Brake noise when reversing - is this normal?

[nidgemo]

Hi all - recently changed from an ECLass to an IS300H - am really really impressed with the car, and really happy with it - however, I do have one niggle which may (due to the braking system also harvesting energy) be perfectly normal - but thought it best to check!

This never happens when driving forwards, but when reversing (even at very low speeds) and applying the brakes, there is a distinct and quite loud noise from the rear (i think) brakes - is this a normal thing for a 300h?

Thanks!

[NemesisUK]

I've not experienced this and suggest it's not normal.

Get the calipers and pads checked out.

[nidgemo]

Thanks Nemisis - anyone else ever had this with their 300h?

[Rabbers]

Every morning, before driving off in either direction after reversing out of my front gate, I need to do an upwards-downwards three-point turn on a very steep incline with a low-grip cobbled surface that calls for firm braking.  Like my present RC, the IS managed this manoeuvre without undue strain on the brakes and perfectly noiselessly, so I can only echo Peter’s suggestion that you have your pads etc., checked.

[wharfhouse]

I always reverse out of my drive when I leave the house and never had any noises from the brakes reversing at this time or any other time 

[ColinBarber]

Do a couple of hard stops from 60 mph to clean the disc surfaces and see if the noise continues. The rear brakes don't get much use on a hybrid and so can start to corrode.

[darrude]

I have a ridiculously steep drive (car often wheel spins getting into the garage), and reverse out (reversing downhill) and never get any unusual noises.

[malcolmw]

We quite often get a "grinding" noise when reversing off the drive first thing in the morning. After that, absolutely no noises from the brakes. I suspect this is normal removal of overnight corrosion etc from the discs. I don't think this is a problem.

[rayaans]

A grinding noise is normal providing its not long lasting and should only happen after a wash or if sitting outside after its rained. 

[The-Acre]

4 hours ago, malcolmw said:

We quite often get a "grinding" noise when reversing off the drive first thing in the morning. After that, absolutely no noises from the brakes. I suspect this is normal removal of overnight corrosion etc from the discs. I don't think this is a problem.

Me too, I've had the calipers lubricated and new pads but I always get a slight grinding noise when reversing, doesn't seem to be a problem.

[nidgemo]

Thanks all - I'd call it more of a click or quiet knock, so definately something worth looking into.

[ColinBarber]

Pads moving in the callipers will cause a knock sound - it will only occur once each time you brake in the opposite direction as they move from one end to the other. Normally there shouldn't be play if all the clips and shims are installed, the pads are OEM and a bit of grease is applied in the correct locations.

[nidgemo]

Cheers Colin

I tried to get a video to catch the noise - there is a bit of gear changing noise in the car, but it's the noise on braking when reversing (remember, this is the noise from in car, with all wondows closed, so isn't insignificant!) You'll need to turn your speakers up to hear it - would appreciate any comments if anyone thinks this isn't a normal noise, and I should get it looked into (car came like this from the Lexus dealer when I bought it 11 days ago! - I just assumed it was normal!)

[Thackeray]

I couldn't actually hear much on the video. Are you sure the noise is only audible when braking and it's not something to do with the sound of the electric motors? I expect you know that the IS300h has no reverse gear as such (no gears, at all, really). Instead reverse is achieved by using the electric motors. Maybe you could try reversing with EV mode turned on to make sure the engine isn't running as you reverse and you can hear any other noises more distinctly.

In principle, when you apply the brakes the car switches from propelling the car with the electric motors to generating electricity as you brake. I assume this happens in reverse the same as when going forwards. There's probably a change in noise as the load is applied to the motor-generators. There's a kind of whistle you hear as a Toyota/Lexus hybrid car slows down for a junction that's easy to recognise when you're familiar with it.

But it's more of a whistle than a clicking noise. One of the youtube reviews of the IS300h mentions the whistle but I can't find that particular review at the moment.

[ColinBarber]

If it is the thud noise as you brake then no that isn't normal, and possibly is pad movement, or the calliper itself. I don't think it is a big issue but worth getting the dealer to check it out.

[nidgemo]

Hi Colin - yeah, it's the thud noise - definately worth getting checked out!