GS450h service advice

[hprice1099]

Afternoon guys,

Just need some advice on a service I've had done today at my local Lexus service garage, the car is a 61 plate and only covered 27k miles. It went in for MOT, intermediate service and to investigate a squeaking noise from the brakes.

First of all I was told the near side calliper has seized (this is covered under warranty), I was also told the cause of the squeaking was scored brake disks. Does anyone know the cause of this?? I was told the pads are fine but all will need replacing (eventually), the front discs are worn 70% and the rear 30%. I'm assuming thats because of RWD?

I'm guessing the main question is why the disks are scored and is it covered under warranty?

 

Cheers

 

Howard

 

[AmbroseJohn]

Seized calipers is a common problem. Some Lexus dealers consider them consumables.

Years ago when brake pads were made from asbestos, they wore out quickly but disks lasted forever. These days pads are much harder and last forever, unfortunately the disk don't and are consequently, definitely consumables.  

Good luck with the warranty claim. He who shouts loudest usually wins. :)

[hprice1099]

7 minutes ago, AmbroseJohn said:

Seized calipers is a common problem. Some Lexus dealers consider them consumables.

Years ago when brake pads were made from asbestos, they wore out quickly but disks lasted forever. These days pads are much harder and last forever, unfortunately the disk don't and are consequently, definitely consumables.  

Good luck with the warranty claim. He who shouts loudest usually wins. :)

Ha thanks mate, I'm going to try my luck :) 

[Shahpor]

Hello.

It can be difficult to diagnose brake discs without seeing them.  By scored I assume you mean there are grooves cut into the disc surface?  If so, then it is usually something like foreign matter (dirty or small stones) that gets caught between the disc and the pads that damage the disc when the brake is pressed.  Normally the scoring is minimal though, and it can be ignored until it is time to change the pads as well, or the disc is worn out.

Also, by squeaking noise do you mean squeal? Squealing generally tends to be from a lack of copper grease on the pads shim plates.

As for the wear rates front to back, this has actually nothing to do with the fact that the car is RWD.  FWD cars use their brakes in the same way.  It is because most of the braking force is applied to the front wheels when stopping the car.  This is done because the weight transfer that takes place from back to front when the car is slowed down, which aids traction.  If the rear brakes were applied at the same rate, the wheels would probably lock up.

It is unlikely that the warranty would cover the discs.  The only scenario where that would happen is if you argue that the seized caliper somehow contributed to the scoring, which is not very likely.  Still, no harm in trying.

[hprice1099]

7 minutes ago, Shahpor said:

Hello.

It can be difficult to diagnose brake discs without seeing them.  By scored I assume you mean there are grooves cut into the disc surface?  If so, then it is usually something like foreign matter (dirty or small stones) that gets caught between the disc and the pads that damage the disc when the brake is pressed.  Normally the scoring is minimal though, and it can be ignored until it is time to change the pads as well, or the disc is worn out.

Also, by squeaking noise do you mean squeal? Squealing generally tends to be from a lack of copper grease on the pads shim plates.

As for the wear rates front to back, this has actually nothing to do with the fact that the car is RWD.  FWD cars use their brakes in the same way.  It is because most of the braking force is applied to the front wheels when stopping the car.  This is done because the weight transfer that takes place from back to front when the car is slowed down, which aids traction.  If the rear brakes were applied at the same rate, the wheels would probably lock up.

It is unlikely that the warranty would cover the discs.  The only scenario where that would happen is if you argue that the seized caliper somehow contributed to the scoring, which is not very likely.  Still, no harm in trying.

Thanks Shahpor, very detailed reply :) Yes your correct its more like a squeal, its extreamly annoying. But I was told its doing no harm and if I could put up with it, it only needs replacing when its due. Or pay £300 to replace the rear disks/pads. Decisions Decisions :) 

[Shahpor]

No probs

Well, they are correct that if it is lack of grease, then it will do no harm to continue to drive it.

However, it is not a big job to take the pads out and apply the grease.  But I suppose from their point of view, you might as well change the brakes since they will be off the car already.  You are right, it is a tricky one.

Having said that, if it is the rears that are causing the noise, then I would suggest just getting someone to grease the shims since rear brakes wear out very slowly, so you could be putting up with the noise for a long time.

[Britprius]

Another reason that the rear brakes pads wear out more slowly than the fronts is because braking to the rear is done much of the time by regeneration. This is done by using the electric motors in the transmission as generators to produce electricity to put back into the HV Battery "regeneration". This electricity can then be used to help propel the car thus saving fuel. This affect can be seen if you brake steadily the large gauge showing kilowatt used will go into the green "kilowatts recovered" the more you brake "within reason" the more the needle goes into the green.

Changing discs is easy not a job for the dealer, and branded quality discs can be bought on eBay at very good prices. I bought a pair of rear discs by Quinton Hazel for £19 the pair. There is no evidence that the OEM discs are any better than known branded versions.Branded pads can also be bought at good prices.

With pads people often have there own preferences depending on how the car is driven. Hard pads last well often with less brake dust, but you pay the penalty of the discs warring instead. Generally if you fit new discs you also fit new pads, but fitting new pads does not require fitting new discs.

John.

[RgrWynne]

A cause of disc scoring and also high wear is when the vehicle is not used and the discs rust. Depending on how long the vehicle is left will decide how bad. This happened to a friend who did low mileage , but had very high disc wear. Good luck with your claim

[GSLV6]

As above, scored discs happen for a variety of reasons.  The most common is simply picking up a bit of grit from the road which, for obvious reasons will end up with other mud and muck plastered around drive shaft and wheels, eventually some muck is bound to get onto brake calipers.  Grit or rust can become embedded into the brake pad surface where the pads may be grooved, thus scoring the discs when the brakes are applied.

Some pads (such as EBC Green) can be very soft and result in loads of black brake dust coating the wheels, and as well as wearing very quickly, these are more prone to dirt becoming embedded and scoring discs.  OEM (standard) and fast road brake pads tend to be harder, and often made with sintered metals in the compound, so brake disc wear is higher than with older (banned) asbestos pads.

To prevent seized calipers, it's always a good idea before and after each winter to jack the car up, remove each wheel in turn and use brake cleaner on the calipers, remove each pin for the pads, clean and re-grease with copper-slip, ditto for any brake pad shims. It allows inspection of any floating caliper pins too (which can also be cleaned).  This doesn't take long and can pre-empt any MOT issues.  If a brake part (caliper, pads or disc) are replaced on one side, ideally the other side ought to be done too, as brakes have to work with the same efficiency in pairs to avoid any potential safety concerns.  However, most warranties won't allow for calipers to be replaced in pairs because the argument is that a caliper, as long as it is working, shouldn't have any detrimental impact on braking force.  That needs to be checked after work is done to be sure.  This is something most people miss.  Always ask for a report  which details independent front left and right braking force checks after work is done and refuse to take any vehicle back if they are not both very closely matched.

I would be very careful about buying unbranded discs from eBay.  Some are Chinese imports, and when you compare OEM/Branded against unbranded, things like run-out measurements can be miles out.  I know several people who've bought and fitted new discs only to encounter brake judder from discs which are only a little out on run-out, but this has been enough to cause issues.  The other thing to be aware of is the receiving hub surfaces need not just to have loose dirt etc removed, they have to be spotlessly clean and smooth as any tiny amount of surface unevenness will result in the same symptoms as high run-out and will lead to juddering under braking and other problems.  Whilst it is not difficult to change discs (providing you can get the old ones off in the first place), all mating surfaces must be prepared properly and be very smooth and even.  Finally, you never know what metal quality you are getting on unbranded eBay discs.  Some are complete rubbish and even if they have been well enough machined and have close tolerance on run-out, they can soon warp when overheated due to the inferior alloys used.  Stainless steels are particularly prone to this.  A quality cast/machined disc will rarely suffer the same fate.  Bearing in mind we're talking about the safety of the driver, family and other road users, discs, pads and tyres are areas where I would never cut corners.  You can buy decent products much cheaper than from the dealers, just be sure of the quality of what you're buying.

 

[GSLV6]

double post 

[RgrWynne]

I totally agree with Paul, just be very careful, it is not worth cutting corners, for a relatively small saving. I would also add that my colleague whose brake discs were rusted also suffered with a seized caliper on a front wheel. It overheated the disc and wheel making the car violently judder at high speed and frightened the living daylight out of him. The car had just been mot'd here, he lives in France, and it was not picked up.

[hprice1099]

3 hours ago, Britprius said:

Another reason that the rear brakes pads wear out more slowly than the fronts is because braking to the rear is done much of the time by regeneration. This is done by using the electric motors in the transmission as generators to produce electricity to put back into the HV battery "regeneration". This electricity can then be used to help propel the car thus saving fuel. This affect can be seen if you brake steadily the large gauge showing kilowatt used will go into the green "kilowatts recovered" the more you brake "within reason" the more the needle goes into the green.

Changing discs is easy not a job for the dealer, and branded quality discs can be bought on Ebay at very good prices. I bought a pair of rear discs by Quinton Hazel for £19 the pair. There is no evidence that the OEM discs are any better than known branded versions.Branded pads can also be bought at good prices.

With pads people often have there own preferences depending on how the car is driven. Hard pads last well often with less brake dust, but you pay the penalty of the discs warring instead. Generally if you fit new discs you also fit new pads, but fitting new pads does not require fitting new discs.

John.

Thanks mate, I never thought about getting it done elsewhere. I useless at that type of thing lol Lexus quoted me £300 to replace with new. I wonder how much an indy would charge?

Cheers

[hprice1099]

30 minutes ago, GSLV6 said:

As above, scored discs happen for a variety of reasons.  The most common is simply picking up a bit of grit from the road which, for obvious reasons will end up with other mud and muck plastered around drive shaft and wheels, eventually some muck is bound to get onto brake calipers.  Grit or rust can become embedded into the brake pad surface where the pads may be grooved, thus scoring the discs when the brakes are applied.

Some pads (such as EBC Green) can be very soft and result in loads of black brake dust coating the wheels, and as well as wearing very quickly, these are more prone to dirt becoming embedded and scoring discs.  OEM (standard) and fast road brake pads tend to be harder, and often made with sintered metals in the compound, so brake disc wear is higher than with older (banned) asbestos pads.

To prevent seized calipers, it's always a good idea before and after each winter to jack the car up, remove each wheel in turn and use brake cleaner on the calipers, remove each pin for the pads, clean and re-grease with copper-slip, ditto for any brake pad shims. It allows inspection of any floating caliper pins too (which can also be cleaned).  This doesn't take long and can pre-empt any MOT issues.  If a brake part (caliper, pads or disc) are replaced on one side, ideally the other side ought to be done too, as brakes have to work with the same efficiency in pairs to avoid any potential safety concerns.  However, most warranties won't allow for calipers to be replaced in pairs because the argument is that a caliper, as long as it is working, shouldn't have any detrimental impact on braking force.  That needs to be checked after work is done to be sure.  This is something most people miss.  Always ask for a report  which details independent front left and right braking force checks after work is done and refuse to take any vehicle back if they are not both very closely matched.

I would be very careful about buying unbranded discs from Ebay.  Some are Chinese imports, and when you compare OEM/Branded against unbranded, things like run-out measurements can be miles out.  I know several people who've bought and fitted new discs only to encounter brake judder from discs which are only a little out on run-out, but this has been enough to cause issues.  The other thing to be aware of is the receiving hub surfaces need not just to have loose dirt etc removed, they have to be spotlessly clean and smooth as any tiny amount of surface unevenness will result in the same symptoms as high run-out and will lead to juddering under braking and other problems.  Whilst it is not difficult to change discs (providing you can get the old ones off in the first place), all mating surfaces must be prepared properly and be very smooth and even.  Finally, you never know what metal quality you are getting on unbranded Ebay discs.  Some are complete rubbish and even if they have been well enough machined and have close tolerance on run-out, they can soon warp when overheated due to the inferior alloys used.  Stainless steels are particularly prone to this.  A quality cast/machined disc will rarely suffer the same fate.  Bearing in mind we're talking about the safety of the driver, family and other road users, discs, pads and tyres are areas where I would never cut corners.  You can buy decent products much cheaper than from the dealers, just be sure of the quality of what you're buying.

 

Thanks for the interesting read, good to know. They told me they would replace both callipers, even though only one is seized. I assumed it was standard lol Yes I would never buy disks of eBay, I've got a very expensive habit of sticking with dealers and paying out :( :( I might look into an indy to do the job :)