Look what my dealer just found:
(http://gsb.bulldoghome.com/pages/gsb_bulldoghome_com/GSB/corrosion.jpg)
Both my front discs look like this despite only being 18 months and 20,000 miles old... The odd thing is, that the corrosion is on the inside of the discs only, the outside are perfect, with not even a hint of rust...
The car is hardly ever driven in bad weather, and is garaged every night.
Looks more like a record than a brake disc..
Replaced under warranty, I hope?
strange how it wore that pattern, looks almost like half a tonne of stones got stuck up in there s:? :? s:?
Quote from: "kanujunkie"strange how it wore that pattern, looks almost like half a tonne of stones got stuck up in there s:? :? s:?
Yes, except both discs were exactly the same, and the grooves you can see arent scored, like when you run out of pad material for instance, but rotted. Its like the metal has been etched away rather than scraped... Wierd.
Oh, and yes, they did it under warranty. In fact I had no idea there was any problem prior to taking it in for a service. They found it, they fixed it, I had no input whatsoever to the process.
Looks the same as mine did last year, a mechanic friend of mine suggested that it was problem with the metal. They didn't replace them under warranty till I took them into the showroom and started complaining
I have the same problem,but mine are both sides and they are just over a year old.I replaced them with genuine Toyota parts as I was advised to.This time I will be using aftermarket ones!! s:x :x s:x bleedin Toyota,lol
Mine were skimmed under warranty on the 30k service needless to say they are just about shigged (sp) now, recon I'll be going down the "get & fit myself road s:wink: :wink: s:wink:
mine were reoplaced this time last year, again the corriosion was on the inside face only.
Personally i blame single piston sliding calipers (like ours) of they were twin piston opposed calipers this would probably not happen
But then im an idiot and dont know much so i could be wrong s:oops: :oops: s:oops:
I thought i'd read somewhere that they were two piston ones, so I guess you can't be that much of an idiot!!!! s:wink: :wink: s:wink: s:lol: :lol: s:lol:
Quote from: "jamesr1"I thought i'd read somewhere that they were two piston ones, so I guess you can't be that much of an idiot!!!! s:wink: :wink: s:wink: s:lol: :lol: s:lol:
nope definatley single piston
Greetings all,
Seems I am another victim of the MR2 front disc inside face corrosion problem. I am on my second set of discs now and am looking at replacing them again after they were flagged on my most recent service.
The first time this happened I had only had the car a short time (bought from a rather unhelpful dealer in Manchester) and I did eventually get them replaced under warranty. As was posted by Bowman, this was only after kicking up a stink.
The discs that were taken off looked just like those in the picture. However, I kept these discs as I figured I could get them skimmed and have taken them out of storage after a year to do so. What is interesting is that all that horrible ringed/scored material has now flaked off to reveal a very even (yet mildly rusty) surface underneath. I am now curious as to whether that scored material was actually the brake discs itself, or just baked on debris from the pads? (Sorry, I'm a bit of a nerd s:idea: :idea: s:idea: ).
I've shown the old discs to a mechanic buddy of mine (he supports a local rally team up here) and he is certain this is a result of callipers not working effectively on the back face. This means the surfce oxidation (rust) does not get cleaned off by the pads during normal use, hence the tendancy to rust severly.
I am going to strip down the brakes myself to see what's going on, but it sounds like the sliding mechanism may be obstructed.
Having said all this, I would be interested to hear if this problem is limited to Toyota discs. i.e. do 3rd part discs suffer the same fate. This would help isolate calliper problems from materials issues.
Thanks for listening.
Tobes.
Tobes, keep us updated with your findings
Hmm, not sure if anyone has identified the problem with the roadster, but certainly on the Mk2 the sliding pins the front calipers moved on had a tendency to seize up. Cleaning them up, and re-greasing them with sliding pin specific grease (NOT Copperslip - it dries and hardens!) the problem was cured.
Hi
Having had the discs flagged up on service for scoring, I was planning to replace as wear and tear. Lookig at this, I went out and had a look for myself and my discs look pretty much identical to that.
How can they have got it so wrong design wise? Been on to the local Toyota dealer who is going to ask Toyota to cover it under warranty.
Chris
Quote from: "ChrisGB"I went out and had a look for myself and my discs look pretty much identical to that.
How can they have got it so wrong design wise?
I bet you've driven on salted roads?
It just does that. To most cars, not just MR2's, nor even just Toyota. s:oops: :oops: s:oops:
My Yaris did the same is the picture.
Interesting reading leaving them for a bit of corrosion to get in there and remove this contamination. I wonder if it's the brake pads?
I had brand new front discs put on my '2 when I bought it. Then two months later at the service Mr T said I needed new front discs because they were so badly corroded..... What? 2 months old!!!
I replaced my 2001 discs yesterday at 36,000 mls. Front face fine, rear face severly corroded. A word of warning, my MR2 ended up on a car transporter last week in France because the friction material broke away from the backing steel plate on one of the inside pads. Still 5mm of material on the pad that broke way !! - caused by corosion ?
I used after marked discs so it will be interesting to see how they compare
Quote from: "Tem"Quote from: "ChrisGB"I went out and had a look for myself and my discs look pretty much identical to that.
How can they have got it so wrong design wise?
I bet you've driven on salted roads?
It just does that. To most cars, not just MR2's, nor even just Toyota. s:oops: :oops: s:oops:
Hi Tem
I have only had the car a few weeks, so have never driven it on salted roads, however, I have had a few cars over the years and driven around 1.1 million miles, do much of my own servicing / repair and this is the first time I have seen anything like it. Disc wear, scoring and even heat fracture, yes, but this is something else.
The service guy at Mr T reckoned they corrode due to a comination of lack of use and poor airflow holding moisture round the back of the disc. Having never had this problem before, I reckon it is a design fault. Toyota would not be the first to get brake discs wrong. Ford had problems in the late 1990s when they changed alloy composition and had discs warping all the time. I bought a new car that had warped discs when I collected it and quite a few (5 if I remember correctl) others that developed warped discs in under 5000 miles.
I am looking forward to serious improvement in braking capability when it is fixed. Just a bit worried that at the moment the rear discs will be taking most of the load.
Chris
I had a MK1 MR2 for eleven years, 35,000 miles when I got it on original discs, full service history. It went on to do 162,000 miles until I sold it for the Roadster this last February. I replaced the front and rear discs after 127,000 miles because they were wearing thin, single piston, no problems.
How could they cock up the Mk3s brakes? s:? :? s:?
Keith
Quote from: "ChrisGB"lack of use and poor airflow holding moisture round the back of the disc
If that's the problem, just take the shield off from the back, it also helps to keep the brakes a bit cooler when you're pushing it.
Might wanna check your local laws first though, over here they are a must, not that anyone ever checks them.
Quote from: "ChrisGB"I am looking forward to serious improvement in braking capability when it is fixed. Just a bit worried that at the moment the rear discs will be taking most of the load.
Chris
The rears will never take most of the load as brakes are always bias to the fronts otherwise we would be leaving a pair of black lines on every brake application s:wink: :wink: s:wink:
Quote from: "Les"Quote from: "ChrisGB"I am looking forward to serious improvement in braking capability when it is fixed. Just a bit worried that at the moment the rear discs will be taking most of the load.
Chris
The rears will never take most of the load as brakes are always bias to the fronts otherwise we would be leaving a pair of black lines on every brake application s:wink: :wink: s:wink:
Well more of the load than they would normally, so if braking at 50%, the rears would be doing a lot more of the work than they normally would. The car does feel a bit rear biased under braking and this would account for it.
Chris
Quote from: "Tem"Quote from: "ChrisGB"lack of use and poor airflow holding moisture round the back of the disc
If that's the problem, just take the shield off from the back, it also helps to keep the brakes a bit cooler when you're pushing it.
Might wanna check your local laws first though, over here they are a must, not that anyone ever checks them.
First thing I thought of. I will have a look at the pipework routing and see if it is possible.
Chris
I noticed the inner fronts were scored as well (1 year, 6k miles!) told MrT during the first service and they replaced them under warranty today (had to buy the pads though, wear and tear item not covered).
What is the deal with these disks?
I've not had this problem with the '2 yet, but the Yaris Ts has the same problem, and on the outside surface.
I've never seen corrosion on the swept surface of brake disks, uneven wear because of sticking sliders but never corrosion.
My betting would be;
Poor cooling (made worse by the rear shield)
Poor ventilation not allowing pad dust and gases to escape (that shield again and pad design)
Poor pad composition.
I'd like to know if it's legal to remove the rear guards from the brakes as these cannot be helping the situation - I don't remember seeing anything like these in my pre- Toyota days!
This was reported on my 54 plate when they did the 2 year service at 5.5K miles
seems to be a common point of concern on the 2
Update:
I finally got around to looking at my brake system to see if I could find a source of the problem with the scored/corroded discs. It looks like my original mutterings about the slider not working were correct, but not in the way I thought... s:shock: :shock: s:shock:
When I dismantled my system yesterday I found that the inside pad was very heavily worn and the outside pad had seen very little use (estimate inside pad was 3-4mm remaining and outside was 7-8mm remaining). This proves that the slider on my car is not working properly as forces on the inside and outside of the disc should be equal, hence wear should be equal. Judging by the similarities here I would suggest the same is true for some of you poor souls. s:( :( s:(
What appears to be happening is that the inside pad (pressed directly by the calliper) is making good contact against the disc. However, the outside pad (which is drawn against the disc by a sliding mechanism) is not making very much contact with the disc. This means that nearly all the braking load is taken up by the inside pad. This means that a lot of heat is generated by one side, which increases the rate of corrosion.
The slider itself was quite stiff when I first took it off, but after a little working it became free. The pins that the slider run on are sealed and greased, but this had baked a little and is now more like a paste. I will clean this section up carefully and make sure that there are no rusty bits on the pins (and recess – if possible) before re-greasing. I will also make sure that the whole area is as clean as possible before refitting.
As mentioned the piston in the calliper seems to work ok, but as you might expect it was very stiff due to fact that you are trying to push a relatively thick fluid up very small pipes (I do not have one of the special tools for pushing the piston). I did not get under the boot that protects the piston, but I would like to do so in order to make sure this is clean and running as freely as possible.
Interestingly, BenF makes a good point here about Copperslip. The old remains of copperslip that had been applied to the brake pad sliders was revolting! It bore no resemblance to grease and was actually inhibiting the movement of the pads. This could be adding to the problem. I will try and source a high temperature grease of another type. s:?: :?: s:?:
In short, it looks like we need to service these parts regularly. There is nothing there that is particularly scary to work on so it is something you can do with a little bit of knowledge. Further more, I doubt that changing the type of disc or braking material will help with this problem as I'm pretty sure that if the calliper/slider system works properly then this problem will go away.
I'll see how things progress after I've got mine back on the road and will keep you posted.
My front discs and pads were changed under warranty at just under 20K miles. This is before I owned the car, but I have noticed a slight knocking on the brakes over the last few weeks. It's like a rythmical thud on the brake pedal which is related to speed so it slows as I slow. There is no nasty noises, the car doesn't pull to the left or right and the steering wheel doesn't vibrate. It does seem to happen more when I am braking harder.
I had my intermediate 5 year/50K service done in March with no reports of problems with discs or pads, the car's done 40k miles now. Is it worth checking them out with my local garage as I have no warranty left now?
Quote from: "1bloke1dog1mr2"It's like a rythmical thud on the brake pedal which is related to speed so it slows as I slow. There is no nasty noises, the car doesn't pull to the left or right and the steering wheel doesn't vibrate.
I would say yes, its worth getting them checked. What you describe is exactly the feeling I was getting from Lynn's car before I changed the disks and pads. Brake feel was smooth as silk after the change. Got a nasty feeling the bumpiness is kreeping back now. Think it may be time for me to have a look at those callipers!!
David
I just checked my discs after this subject arose.My car has 120,000 up on it,now I'v only had it since there was 99,000 on it last august but my discs are perfect.Quite possible that the previous owner had them changed but who knows....is it a relatively isolated problem to a handful of cars or a epidemic?
Hey guys,
Just a quick update. It's nearly 18 months since I last commented on this topic and I thought I'd bring you up to speed.
The servicing of the calliper/slider system seems to have done the trick. I have now replaced the pads on the front/rear twice since my last post ( l viewtopic.php?f=11&t=11672#p154503 (http://www.mr2roc.org/phpBB3/viewtopic.php?f=11&t=11672#p154503) l ) and I can confirm that the scoring/ringing of the internal surface has not come back.
This confirms that the scoring is a symptom rather than the problem itself. If you regularly service your bakes and keep them running smoothly you will achieve equal braking on the inner/outer pad which removes the scoring issue and results in fantastic braking performance!. Seriously, I thought the brakes were good before, but when all four corners are working properly its simply unreal.
Note: One thing I immediately noticed after servicing the slider is how the outer (visible from the road) surface of the disc is visibly brighter/shinier than before. In other words the pad is making contact under braking.
Looks like this is worth doing for me. The outer face is not being swept as effectively as the inner face on both fronts with mine, so will have a go. When I replaced the discs and pads, it all seemed to be sliding reasonably freely though. Anyone got an exploded diagram of the calliper for reference?
Chris
I think it may start to be a problem for more members as the cars get older. Mines a 2000 and over 100K and I have the calipers off to paint them. Am really glad I did as they were in need of a good service. I may try and do a "How to" on it.
Quote from: "custardavenger"I think it may start to be a problem for more members as the cars get older. Mines a 2000 and over 100K and I have the calipers off to paint them. Am really glad I did as they were in need of a good service. I may try and do a "How to" on it.
Mine have been having problems since 30,000 miles and less than 2.5 years old. I wonder if using a jet wash on them has any relevance. Certainly can cause issues on some older cars.
Chris
I definately wouldn't recomend jet washing the calipers. The rubber seals arn't that good.
Quote from: "custardavenger"I definately wouldn't recomend jet washing the calipers. The rubber seals arn't that good.
I try to avoid it, but previous owners may not have done.
Chris
Just to add my 2p worth - I also had a really bad set abuot 12 months ago ( see also m http://www.imoc.co.uk/forums/viewtopic.php?t=153178 (http://www.imoc.co.uk/forums/viewtopic.php?t=153178) m ) and suspect the issue was the sliding pins getting seized up, causing the inner brake pads to do the majority of the work resulting in gazed inner pads.
I fitted new disks and pads, and have tried HT grease, and even not using any grease but both would eventually bind again.
After being on the car for 12 months, I recently checked them and noticed the new pads and disks again had some light scoring on the inner surface and so discarded them and got another set of pattern disks and Mr T pads.
At the same time I looked for a source of 'Lithium Red Grease' or 'Lithium Soap' to use on the sliding pins. Although a little used to be included in brake refurb kits it doesn't tend to be nowadays.
Calling around different local motor factors, I found one selling 'red brake grease' sold in a big ~ 300g tin - something like this from ebay m http://www.ebay.co.uk/itm/Millers-Oils- ... 0413202450 (http://www.ebay.co.uk/itm/Millers-Oils-Red-Rubber-Grease-500g-Tub-Brake-Seals-/360413202450) m but the one I had was a different brand ( if there's interest, I'll grab a photo tomorrow ). Certainly assembling the caliper again, the grease is different to others I've tried as even with a thin film there's very little resistance to movement - there was a little more 'stiction' with the other greases I've tried.
I've reassembled the brakes, and since done a trackday. The brakes still feel OK now, but I need to take some time to strip down and confirm the red grease is doing the job needed, but at the moment I'm hopeful it has done the job.
The thread that refuses to die and resurfaces every three years.
Red grease, or Red Rubber Grease is intended to ease the assembly of rubber components. Its not designed for metal to metal contact. It is designed to be brake fluid compatable.
The biggest problems on calipers is the combination of water, heat, and neglect. The best greases for the sliding pins are lithium based designed to resist water washout.
Steve - ok - where would you get some then? Other online forums suggest lithium spray on grease and similar, but I would have through that was much too thick and would suffer the same fate as Molly and copper slip based greases in that the sliding pins eventually seize up.
My prefered option would be
http://www.opieoils.co.uk/p-6315-castrol-moly-grease.aspx
The grease has good water wash and sliding characteristics.
Brakes are a bit of a thing for me, if you look at the How To section.
I like the idea of being able to stop. That means that every couple of years, I strip, clean and lubricate my calipers and do not replace pads without doing a complete checkover and replacing external seals etc.
FWIW, have had exactly the same issue and swapped front disks a number of times on my 2003 car. The root cause I found was sticky sliders as you found.
I've tried most greases for the sliding pin ( White Lithium, Red brake grease, CV grease ) but all of those have baked hard with time / use and the pin seizes up.
What you really need is some silicone grease - very difficult to find the right stuff ( similar comes as part of the Toyota brake caliper refurb kit ) - I found that Bigg Red were selling some via ebay - :
m http://www.ebay.co.uk/itm/Silicone-grea ... 4171da1bcf (http://www.ebay.co.uk/itm/Silicone-grease-high-temp-Brake-calipers-/281082993615?pt=UK_CarsParts_Vehicles_CarParts_SM&hash=item4171da1bcf) m
I bought 6 packets and stripped and re-lubed the sliding pins on the front and rear of my car with some about six weeks back.
Since then, the brakes 'feel' good and are working well but I've not stripped the brakes to confirm the pins are still OK
The brake section of the Toyota service documentation states "lithium soap base glycol grease" (I'd upload the pdf file if I could find a way, but happy to email to anyone interested).
Didn't have any when I replaced the front disks about a year ago, so used this instead... m http://www.ebay.co.uk/itm/CARLUBE-SILIC ... 1501wt_721 (http://www.ebay.co.uk/itm/CARLUBE-SILICONE-MULTI-PURPOSE-GREASE-20g-WATER-REPELLENT-/400344619952?pt=UK_Vehicle_Oils_Lubricants_Fluids&hash=item5d36661bb0#ht_1501wt_721) m ... still good when checked a couple of weeks ago.
I'm well pleased with the Mintex Ceratec grease,my other car,the Ford Probe has Mazda brakes,sticking on the sliders is a common problem,they would need stripped and greased yearly if not twice a year......used the Ceratec 3 years ago and i have not had to re grease them yet.The grease stays there,it does not go hard and cause sticking like the old copper slip......also done my Rav4,the Mondeo and the rear of the Mr2.
My original Mondeo front discs were rotted through on the inside at 4 years old.......on the subject of removing the brake disc guards/shields,i asked at the last Rav4 mot as the fronts are a bit rotten,i was told it would fail as they protect the flexi hose from disc heat.....so they can be there and rotten and pass but take them off its a fail,alot of cars dont even have them now,new vauxhalls for one.....got nice new ones from CTP,must fit them sometime s:lol: :lol: s:lol: