A question for gen2 RX-300 owners with OEM brakes

m4rkw · July 25, 2020

If you have a gen2 RX-300 with OEM brakes, when stopping if you ease off the brake pedal as you're coming to a stop and apply just enough pressure at the last moment to stop the wheels, do you hear a very brief (less than a second) faint groaning sound from the pads against the discs?

Asking because my old brakes were knackered and this groaning sound was very loud and pronounced when I came to a stop, over several seconds. I had the brakes changed and the garage put Brembos on it, which I understand are very good brakes. The tech told me a story about another harrier they'd had in that had the same groaning brake issue as mine had, and they put pagid pads on it and even though they were brand new he still had the groaning. Eventually they had to take them off and put lexus brakes on to keep the customer happy.

The brembos do still make a noise in that last tiny moment of friction when stopping (or when moving off slowly), but it's dramatically better than my worn out old brakes. I'm just curious of other users see this with OEM brakes though - the tech told me that Lexus brakes do it too a tiny bit. But i've driven many cars that don't do this so I'm wondering why my car does. Could it just be the sheer weight of the thing coming to a stop?

ColinBarber · July 26, 2020

did you just get pads or discs too? This can certainly happen with OEM brakes as well as third party ones. You need to bed your new brakes in which will help - light braking for 100 miles then increase braking load and then do five 50-10 mph heavy stops one after the other.

Groaning is often a problem with auto transmissions as you are fighting against the constant forward motion - not an issue with a manual transmission.

m4rkw · July 26, 2020

Pads and discs, all Brembos. And yes I see what you mean about the forward motion - it's noticeably worse if I'm going up an incline when I move off, or down when I stop.

You don't think it's worth taking the car back and insisting on OEM parts then? I'm pretty sure I've driven other automatics that don't make this noise.

ColinBarber · July 26, 2020

If you aren't happy then ask them for options. If they let you bed the current ones in and then if still an issue replace them then I'd try that.

m4rkw · July 26, 2020

4 minutes ago, ColinBarber said:

If you aren't happy then ask them for options. If they let you bed the current ones in and then if still an issue replace them then I'd try that.

If this is just how they are even with OEM brakes then there's no point in complaining, I'm really curious to hear from other RX-300 owners to see if it's actually wrong or not. The noise is dramatically better than my old worn out brakes which used to groan like hell coming to a stop, now it's usually just a tiny blip unless there's a slope involved.

Jaystar77 · July 26, 2020

I fitted a set of cheapo discs and pads (Mintex pads and mtec discs) to my RX350 at the start which gave a great squeak noise in that last moment of travel before stopping. Removed, regreased the back of the pads, made sure everything was secure, etc. but ended up fitting the genuine pads from Lexus after about a month (the noise was irking me way too much). This took about 99% of the noise away, only got it when cold then so figured it was something to do with the friction material of the pads more than anything else.

Might be worth a set of genuine pads from Toyota to see if yours is similar? Also means you can doublecheck the sliders are moving as intended while you are fitting them.

BTW I really do not rate the Mintex pads at all - had three sets now that the pad material had rusted off the back plate and separated.

m4rkw · July 26, 2020

5 minutes ago, Jaystar77 said:

I fitted a set of cheapo discs and pads (Mintex pads and mtec discs) to my RX350 at the start which gave a great squeak noise in that last moment of travel before stopping. Removed, regreased the back of the pads, made sure everything was secure, etc. but ended up fitting the genuine pads from Lexus after about a month (the noise was irking me way too much). This took about 99% of the noise away, only got it when cold then so figured it was something to do with the friction material of the pads more than anything else.

Might be worth a set of genuine pads from Toyota to see if yours is similar? Also means you can doublecheck the sliders are moving as intended while you are fitting them.

BTW I really do not rate the Mintex pads at all - had three sets now that the pad material had rusted off the back plate and separated.

So when it's not cold you don't get any noise at all when stopping even if you gradually ease off the braking pressure and slow down as slowly as possible?

Jaystar77 · July 26, 2020

Pretty much, you'll still hear the disc and pad contact if you have the windows down but the (really irritating) squeak was gone. They served me well, car is written off now but they performed well when the worse came to the worse.

Also fitted a set of EBC Greenstuff pads to the gen1 RX before lockdown and have no noise issues at all. Bit of a tight fit and pricey but would recommend.

m4rkw · July 26, 2020

6 minutes ago, Jaystar77 said:

Pretty much, you'll still hear the disc and pad contact if you have the windows down but the (really irritating) squeak was gone. They served me well, car is written off now but they performed well when the worse came to the worse.

Also fitted a set of EBC Greenstuff pads to the gen1 RX before lockdown and have no noise issues at all. Bit of a tight fit and pricey but would recommend.

The fact that it's possible to not have the groaning noise as you stop makes me think I should go back to the garage and ask for OEM parts.

m4rkw · July 26, 2020

I am surprised I have issues with Brembos though as they seem to be a very well established brand.

Jaystar77 · July 26, 2020

Tell then you are willing to give it the bed in period (around 50-100 miles with light braking) then reassess. Hopefully the new surfaces just need to get used to each other.

Might find it's the same issue as mine in which case I just kept the noisy pads as emergency spares in the boot.

m4rkw · July 26, 2020

1 hour ago, Jaystar77 said:

Tell then you are willing to give it the bed in period (around 50-100 miles with light braking) then reassess. Hopefully the new surfaces just need to get used to each other.

Might find it's the same issue as mine in which case I just kept the noisy pads as emergency spares in the boot.

The only trouble with that is we're driving to Brittany next month and I'm not sure if I'll do 100 miles between now and then, even if I do it might not leave enough time to get the problem resolved. I'll give them a call tomorrow and let them come up with suggestions. I don't know how much more expensive the Lexus brakes are but given how minimal the noise is I'm tempted to just leave it, most of the time it's barely noticeable.

Barry14UK · July 26, 2020

I don't think it's a safety issue and provided the pads are genuine brembo, retard the car as OE in normal driving conditions and don't fade more than stock brakes it comes down to how much you are irritated by the noise. Pad material is a bit of a compromise. Some pads work better when hot with reduced fade as used for racing, others are designed to produce less dust, Greenstuff have a different layer of break-in material (or did when I last fitted them) on another car. Some pads wear quickly but work well. In my experience of many automatics for everyday use, pads fitted originally by the factory give best results. However, for Mercedes and BMW I go with factor sourced ATE which are one of the makes used by these marques. I go along with what Colin has said about progressively breaking in new pads, but would add that particularly when the car has been slowed rapidly from high speed the brakes should not be then held on in the same place because this can lead to minute amounts of pad material being transferred onto the disk in one area and this can lead to brake judder. It certainly helps the smoothness of operation in breaking if all parts that the pads make contact with (other than of course the pad material) are appropriately lubricated. Even then with automatics where creep is a given, you are likely to get some noise and vibration with differences in pad material at slow speed.

m4rkw · July 26, 2020

I just drove to the park to walk my dog and it made a terrible creaking groan as I came to a stop in the car park. I think I'm going to give them a call in the morning as I'm pretty sure it shouldn't be like this.

Delphius1 · July 31, 2020

You can get the groaning on any brake, it's not cleared by fitting any specific pad or discs.

Generally it's something to do with the ease at which the pads grip the disc. If they don't grip properly or squarely on the discs, or in the pad carriers aren't cleaned, the spring clips are not working correctly then it can set up a vibration as the pad "skips" across the surface of the disc.

I've done the brakes on my RX and to be honest the thing looked like it had been bathed in salt water. The spring clips that hold the pads in the carrier were seized in solid. It took a while to clean up the rust, fit new spring clips and also I had the issue where the paint on the aftermarket pads was too thick and caused the pads to stick in the spring clips.

A few hours of cleaning and filing later, I had pads that could slide through the spring clips using easy hand pressure.

I also renewed the slider pins so the caliper could move freely too.

I doubt a garage would be so thorough. So there's a good chance the pads are binding a little bit and not pressing on the disc properly, setting up the vibration and causing the groaning noise. Especially when the pressure from the pedal isn't enough to resist the binding action of the pads.

PCM · July 31, 2020

I have my slider pins re-greased at every service.

It has served me well.

m4rkw · July 31, 2020

@Delphius1 that was a really useful reply, thankyou. I will bring this up with the garage and hopefully they can stop the groaning.

m4rkw · August 4, 2020

I took the car back to the garage yesterday and the owner sat in the car with me and I showed him the noise and he said it’s normal and that swapping to OEM brakes would not make any meaningful difference. He also said that all of the stuff that @Delphius1 mentioned is part of their normal brake servicing procedure. He was still happy to go through the warranty process if I wanted, but it would mean first making a warranty claim with brembo, getting a new set of pads, if they were still the same then *maybe* we might have an argument to return them and go OEM, but he assured me that the noise would still be there at the end. I decided to just accept it and drive the car as the noise was fairly minimal anyway and it seemed like it would be a massive waste of everyones time.

Also on the drive down I went down a couple of steep hills and had to brake a fair bit, I noticed after doing so that the noise had diminished significantly. So there might be something to the suggestions about the bedding in process.