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the mot are we now allowed hydraulic handbrakes
thunderace - 6/3/09 at 10:06 PM

the mot says the hand brake must me merchanical so was shocked to see its a button???on the new vw Passat so are we now allowed hydraulic handbrakes.

blakep82 - 6/3/09 at 10:07 PM

nope.

passat is electro-mechanical

rusty nuts - 6/3/09 at 10:12 PM

Some Mercedes, Renaults and Range Rovers use electro mechanical handbrakes. Going to be fun changing brake pads

goaty - 6/3/09 at 10:12 PM

yes, but needs to be able to lock in position i thought....

Gazeddy - 6/3/09 at 10:34 PM

afaik you could have always had a hydro handbrake it just has to be completely separate from the main brakes ie second caliper

jollygreengiant - 7/3/09 at 06:36 AM

quote:
Originally posted by rusty nuts
Some Mercedes, Renaults and Range Rovers use electro mechanical handbrakes. Going to be fun changing brake pads

Some of them have an automatic function as well, - when the engine is off (even key in but engine not running & no motion sensed from wheels)) the handbrake is activated automatically. These do have a service mode that I believe allows about an hour of wheel free before it re-activates the parking brake. I have not worked on these but as you say they are I believe interesting to work on.

speedyxjs - 7/3/09 at 08:10 AM

I believe jaguar use a hydraulic handbrake but there must be something mechanical about it or they wouldnt be road legal.

Gazeddy - 7/3/09 at 08:47 AM

when you get them in service mode you just push the piston back or wind it back like you would normally

adithorp - 7/3/09 at 08:55 AM

Hydralic handbrakes are not allowed. On hydro/mechanical calipers the handbrake is mechanical using a cam or screw to apply force to the pads and not hydralic pressure.

Electro/mechanical handbrakes fall into two categories.

First is older type, like Jag/Ford/older Merc's, where the normal handbrake cable system is pulled by (basically) an electric moter turning a screw to pull the cable. Electronics control the operation of this motor and can include automatic setting. Without the motor turning the cable can't release.

The second and new system, fitted to the latest VW,Audi,Mercs, Uses a moter inside the caliper itself and winds the piston out with the aid of a swish plate (look it up) to create presure. Again this is mechanical presure. This has very sophisticated electronics controling it. With automatic setting, anti roll-back, padwear warning, etc. Special diagnostic kit is required to reset the pistons and change the pads and the manufacturers are not using a common system so VW kit won't reset Merc and they're not cheap! You won't be changing your own rear pads!

adrian

prawnabie - 7/3/09 at 09:35 AM

Newer renaults have a motor inside a box that has two handbrake cables coming out of it to the calipers.

adithorp - 7/3/09 at 09:56 AM

quote:
Originally posted by Gazeddy
when you get them in service mode you just push the piston back or wind it back like you would normally


For the first system I decribed then yes.
For the second definatly NO, unless you want a big bill.

adrian

40inches - 7/3/09 at 10:07 AM

Gendan now sell a service module just to allow a change of pads http://www.gendan.co.uk/product_VS8621.html

britishtrident - 7/3/09 at 10:44 AM

On the VW the mechanism works by a stepper motor driving a worm which turns a cog which applies the brake ---- a worm drive "ovehauls" ie worm can drive the cog but the cog can't drive the worm.



Needles complexity the real reason is probably connected with so calleds green cars that turn the engine off when stopped at the traffic lights.