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I wonder whether anyone might have an answer to this - I left my 300h for a week or so, after Christmas, and when I went to drive off the rear brakes [I think] took a few milliseconds to release, and when they did it was quite a thump. They seem to be stuck on for some reason. The car is driven like a race car so the brakes don't get over-hot, and there is only a slight lip on the discs. Also, the hand brake wasn't, as the car was left in "Park".

Could it be that the brake pads need replacing ? I do know that there is a slight sort of "shussing" noise when I put my foot on the brakes, so is this a sign of worn pads so that there is metal touching the discs ? I bought the car from Lexus themselves last August with a full service history, and it had been serviced four months before I bought. There is only 34,000 miles on the clock.

I can live with the issue, but I would like to find out what causes the sticking.

Parkman.

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Probably rust on the discs causing the pads to stick to them. The discs can have a slight coating of rust develop very quickly, especially noticeable when washing the car. More Han likely nothing to worry about, but have them checked over to be on the safe side.

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I get this on my car but it's more of a ping noise.

I thought it was the handbrake but I left this off and still get it. After some reading around online, relying simply on Park mode is not good but that's another matter. A lot of strain on the "parking pawl"

I've concluded that the discs and pads are rusting and bonding to each other when left sat. Even without the handbrake squeezing the calipers and holding the pad to the disc, there is still some contact. All it needs is a bit of wet weather and time. If it's wet but I've not left it long (eg. Just a few hours since last drive), or it's completely dry (Summer) then there is no issue.

My theory but I've yet to do it (as my brakes don't yet need changing) is that putting on ceramic pads will stop it. The discs will still rust but the pads won't. I imagine it's highly unlikely a rusted disc can bond to a piece of ceramic.

I'm told the ping is not good for the calipers so I do want to do this change ASAP.

As expected, Lexus advised me they do not offer any ceramic pads.

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Pads sticking to disks is pretty common, maybe due to our damp climate.

My car often sits on my drive all week and can often take a few rev's to free of the stuck pads.

There was this one time (at band camp!) that a few rev's didn't release one of the wheels. So I ended up driving/dragging it off the gravel drive, digging a trench as it went.  It finally released when it hit solid tarmac, with a bang.

As my drive is flat, I've now taken to leaving car parked in gear with the handbrake off.  No more sticking pads.

I suspect the shush sound you hear Peter, is corrosion being cleaned off the face of the disk. 

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Regularly stick, I’ve taken to driving my car around my estate after washing it to dry the brakes, I sometimes forget.   :lol:

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The brakes stick on mine and can release with a bang after leaving it standing for a week. I don't use the parking brake at my house and just leave it in P but still does it - the "swoosh" sound is just the pads taking off the rust layer than forms - goes after a few applications

 

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16 hours ago, parkman said:

I wonder whether anyone might have an answer to this - I left my 300h for a week or so, after Christmas, and when I went to drive off the rear brakes [I think] took a few milliseconds to release, and when they did it was quite a thump. They seem to be stuck on for some reason. The car is driven like a race car so the brakes don't get over-hot, and there is only a slight lip on the discs. Also, the hand brake wasn't, as the car was left in "Park".

Could it be that the brake pads need replacing ? I do know that there is a slight sort of "shussing" noise when I put my foot on the brakes, so is this a sign of worn pads so that there is metal touching the discs ? I bought the car from Lexus themselves last August with a full service history, and it had been serviced four months before I bought. There is only 34,000 miles on the clock.

I can live with the issue, but I would like to find out what causes the sticking.

Parkman.

As already mentioned, its rust causing the discs and pads to stick together. Its more prominent during colder weather but nothing to worry about

Best thing to do is just leave the parking brake off. 

The shushing noise is more likely to be the rust being grazed off when the brakes are touched. 

Every so often, it is certainly worth doing some very very hard braking. 

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44 minutes ago, rayaans said:

As already mentioned, its rust causing the discs and pads to stick together. Its more prominent during colder weather but nothing to worry about

Best thing to do is just leave the parking brake off. 

The shushing noise is more likely to be the rust being grazed off when the brakes are touched. 

Every so often, it is certainly worth doing some very very hard braking. 

I leave my parking brake off and the pads still stick to the discs - I wonder if it's to do with the car automatically applying the brakes when stopped - when I stop with the brakes on I can hear something after a few seconds something like the parking brake going on?

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2 hours ago, wharfhouse said:

I leave my parking brake off and the pads still stick to the discs - I wonder if it's to do with the car automatically applying the brakes when stopped - when I stop with the brakes on I can hear something after a few seconds something like the parking brake going on?

The IS doesn't have an automatic parking brake, unlike some of the other Lexus vehicles.

The sound you are hearing is possibly a hydraulic pump?

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4 minutes ago, ColinBarber said:

The IS doesn't have an automatic parking brake, unlike some of the other Lexus vehicles.

The sound you are hearing is possibly a hydraulic pump?

Thinking about it could be the brakes applying themselves as part of the hill assist - was just reading the manual and the brakes are applied in this way every time you stop (not just on a hill...) 

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Hill assist only works for 3 seconds. It doesn't apply the brakes, it just holds the pressure you have already applied. I'm sure it does only work when on an incline.

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Same thing used to happen with my BMW when parked for +-2 weeks with handbrake on.  Resistance and then a real thump.  Since then, if I can, I avoid using the handbrake when car to be parked for a while.

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Hi, and thanks to everyone who replied.

I thought that, as Rayaans says, it could be rust, but to be honest I don't think that that is the case here. I have checked the discs a number of times and they are very clean, with just a vague sheen of rust after a few days and heavy rain.
 

I never leave the handbrake on with an automatic car. I only ever use park, unless I am on a car ferry, or unless there is a demanding reason to put the handbrake on. I do use the handbrake when in traffic, such as at traffic lights, but otherwise it doesn't get used. I had an Isuzu Trooper many years ago, and the handbrake actually partly siezed, because in 4 years I never used it once !!

I have the same issue as wharfhouse ! I sort of think that the hill start suggestion could just be an explanation as my drive has a slight slope. Over the length of the drive, about 14 feet, the drop is around 18 inches. Not a lot, I know, but could that enough to trigger the hill start, that is of course if hill start is fitted to the 300h Premier. I didn't think that it was.

I will be changing the pads when the weather gets warmer, and I always have this idea that the pads are worn to the point where the metal is rubbing on the discs. But I doubt it because I have had a brief look inside at the disc and there is a definite impression of there being plenty of pad left.

All I can do is wait until I change the pads and then I will really see what the condition of the pads is.

That [sorry for this bit] begs the question - do I just buy the pads from Lexus, standard 300h pads, online, or [and I know that I have brought this up a couple of times so I don't mind being criticised] does anyone know where I can buy a low dust alternative set of brake pads in the UK. The only place I have found was a motor sport parts supplier around Cambridge, but he doesn't have anything in stock, and he quoted £220 for front and rear pads.

Thanks again for all the replies.

Parkman.

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Never had issues with buying brake pads from ECP, or the other car parts suppliers. It’s just s case of shopping around.

I know some people are a bit precious over buying from such places.

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15 hours ago, parkman said:

Hi, and thanks to everyone who replied.

I thought that, as Rayaans says, it could be rust, but to be honest I don't think that that is the case here. I have checked the discs a number of times and they are very clean, with just a vague sheen of rust after a few days and heavy rain.
 

I never leave the handbrake on with an automatic car. I only ever use park, unless I am on a car ferry, or unless there is a demanding reason to put the handbrake on. I do use the handbrake when in traffic, such as at traffic lights, but otherwise it doesn't get used. I had an Isuzu Trooper many years ago, and the handbrake actually partly siezed, because in 4 years I never used it once !!

I have the same issue as wharfhouse ! I sort of think that the hill start suggestion could just be an explanation as my drive has a slight slope. Over the length of the drive, about 14 feet, the drop is around 18 inches. Not a lot, I know, but could that enough to trigger the hill start, that is of course if hill start is fitted to the 300h Premier. I didn't think that it was.

I will be changing the pads when the weather gets warmer, and I always have this idea that the pads are worn to the point where the metal is rubbing on the discs. But I doubt it because I have had a brief look inside at the disc and there is a definite impression of there being plenty of pad left.

All I can do is wait until I change the pads and then I will really see what the condition of the pads is.

That [sorry for this bit] begs the question - do I just buy the pads from Lexus, standard 300h pads, online, or [and I know that I have brought this up a couple of times so I don't mind being criticised] does anyone know where I can buy a low dust alternative set of brake pads in the UK. The only place I have found was a motor sport parts supplier around Cambridge, but he doesn't have anything in stock, and he quoted £220 for front and rear pads.

Thanks again for all the replies.

Parkman.

ECP is fine for pads

Although I tend to use CP4L which usually work out a lot cheaper compared to ECP whilst being the same company for different markets

However, I have almost always found that OEM is better

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Thanks guys. I will take on board all the comments.

I will look at ordering brake pads fairly soon, so that they will be here if the weather improves and I can get out and change them.

Parkman.

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The manual says that in winter weather you should: "Park the vehicle and move the shift lever to P without setting the parking brake.
The parking brake may freeze up, preventing it from being released."

As for the pads being worn, I was given some useful information from a dealer, who said the front pads measure 12mm when new and the rear ones 10mm. I expect the rear ones are smaller because they're assisted by the hybrid drive. Mine have all worn around 20% after 40,000 miles. If that continues, they should last 200,000 miles!

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