Weird vibration of EPB Manual Release Wire

[ledgewalker]

Hi Everyone -

I'm a long time reader but first time poster. I have a 2012 D4 HSE SDV6.

My EPB module was replaced recently (don't ask me the cost!!) and then today, the EPB manual release wire started vibrating weirdly. The vibrations are in sync with the movement of the car; at rest no vibrations, then they start and increase as the car begins moving and speeds up. I literally hold my hand on the release wire and feel it vibrating. At slow speeds it's like something is flicking the wire reasonably close to where the wire loop is (obviously I can't see past where the wire disappears beneath that area under the cupholders.

I haven't tested the EPB on a hill but I don't think it's working as I can't hear that mechanical locking sound it usually makes when it's first engaged. But there don't seem to be any noises / smells coming from the rear calipers or elsewhere. The car seems to drive normally even at highway speeds, just with this weird vibration on the wire.

My question really has to do with whether I'm damaging anything by continuing to drive the car until I can get this looked at?

Cheers,
LW

[ledgewalker]

Update: I tested the EPB and it's actually working fine. So it's just the vibration; no other symptoms.

[RANDLOVER]

The EPB might not be adjusted correctly/releasing properly and is rubbing on the rear brake discs. I had this happen once but that actually caused a shudder while driving at freeway speeds, scraping might be heard at low speeds, and just put it on/off a few times which seemed to fix it, until my mechanic could adjust it IIRC. I might've even done that while in Low Range, as I have a theory that the car applies the EPB with more force, when in low box.

[DiscoJeffster]

The EPB might not be adjusted correctly/releasing properly and is rubbing on the rear brake discs. I had this happen once but that actually caused a shudder while driving at freeway speeds, scraping might be heard at low speeds, and just put it on/off a few times which seemed to fix it, until my mechanic could adjust it IIRC. I might've even done that while in Low Range, as I have a theory that the car applies the EPB with more force, when in low box.

Turns out that’s not a theory but fact. It’s documented in the workshop manual if I recall. I was skeptical of this but looked it up and it’s correct.

[BradC]

Turns out that’s not a theory but fact. It’s documented in the workshop manual if I recall. I was skeptical of this but looked it up and it’s correct.

You can verify it yourself by measuring the application force with an IID.

[ledgewalker]

Thanks for everyone's comments. The EPB does work and I've tried on/off in both hi/low range to try to get it to self adjust, but no luck.

But I'm not sure the problem is the brakes grabbing on the discs.

I found this Powerful UK video:

Land Rover Discovery 3&4 Rear Hand Brake Shoe Adjustment LR3 LR4 - YouTube

and in particular this image:

Screen Shot 2021-05-02 at 12.16.21 pm.jpg

which I'm guessing is part of the manual release mechanism (total guess).

The way it feels in the car is as though, on releasing the EPB, the top nib of this mechanism isn't retracting far enough and is hitting a point on the drum every turn it makes. That then causes the weird vibration I'm feeling on the manual release cable in the car.

Does this sound plausible?

I'm asking because in a few days I've got a few hundred kms to get back home where my indie can inspect. I'm trying to satisfy myself that I'm not doing any real damage by driving at highway speeds for a few hours. If it's just this mechanism and the discs are otherwise free of the brakes, then I'm hoping I'll be fine.

Grateful for any further thoughts anyone has.

[ledgewalker]

It turns out that the manual release wire had come loose from its clip/bracket on the underside of the console. A very simple fix.

My suspicion is that this wasn't clipped in properly when the EPB module was replaced, and it eventually worked its way loose.

My theory in my post above was way off; I now know that the manual release wire goes to the module, and the problem couldn't have been with that mechanism in the picture I posted that is part of the disc assembly.

All's well that ends well.