Determining Service Requirements

[911hillclimber]

The inside faces on my front discs were far worse than that but equally corroded.

Best thing about a full replacement of discs and pads etc is that all the faces are true and so work the best.

New discs/old pads is a bad combo as the friction faces are not true to each other and will load the pads possibly unevenly and the pistons in the calipers suffer.

All the expense will be worth it!

 

[BrianJ]

We had something similar to those discs occur to an Audi. Under normal braking it had appeared fine and I never realised what they were like until I had to do an emergency stop one day which took significantly longer than anticipated. Fortunately I missed the offender but at the service shortly afterwards the servicing garage rang me to say "have you seen the inner side of your discs?". The rears were even worse - chunks had come off the inside. At the MOT 6 months previously there were no advisories but the near miss incident was a few months after car had stood outside for 6 weeks in the winter while we were away so I could only assume that the rot set in then. After new discs and pads all round the braking was transformed.

 

[smithyithy]

That's good to hear! I can't say the brakes feel like they're underperforming currently, but as in your scenario Brian, sometimes you may not notice until there's a serious situation like an emergency stop.

Nice new PS4s arrived this morning and will be fitted tomorrow on my lunch break - benefits of working from home lol

 

[JohnCRS]

It is a common situation. The inside, outer lip of the disk gets the most water and grit splashed up in use. Also, in general motoring, the brakes are not used that harshly. They often seem to require replacement due to corrosin rather than wear. For any MOT or other inspection it is worth getting the brakes hot and doing a few high speed stops to get a proper visual assessment of their condition.

Looking at Smithy's photos, they don't actually look too bad to me. Certainly seen far worse. I would check the free movement on the caliper pistons though and, lets face it, knowing that you have brand new brakes and tyres to start the year is a great feeling!

 

[Hardy]

Chris, JohnCRS has made a very good point that was occuring to me as I was reading the thread. You need to get those brakes really warmed up with a few hard brake applications, not just after washing but every time you use the car. That will help minimise the rust build up on your new brake discs.

 

[smithyithy]

Just a quick update, we now have lovely new Michelin PS4S on the front; new disks, pads, sensors all around and new pipes at the rear; and 4 wheels nicely aligned:

 

[Motorhead]

All good to go then Chris now the weather is improving.

It looks as though the MPS4S tyres give decent rim protection, which is a bonus. I assume that they’re not N-rated for your 987.2?

Jeff

 

[smithyithy]

They do seem like a good tyre.

I wasn't able to find N-rated in this exact variant oddly enough - I bought from Black Circles who had a slight discount on at the time. They had these PS4S which are not N-rated, then they had PS2 and PS2 Cup which were N-rated (and notably more expensive).. I think the modern PS4S will be more than good enough either way