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Re: Grand Scenic Electronic Handbrake Stripdown Plus Photos
Thanks for the detail. I had the misfortune to have the cables retract on my Laguna .I released them by applying a 12v current in reverse to the motor been careful not to touch off the circuit board which worked and allowed me to reattach the cables but now the motor does not work resulting in no handbrake and a fault light is shown up on dash...any ideas ?
How to remove and take apart the handbrake control unit on a 2005 Grand Scenic II.
Most of this guide was written after reading a brake unit replacement by Gonescenile I suggest you read that also.
This is my version with unit strip down and service from my experience working on it.
The photos should make sense of things detailed in the text.
Do not start the car at anytime during this process.
Park the car on level ground, chock the front wheels. If the unit still operates ok but the cables do not release fully do the following. Put the key card in the ignition and press the start button until the instrument panel lights up and the steering lock releases. Operate the handbrake so that it is OFF. Press the button twice and remove the key card. It will beep and complain that the handbrake is OFF. I then disconnected the battery negative terminal.
Put the car in gear.
I jacked the car up at the Off/side jack point, until just before the wheel lifted, just to give me more room to work under the car.Use an axelstand as well for safety.
Working inside the boot remove the boot carpet and then the plastic cover just behind the normal rear seats. Three big plastic knobs. Remove the jack and tools.
Lift up the extra rear right seat; locate the spare wheel release bolt under a small flap in the carpet. Release the spare wheel using the wheel nut spanner or a socket set.
From under the car pull the wheel towards the back of the car and release more cable until you can release the wheel. The mechanism may be a bit rusty so apply plenty of WD40 or similar. Grease the unit later prior to refitting the wheel.
Put the seat down again. Open the central storage section and then remove the plastic cover over the yellow handbrake release handle. Take care not to break the plastic clip. (I did) Pull the handle up a bit but not fully up, as this will release the handbrake mechanism inside the unit. At the top of the handle there is a small plastic clip that needs to be pushed upwards so that the cable nipple can be released from the handle. (See Photo 1)
With the handle removed go under the car and gently pull the black plastic mounting free from the floor. (See Photo 2) Release the two clips holding the cable.
MEASURE the distance from the cable end round nipple to the support arm holding the cable end at the C-clip. If the arm is fully back on its stop then add about 10mm to this measurement. If not estimate the extra needed plus the previous length. This is so that when you have reassemble the control unit you can set the internal screw to the required length of exposed cable to fit the unit back on to the callipers. (See photos)
Unbolt the nuts on the actuating arms of the brake callipers and carefully lever them off the splined shaft. This makes releasing and refitting the cables easier.
Carefully remove the C-clip on the cable end, the clip will be a bit rusty and you don***8217;t want it to break if you are going to use it again. (A new unit will have new C-clips).
With the cables now free push them sideways out of the mounts half way along the cable. On the N/Side above the exhaust pipe there is a tie wrap that will need cut as this holds the cable in place.
Unclip the electrical cable on the unit. Lift the small bar slightly and turn it, this should eject the plug as it turns. Release the clip holding the cable to the unit.
The unit has 3 mounting points, two bolts located in the recess beside the jack storage area inside the car and one smaller bolt holding the unit in place from underneath. Working inside the car release the two bolts holding the control unit. (They have big square washers underneath them)
The unit is now only held on by one screw under the car as shown in the photo. When you unbolt this, the unit is free. Feed the cables around the springs etc to get it out from under the car.
Check the rubber shock mounts on the unit, one of mine was broken.
To open the unit unscrew the Torx screws on the cover. Very carefully prise up the lid and try to remove the lid without damaging the seal beneath it. Work a thin blunt tool round the seal to release it, try to keep it intact so that it doesn***8217;t leak when refitted. Easier said than done, use silicon gasket sealant sparingly when refitting.
With the lid removed your will think, this is a bit complicated. However the unit is quite simple, mechanically that is. Avoid damaging the circuit board.
Using a large spanner release the cable end caps. If the cables are jammed and the inner cable does not move inside the cable try the following. Find a way of holding the unit so that one cable faces the floor.
Hold it in a vice or get someone to hold it for you. Fill up the big cable end at the unit end with WD40 or release oil. Try bending the cable back and forth all the way up towards the top to try and work the lubricant down the inner cable. Keep doing this until the cable moves freely. Eventually it should. I used 3 in 1 oil once the cables were free.
Check that the calliper end is not broken or the inner cable plastic covering wrinkled. If they are they will probably always give you trouble.
If you can find replacement cables then they are easily fitted. Reno does not sell them. Donor cables from a scrap unit will probably have the same faults. You might get lucky.
Do the same to the other side.
The length of the outer cable is important so do not remove any damaged rusty broken bits unless you fabricate a spacer to go on the cable to compensate for the missing cable. I did and that caused other problems. (The motor wound the cable in and jammed as the screw fully wound in due to too much slack cable, see photo)
You will see from the internal photos how the unit comes apart. First release the plastic clip on the O/side end where it meets the Switch assembly. Carefully prise out the lugs a little either side and it should slip off. Release the cable from the switch peg. The emergency release cable pulls a round bead on the internal small cable on to the release arm; this disengages the switch assembly from the motor screw assembly. This is why once the emergency cable is pulled the brake will remain off until this is re-engaged. Carefully remove the plug on the flexi cable at the PCB end. Note how it is fitted.
Three Torx screws hold the motor in place remove them and carefully lift the motor partly out. Unscrew the N/Side cable out of the tube that goes though the motor. This is a LEFT HAND THREAD. The cable can be removed from the unit and the tube part from the motor. The tube part should rotate freely on the release actuator block.
Do not take the Switch apart; it is very unlikely that this unit will fail. You will not get it back together as the top gets damaged taking it apart.
I have shown it in detail in the photos to show how it works. Basically the action of pulling the cables on, compresses the spring and the pin with the magnet moves with it to operate the switch in the plastic lid. This indicates that the brake is on. Releasing it does the reverse. If the emergency handbrake lever is pulled then the switch will never indicate that the brake is on, as it will not move. (The instrument service light would come on and stay on)
(As we have the battery disconnected no fault codes will be stored. That***8217;s why I did it, plus safety)
Before you put the motor back replace the rest of the assembly without the tube through the motor. With the main cables fitted CHECK the exposed section at the end of the cable. Rotate the tube section until you have the correct length of exposed cable as measured before removing from the calliper. Allow a bit extra rather than less.
Now measure the distance between the screw end and the tube end. Unscrew the cable and refit with the motor in place, screw the cable in until the length of screw is the same as above. Bolt the motor in place.
Grease all the moving parts. ENSURE the brake release cable passes through the actuator arm. Refit the plug from the Switch to the PCB.
You may want to leave the lid off until you test the unit on the car its up to you.
To refit the unit, run the cables in the general direction they would take.
Loosely fit the small supporting bolt before locating and tightening the two bolts inside the car followed by tightening the small lower bolt fully.
Clip the cables though the brackets and feed the cables though the mounting plates on the callipers.
Fit the C-clips. If you have measured correctly the cables should have enough exposed cable for the actuator arms to be refitted.
Before fitting, put the arm on the shaft and CHECK that the brake calliper mechanism works properly. It should not stick and it should return fully to the end stop.
The wheel may have to be raised off the ground to check that the pads and discs do not bind with the cable not fitted.
There is no point in fixing the handbrake cable if the calliper and discs are not operating properly. Check the travel of the actuating arm.
If everything is OK refit the arm and cable with the arm against the end stop. Torque the Nut up.
Refit the emergency release cable, clip in place, pushed through the floor and fit the handle.
Check that all bolts and clips are secure; refit the wiring loom plug and clip.
Lower the jack.
Take the car out of gear.
Refit the battery terminal. (You will need to reset the radio, hope you have the codes)
Insert you key card and press the start button until the steering unlocks. Don***8217;t start the engine. (The car may be complaining that the hand brake is off)
Pull on the handbrake switch. The motor should operate and take up the slack cable. Release the handbrake and repeat a few times with your foot on the footbrake, this should self adjust the calliper position. Hopefully it works OK without any strange noises. (If there are stop and investigate)
Check that the lever on the calliper releases fully and that the brake does not bind. Check the handbrake later on a road test.
If you did not fit the unit lid earlier do it now if all is well. If the seal was damaged use a little silicon gasket sealant. If it was intact use a little silicon grease on it.
If you do need to replace the pads or adjust the calliper you WILL need a brake winding/unwinding tool.
If you do remove the calliper do NOT let it dangle on the handbrake cable that WILL damage the cable.
If the cables move freely and appear OK then the pads may be causing the problem being worn right down, you may also need a special tool to release some slack cable from the control unit.
I made a tool up for that purpose from an old tyre lever and two lengths of 10mm screwed rod as in the photos. Fit to the cable as shown (with the handbrake off) ( See photos 29 & 30)
Screw up the nuts until the cable is tight. Operate the handbrake. Release the handbrake, there should be some slack on the cable now. Screw the nuts up to take up the slack. Repeat the process until there is enough slack cable so that the actuator arm will be at its fully open position. Adjust the calliper action on the disc so that it works correctly. Refit the cable and arm.
DO NOT operate the handbrake without the special tool ON or the cable fitted to the brake correctly. If you do the cable will get drawn into the unit and keep going until the motor jams. You will need to strip the unit as above to sort it out.
NOTE 1: This will also cause the brake fail on the instrument panel to come on and stay on. The same will happen if you pull the emergency release handle or if there is any other fault. You will need to get it reset by Reno or an independent garage preferably.
Note 2: This unit is on the CAN Bus and has the VIN number embedded into it when programmed. This means that a unit of another car will not work. Since the unit can be reprogrammed in theory it should be able to be reprogrammed. However as it has a different VIN that the car its fitted to it may not be recognised on the bus.
I have heard that it cannot be reprogrammed but that may be the reason.
A brand new unit is blank and has to be programmed using the clip software but this probably sees it as a new blank unit that can be programmed.
If the above does not fix your handbrake problems or the motor does not run, then the electronics may be the cause.
You will need to check that the clutch, brake and handbrake switch assembly are all working.
I do not have a wiring diagram and the Haynes manual is sadly lacking with no references to the electronic handbrake whatsoever.
I don***8217;t know if there are any fuses in the circuit.
The plug on the unit has a lot of connections. The big pins are power. The smaller have the Can bus wires and I imagine the rest are to the switches mentioned above plus control wires to the instrument panel and the main ecu.
I don***8217;t know so don***8217;t take my word for it
This was about stripping down the brake unit after all...
Good luck if you try a strip down it is not very difficult.
I hope this clears up all questions on the Electronic Handbrake.
My Cables were too far gone and I had the ***8220;pleasure***8221; of having my wallet dipped for £530, unit fitted and programmed. The units cost around £420 upwards and programming £48 (independents) and from £60 by Reno (plus time to fit)
I would have fitted it myself but I ran out of time, wife needed the car.....
Currently in Fitzpat's garage: