Rav4 Disks

[anchorman]

Been offline for a while due to a technical ***** up in changing ISP.

abraxas

Its hard to understand who you are dealing with in these situations as some dealers seem to try and field warranty issues themselves and others seem very willing to get on and do things. I don't even think in some cases dealers like the one you are dealing with even bother consulting Toyota, they just make their own decisions. Its also harder for those that depend on a garage than those that have the confidence, tools and time to do it themselves as when something like this happens it needn't be that expensive to rectify (if I could only work out how to search on here I'd try and find those prices I posted recently).

A couple of further considerations;

Cars that do long periods of standing will be worse than those used every day

If you do the reconditioning I described earlier it is likely to change the colour from brownish to blackish/blue initially but continuous higher duty will bring them back to shiny - friction materials enjoy work!

My discs were renewed after 2 years BTW. Maybe you need to practice your writing skills and see whether TGB will give a bit.

Jedi

You unwittingly raise a an interesting point in your comparison to the durability testing of the accelerator. We used to spend millions on pad development and whilst destructive testing was quite easy and quick, durability in terms of extended life testing was not so easy within strict development and launch times. In the case of the accelerator, Toyota have been hammered relentlessly over a component that they have bought in. No doubt by the time the supplier has picked up his share of the warranty it will probably finish him but in fact he was probably contractually charged with making sure the component was durable and that its behaviour didn't change significantly over time. In fact the device was badly affected by normal in car dust and slight wear which caused the teeth of the friction device to bind on each other. My point is that no matter how much durability testing you do in house, the real test is out in the field when even the most unlikely faults come out of the woodwork. One thing is for sure; given the cost of recalls and blanket warranty campaigns, there is no way that Toyota or any other manufacturer would risk introducing any part that they deemed susceptible to failure yet everybody seems to have the opinion that it was a negligent oversight. We can thank the Americans for this culture and although I thoroughly enjoy my holidays there that is one aspect of American lifestyle that they can keep.

Now after that little rant on to your question about pad attachment.

Although adhesives have improved to unbelievable capabilities these days, they cannot be relied upon to attach friction material to backplates alone. They are subject to high shear load but they are also under compression when under pressure but they obviously have to be held in place otherwise. The traditional way is with spigot holes in the pad. I took these pictures from a set of genuine RAV front pads and you can see in this case that there are three spigots one of which is indented.

Indenting is usually done to improve the density in the area of the spigot but in some cases it is done to accommodate an accessory or locating feature. The pads are always bonded as well with very high temperature adhesive as the pads are tested well above 1000 degC but in service will see many cycles above 550 degC which will make them glow cherry red in the dark. The main function of the adhesive is to stop corrosion forming between the material and the backplate which would cause them to break up. The environment around the brake is horrible - a mix of cycling temperature and being lashed with all sorts of atmospheric conditions and contaminants. As a matter of interest you can see from this picture that the pad has been scorched in production.

Bedding the pad is a two stage process. The first and most obvious stage is the pad makes 100% contact with the disc. The second is less obvious but can only take place while being subjected to heat. In this phase, the resin system is burned away and the friction particles are exposed to the disc. The pad manufacturer in this case has attempted to provoke this process by searing the surface with heat in production, in other words they are partially conditioned before duty.

Another interesting photo is this one from my brake development days which shows another method of attaching a heavy duty pad for a truck. We developed a meshed backplate that locks the material to the backplate.

Eventually the weld were done away with and we started fusing the mesh to the plate with an electrical charge.

Finally your question about what a pad is made from. Firstly there is fibre in quite large quantities (about 60%)which provide a framework to hold the whole thing together. These days in a pad it tends to be largely steel due to its high strength but might be blended with aramids (man made) and Rockwool (processed mineral fibre) the latter two are there to control thermal conductivity and push the heat out through the pad and not via the backplate and caliper. Then there is the friction element which are abrasives and lubricants like silica and graphite. These are blended to maintain the friction through a wide temperature range and some are active at certain temperatures and some are dormant but becoming active as the pad gets hotter. The lubricants might stop the friction getting too high (a very bad trait) and some merely to control noise. Next inert fillers do nothing more than provide resistance to wear and the whole thing is bound together with phenolic resins. These are dry thermo setting resins so the pad is moulded dry then baked to allow the resins to flow and cure.

There you are, you can now set up make aftermarket "blue stuff" or "orange stuff" or whatever you call it!!!

shcm

I think the bit about discs soaking up contamination is a bit of whitewash. I never heard of it in all my years in that industry. Mine seem to dust more so maybe there has been a material change.

[jedi134]

Well all I can say is if my pads were decomposing/breaking down, what ever you want to call it. As in the pics in the previous posts, I would whip them out and launch them as far as I could and replace them with something else, maybe something non-Toyota.

Do the Toyota pads say " made in china" by any chance???

To stop giving warrantys on a main component of the car ie "THE BRAKES" amazes me. will toyota never learn, if there are problems with the brakes,then this should be addressed ASAP should it not,???

Or is the mind set: "well there have been no deaths from these known pads and discs yet, so lets not warranty them anymore"???

Your talking brakes here Anchs, probably the main part of the car. I would think these need to be 100% tip top, any sniff of a problem should be addressed ASAP, Surley?

PS: Are you in Toyotas pocket? :P

Just Googled "Advics" seems they have some connection to china, Hmmmmm I rest my case :(

[scar]

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.

You might have well taken a photo of my car,identical.

It's a 4.3 2008 March 13k miles.

Thanks!

[anchorman]

Well all I can say is if my pads were decomposing/breaking down, what ever you want to call it. As in the pics in the previous posts, I would whip them out and launch them as far as I could and replace them with something else, maybe something non-Toyota.

Do the Toyota pads say " made in china" by any chance???

To stop giving warrantys on a main component of the car ie "THE BRAKES" amazes me. will toyota never learn, if there are problems with the brakes,then this should be addressed ASAP should it not,???

Or is the mind set: "well there have been no deaths from these known pads and discs yet, so lets not warranty them anymore"???

Your talking brakes here Anchs, probably the main part of the car. I would think these need to be 100% tip top, any sniff of a problem should be addressed ASAP, Surley?

PS: Are you in Toyotas pocket? :P

Just Googled "Advics" seems they have some connection to china, Hmmmmm I rest my case :(

I'm not condoning TGBs warranty policy regarding brakes, as I've said, they honoured mine when it was over 2 years old so I don't know why they have done a U turn on them now - possibly for the same reason they have done it on EGRs as well???

I am indeed talking brakes and I probably know more about them than the person that decided not to honour the warranty after 12 months. To me a warranty is a warranty and if it is for 3 years it should be so until the last day. I can understand why they won't guarantee them against wear and tear but they should honour a claim for judder as this is clearly a specific fault. I'm not in Toyota's pocket and I thought I'd simply answered the questions I was asked in an unbiased manner.

Advics is a joint venture between Aisin, Denso and Sumitomo which are three of Japans most respected component manufacturers. Whatever anybody thinks about this TGB decision on brakes, these manufacturers are amongst the most competant in the world but as I said, sometimes these things don't emerge until they are well into production.

http://www.aisinaftermarket.com/English/products/Advics.php

[abraxas]

Hi AM, Thanks for the masterclass in brakes and braking technology. :) Personally, I found it a very interesting and educational read.

You are absolutely right about some dealers finding things to do and others avoiding warranty work. I think it is, as most things in life, financially motivated. I believe that warranty work is capped-prices basis so not as attractive/lucrative as charging the customers directly. If, however, the workshop bookings have hit a slow patch, any work is better than none.

However, this issue seems to be TGB driven. It appears that Toyota (and other manufacturers) have been let off the hook by some EU regulation, so that they are only forced to provide warranty for the first 10k miles and 1 year. This probably extends to the dealer warranty on "approved used". It would be good to get this one confirmed by a resident man-in-the-know, but it is unlikely that he will risk sticking the neck out on this one. :) so I won't all him out by name. I am sure TGB PR person that we heard from recently won't bother either.

It was just a flippant remark on my part that the RAV the disks were cheap, I am only certain that they are the cheapest possible Toyota could have got that satisfy the requirements. That is just the nature of business. But clearly, expense and quality of each component aside, they have an issue with the current disk/pad combination that results in warping, and quite early in the car's lifetime too. And they know it... and they still decided to reverse position on warranty accross the board. That really sucks.

My issue with the dealer is that I only had a slight judder on the brakes before they skimmed them; and then it came back in a worse state, in that it would no longer brake properly. Gave me some nonsense about the skim being a "good will gesture" by them. How is making someone's car _worse_ a good will gesture goes beyond me.

I didn't really want to approach this issue all-guns-blazing as I recently had (what turned to be a very expensive) warraty fix and Toyota picked up the tab. Actually, as I typed this, I don't know why am I giving them any credit for it, they should have done it right the first time. :) But you are right, I can always buy the disks myself. It is a couple of hundred pounds rather than a couple of grand for (for example) a gearbox. Life's too short.

Anyhow, thanks very much for the tips about working the brakes hard, I have started "re-conditioning" as per your suggestions, and they seem to work a bit better than they did. I still have that band on one of the disks that is not going away, but if they work.. I don't really care that much.

Thanks everyone for your comments!

[jedi134]

Buy some known good discs and pads yourself and fit them. then launch the old ones through the Toyota dealership window, with a note attatched "warranty this"

3 years warranty should mean 3 years warranty. Its alll a load of horlicks!

[abraxas]

hehe. Someone has crossed over to the dark side ! :)

Good idea about a "known good discs", though.

Now, for the sake of completeness, you can guess the next question: What are known good disks? (And pads?) :)

Anyone got any suggestions about quality brands? Personal experiences? Recommendations?

I am still sticking with AMs suggestions and plan on some serious reconditioning, but in case it doesn't work...

I fully agree about the warranty. Should be a binary function. It either is or it ain't. None of this "yea,but...no,but" nonsense.

[jedi134]

I`d just change the pads to be honest, unless your discs are warped. As for brands I`d go for anything non toyota, give them a try, EBC do aftermarket pads which seem to be rated quite highly.

Any motor factors should supply them, just make sure its non toyota, ferodo maybe.

[Hoovie]

 Just on the question about replacement discs under warranty....

FWIW, I had all four discs replaced on my May 2005 Registered RAV4 in September 2009 - so well over 4 years old and there was no real question about if they were covered or not.

Conversation went along lines of

Mr T: "you need discs and pads replaced all round - £500 please" (bad brake judder)

Hoovie: "I have extended warranty"

Mr T: "We will call Toyota for authorisation"

1 Day later

Mr T: "You will need to pay for pads, Discs and fitting will be free"

Hoovie: "Thanks" (Pads were up for replacement at next service anyway)

Now I may have been lucky in that this was just before the quoted change of policy in October, but the extended warranty document makes it pretty clear that discs are covered - at least to me - and not as a good-will gesture.  This could be changed for a new purchase of car or warranty, but a company cannot change the T&Cs of a contract on anything that has already been bought I would think.

[stewyinpagham]

I think I have resolved my braking issue.

Wife insisted that we keep winter "stuff" in box in boot. 'Stewy' as ever, to lazy to strap it in properly, resorted to driving more sedately to keep "stuff" in box.

Having now rigged for AM brake "reconditioning", hence securing the "stuff", I am now driving the T180 like it's stolen again. Brakes are getting better daily.. Hmmmm.

[anchorman]

I think I have resolved my braking issue.

Wife insisted that we keep winter "stuff" in box in boot. 'Stewy' as ever, to lazy to strap it in properly, resorted to driving more sedately to keep "stuff" in box.

Having now rigged for AM brake "reconditioning", hence securing the "stuff", I am now driving the T180 like it's stolen again. Brakes are getting better daily.. Hmmmm.

Its surprising! The harder you work them the more they will respond and you will see those discs shine again. However, just keep in mind that the hotter they get the quicker they will wear.