Brakes overheated going downhill

[Seb_90]

Hi all. I had a new experience while on holiday in Italy (Alps). I was going down this huge mountain for good 30 min, all the time on the brakes. At some point I could smell some burning smell, I thought it was the clutch of the cars coming up this mountain (1st or 2nd gear only possible). But then I realised the brakes power had dropped. I did manage to brake without issues just by going down in 2nd gear and pulled into car park to cool down the brakes.

 

Just wanted to share this experience, as I in all the years of driving in the UK and Europe this is the first time happened to me.

 

Once the bakes have cooled down, its function returned back to normal. The disks didn't wrap or changed the colour. I will be changing the brake fluid on the weekend as it's due anyway and will give the brake disks a bit of sand with a 150-grid sand paper to make sure there is no film build up from the friction with the pads. Anything I can do with the pads? They still have plenty of meat left and are good brand (Pagid).

 

 

 

I did 2780 miles on that trip, first 970 miles in one go with just 2 stops to refill, driving through 37-degree heat, driving in the 1st or 2nd gear for 45 minutes up the huge mountains. Then doing hours of 90mph on the motorways in Europe. The only thing I am missing in this car is the cruise control. 

[2009joe]

id like to take a trip like that on my 2014 t27 2.0 d4d avensis 

[TonyHSD]

Nice trip 👍

Ypu process don’t need to do anything on the brakes , but you can also diy service them if you want. Was it not posted to maintain speed with the engine and lower gear and use brakes from time to time ? 
Check the pads friction materials if cracked, give them a wire brush clean and brake cleaner spray, discs use sandpaper for wood, don’t use any grease anywhere except slider pins and you will be good , plus the new fluid. 
If you are about to change pads , do so with new discs. 

[Toyota-fan]

Pretty common when going downhill a good distance with constant dependency on wheel brakes. The best approach is to use wheel brakes intermittently with engine brakes to avoid loss of brakes. You can easily lose brakes more than 50% when the brake discs/drums and pads/shoes get red hot, and also potentially damage the rubber dust seals of the brake callipers.  Basically, avoid going downhill for more than 10 minutes entirely on wheel brakes as it won't do any good when you can't stop immediately in an emergency once the wheel brakes are overheated, which can be a dangerous situation. 

[Seb_90]

17 hours ago, 2009joe said:

id like to take a trip like that on my 2014 t27 2.0 d4d avensis 

It's a nice engine to do long distances, you should do it!

 

3 hours ago, TonyHSD said:

Nice trip 👍

Ypu process don’t need to do anything on the brakes , but you can also diy service them if you want. Was it not posted to maintain speed with the engine and lower gear and use brakes from time to time ? 
Check the pads friction materials if cracked, give them a wire brush clean and brake cleaner spray, discs use sandpaper for wood, don’t use any grease anywhere except slider pins and you will be good , plus the new fluid. 
If you are about to change pads , do so with new discs. 

There was no sign about changing the gears down, tbf I knew it's the process anyway just haven't changed gears low enough.

Will follow your advice and DIY service the brakes. 👍

 

3 hours ago, Toyota-fan said:

Pretty common when going downhill a good distance with constant dependency on wheel brakes. The best approach is to use wheel brakes intermittently with engine brakes to avoid loss of brakes. You can easily lose brakes more than 50% when the brake discs/drums and pads/shoes get red hot, and also potentially damage the rubber dust seals of the brake callipers.  Basically, avoid going downhill for more than 10 minutes entirely on wheel brakes as it won't do any good when you can't stop immediately in an emergency once the wheel brakes are overheated, which can be a dangerous situation. 

 

Lesson learned for the future. 

[Toyota-fan]

On 8/5/2024 at 2:09 PM, TonyHSD said:

If you are about to change pads , do so with new discs. 

You can machine the discs within the safe thickness limit of the discs.

Changing discs when changing pads is not necessary, unless of course discs are badly worn beyond the minimum thickness or warped or has deep grooves etched onto them for some reason(usually from dirt, soil particles getting stuck ).  Discs are usually far far more expensive than pads and expected to last lot longer than pads. I am having the same discs in my vehicle for the last 10 years while I have been through several batches of brake pads. Each time I lightly machined the discs and they are still within the safe limit of thickness. You can find the minimum recommended thickness of the car from the service/repair manual or online.

[avetoy]

1 hour ago, Toyota-fan said:

You can machine the discs within the safe thickness limit of the discs.

It is possible, yes... if you have a lathe. But if you have to pay someone for the work, it's no longer worth it.

[TonyHSD]

Plus new pads on old discs likely to cause noise, vibrations and poor stopping performance. The discs and pads on most standard Toyota cars are same or similar price, the machining or trying to save an old brake discs really not worth on these cars. Just buy a new set and replace together is the best practice. £30 pads + £40 -£50 discs 

[Tif]

Hello, Avensis Is a pretty heavy car It Is a car likely to have this problema.

In muy opinion the best thing to do is new fluid dot 4 and a thin papersand(p360 or thiner) only to the pads. They are likely to have became harder and glazing. If this happens they Will be "shiny", after the sandpaper the should look matte.

After that, just clean the calipers and a bit off grease on the sliders pins as said TonyHSD.

[APS]

Very common symptom, especially when on summer holiday with the car fully loaded with people, animals and all related paraphernalia. I can just say, be glad that you have a relatively modern car with reasonably sized and vented discs. Then you have a fighting chance of keeping the brakes working.

Back in the days when cars had plain solid discs at best and drum brakes at worst, things could be a bit "interesting". I can recall several occasions where we nearly lost all brake capacity coming down each mountain. And then you'd have the engine overheating on the way up. Same scenario repeated for every mountain pass. Very scenic, mind you. 🙂 

Cars have come a long way since. 

[Cessna]

I agree with TonyHSD's first post above. Braking returned to normal, so no work required.

[Toyota-fan]

On 8/8/2024 at 8:02 PM, avetoy said:

It is possible, yes... if you have a lathe. But if you have to pay someone for the work, it's no longer worth it.

Good point. 

You just have to take the discs off the wheel and take them to a machine shop. It is pretty cheap when you do the labor part. You leave with the machine shop for few hours and pick up. There are guys who do it from home for very cheap as well. 

FYI, the factory discs are usually good when compared to the aftermarket ones you buy. Therefore, you do want to use the factory ones until they are no longer safer to use beyond minimum thickness. Factory quality discs are pretty pricey. 

[Toyota-fan]

On 8/8/2024 at 8:07 PM, TonyHSD said:

Plus new pads on old discs likely to cause noise, vibrations and poor stopping performance. The discs and pads on most standard Toyota cars are same or similar price, the machining or trying to save an old brake discs really not worth on these cars. Just buy a new set and replace together is the best practice. £30 pads + £40 -£50 discs 

The discs you buy off the internet are nowhere near the quality of the factory ones. 

You machine them with new pads for a reason, because they grip better. You need to bed the new pads with the machined discs by mildly applying brakes for few kilometers after the installation. 

Machined discs perform better initially than new ones because of the slightly gritty machined surface. Noises and vibrations are only an issue if you don't know what you are doing, in which case it is better to leave it to a professional mechanic. 

[Toyota-fan]

1 minute ago, Toyota-fan said:

The discs you buy off the internet are nowhere near the quality of the factory ones. 

You machine them with new pads for a reason, because they grip better. You need to bed the new pads with the machined discs by mildly applying brakes for few kilometers after the installation. 

Machined discs perform better initially than new ones because of the slightly gritty machined surface. Noises and vibrations are only an issue if you don't know what you are doing, in which case it is better to leave it to a professional mechanic. 

Yes, definitely leave any brake service jobsto a professional mechanic if you are not familiar with the careful precautions of working with the brake system. It is not for somebody who has never done it, unless willing to take time and do slowly by followin the proper procedures from the repair manual.

[avetoy]

35 minutes ago, Toyota-fan said:

You just have to take the discs off the wheel and take them to a machine shop. It is pretty cheap when you do the labor part. You leave with the machine shop for few hours and pick up. There are guys who do it from home for very cheap as well. 

FYI, the factory discs are usually good when compared to the aftermarket ones you buy.

 

So, the car is "paralyzed" until the brake discs can be returned home... then how are they transported? Of course, if there is another car or a good friend who transports discs back and forth... I still don't think it would be very cheap. But of course it's possible.

If factory brake discs mean those that can be bought from Mr. T's marble counter, I can assure you that Mr. T does not manufacture brake discs, but buys them from somewhere as well.

My current car was serviced at Mr. T's workshop just before I bought it, and all discs and pads were replaced. After approx. 20,000 km, the brakes started vibrating; the nearside front disc had gone crooked. I replaced the discs and pads with aftermarket parts and since then I have driven 18,000 km and still no vibrating. The discs were not the cheapest ones at the market but much cheaper than "originals".

[TonyHSD]

3 hours ago, Toyota-fan said:

The discs you buy off the internet are nowhere near the quality of the factory ones. 

You machine them with new pads for a reason, because they grip better. You need to bed the new pads with the machined discs by mildly applying brakes for few kilometers after the installation. 

Machined discs perform better initially than new ones because of the slightly gritty machined surface. Noises and vibrations are only an issue if you don't know what you are doing, in which case it is better to leave it to a professional mechanic. 

That’s not true. 
No arguments though. 👍
 

[Seb_90]

Not sure which discs I've got currently, my local garage has fitted them for me 4-5 years ago. The pads are PAGID and I am happy with it. 

Usually the good companies which produce brakes are: PAGID, Brembo, Ate. I am pretty sure we have Bosch from factory but I've heard if you buy them from the shop they do tend to squeak.

 

I did change the brake fluid, removed the pads, clean all them all up, sanded the discs with sand paper, replaced the grease on the glide pin (rear were fine but the front were stuck!). Pleanty of meat left on the pads. Hopefully the brakes can last another 30k miles.

[APS]

Perfect. 👌 

[Tif]

1 hour ago, Seb_90 said:

Not sure which discs I've got currently, my local garage has fitted them for me 4-5 years ago. The pads are PAGID and I am happy with it. 

Usually the good companies which produce brakes are: PAGID, Brembo, Ate. I am pretty sure we have BOSCH from factory but I've heard if you buy them from the shop they do tend to squeak.

 

I did change the brake fluid, removed the pads, clean all them all up, sanded the discs with sand paper, replaced the grease on the glide pin (rear were fine but the front were stuck!). Pleanty of meat left on the pads. Hopefully the brakes can last another 30k miles.

I just did front brakes last week and my  T27 came with with Textar from factory. 

I usually go for Brembo or ATE but this time Bosch was on sale and decided to give them a try. I prefer Textar to Bosch.

[Toyota-fan]

On 8/11/2024 at 9:20 PM, avetoy said:

 

So, the car is "paralyzed" until the brake discs can be returned home... then how are they transported? Of course, if there is another car or a good friend who transports discs back and forth... I still don't think it would be very cheap. But of course it's possible.

If factory brake discs mean those that can be bought from Mr. T's marble counter, I can assure you that Mr. T does not manufacture brake discs, but buys them from somewhere as well.

My current car was serviced at Mr. T's workshop just before I bought it, and all discs and pads were replaced. After approx. 20,000 km, the brakes started vibrating; the nearside front disc had gone crooked. I replaced the discs and pads with aftermarket parts and since then I have driven 18,000 km and still no vibrating. The discs were not the cheapest ones at the market but much cheaper than "originals".

If the discs  has developed issues after 20k, then I would also start worrying about the rest of the car as well.

Yes, if you don't have another car or a motorbike or somebody to help to take the discs to a nearby lathe or brake service place, you are better off taking the whole car to a mechanic and get it done professionally because there won't be whole lot of money saving. Besides, brakes are the most important safety appliance of a car. Buying set of new discs and replacing them at home is entirely doable o course, but usually can end up more expensive than going to a professional mechanic to get the brakes done because of the price of the discs. However, if you get the discs cheaper and ensure you can get the whole job done half the price of a professional brake service garage, then go for it.  Just make sure you know what you're doing when you remove the discs and install the new discs and pads. The calliper cylinders need pushing in, in order create the space for new pads. There are certain serious precautions you need to take when you do that and of course there are specific tools as well. You need to bed the pads and discs carefully after installation by driving and applying the brakes for few kilometers. If you don't have the knowledge or experience and the tools, it is a professional job. It is better to be safe than sorry.

AFAIK, for most Japanese cars, factory brake discs are far superior to after market ones, hence the reason for hanging onto them as long as safely possible. Professional brake service places machine the discs where possible. They don't whack in brand new discs every time because doing so makes no sense for the car, the owner or the mechanic.

[Toyota-fan]

On 8/12/2024 at 4:24 AM, Seb_90 said:

I did change the brake fluid, removed the pads, clean all them all up, sanded the discs with sand paper, replaced the grease on the glide pin (rear were fine but the front were stuck!). Pleanty of meat left on the pads. Hopefully the brakes can last another 30k miles.

Well done.  You seem to know what you were doing. Only thing I would consider is machining the discs everytime you install new pads because that helps with brake performance and bedding of the pads. Discs tend to develop uneven wear due to dust and other particles getting in and the machining usually fixes that problem.  I personally never puts new pads without machining the discs.  It is a bit of a pain to take the discs off and take them to a nearby lathe or brake service place, but it's worth the trouble or the peace of mind  with the brakes.  I get the discs machined dirt cheap because there is a guy nearby who does it from his garage.

[Toyota-fan]

On 8/11/2024 at 11:24 PM, TonyHSD said:

That’s not true. 
No arguments though. 👍
 

Yes, lets agree to disagree.

I know what I am talking about because I worked in a brake servicing and general mechanical shop for years, hence the reason I am pretty confident with doing all the work in the brake system myself. 

[Toyota-fan]

On 8/8/2024 at 8:07 PM, TonyHSD said:

Plus new pads on old discs likely to cause noise, vibrations and poor stopping performance. The discs and pads on most standard Toyota cars are same or similar price, the machining or trying to save an old brake discs really not worth on these cars. Just buy a new set and replace together is the best practice. £30 pads + £40 -£50 discs 

This is absolutely incorrect where I live unless you live in a location on the planet where the discs are that cheap and as good as most factory ones. The claim any properly machined discs causing brake performance issues and noise is plain wrong. The bigger the vehicle, beefier the discs and they are expensive to replace, be it factory quality ones or cheap eBay ones. 

What you don't and should not do is to install pads with the old discs without machining them. That is an absolute NO in my book if you care about the brake performance and safety. Machining brings the discs back to alignment when done properly at a proper machine shop.

If you can get discs very cheap as indicated above, then go for it. It is not possible in my neck of the woods.  Brake drums are even super expensive in my side of the world. 

[TonyHSD]

5 hours ago, Toyota-fan said:

This is absolutely incorrect where I live unless you live in a location on the planet where the discs are that cheap and as good as most factory ones. The claim any properly machined discs causing brake performance issues and noise is plain wrong. The bigger the vehicle, beefier the discs and they are expensive to replace, be it factory quality ones or cheap ebay ones. 

What you don't and should not do is to install pads with the old discs without machining them. That is an absolute NO in my book if you care about the brake performance and safety. Machining brings the discs back to alignment when done properly at a proper machine shop.

If you can get discs very cheap as indicated above, then go for it. It is not possible in my neck of the woods.  Brake drums are even super expensive in my side of the world. 

You are correct on most things about brakes but incorrect about brake discs quality and prices.
Even the cheapest aftermarket brake parts from well known brands will do as good as Toyota oem or even better as long as they are fitted correctly and all components work as they should. Majority of brake problems comes from improper fitting, and use of grease in places that should not be used.  
I see you have knowledge and I have no intentions to argue. Just disagree about the machining and the aftermarket parts opinion, but we all have different opinions, right 👍

[Toyota-fan]

11 hours ago, TonyHSD said:

You are correct on most things about brakes but incorrect about brake discs quality and prices.
Even the cheapest aftermarket brake parts from well known brands will do as good as Toyota oem or even better as long as they are fitted correctly and all components work as they should. Majority of brake problems comes from improper fitting, and use of grease in places that should not be used.  
I see you have knowledge and I have no intentions to argue. Just disagree about the machining and the aftermarket parts opinion, but we all have different opinions, right 👍

I won't argue with you about the aftermarket brake discs and their quality, because I don't have any empirical evidence in front of me to prove my point and I shouldn't debate about it anyway because you may have access to quality brake discs for cheaper price in your part of the world.

However, I can vouch for the accuracy of my point about machining discs instead of replacing them, and most definitely in my part of the world.  Yes, you are right about improper fitting in mechanic workshops can also cause problems, particularly when inexperienced mechanics or apprentices do half a job.  As for DIY, you take the risk when you do that. As I said, I have professional experience to back up my points, particularly when my points are accurate. It costs closer around $600 to replace the four brake discs of my medium size SUV, and that's with aftermarket ones, and I ain't kidding about that.  The point is that it is entirely unnecessary anyway because they are meant to be machined and it is also clearly stated in the factory service manual as well. 

You need to go by what is available and suitable for your locality.