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-   -   HUGE clunk sound during reversing in my Toyota Altis (https://www.team-bhp.com/forum/technical-stuff/104594-huge-clunk-sound-during-reversing-my-toyota-altis.html)

My family owns a Toyota Corolla Altis, almost brand new, we've had it for a year and a half . Yesterday when I was reversing the car out of the parking lot, after I put the handbrake down and feathered the accelerator and slowly released the clutch, a huge clunk( no other word to describe ) sound came from underneat the rear of the car. It was definetly metal on metal friction. It has happened a few times before but I thought it would be passive.

It's not a whirring sound, so whatever happened, it wasn't rotating. It's almost as if something snapped, or something broke. I guess nothing broke because how can something break more than once(this clunk sound happened a few times before as I said).It sounds pretty harsh, but it's also very quick.

I think it has something to do with the handbrake? Everytime this CLUNK occurs, I feel like there's some obstruction at the back, something hindering the rear wheels from moving because the car kind of surges back during the clunk sound phase.

Here's what happens:
Turn car on -> Release Handbrake -> Put gear in R -> Slowly release clutch -> Car moves an inch back -> CLUNKKKKKKKK.


I don't know if it has anything to do with gears, because I have no space to test any of the forward gears (parked in a lot facing a wall). In fact, since this is a front wheel drive car , how can it have anything to do with the transmission if the sound is coming from the rear.

I've looked under the car and there is no sign of any visible damage.

Any sort of advice/help/answers would be greatly appreciated !

The brake shoes are sticking to the drums, and that is the sound of the brake shoes releasing with a snap. The assembly would need lubrication. Presumably, you may have driven the car in water up to drum level sometime in the past. Also, try moving the car a few inches forward after disengaging handbrake, then reverse - you won't get that sound.

AFAIK Altis comes with rear discs. I am not sure what kind of mechanism is used for handbrake? Is it a separate drum?

^^^Exactly what I was thinking. The altis has discs on all four wheels.

BTW: I'd like to say I'm not too sure about where the sound is coming from. So the sound originating from the engine bay is a possibility.

@MayankJha: The car runs smoothly thereafter. But recently it had to go back to the dealer and get fixed because a nut was missing in the tierod(faulty servicing). Don't have any idea how that could relate to this. But i thought it was worth mentioning as it's weird for this stuff to crop up for such a new car.
Haven't tried going forward and then going back, will do.Thanks for the advice. And this doesn't always happen.
@Anushman : I have no idea what the mechanism used for the handbrake is.

You're right - the Altis does come with all-wheel discs. But IIRC the parking brake is operated through auxiliary drums.

Its relatively new car and haven't have a hands on experience in opening it.

But the parts list suggest that there is a separate drum for the mechanism.

Get it checked at a service station, As your cars still seem under warranty.

One thing I didnt understand, after yesterday, is this sound coming everytime you reverse? What happens if you park the car and engage the first gear?

It's been happening for a while now. And it doesn't happen everytime. I still have to try going forward then reversing to see if the same happens in the forward gears.

I've googled about this and the fault seems to be witht the CV joints or the transmission mounts.
Next time I'll have someone reverse it with the hood open to see if I can understand something.

Hi mate. Faced similar problem with my santro last year (it has drums though). Oil from handbrake assembly had leaked and caused bloating of handbrake pads. One day car came to a standstill. Had to get the entire assembly changed. A visit to the dealer might be the way forward. Better to get it checked now than be stranded.

Regarding sound one way of finding if anything to do with underbody. Take the car onto a typical car wash ramp and someone preferably expert can go underbody and ask another person trying reversing / to reproduce the sound.

The above technique was used to identify a minor issue with my Honda City where the silencer pipes were rubbing off the underbody while reversing. It was fixed with tightening the bush of the exhaust silencer pipes. So one pointer for you to check silencer pipes.

Also I had observed a fluid like noise while coming to a complete halt/starting up. It was fuel in the fuel tank actually.

Your first post mentiones that 'sound came from underneat the rear of the car' so I dont think anything to do with Engine bay.

Also pls check with brake pads getting released properly or not.

Pl keep us posted

Cheers
narayanang76

SS-Traveller is spot on! This happens frequently in my Civic too, especially when it's not been used for a couple of days & has been parked with the handbrake engaged. Try to park it without the handbrake and you won't hear any clunking sound.

D33,

The Corolla Altis has discs all round & (I believe) the hand brake cable goes directly to the the rear discs via a screw mechanism within the rear discs. The brake cable runs within a sheath. When the lubrication between the sheath & the cable is lost, the e-brake does not dis-engage immediately when the brake cable is released, but releases with a snap. That is the sound you are hearing. If you service your rear brakes, the technician will resolve this problem. I had the same problem with my Elantra.

The handbrake system is independent of the disc brake system. E-brake have separate drums inside the hub.

If CV joints go bad then a continuous "clack clack" sound comes from the front wheels. CV joints dont go bad so fast, it should last for 100000+ kilometers. If the transmission mounts have gone kaput, you should also hear the sound on continuous basis.

Will look forward to hear what happens if you engage first gear from park.