[metalmaker80]

Hi all. I have a 99' 2.0 that is having a problem with the front driver side caliper sticking. I have searched and read many fixes for this here on the forum but, I can not seem to get past this. These are the things I have done so far.
1) 4 brand new calipers. (2)on this problem side, thought 1st one was bad. Ensured piston moves freely, also slide pins are free and lubed.
2) Replaced master cylinder (2) and power booster. Bench bled masters twice.
3) Ensured that there is some relief in the booster rod from pedal.
4) Replaced all brake lines and hoses including master to abs.
5) Replaced all wheel bearings and drive axles.
6) Checked caliper bracket for misalignment. No restrictions, caliper slides freely until pressure applied. Open bleeder and fluid comes out and caliper will release with use of a clamp.
I think there must be a problem in the abs system, which is not currently working. No light on dash, all wheels lock and slide on dirt/gravel road. I have checked all fuses and relay, all ok. I do not have vag com yet, will be ordering soon. Is there anything I may have missed? Driving me nuts.
Thank you for any suggestions.

 

[PRM502STREET]

Is the left front caliper actually sticking, or is it just jerking to the left when you hit the brakes?

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[metalmaker80]

Thanks for looking. It is sticking, there is no pull to either side when braking. Press the pedal 1 time and it sticks from there.

 

[PRM502STREET]

Sounds bizarre, but it sounds like you have covered all the bases. One thing many people miss is the brake lines, actually the rubber hose that will collapse and cause calipers to stick. But, you have already addressed that issue. I have never heard of an ABS unit go bad, but there could be a first time for everything. Maybe some trash got stuck in there somewhere,somehow. ABS and airbag have hard fault codes, so there's going to be a fault showing or it will be clear. Hopefully someone here can help you get this figured out! O, by the way Welcome to New Beetle .org!


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[FuzzyFish]

Everything else looks to have been eliminated, sounds like a possible ABS issue.

Could try pulling the fuse see if the issue still occurs. Or once you have access to someone with VCDS, cycle the pump a few times to see if that fixes it.

 

[metalmaker80]

Thank you PRM502STREET, and FuzzyFish. I will pull the fuse and see what I get. I usually am able to take things apart, find the problems and make the repair. After reading up on ABS, there seems to be a better than average chance of making it worse, especially without VAG. I think it is time to go ahead and get VAG to solve this problem as well as some other things I would like to do with it also. Thanks again.

 

[billymade]

To bleed the abs system; VCDS, has a process that will activate the abs system and cause it pump fluid to bleed the system. Make sure you have a decent amount of new brake fluid and keep checking the fluid levels as you go through the process.

Ross-Tech: VAG-COM: ABS Brake Pump Bleeding

VCDS will guide you through the process (tells you what to do; at each step of the way); you will need two people to do the procedure and the car is supposed to be off the ground. More info here:

VCDS (VAGCOM) ABS Bleed Procedure - uk-mkivs

 

[esse10]

darn

Darn man it seems like you did everything possible that could be causing this problem. So by brake sticking you mean that you have the car up on stands and press the brake pedal and the caliper does not release back? IF so then here is a stupid possibility, I believe it takes the rotor to be turning and the weight of the vehicle moving to push the brake pads back to their starting position. I seen that once when I had the car lifted up , wheels off and I would push the pedal and it seems like the calipers would not release back, but it would take the cars rotors turning and the weight of the car to push them back...I know it sounds crazy but that's what It wind up being , in my case that is. In other words there never was a problem... Good luck man.

 

[metalmaker80]

Thank you for the info and links billymade. I am ordering VCDS today so that I can bleed it properly. Also thank you esse10 for your response. I have had a similar situation in the past, however, I am putting the vehicle on the road to test it as you are right about it returning or loosening the pads on the stands. I am starting to zero in on it being a problem in the ABS and will have a go at it this afternoon. Thanks again.

 

[Darwin]

make sure one of the metal pipes is not squashed , you forcing fluid in under presure but it might not be able to escape at the same speed

 

[metalmaker80]

Thank you Darwin. I agree with the force of the fluid in one direction and limited in the other. I have followed the new lines and hoses from the calipers all the way to the ABS module and on to the master cylinder to be certain there are no kinks. All clear. I took out the fuses and unplugged the connectors to the module, cleaned them good with contact cleaner and put back together in the hope that something was not making good contact. I also cleaned the wheel sensors and connectors as well and still no joy. I think at this point there is nothing else I can do until I can get the VCDS and go from there. Thanks to everyone for your help.

 

[Jeff2]

For other makes of cars, I've heard that the flexible brake line can sometimes collapse internally, causing the problem you describe. I've heard you really can't tell from looking at the outside of the flexible brake line that this is the problem.

 

[jfoj]

I take the ultra simple approach.

Assume if the caliper is sticking we are really talking about a dragging brake where you can compare to the other side and see a major difference between the 2 sides.

What I would do is just crack the bleeder screw on the side that is sticking so see if the problem is a fluid pressure problem.

If you crack the bleeder screw and the caliper does not release properly, then likely you have a basic mechanical problem. The you have at least split the problem and can focus on fluid pressure not releasing some basic mechanical problem.

The mechanical problem could even be something as simple as the caliper carrier than bolts onto the steering knuckle. This is a pretty simple thing to check and remove and inspect. Also make sure the caliper carrier bolts are tighten properly as well.

 

[metalmaker80]

Thank you both for your suggestions. I have replaced all of the brake lines and rubber hoses as well, and even exchanged front ones to double check their function. All good. I have checked all of the mechanical aspects of both front brakes and cannot find any problems with either side. Opening the bleeder does release the pressure on the caliper, and that has led me to test the abs through someone with vcds. We found that the front brake sensors are working properly and the rears are not working at all. there was also a code about the hyd pump working interm. I have not had a chance to work on it since that scan, but I will be checking into the rear sensors first and replacing if nec and keep going from there. I feel much better now at least knowing where my problems lie, and can zero in on the repairs. It's all downhill from here boys! We'll be cruisin' again soon. Thanks for your help, and I will post the repairs made in the hopes it may help someone else in the future.

 

[esse10]

good

Good to hear you're making ground on your problem. Yea good Idea to post your results here so other folks can learn from this past experience.