you indicated. This would definitely cause pull and shimmy when applying the brakes. I recommend Seatman's suggestion. Applying brake may pop the piston in the caliper or it may remain stuck. If you are lucky to get the piston in the caliper to pop and move, it may still be a candidate for replacement/rebuild if possible. The inside bores of calipers get pitted and the piston could start leaking. I had a frozen piston on the rear right caliper on my 2006 Beetle TDI. I got it to pop and luckily never had any leaks. Good Luck.

 

[almir]

Gentlemen, I tried your advice. I did not have a helper near me, but I did pump the brake pedal 3 or 4 times with caliper removed. Then I opened the brake reservoir cap and used channel locks to compress the piston back in. Piston did move in and out easily without any obstructions. There was no any signs of dirt or rust on the piston at all. It was nice and smooth surface. Anyway, I lubricated it with the PB blaster, and installed everything back. I also cleaned and lubricated sliders. Now here is the funny part: obviously piston moves in and out easily, but when I installed everything back and pumped the brake pedal several times there was no pressure on the brake pads of the mentioned caliper at all, and caliper can still be moved left and right. Very weird. I did not have anyone around me to help me with brake bleeding this time, so that will be my next attempt, but the way everything is going, I already have a feeling that line bleeding will not help. Is front left line diagonally connected with rear right or? I also wonder if this problem had anything to do with my shifting problems since clutch line and brake lines share the same fluid.

 

[chittychittybangbang]

You have ESP right? I believe all the brake lines are separate from the ABS pump / brake regulator.