Always change pads AND discs?

[philharve]

Hi All

Whilst reflecting upon almost 40 years of driving and the costs of maintenance throughout these years I suddenly became aware that, on average, I am replacing my discs almost as often as I am renewing my brake pads. I feel sure there was a time when brake discs lasted a lot longer. Is this my imagination or are pads becoming more effective/abraisive and therefore taking their toll upon the discs?

Would driving style impact upon disc life? Heavy braking will shorten disc life but so would light braking which could increase the likelihood of the formation of rust. Now that I'm retired I expect to travel fewer miles, however, lack of use could also contribute to a shortened disc life too.

Is it time to sell the car and get a bus pass!

REGARDS

Phil

 

[television]

Hi phil,its more normal to use 2 sets of pads to 1 disc, that should equal out to around 40k miles plus

 

[philharve]

Hi phil,its more normal to use 2 sets of pads to 1 disc, that should equal out to around 40k miles plus

Hi Malcolm

I was tempted to state 2 sets of pads per disc but it sometimes feels like 1:1.

As for mileage ... I've replaced all 4 discs between 90 - 115kmiles and I figure the original owner must have replaced them at least once between 0 - 90kmiles. So your estimate of 1 set of discs per 40kmiles isn't that far off the mark.

REGARDS

Phil

 

[Phil D]

Not sure if it's BS or not, but a dealer recently told me that EU regs outlawing the use of asbestos on pads has led to harder materials being used, which wear discs out quicker. - Certainly I've had the experience of discs being worn to beyond acceptable tolerances without any warning lights - 11,000 miles earlier both pads & discs were declared AOK at a service
Phil

 

[jberks]

I get 2:1.
The reason I am told is that they no longer use asbestos in the pads (for obvious reasons) and this change has increased the disk wear dramatically. I believe the change came in the last 5 years or so as I never changed the disks on my 202 or previous cars but did on my 210 which I bought in 2001 and having now changed all the pads in my 211, my next brake service will be a pricey one I expect.
Mileage wise, at 49k I'm well into my 2nd set of front pads and have just recently changed the rears.

 

[brandwooddixon]

It's also worth noting that occaisionally dealers will tell you that discs need replacing due warpage when in fact it's due to corrosion. Unlike garages of old they don't offer a skimming service to remove any rust built up if the car has stood for a while or not been used much.

 

[television]

It's also worth noting that occaisionally dealers will tell you that discs need replacing due warpage when in fact it's due to corrosion. Unlike garages of old they don't offer a skimming service to remove any rust built up if the car has stood for a while or not been used much.

Other makes do skim them if warped, I will try and do some comparative disc thickness measurements.

Many times the disc just get replaced by looking at the burr on the edge, rather than the thickness

 

[David Nock]

I get 2:1.
The reason I am told is that they no longer use asbestos in the pads (for obvious reasons) and this change has increased the disk wear dramatically. I believe the change came in the last 5 years or so as I never changed the disks on my 202 or previous cars but did on my 210 which I bought in 2001 and having now changed all the pads in my 211, my next brake service will be a pricey one I expect.
Mileage wise, at 49k I'm well into my 2nd set of front pads and have just recently changed the rears.

I did read somewhere that softer pad materials are being researched urgently to get us back to the old status quo of pads not discs. Anyone else heard this?

 

[wireman]

The problem is is due to the modern pad material being more abrasive than the old stuff. The old disks were made of chilled cast iron which is very hard and wear resistant but incompatible with non asbestos pads, so the modern disk is made of nice soft grain oriented cast iron that you can cut with a stanley knife or brake pad.

The price of disks has fallen considerably due to the easier machining requirements of soft iron and the brake designers have made the servicing of brakes much easier in the disk replacement area, so much cheaper that disks are often sold at prices less than the pads.

I am not sure but believe that the filler in modern pads is a hard iron powder instead of the asbestos and bronze of old.

There is much to be gained from nice feeling brakes and nice flat new disks are a step in the right direction in achiving this, I am quite happy with this situation, since in them there days when you had the hard disks you had to pay a hugh sum to achive the feel of new brakes and they were invariably mounted behind the hub flange where it was harder to remove and replace.

The old hard disks were just as vulnerable to becoming less efficient as the new ones, surface glazing being a common problem but they did not wear and get thinner and hence require immediate replacement as we now find.

Disk brakes saw very little use on trucks before the non asbestos pads became the norm, almost all lighter trucks are now disk braked on the front axle because they are so much better than the drums that used to be fitted.
Prior to the modern materials setup disk brake trucks required much more regular brake servicing and fleet owners want low cost servicing, asbestos pad/hard disks did not provide this.

 

[busby20]

The problem is is due to the modern pad material being more abrasive than the old stuff. The old disks were made of chilled cast iron which is very hard and wear resistant but incompatible with non asbestos pads, so the modern disk is made of nice soft grain oriented cast iron that you can cut with a stanley knife or brake pad.

The price of disks has fallen considerably due to the easier machining requirements of soft iron and the brake designers have made the servicing of brakes much easier in the disk replacement area, so much cheaper that disks are often sold at prices less than the pads.

I am not sure but believe that the filler in modern pads is a hard iron powder instead of the asbestos and bronze of old.

There is much to be gained from nice feeling brakes and nice flat new disks are a step in the right direction in achiving this, I am quite happy with this situation, since in them there days when you had the hard disks you had to pay a hugh sum to achive the feel of new brakes and they were invariably mounted behind the hub flange where it was harder to remove and replace.

The old hard disks were just as vulnerable to becoming less efficient as the new ones, surface glazing being a common problem but they did not wear and get thinner and hence require immediate replacement as we now find.

Disk brakes saw very little use on trucks before the non asbestos pads became the norm, almost all lighter trucks are now disk braked on the front axle because they are so much better than the drums that used to be fitted.
Prior to the modern materials setup disk brake trucks required much more regular brake servicing and fleet owners want low cost servicing, asbestos pad/hard disks did not provide this.

Given the cost of discs and the relevant ease of changing them etc. this should not be considered a great outlay nowadays. The benefits of having new discs and pads is more about how the car feels when braking, i.e. no shudder / judder etc. rather than a decrease in braking efficency. I had an experience many years ago when I submitted a V/Hall Carlton for a "Taxi test" the examiner decided to fail the car on the basis that the discs were "corroded" and worn. I duly replaced the discs and pads as a matter of course, and the car passed on the 2nd. attempt. Just as a matter of interest, I checked the print out of the brake "efficiency" in the 1st. test against the print out of the 2nd. test - guess what? the braking efficiency in the 1st. test was much higher than the 2nd. test, so, obviously the new kit needed time and miles to obtain the best braking efficiency. This matter re-surfaced just last week when a friend submitted thier car for an MOT, it failed because the examiner didn't think the brake pads were "thick" enough, however, after new pads were fitted and the car-tested - and passed, we checked the brake efficiency print outs, - and - you guessed it - the new print out showed a decrease in brake efficiency over the original print out. In my experience (40yrs.) I have never had a disc fail - pads, calipers, hoses - yes, but never a disc.

 

[grpar]

Mine were 95% worn after 30k miles

All four wheels (i.e. pads + discs) needed changing at just 30k miles on my C180. A nice bill for £760. Lovely.

 

[television]

All four wheels (i.e. pads + discs) needed changing at just 30k miles on my C180. A nice bill for £760. Lovely.

Some thing not right with that price,too expensive by far

 

[jberks]

Some thing not right with that price,too expensive by far

Absolutely - I never saw a bill near that for brakes.
Pads £60-£80 disks - £50 each? Thats a lot of labour!

 

[philharve]

Hi Guys

Thanks for your comments. You've answered one of my queries concerning disc wear rates. It wasn't my imagination, discs do wear more quickly these days and its probably due to harder pad material.

I'm interested in the comments about the prices of pads and discs and, in particular, labour charges. I've not attempted pad & disc replacement on my W202 but I recall it wasn't a particularly long job on my Celica. Would an hour per corner be about right?

The earlier comment by 'grpar' about his C180 having all 4 discs, with pads, replaced for GBP760 sounds a little steep. Would this be what a dealer would charge?

REGARDS

Phil

 

[television]

Hi Guys

Thanks for your comments. You've answered one of my queries concerning disc wear rates. It wasn't my imagination, discs do wear more quickly these days and its probably due to harder pad material.

I'm interested in the comments about the prices of pads and discs and, in particular, labour charges. I've not attempted pad & disc replacement on my W202 but I recall it wasn't a particularly long job on my Celica. Would an hour per corner be about right?

The earlier comment by 'grpar' about his C180 having all 4 discs, with pads, replaced for GBP760 sounds a little steep. Would this be what a dealer would charge?

REGARDS

Phil

With the correct tools and jacks 1½ hours to 2 max would be normal

I say correct tools so much easier on a lift, I would do it in 2 hours without, and I am old now

 

[bigasotonuk]

Hi,
I,ve replaced the discs and pads on my W202 C230K about 20 minutes a side providing the pins come out ok.
'Apparently' i have been you should replace the caliper mounting bolts everytime but this i was told was because they come already treated with a loctite material i,ve always just inspected them and put loctite on myself.

 

[Geoff W]

Hi. I have just replaced the front discs and pads myself, bought from main dealer they cost £116.00 including vat with new sender units and new mounting bolts, took me about 1 hour per side, but i did clean and check other things whilst wheels off, very easy job. 1997 C180.
Regards geoff.

 

[television]

Hi. I have just replaced the front discs and pads myself, bought from main dealer they cost £116.00 including vat with new sender units and new mounting bolts, took me about 1 hour per side, but i did clean and check other things whilst wheels off, very easy job. 1997 C180.
Regards geoff.

Thats the way to do it, giving a good clean up and checking and looking around is a good thing and rewarding as you know that when you put the wheel on that everything is OK

 

[JEZ.S320L]

Thats the way to do it, giving a good clean up and checking and looking around is a good thing and rewarding as you know that when you put the wheel on that everything is OK

Very true.

I - along with the help of an enthusiastic neighbour - replaced the discs and pads on my XJ. I bought the OME parts off ebay, helped fit them - and saved approx £700 against what the main dealer quoted. Took just a tad over 2hours - including a 'fag & beer' break.

 

[grpar]

Absolutely - I never saw a bill near that for brakes.
Pads £60-£80 disks - £50 each? Thats a lot of labour!

That was an MB main dealer in west London .... I have the itemised bill and added up all the parts and labour charges. The "A" service was £240 and the rest of the bill was the brakes at £760.

Was I diddled ... ?