Leaf Electronic parking brake

Nissan Leaf/e-NV200 drive stack topics
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Extremetaz
Posts: 54
Joined: Thu Sep 19, 2019 9:35 am
Location: Kildare, Ireland
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Leaf Electronic parking brake

Post by Extremetaz »

A bit of a segue for this place but I figured it might be useful so here it is.

We've just crossed the 300,000km mark and I was writing up a piece about living with the car over that distance and the last 8 years. The piece is *WAYY* too long to publish so I'll have to distill it down a bit, but one of the nuggets that came from it is that I recounted how I dealt with the failure of my handbrake a couple of years back.

Anyone who's had any dealing with the Leaf for any extended period will be aware that the parking brake has a tendency to fail after a few years. It's a €700 part and allegedly isn't serviceable. Naturally, ours failed whilst I was away working in Spain for the week and I got a call from my wife to tell me that the handbrake on the car was stuck on and wouldn’t release. I provided instructions relating to the manual release and she duly tried that, then got my brother-in-law across the road to give it a go when she had no success. He fared no better and so the car sat, blocking the driveway but thankfully inside the gate, until I returned.

On inspection sure enough, the handbrake was bound tight. I ended up releasing it using the cable adjustment under the boot and got the car back to a drivable state. We continued to use it without the handbrake for a couple of weeks while I gathered some information on our options. The word coming back was that the unit wasn’t serviceable, wasn’t sold in parts form, and so would require full replacement at the princely sum of ~€700.
So 9 & 10 in the below, along with the cables from them to the junction plate for the parking brake cables are all one catalogue part.
Manual screenshot (PB)
Manual screenshot (PB)
and this is a shot of part 10 in isolation:
Handbrake actuator
Handbrake actuator
I wasn’t happy with that price, but that wasn’t what annoyed me. What annoyed me was that this was, ostensibly, a very simple piece of kit and should be serviceable. So I took it out of the car altogether and began dissecting it – and it transpires that it is indeed a very simple piece of kit. In fact it’s so simple that there really should only be a couple of likely failure modes in it (and none of them should really be all that likely) – the motor which drives it, the actuator shaft bearings, and the tension sensor which relates to the motor. A bit of testing showed the motor to be just fine, and the actuator shaft moved freely. The tension sensor I was happy to assume good until symptoms suggested otherwise.

It transpired that what had failed was a shim on the reduction gear – and this shim hadn’t fallen apart or broken up, it had swollen and bound the gear tight to the shaft that it was supposed to rotate on. The reason the manual/emergency release hadn't worked was that the steel cable it relies on had sheared before it managed to persuade the 'shimmed' reduction gear to move. The reduction gear is plastic course despite every other gear in there being alloy(!) and it was resisting every attempt made to shift it without damage.
'The shim'
'The shim'
Things got to the point that I was pretty sure it was going to break so I recorded its exact specs to see about getting a replacement before going to town on it. Replacement was going to involve a custom cut gear, which wasn’t cheap, but was still under €200 so I figured that’ll do. Time to get heavy on this thing – time to call in ‘the auld boy’.

Now this sheer weapon of a man grew up working on farm machinery and is without doubt one of the very best ‘get it working right now!’ people you will ever meet. This is not a man who waits for parts. This is not a man who 'doesn’t have the right tool'. He’ll either find or make something that will do the job, or come up with some way around the problem. In this case it transpired that all we needed was a 1” chisel and a cloth to wrap around the teeth of the offending gear. Given these two things he was able to twist the seized gear by hand (I use this term purely in the anatomically correct sense as his are more akin to a pair of industrial presses) and simultaneously lever it off its shaft with the chisel.

It came off perfectly intact!

The fix then was to bore the offending shim out from its supposed 6mm ID to 6.5mm, and then simply pop the gear back on the shaft.
That was more than a year ago now and it’s been working perfectly ever since.

So tools required:
- Trim clip wrench for the underbelly panel
- Standard socket set for handbrake unit removal
- Torx set for opening up the actuator
- 1 Dull and otherwise quite useless 1" chisel
- Your local Oranguman
- 6.5mm drill bit
- A very small amount of finess in resetting the brake cables in the car on reassembly


So there ye have it.
Hope this is useful. 8-)
Break it; Fix it; Repeat;
whereswally606
Posts: 17
Joined: Sun Nov 14, 2021 6:16 pm

Re: Leaf Electronic parking brake

Post by whereswally606 »

have a gen1 leaf that I intend to keep for a very long time. this is beyond useful. Just need to identify my local oranguman.
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