Rav4 Disks

[abraxas]

Hi All!

Here is a wee quiz for the braking systems gurus... get your CSI hats on.

(oh you know you want to ...go on, go on, go on, go on!... please? )

Q1) Is it normal for RAV disks to look like these?

Q2) What makes the nice shiny disks go like those?

I don't want to prejudice the discussion, so I'll leave it at that for now. :)

And by the way, this may take me a few tries, first time I am posting images.

Thanks!

[jedi134]

Infrequent use of the car? they tend to rust here, and then that part of the pad gets a grove and does not make contact with disc

Cheap discs?

[MarsKy]

That's how mine look (OEM parts).

Depending on what I'm working on, the RAV could be used daily, and the discs are nice and shiney.

Or it could be idle for most of the week, for weeks on end, and they go rusty brown.

Which is why I was costing pads and discs on earlier posts recently. My old Mazda had to have a full set of pads, discs and a new calliper fitted because it sat around. (Might be the corrosive atmosphere of Lanarkshire too).

So forget about engine braking and stamp on the brakes, corrosion can be as bad as wear - possibly worst as you can feel the wear out, but with corrosion it could go adverse at any time.

[abraxas]

Infrequent use of the car? they tend to rust here, and then that part of the pad gets a grove and does not make contact with disc

Thanks for trying... but the car is used every day; Just parked it an hour before the pic was taken. And the black stuff is not rust. That band on the second pic is not rust either. Don't really know what the black stff is, though; I just know it is not rust.

Cheap discs?

Probably :) ... but they are meant to be the OEM Toyota ones that came with the 4.3

[MarsKy]

Okay - adjusted my screen's brightness and I see the band.

So no, apart from the rust bits, mine's aren't like yours. :)

[MarsKy]

Charring?

[richwafta]

I had the same problem with the front discs. Also noticed they would show a film of rust within minutes of washing.

I started to get a shudder when breaking a few weeks ago and decided to let the local dealer take a look. I've now got a set of new discs and new pads, not what you would expect on a two year old car with 28000 on the clock.

I tend to agree with the "cheap discs" comment

[anchorman]

Gee whizz - I'm going to have to ask Steve to get attachments to open in a seperate window!!!

I'm afraid that the pads on these first generation 4.3s have let the Jap side down. The Japanese are without doubt the best manufacturers of friction material. In my days of pad development we (the Europeans) could not even come close in most aspects with the exception of one thing.........price. They were typically 8 times more expensive than we were and that was lucky for us otherwise they would have taken the world market as performance wise they can wipe the floor with us.

However, it seems that they have lost the way a little bit with these 4.3s and the problem you see on your discs is known as "depositing". Its a slightly unfortunate term but refers to the transfer of material from the pad to the disc. It shouldn't happen to that extent (it often does a little bit especially at lower duty/temperature) but the problem is that when it does it invariably leads to part of the disc being contaminated and part of it being clean and exposed to the pad. Eventually the inevitable happens and you get an unevenly worn disc. This is not run out but both sides of the disc wearing at uneven rates and not necessarily opposite. This condition is called DTV (disc thickness variation) and what do you know, 4.3s are known to suffer from brake judder.

The way the Europeans address it is to use more in the way of abrasives. The discs suffer a bit in terms of pure wear but they have a self trueng effect. You might be able to recover them a bit but it takes a bit of courage. You have to get them hot - quite hot! You can do it with a succession of stops on a quiet but fast road or down a steep hill but you need to wind it up to quite a good speed (60-70) and then make a quite high decel stop of about 0.5g (thats about enough to shoot a bag of groceries off the passenger seat onto the floor but not enough to lock the wheels on a dry road. Keep repeating it for about ten times and then go and have a look. You want them just smelling and the odd whisp of smoke (about 400C if you have a infra red temp gauge). After that it is important that you go for a drive but use normal braking as what you want to do is remove any rubbish that you have burned off the pad surface. You may find that if you brake from 70ish on a dual carriageway for an island that you already have judder in which case its off to Toyota for some new discs and pads. Presuming you are still under warranty they may skim them for you but unless they have changed the pad material it will do it again with time. The same applies to front and rear brakes.

The new RAVs have a completely different feel to them and of course the !Removed! are quite good at responding to warranty issues so this may have been down to a friction material change. Doing the brake approval at the same time as the engine approval makes a lot of sense. It could be down to piston sizes or the amount of servo boost but they have also addressed another critisism and that is poor or dead feel to the brakes. It takes a bit of getting used to and I kept doing emergency stops until I got used to them. Perhaps Kingo can say if the pads have a new part number but I will be watching to see what happens!

Good luck!

EDIT: I notice some comments about the discs. I doubt whether they are cheap discs as far as discs go. Discs are fairly inert components as far as the friction couple is concerned. They are generally grey cast iron and will have a specified brinnell hardness and titanium content. Other than that in most cases discs are discs but the Toyota spec' for dimensions will probably be far in excess of aftermarket discs and drive the poor supplier to distraction as they will be over the top. They will be at the better end of brake disc specification in all respects but still plain old cast iron discs!

[stewyinpagham]

Gee whizz - I'm going to have to ask Steve to get attachments to open in a seperate window!!!

I'm afraid that the pads on these first generation 4.3s have let the Jap side down. The Japanese are without doubt the best manufacturers of friction material. In my days of pad development we (the Europeans) could not even come close in most aspects with the exception of one thing.........price. They were typically 8 times more expensive than we were and that was lucky for us otherwise they would have taken the world market as performance wise they can wipe the floor with us.

However, it seems that they have lost the way a little bit with these 4.3s and the problem you see on your discs is known as "depositing". Its a slightly unfortunate term but refers to the transfer of material from the pad to the disc. It shouldn't happen to that extent (it often does a little bit especially at lower duty/temperature) but the problem is that when it does it invariably leads to part of the disc being contaminated and part of it being clean and exposed to the pad. Eventually the inevitable happens and you get an unevenly worn disc. This is not run out but both sides of the disc wearing at uneven rates and not necessarily opposite. This condition is called DTV (disc thickness variation) and what do you know, 4.3s are known to suffer from brake judder.

The way the Europeans address it is to use more in the way of abrasives. The discs suffer a bit in terms of pure wear but they have a self trueng effect. You might be able to recover them a bit but it takes a bit of courage. You have to get them hot - quite hot! You can do it with a succession of stops on a quiet but fast road or down a steep hill but you need to wind it up to quite a good speed (60-70) and then make a quite high decel stop of about 0.5g (thats about enough to shoot a bag of groceries off the passenger seat onto the floor but not enough to lock the wheels on a dry road. Keep repeating it for about ten times and then go and have a look. You want them just smelling and the odd whisp of smoke (about 400C if you have a infra red temp gauge). After that it is important that you go for a drive but use normal braking as what you want to do is remove any rubbish that you have burned off the pad surface. You may find that if you brake from 70ish on a dual carriageway for an island that you already have judder in which case its off to Toyota for some new discs and pads. Presuming you are still under warranty they may skim them for you but unless they have changed the pad material it will do it again with time. The same applies to front and rear brakes.

The new RAVs have a completely different feel to them and of course the !Removed! are quite good at responding to warranty issues so this may have been down to a friction material change. Doing the brake approval at the same time as the engine approval makes a lot of sense. It could be down to piston sizes or the amount of servo boost but they have also addressed another critisism and that is poor or dead feel to the brakes. It takes a bit of getting used to and I kept doing emergency stops until I got used to them. Perhaps Kingo can say if the pads have a new part number but I will be watching to see what happens!

Good luck!

EDIT: I notice some comments about the discs. I doubt whether they are cheap discs as far as discs go. Discs are fairly inert components as far as the friction couple is concerned. They are generally grey cast iron and will have a specified brinnell hardness and titanium content. Other than that in most cases discs are discs but the Toyota spec' for dimensions will probably be far in excess of aftermarket discs and drive the poor supplier to distraction as they will be over the top. They will be at the better end of brake disc specification in all respects but still plain old cast iron discs!

Just as I get my RFT sorted.. (Mr T's man in Botley, Southampton. repaired punctures and did a full valet for sub £90.00.) I now have the disc shudder and noise @ only 32K. On the first annual service at 6K, the discs were skimmed under warranty so lets see if Mr T's extended warranty covers a(nother) skim. I'm not pleased about having to buy pads especially as it appears to be another warranty issue.

Question... As I've already had a claim for a skim, does anybody know if there a TSB from 2006, that I could quote??

Bu$£er.. I was happy with the car again for 1 day...

[anchorman]

Hi Stew

No TSB as far as I am aware but it is worth trying them anyway. If not and you are willing to have a go you can get them at a fraction of the price and it isn't such a big job. I can give you the info but its virtually the same as the ones pinned in the 4.2 maintenance tips.

[jedi134]

Well there you go, below par pads, never seen that before? Is there a danger of these pads just disintergrating Anchorman?

[anchorman]

Well there you go, below par pads, never seen that before? Is there a danger of these pads just disintergrating Anchorman?

They are anything but below parr. In terms of performance they are probably as good as any brand in the world and part of the physical testing will have been destructive or durability testing. They subject them to the most merciless testing - way over the top for anything they would normally see in service like mountain descents (sometimes done by dragging them around a track) and fade testing that will involve high pressure tests done in quick succession. During these tests the disc will glow bright yellow and at the end of them although the pads are looking pretty charred they then try to detach the material off the backplate - trust me there isn't much you can do to even come close to getting them to desintegrate.

If anything the depositing and DTV comes at the other end of the scale and somebody who drives hard in the mountains is far less likely to have any such problems. This may be a weakness of this particular pad and the application (the same material could be fine on a different vehicle) but they are still world class pads - top notch stuff!

[jedi134]

Well there you go, below par pads, never seen that before? Is there a danger of these pads just disintergrating Anchorman?

They are anything but below parr. In terms of performance they are probably as good as any brand in the world and part of the physical testing will have been destructive or durability testing. They subject them to the most merciless testing - way over the top for anything they would normally see in service like mountain descents (sometimes done by dragging them around a track) and fade testing that will involve high pressure tests done in quick succession. During these tests the disc will glow bright yellow and at the end of them although the pads are looking pretty charred they then try to detach the material off the backplate - trust me there isn't much you can do to even come close to getting them to desintegrate.

If anything the depositing and DTV comes at the other end of the scale and somebody who drives hard in the mountains is far less likely to have any such problems. This may be a weakness of this particular pad and the application (the same material could be fine on a different vehicle) but they are still world class pads - top notch stuff!

Not the same physical destructive & durability tests as their accelerator pedals I hope ;)

what is a brake pad actually made up from, and what bonds it to the backing plate to be able to sustaine such forces?

[abraxas]

Hey guys.

Ok, first the full story I typed earlier, and it goes like this: "Boy meets RAV..." :) hehe.

No, seriously:

- Had this RAV for more than a year / disks always shiny as you'd expect

- Noticed a slight judder on the brakes and asked the dealer to look into it when I brought it in for a service in January.

- They did the service but could not find any judder.

- Took it in again for a warranty fix of fuel-tank noise a few weeks after.

- They looked into the judder again and this time they managed to find the judder.

- Skimmed the disks / vibrations gone.

- A week later, I noticed that the braking is getting progressively worse / more hesitant.

- Looked at the disks and saw that they turned into the above (same usage pattern as always)

- Took it back to the dealer, main mechanic looked at them and said "we'll fit new disks then".

- He also noticed the "clutch release bearing" noise and said that will be replaced. (I will comment on that in separate thread).

- Went over to get the car yesterday and the aftersales manager tells me "We have cleaned the pads." WTF?! Not happy with that at all, I insisted that the disks be changed as they are worse than when I brought the car in. He didn't budge. Kept telling me that Toyota has brought in a policy (in October, allegedly) that they will only pay for disks with cars up to 1 year old and less than 10k miles. He did a braking test and claims that the braking is fine.

Not a happy bunny at the moment. :ffs:

[stewyinpagham]

Having just booked a European round tour and regular weekly commitments from Hampshire to Cornwall I will see how good the Mr T extended warranty is. This is my 3rd new Toyota and if this run of "dealer opportunities" as we call it in Volvo-Penta land persists, I will have to consider jumping to a "Fuji heavy industries" model next.... I've been waiting for the FT86 from Mr T but I could be tempted or forced to jump all the way into a new Forester.

[abraxas]

Thanks AM. I was hoping you'd pop in. :) I think you got it spot-on as usual. It did seem to me that the black stuff was deposited on the disk. I thougth that it may be resin of some sort that binds the friction materials together, but I can't figure out why is it like that now and it never used ot be before. I will try to do as you suggest and try to burn off the deposits. That black band I got on one of them does not look good though, i picked at it wih my fingernails and it does seems fairly fat. That disk is definitelly not wearing evenly. :(

I think this is a common one Marsky. Coming to think of that there was a lass from up north that was complaining about the same issue recently. May be a Scottish RAV thing. I am just waiting for the Kevster to

get the same problem. He'll be opening a can of whoopa$$ on 'em so we all get some revenge... :)

Quite interesting richwafta got his disks and pads replaced a few weeks ago! And not on a car less than a year/10k miles, too.

And yeah, I got MrT extended warranty too (even though my 3yr is not up for a couple of months yet) Stw. But I am starting to doubt I'll get much joy out of that.

Aye, must be that testing ,Jedi ... and to think I was defending Toyota over the accelerator pedal and brake issues the other day. GRRR.

Thanks for your comment, everybody.

[richwafta]

Quite interesting richwafta got his disks and pads replaced a few weeks ago! And not on a car less than a year/10k miles, too.

And didn't even have to ask! The Rav was booked in for a check as I wasn't sure what was causing the shudder. Interestingly, they had to keep it for a second day cause the discs that were ordered were'nt the right ones. The guy commented that there were two types for the 4.3?

[bitman]

we just had some kind of winter -> salt on the roads :!Removed!:

[bothwell_buyer]

always keen to jump in with my tuppencewurth...

as some will know, I changed the front brakes of my number 1 RAV to uprated calipers and larger discs. I still had problems with pad material deposits on the disc leading to shudder. With ancs help, we moved to a slightly more aggressive pad and the problem seemed to go away. However, it did start again so it was a full brake strip down.

What was happening was that the calipers are 6 pot jobs.... and 1 piston in the nearside caliper was sticking, causing the pad to remain in contact with the disc and lead to pad material transference. The piston was so stuck that the calipers had to be returned to the manufacturer to be removed, then the whole lot rebuilt with new seals, and painted the nice red (powder coated) as before so they look like new. My pals at the garage reckon that brake dust is depositing on the piston and getting drawn back into the caliper, into the space between the seal and the pad surface. The solution to be tried is using a special silicon brake lubricant friendly goo to stop the brake dust getting into the caliper.

Bear in mind I use the car for fast road use, and 1/4 mile sprints with braking from 100mph-0 like an emergency stop several times an hour! (The original T brakes were inadequate for the use I intended).

The original T brakes on RAV number 2 (which also sports a turbo engine running at more than twice the original cars bhp) cope well with that cars performance and I haven't had trouble with shudder.

As ancs says, discs are basically discs. I've tried various different and fancy types with grooves; slots; and even wavy circumference type ones. Made no real difference. The pads and the operation of the caliper is more important.

[bothwell_buyer]

just a comment on the pics of the disc - i have seen discs much much worse than that - the rear discs of my Previa were in a shocking state. Required replacement and the reason was the calipers were sticking. Horrible mess it were!! Nobody had seen discs in such a bad state!

[shcm]

The new RAVs have a completely different feel to them and of course the Japs are quite good at responding to warranty issues so this may have been down to a friction material change.

Well, there seems to be a whole heap more material (black) being deposited on the wheels than with the old RAV. Then again, is that because they are new? Think I've noticed new pads/discs behave like this before, then the amount slowly reduce.

May be a Scottish RAV thing. I am just waiting for the Kevster to

get the same problem. He'll be opening a can of whoopa$$ on 'em so we all get some revenge... :)

My old RAV was showing signs of it and I'm a fair way south (but thankfully not too far :P)

Anchs - I read somewhere that with depositing, you can get a chemical reaction within the disc and basically if that goes to far (beyond what can be removed by skimming), it is new discs time. Is that correct or just ***locks?

[jedi134]

Are brake pads made from different materials nower days? I`ve had siezed sticking calipers on a few different cars, admitidly not a Toyota and never had this type of deposit.

On the Rav 4,2 the pads look like green pads, like EBC do, are these standard Toyota pads. They look likeThese

[abraxas]

Ok, a quick update for you all... just off the phone to another dealer whose Service Manager I know and trust a lot more and he has confirmed to me that Toyota has stopped autorising 2nd and 3rd year warranty replacements of disks in October last year. Now, that will go down well with the customers! So, they are fully aware that RAV4 disk/pad combination has the higher-than average propensity of resulting in warped disks, particularly in year 2 and 3 and they are making the fix unavailable. Some nonsense about European legislation changing, allegedly. :ffs:

Still not happy…. You know what? I should stop reading this forum, with all the issues I had with the RAV and hearing about all the others, my next one is not going to be Toyota. :!Removed!:

Richwafta, did your dealer replace this within 1yr of you buying the car? Or do you just have a good dealer? :)

[jedi134]

They`ll soon start changing them if someone has a nasty accident. Do we have to wait for a death again?

[richwafta]

Richwafta, did your dealer replace this within 1yr of you buying the car? Or do you just have a good dealer? :)

It's an '08 plate. I bought the car last January as an ex demonstrator, so outside the one year that you are being quoted.

If it was pads that they were arguing about I could understand that as it is a consumable item, but discs?? Surely there is an argument for a major component to last longer than a year? Maybe someone with technical knowledge will answer this but, if the discs are warping and causing shudder, wouldn't this lead to a possible failure of the disc through stress or fatigue?