Rear Brakes - electronic handbrake arsery

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scotta
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Rear Brakes - electronic handbrake arsery

Post by scotta » Wed Sep 04, 2019 10:33 pm

I seem to remember someone on here saying they had a way to do rear pads on a passat?

Dad's Tiguan needs rear pads as the offside rear seems to have been binding a bit.

Ordered pads today and i ha a crack at changing them tonight.

I cant get the piston to go back at all. Had so much force on it that it was bending the tool metal plate.

I see three potential issues

A - My tool only has two pins on it and the VW has three meaning i cant turn the piston when im trying to wind it back

B - The electronic handbrake is on and i dont have VCDS to put it in maintenance mode. Seen a suggestion that you can remove the electronic handbrake and manually release it but my halfords hex tool is too big to fit alongside the body of it.

C- The calliper is fucked - which given it was binding and has worn the pads through is highly possible.

Thoughts?

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Simon
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Re: Rear Brakes - electronic handbrake arsery

Post by Simon » Wed Sep 04, 2019 11:39 pm

My Merc has an option in the dash menu to put the electronic handbrake into service mode, so that you can DIY it. Doesn't the VW have the same?
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scotta
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Re: Rear Brakes - electronic handbrake arsery

Post by scotta » Thu Sep 05, 2019 12:06 am

Simon wrote:
Wed Sep 04, 2019 11:39 pm
My Merc has an option in the dash menu to put the electronic handbrake into service mode, so that you can DIY it. Doesn't the VW have the same?
Nope.

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integrale_evo
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Re: Rear Brakes - electronic handbrake arsery

Post by integrale_evo » Thu Sep 05, 2019 1:51 am

If the piston has dimples or a slot then in every one I've done the piston will not just push in without being turned at the same time.
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NotoriousREV
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Re: Rear Brakes - electronic handbrake arsery

Post by NotoriousREV » Thu Sep 05, 2019 5:18 am

Every VAG caliper I’ve ever worked on since the millennium has needed to be screwed back.
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unzippy
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Re: Rear Brakes - electronic handbrake arsery

Post by unzippy » Thu Sep 05, 2019 5:19 am

NotoriousREV wrote:
Thu Sep 05, 2019 5:18 am
Every VAG caliper I’ve ever worked on since the millennium has needed to be screwed back.
This. Including pre millennium.
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Gavin
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Re: Rear Brakes - electronic handbrake arsery

Post by Gavin » Thu Sep 05, 2019 7:51 am

When I had my Passat I was told it was "impossible" and people had chopped fingers off trying. This may be as likely as all the people who got their arms broken by swans though!

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Sundayjumper
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Re: Rear Brakes - electronic handbrake arsery

Post by Sundayjumper » Thu Sep 05, 2019 8:25 am

scotta wrote:
Wed Sep 04, 2019 10:33 pm
I seem to remember someone on here saying they had a way to do rear pads on a passat?
That'll be me, I guess, I get stroppy every time Gavin does his post :lol:

A - you definitely need to turn the piston

B - if you remove the handbrake motor from the caliper you can use an allen key (or possibly torx, it's a while ago now) to wind the handbrake mechanism back. That's assuming it's the same as a Passat, I can't imagine it'll be hugely different.

C - quite possible, but that's not the reason you can't push the pads back

The handbrake is concentric to the brake piston so you'll need to wind both of them back to get new pads in.

When you put it all back together you need to set the handbrake so that the car doesn't freak out. The thing to understand is that it doesn't monitor the absolute position of the pads. When you apply the handbrake it runs the motor until the current draw reaches a set amount *or* a time limit is reached. When you release the handbrake it runs the motor for a set period of time. You just need to set the pads close enough to the disc that it all behaves normally. Once the hydraulics are all set, turn the handbrake mechanism until the pads bite, then back off (IIRC) about 1½ turns. Reattach the handbrake motor. All should be well.

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scotta
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Re: Rear Brakes - electronic handbrake arsery

Post by scotta » Thu Sep 05, 2019 10:18 am

Sorted. Found a Mate who has VCDS and he came round this morning with it. As soon as we deactivated the handbrake the pistons eased back.

He recons the pad was sticking in the sliders as they were tight which is what caused the pad wear and that the calipers are fine. He knows his stuff - He was a race engineer for two BTCC Teams.

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