Brake pads and automatics

[Mart 63]

Taking my motorhome to storage today, I have quite a few roundabouts and speed humps. Normally in my car or old motorhome, I used the gears to slow down. In my new automatic motorhome I'm constantly using the brakes. How long do brake pads last with automatics, as its the first time with an automatic.

 

[Roby2008]

We have automatics, car and MH ( Madame needs hand controls).

The last MH was 7m coachbuilt with a comformatic, we did 100,000 km in 9yrs, the discs were original and I did 3 pad changes in that time ( 3 front,1 rear), approx 30,000 km was the average lifes on pads , the driving is mixed with autobahn and mountains, the new MH is on the 9 speed ( same sized 7m MH) and is up to 18,000km now, we shall see how the pad wear compares at around 30,000km .

Her car is a SEAT Alhambra with a DSG, its a nice drive and quite nippy for its size, this has 108,000 km on it (6 yrs) and is on its 3rd set of front pads and 2nd set of front discs, her previous car was a Chrysler voyager and that averaged the same wear on the discs and pads, being her essential transport, a lot of town driving is involved too.

So for our driving style and distance, around 30,000km is the average lifespan on pads.

 

[jockaneezer]

When I was repairing garage equipment, I was at a VW dealership that did Motobility cars. One of the mechanics said "Hey, come and see this ! This old geezer brings his car in for new discs and pads about 3 or 4 times a year and we keep telling him what he's doing wrong, but won't listen ?" The old guy got in the car (an automatic) and set off up the road with his brake lights shining brightly all the way off into the distance, one foot on the gas, the other foot firmly on the brake !

 

[bigwood]

I have distant memories of changing front pads on an automatic car. When I went to the motor factors to buy the pads they said they only had pads for the manual and would have to ordered the pads for an automatic.
At the time it seemed a bit of a rip off but at the time engine braking was part of learning to drive.

 

[Silver-Fox]

when braking you get tremendous vibrations through the brakes..

Probably caused by glazing the pads and or the discs.

Happens if you don’t use enough force and lightly brake down hills etc.

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[Silver-Fox]

Nope.. definately not disc distortion....
Pitting on surface of disc...

Highly unlikely due to pitting given the surface area of the pads.

Also some competition discs are drilled and grooved.
Can you imagine the vibrations you’d get from them

 

[Lenny HB]

.

 

[Silver-Fox]

I have distant memories of changing front pads on an automatic car. When I went to the motor factors to buy the pads they said they only had pads for the manual and would have to ordered the pads for an automatic.

That’s a first on me.
Sure they weren’t pulling your leg???

I’ve worked on cars since the mid 70’s and never heard that one

 

[Lenny HB]

The last MH was 7m coachbuilt with a comformatic, we did 100,000 km in 9yrs, the discs were original and I did 3 pad changes in that time ( 3 front,1 rear), approx 30,000 km was the average lifes on pads

That's heavy our last van was a 4.5t Comformatic still on original pads and discs when I traded it at 46,000 miles (75,000 km) and I'm quite heavy on the brakes.

 

[funflair]

Brake pads probably last longer on an auto as soon as you take your foot of the gas the box changes down the more the van slows the lower the gears go giving engine braking.
Manuals have such a high top gear lifting off the gas you get very little engine braking unless you do a lot of cog swapping.

That's my experience as well Lenny I think a lot of the comments re lack of engine braking in auto's is related to experience with older auto boxes, our ZF8 auto knows the difference between slowing down, where you use the brakes and it will follow down with the gears and steep decent's where you come off the throttle and the van speed increases so it starts dropping gears quite aggressively, OK in the first scenario an "old school" driver might be using more engine braking by shifting down but of course you can still do this in a modern auto, as we have a Telma retarder we can negate the aggressive downshifts on hills by engaging the retarder before coming off the throttle then the speed sensors and ECU see that everything is in control without those downshift and the auto box will then just follow as if we were on the flat, makes for a quieter and more pleasant experience in my book.

For information (you will know this Lenny) a Telma retarder is a "eddy current" braking unit that is incorporated into the prop shaft, it's totally contactless as it relies on the principles of an electric motor but in reverse, it operates automatically when the brakes are applied or can be set on manually at say the top of a hill to avoid using the brakes at all sometimes, I am not aware of any front wheel drive units although an exhaust brake would do similar and be easier to integrate.

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[daimlermg]

Last Motorhome 4 1/4 ton 55,000 miles Comfort Matic and just changed the rear pads for the first time in 11 years
When in France and I see the sign saying 500 m to roundabout, I lift off the throttle and coast to the roundabout

 

[Roby2008]

That's heavy our last van was a 4.5t Comformatic still on original pads and discs when I traded it at 46,000 miles (75,000 km) and I'm quite heavy on the brakes.

Driving styles differ, Madame tends to ride the brake a lot more, when you only have 2 hands for the steering, throttle and brakes, it is not so easy to drive.....I have no excuse, I am just heavy handed and lead footed..

 

[Scottish Scrutineer]

Brake pads probably last longer on an auto as soon as you take your foot of the gas the box changes down the more the van slows the lower the gears go giving engine braking.
Manuals have such a high top gear lifting off the gas you get very little engine braking unless you do a lot of cog swapping.

VAG (and others) with DSG gearboxes have a coasting function. When you lift off the throttle, they disengage the engine/gearbox and you are freewheeling until you manually intervene, brake or increase the throttle. All in the aim of improving fuel consumption, and it does work as I can get 45mpg from my VW Shuttle on A-roads.

Its rather like the old freewheel that SAAB used to use where it was selected by pulling a chain in the footwell

 

[peterc10]

I’m on 52k with a 3.0L comfortmatic and at 5 tons, 8 years old and still on the original pads

Yep me too. A 4.5t Hymer bought in November 2015 and still going well on existing pads. When slowing down just take your foot gently off the accelerator and let the Comformatic choose the gears.

 

[Puddleduck]

Driving styles differ, Madame tends to ride the brake a lot more, when you only have 2 hands for the steering, throttle and brakes, it is not so easy to drive....

And then you get the warning on the fancy dash to hold the steering wheel as it doesn't recognise you are using the steering knob. Probably not the right terminology but you know what I mean.

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[dunnah01]

2011 4.25t Comfortmatic 55k and still around 50% on original front pads and even more on the rears. Many of these miles are around France where they love a roundabout.
I tend to drive with an I'll try not to ware that out as it'll be up to me to change it attitude

 

[funflair]

And then you get the warning on the fancy dash to hold the steering wheel as it doesn't recognise you are using the steering knob. Probably not the right terminology but you know what I mean.

Is that correct? I thought it worked by sensing steering input rather than physical contact with the wheel.

 

[Roby2008]

And then you get the warning on the fancy dash to hold the steering wheel as it doesn't recognise you are using the steering knob. Probably not the right terminology but you know what I mean.

We know what you mean...we are knob free though, she has a 'gas' ring in the centre of the steering wheel and a big lever to push for the brakes, she locks the lever down intead of using the hand brake.....nice system, better than the old pull to go and push to stop lever we had in one car...

 

[Coolcats]

Most metal parts on modern cars are not of the same quality or durability as older cars , mainly due to the fact it has been recycled quite a few times

so you mean like the 1970’s Alfa’s which had to visit the body shop before being sold to a customer, the steel used to rust from the inside out. Modern cars last a darn site longer than most of the older vehicles.

 

[Coolcats]

Ok folks generally 2 brake pad changes to one disc change in many of the vehicles I have owned and that’s at around 35 to 40k

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[gus-lopez]

I don't ever remember seeing anything of pads or even shoes deteriorating.

I've seen dozens. lack of use is the main culprit.Water gets in .Temps drop it freezes & they crack. usually ok whilst still in the caliper but as soon as you take them out they fall to pieces.

’ve been playing with cars long enough to have seen brake material coming off the backing a

This^^^^^^

Never mind the pads... does anyone else find that the discs do not last like they used to..and always end up having to be replaced because of pitting...

^Since asbestos was removed the sintered material now requires the rotors to be replaced , usually every second brake pad change. They are a 'consumable item' now

I thought the pitting was caused by rust?

It is & usually lack of use

but I am talking about when they start pitting and when braking you get tremendous vibrations through the brakes..

Vibration is usually only caused by warped rotors due to stopping & sitting with the foot on the brake pedal instead of using the handbrake. It is far worse,& occurs easier, on vented rotors.

 

[Puddleduck]

We know what you mean...we are knob free though, she has a 'gas' ring in the centre of the steering wheel and a big lever to push for the brakes, she locks the lever down intead of using the hand brake.....nice system, better than the old pull to go and push to stop lever we had in one car...

I have the push pull system on my car but I don't drive now. When I did use the push pull system I found with it being the opposite way round to both a bike and to my walking frame it wasn't ideal.

The hand brake on mine is electronic and a button to pull for on/off.

 

[pwilmo]

I used to slow down using the gears but
... Did you know !?

Cars motorhomes are nowadays designed to slow down vehicles with 90% front braking: nose down - front heavy trajectory.

If you use the gearbox to slow down your are changing that to: level - even weighted; not how the system has been designed.

Plus wear and tear on brake pads/disks are cheaper to replace than wear and tear on a gearbox.

Info supplied by
Police Driving Examiner during a Defencive Driving Course.

Probably makes a difference if you're in a high speed chase but normal folks !?

I drive an automatic car, slow down using the brake pedal and use the handbrake at stops, traffic lights, junctions etc

Each to their own - I say.

 

[Northernraider]

That's good going

But he only drives in the UK and Germany which is relatively flat. He doesn't go down many hills

Brake pad wear will depend on many things and that's one of them

Where you drive it

 

[poppycamper]

Plus wear and tear on brake pads/disks are cheaper to replace than wear and tear on a gearbox.

Yep.. each to their own as you say..
However you must really be a bad driver to expect engine breaking to increase wear on your gearbox..!!!

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[WESTY66]

But he only drives in the UK and Germany which is relatively flat. He doesn't go down many hills

Brake pad wear will depend on many things and that's one of them

Where you drive it

Who does?? I do more of my miles in the continent, hence LHD, and as many miles as I can in the alps off to Switzerland in a fortnight (yes in the snow) and
French alps next year

 

[Landy Andy]

Cars motorhomes are nowadays designed to slow down vehicles with 90% front braking: nose down - front heavy trajectory.

If engine braking or physical braking on a front wheel drive wouldn’t that make them both “front heavy trajectory”. Only RWD would it be different????

 

[SpeedyDux]

VAG (and others) with DSG gearboxes have a coasting function. When you lift off the throttle, they disengage the engine/gearbox and you are freewheeling until you manually intervene, brake or increase the throttle. All in the aim of improving fuel consumption, and it does work as I can get 45mpg from my VW Shuttle on A-roads.

Its rather like the old freewheel that SAAB used to use where it was selected by pulling a chain in the footwell

My Dad's Rover 75 had a freewheel gizmo. I remember you had to turn a knob to do that. Not much point because petrol was dirt cheap.

My experience is that rear disks tend to be more prone to rust pitting because they do less braking than the fronts so the rear pads don't clean off the surface rust.

Anyway, anticipation is the key to reducing brake wear. When I lift off early, as I approach a junction or roundabout, I always get passed by Leadfoot Luke still accelerating towards a red light. He slams on the brakes at the last minute. His mpg number must be dire too.

I am also a fan of "B" mode in the hybrid that puts energy back into the HV battery after lifting off, so the footbrake is only needed for the final few yards to bring it to a stop. I would love driving a hybrid Ducato but they don't exist.

 

[poppycamper]

Anyway, anticipation is the key to reducing brake wear. When I lift off early, as I approach a junction or roundabout,

Exactly as I used to do... was a very light brake user, but started to have to replace rusty/pitted discs way before pads were worn... So now I try to use brakes more ( very difficult after a life time of minimal braking) to try and preserve the discs...

 

[Mart 63]

I've Hill decent on mine. Is that using brakes or gearbox?

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[SpeedyDux]

I've Hill decent on mine. Is that using brakes or gearbox?

If it is a ComfortMatic then I think it is the gearbox but as it only operates at very low speeds I have never had to use that feature on mine. I could be wrong.

Conversely, I think the brakes together with traction control are applied to stop wheelspin on a slippery surface. That is something I did experience going up a very muddy country lane.