Front Tyres, Discs, Pads, Calipers and things

[oldtimer]

Evening All,
Just for information.

Before fitment I measured the thickness of the new and old front discs.
The old disc was measured at the periphery but inside the lip.

New disc 30mm thick
Old disc 29mm thick

The disc minimum allowable thickness of 28.5mm is clearly cast into the hub of both the new and old disc.

It is interesting that there is only a one and a half mm allowance in total for wear, that being 3/4 of a mm each side of the disc. Earlier in the text I mentioned that the Pads were only about half worn, down to 7mm of 13mm new. Taking that into account, had the pads been left in service a little longer then the discs would have been down to their minimum limit. So it would appear that discs and pads will need to be replaced together.

That disc wear rate seems excessive to what I remember. Has brake disc material become softer or are brake pads more aggressive

I'm totally satisfied with the performance of the brakes but leave you gents to consider the above findings.

Oldtimer

PS I'm sure that Mike K thinks I drive around at about 40mph but have needed to make some pretty quick stops at speeds of three figures - not necessarily in this country ! That is when you find out if the brakes are any good

[Martec]

You surprise me Oldtimer, with your background in parts supply I would have though you would remember the change over of pads away from Asbestos to the new wire wool pads. Gone are the days of discs lasting for ever and pads wearing away. It is coming to the point of discs and pads changed at the same time, hence discs and pads are cheap due to the turn over of them.

Nice to hear you are out and underneath doing your own servicing, a rare thing these days, already today I've had two people come to see me for advice (wanting me to confirm that a cheap option is the correct one for their problem) and leaving disgruntled when told I don't work on others cars and suggested remedial work that will require their input and work!!!

I'm working on my front suspension and am knackered.

Brian

[J44EAG]

Pad and disc materials vary greatly, manufacturer to manufacturer. Not much doubt about that.

I use Mintex pads and discs on my early car. I get two pad sets to one disc on the back brakes and one pad set to one disc set on the front 300mm discs. Early cars are always heavy on from pad and disc consumption. MY52> onwards cars had the 326mm discs which one hopes would make them last a bit longer. Then the STR cars have even bigger discs to help with the extra stopping power and again make the brakes last a reasonable time.

I understand that the Red Stuff (or Green Stuff) ceramic type pads are supposed to have a longer life. I wonder if anyone has any experience of the material in service.

No doubt tearing down brakes annually or even two yearly might help with longevity. Keeping everything clean and well lubricated must surely help avoid issues where uneven wear can occur due to parts becoming clagged up.

I`ve tried expensive discs and pads and also cheaper products and not noticed much difference in life span. Surprisingly, a set of drilled and grooved discs I fitted were shot after just 19k miles of use. I put that down to the grooves which perhaps may have been more aggressive on the pads.

Mike

[oldtimer]

Hi Brian,
I remember the forgiveness of asbestos pads, shame they had to go. I was referring to the variance with the asbestos FREE pads and discs. I think Mike sums it up well enough claiming variations between disc and pad suppliers. I've been out of the business for 17 years now so don't have a clue as to what is going on.
Yes, I manage to get out and get under, it's the getting up bit that gets more difficult !


Mike,
I think your summary is about right. I've had the wheels off and brakes apart for cleaning every 2/3 years. I'm not sure of the merit other than I know every thing is in good order and working. But that is what servicing is all about I suppose

P