B6 Passat Seized Rear Caliper

[ADunbar86]

Hi guys,

Bit of background - Tried taking off the electronic handbrake and got a "handbrake fault" message. Ran the diagnostics and got the fault code 02429 - Right Parking Brake Motor (V283) Clamping Force Not Reached.
However I am nearly 100% sure it is the caliper has seized.
I made an attempt to remove the caliper (using the VCDS (RossTech) to open the pistons etc) however it would not budge. The pads are low and needed changed so I am wondering if this has caused the piston to over extend? Also should I have done this even having existing fault codes?

What are the options for taking off a seized caliper?
At this stage I am considering cutting it off!!!

I know this subject has been asked a million times, but any thoughts or guidance is greatly appreciated.

Thanks in advance,
Andrew

[RichardSEL]

I've put together the best bits seen in the interwebsphere about EPB failure in case it ever happened to me.
PM me an email address for return attach

[DMitch16]

You can unbolt the motor, lift it out of the way, minding the cable and use the hole at the back of the caliper (splined bit) to manually unwind it slightly until it is no longer clamping the piston from inside. Put the motor back on and see if it will retract under the basic settings procedure. If it still won't move then it is shot for sure and needs replacing.

[RichardSEL]

Triple-square MT14 (aka Spline bit or XZN driver) needed + penetrating fluid

[ADunbar86]

Thanks for the replies.
Can I do this with the caliper still attached to the disc? Or can you only do this when the caliper is removed?

I am happy enough to replace the caliper, just wondering if the above suggestion will work if the piston cannot be retracted and I can't get the caliper off.

Thanks again.

[DMitch16]

The motor part is attached with 2 bolts and easy to remove. Unplug the connector and release the wiring from any clips then undo the motor bolts and withdraw. You will then see a fairly deep splined hole in the back of the caliper itself into which you can insert the matching male splined socket. Then undo to release the piston pressure on the disc.

[ADunbar86]

Thanks Mitch, appreciate the comments.
I was going to go with the following process:
- Use the VCDS to open the piston (as per this link (http://forums.vwvortex.com/showthread.php?3865092))
- Remove the caliper. If the caliper won't come off, remove the motor as above and manually wind back the piston
- Replace the brake pads and caliper
- Use VCDS to close the piston again
- Run test/diagnostics again

Anything else anyone would add or any tips/hints?

A couple more questions:
1. Do I replace both brake pads and then close the piston? Or replace one, close the piston, open the piston, replace the other side then close the piston again?
2. I am getting the "Clamping force not reached" fault. Would that make sense to get that fault from a seized caliper? I am thinking the piston has overextended due to the pads being low.

Thanks again,
Andrew

[DMitch16]

Replace both sides then close and perform a brake function test with VCDS. Follow the instructions on the Ross Tech site for changing brake pads on a 3C with EPB.

[RichardSEL]

If manually opening caliper, as Mitch mentioned earlier, do not turn more than one turn -- otherwise the close and re-setup programs run by VCDS will not be able to reset to the correct distance between your replacement pads and disk.

The low pads' warning that comes up on the dash is only measuring your front nearside pad thickness remaining. I've not heard of low rear pads, even if they're down to the rivets, being outside the tolerance for caliper operation or the EPB. But if they're down to the rivets then your disks will probably be damaged

[ADunbar86]

Thanks again RichardSEL.

Hopefully last question.
When I have changed the brake pads and replaced one of the calipers is it just a case of closing the pistons? Do I need to tell the computer it is a new caliper or do I just go ahead and close it with the VCDS? Probably over thinking the process!!

Andrew

[ADunbar86]

Guys,

Can't thank you all enough.

Got sorted - had to take the motor off and manually wind the caliper off to release.. When it came off water was dripping out of the casing, no cracks in the casing though.
The drive on the motor (the splined part) had completely corroded, meaning when the motor turned it wasn't catching the spline in the caliper.

Replaced the caliper (eventually after getting the wrong caliper!), bled the brakes, changed the pads and used the VCDS to run diagnostics. Got quite an abs fault codes (01316), however i was able to clear it in the abs module, re-run a system scan and then run the EPB system test and all was good. Was able to open and close the pistons to change the brake pads on the other side with no bother.

Thanks again for the help everyone. Top job!!

Regards,
Andrew