Brake disc perservation

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Speedex750

Speedex750

Member
Posts
89
Location
North East England
I'm heading towards needing to change the P38's discs and pads.

Recently I did the same on my sons Z4 and they looked great through his spoked alloys with drilling & grooving plus the caliper picked out in red paint. However some months and much rain later, while the running surface is OK the cylindrical section and edge of the discs have gone rusty brown and look somewhat naff.

I notice that new cars seem to have discs with some sort of a finish on these surfaces and don't seem to corrode, what is this and can I DIY it? We may have fitted cheap discs made from boiled down scrap and super duper expensive ones may be immune but have any of you guys found something that keeps them looking smart?:confused:

Thank you.
 
Discs are not supposed to look smart they are for stopping the car. Drilled and grooved discs are a waste of time on a road car. The discs on new cars maybe Cadmium or Titanium plated. But any plating will wear off the swept area PDQ. Why don't you paint the discs yellow to contrast the red calipers and use the hand brake all the time so you don't damage the finish on the discs.:D
 
With some performance disks they have a thin covering of anti rust rust coating that wears off where the brake pads rub but stays on where the disc needs protection. Black diamond discs show an example of this.

Also you can get brake discs that have anodising on them that do the same thing as the anti rust paint.

I have a set on my disco with groves in the discs as i do a lot of towing which would allow me to ride the brakes in an emergency.
 
when fitting new Brembo discs (cant comment on other brands) to my revious car I masked the friction faces up and sprayed the barrells with satin black hammerite before fitting... lasted well for the following 5K I owned the car for
 
Drilled and grooved brake discs just turn your brakes into a cheese grater. You'll **** through pads with no real performance advantage. If you get disc brakes to fade on a road car you need to reassess your driving because you're doing something wrong.

You can buy pain that you spray over the discs to retard the oxidisation process, but it tends to peal off after a few heat cycles. It is really designed for putting a vehicle into storage.
 
Bix said:
Drilled and grooved brake discs just turn your brakes into a cheese grater. You'll **** through pads with no real performance advantage. If you get disc brakes to fade on a road car you need to reassess your driving because you're doing something wrong.

Tis true they do eat pads! You just need good quality discs and pads. Not the cheapest you can find cos they don't tend to be as good!
Click to expand...
 
Speedex750 said:
I'm heading towards needing to change the P38's discs and pads.

Recently I did the same on my sons Z4 and they looked great through his spoked alloys with drilling & grooving plus the caliper picked out in red paint. However some months and much rain later, while the running surface is OK the cylindrical section and edge of the discs have gone rusty brown and look somewhat naff.

I notice that new cars seem to have discs with some sort of a finish on these surfaces and don't seem to corrode, what is this and can I DIY it? We may have fitted cheap discs made from boiled down scrap and super duper expensive ones may be immune but have any of you guys found something that keeps them looking smart?:confused:

Thank you.
Click to expand...


Don't forget to fit them on the worng side so the grove cuts in even more - as this will give you even more stopping power on your way over to the Saxo forum!
 
never understood this one - grooved discs "look better" really???

and they buy them for looks and then moan that they have alloys (again bought for looks) covered in excessive amounts of dust!!
 
Bix said:
If you get disc brakes to fade on a road car you need to reassess your driving because you're doing something wrong.
Click to expand...

You've never owned a X300 or X308 Jaguar XJR then! Brake fade was horrendous - the brakes simply could not cope with the performance of the car. A quick blat between two or three roundabouts in succession was enough to start off the fade. Fixed on the lighter (and better braked) X350 or by the rather expensive factory Brembo upgrade on the X308.
 
StuckAgainSteve said:
You've never owned a X300 or X308 Jaguar XJR then! Brake fade was horrendous - the brakes simply could not cope with the performance of the car. A quick blat between two or three roundabouts in succession was enough to start off the fade. Fixed on the lighter (and better braked) X350 or by the rather expensive factory Brembo upgrade on the X308.
Click to expand...


or an early Merc Sprinter van

poo comes out when you come off the motorway and the thing wont stop!!
 
StuckAgainSteve said:
You've never owned a X300 or X308 Jaguar XJR then! Brake fade was horrendous - the brakes simply could not cope with the performance of the car. A quick blat between two or three roundabouts in succession was enough to start off the fade. Fixed on the lighter (and better braked) X350 or by the rather expensive factory Brembo upgrade on the X308.
Click to expand...
No, was tempted by one and ended up with the P38. Good to know that the brakes will suck should I ever go back down the Jag route.
 
Thanks for the advice and the various skits. Don't fret, unlike some who have been on here I don't feel compelled to react and reply in kind or feel the need to have to justify myself!

D-T is right, retardation is the most important thing. But I fancy something more than boring plain discs. A good going over with VHT may stop them corroding as quick.

Thanks for your help.
 
it is the amount of chromium in the disc material that effects the rusting or rust prevention.
As far as i know, no one states this or what % is required to prevent rusting.

Bristol cars used to have as standard rust free disks. They simply thought seeing rusty discs being unacceptable, to the occasional gentlemen owners!

If you use your RR oaccasionally, then but some bags over the wheels like motorhome users.
 
donp38 said:
it is the amount of chromium in the disc material that effects the rusting or rust prevention.
As far as i know, no one states this or what % is required to prevent rusting.

Bristol cars used to have as standard rust free disks. They simply thought seeing rusty discs being unacceptable, to the occasional gentlemen owners!

If you use your RR oaccasionally, then but some bags over the wheels like motorhome users.
Click to expand...

Discs are made from Grey Iron. And it don't have any Chrome in it. Rusting on brake discs is normal. They can be passivated but heat in use will soon neutralise that.
 
wammers said:
Discs are made from Grey Iron. And it don't have any Chrome in it. Rusting on brake discs is normal. They can be passivated but heat in use will soon neutralise that.
Click to expand...

Interesting though that some discs rust more quickly than others. The Xtrail discs were covered in rust on the braking surface after overnight dew in summer. Left for a week in the rain the initial braking was interesting. The P38 on the other hand shows little rust on the braking surfaces in the same conditions.:)
 
Datatek said:
Interesting though that some discs rust more quickly than others. The Xtrail discs were covered in rust on the braking surface after overnight dew in summer. Left for a week in the rain the initial braking was interesting. The P38 on the other hand shows little rust on the braking surfaces in the same conditions.:)
Click to expand...

Spray with copious amounts of oil. That'll stop em rusting ;)















NO! Really don't do that :eek: :eek:
 
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