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Discussion Starter · #1 ·
Location ... Ottawa Canada

I often travel 3 weeks to a month at a a time and the van tends to sit whilst I'm away.. The brakes a few years back were getting kind of rough feeling so I ordered new disks and pads from "Crossdrilledrotors.ca" ... aka dbc Disc Brake Canada ... Conventional but mid quality disks. (I'd used them before for a Renault Medallion and they were excellent) So they were good on the DGC after fixing the problem of sticking slides. Then I went away not long before covid and on return, they were a little rough, but it seemed to polish out with some use. Had to again go away early spring ... got back and they've been pulsing horribly since (classically described as warped rotors ... but of course real warped rotors are exceedingly rare to the point that some pros say "No such thing!" The car maybe did 20 miles a week at the outside. Without doing a major disassembly it looks like rusty patches on the rotors(especially on the edge of the pads)

So, time for another another brake job.

Any ideas on the best brake discs to cope with "standing" rusting spending only 1 arm and a leg and not 2?

Do NOT suggest Canadian Tire's "Certified" ... I've had those flake away the surface!

Thanks for your recommendations.
 

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You don't drive it enough to merit the cost and the labor. . Ignore the rust patches, and the pulsing. The more you drive it, the smoother it will get. Do 10 high speed, high pressure stops to get them self polished.

"Warping" rotors is from heat/cooling variances across the rotor, holding the pedal down for too long on a hot rotor, or setting the parking brake after coming in from the track. You are not getting them hot enough to "warp" them.
 

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Discussion Starter · #3 ·
You don't drive it enough to merit the cost and the labor. . Ignore the rust patches, and the pulsing. The more you drive it, the smoother it will get. Do 10 high speed, high pressure stops to get them self polished.

"Warping" rotors is from heat/cooling variances across the rotor, holding the pedal down for too long on a hot rotor, or setting the parking brake after coming in from the track. You are not getting them hot enough to "warp" them.
Been there, done that ... didn't work this time! I am a DIY kinda guy and have done them before. I must tear down the brakes to be sure ... but I was looking for best ones to use under these situations if I do need to replace them. And as I said "classically described as warped" and that on the majority of street cars, there's no such thing.
 

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Metallurgy makes the difference. Discussion here:

There's no good answer to corroded rotors. Seems to me the problem has become worse since ceramic pads appeared. Semi-metallic pads may be a better choice.
Ceramic brake pads can create excessive rotor wear if rotors are not the same high quality as the brake pads themselves.
Take a look at Raybestos rotors. They should know something about brakes. Maybe give them a call.



I tend to buy heavy parts from Parts Avatar. They usually pay for shipping over a certain amount of order ($75.00?).

Are you getting any delamination spots on your rotors? I never had that happen with semi-metallic pads. Sure happens with ceramics though.
 

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Discussion Starter · #5 · (Edited)
Thanks Jeepman ... That's given me a clearer picture ...

From what I've been reading, it sounds like they're all pretty much of a muchness when it comes to actual surface rusting. Surface rust from lack of use should be worn off pretty quickly. This suggests that there is some other condition going on that is causing significant rust spots generating the pulsation. The rotor rust on the back of of the rotors looked rather like Mr Raybestos flakes of pad material transferred to the rotors. I did notice a problem on the last change with sticking slide pins and I carefully cleaned and reassembled with synthetic lube. There was some rust on those pins which suggests moisture infilltration through the boots. Those sticking slide pins could certainly explain why there was the layering of pad material on the rotors. To me, it looked like dirty rust ... but the friction material makes sense.

So, Sorry Johnny 5, gotta disassemble! Need to get a close look at the various parts to diagnose properly. And I'll go with a mid quality rotor.

The delaminated rotors (from CTC were for an older Caravan) were truly delaminated metal and not the flakes mentioned by Mr Raybestos ... there were actual flaked dents in the surfaces on both sides! It really was a case of I got what I paid for ... they were really cheap rotors (hey they're just slabs of metal ... haha!)

So, looks like spending more isn't going to get me better anti-rust performance ... just better quality braking ... and since I am no longer driving as much (retirement can do that!) I don't really need that!

Cheers!

I used Rock Auto before and got dinged a significant amount of duties last time.

Stuart
 

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Your rotors from CTC that flaked, I have had that happen with "white box" rotors as well as an OE rotor, both with ceramic pads. My belief is that ceramic pads are hard on rotors.

White box rotors can be fine as long as they don't sit much. They need daily cleaning pretty mich.

The pins have a rubber boot on the end. When I did my rear brakes last year, I removed them as recommended by others on here. They can stick apparently. Their purpose is only for quietness, so they say. My brakes work fine without them.

Heavy items cost a lot (freight charges) from rockauto

Too bad they don't give the metallurgy for rotors. Made in China is about all that's available.
 

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With brakes, you have a rotating surface (rotor, or disc if you prefer that term) and a sliding surface (the pads). Something is going to wear faster than the other something. With ceramic pads, the pads will wear faster but the rotor will live longer. With semi-metallic pads, the pads will last longer but they'll wear out the rotor faster. At least that's been my experience over 45 years of driving.
Ya pays your money, ya makes your choice.
 

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Discussion Starter · #8 ·
I wish I could wear the rotors out! They're dying from rust long before they're anywhere near minimum thickness! I was hoping there were rotors less prone to rust!
 

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So they say:
Because the ceramic pads draw less heat, more heat remains in the rotor, which can cause rotor warping in extreme conditions. Metallic brake pads draw more heat and hold it longer than ceramics, but with the benefit of keeping the rotors cooler.
Maybe that's why rotors had a short life back around 2008 with the use of ceramics. They weren't up to the strength or thickness required by ceramic pads. Still aren't apparently. :) Ceramic pads have their limitations.
  • Possible higher braking system temperatures due to less heat absorbency than other friction materials.
  • Not recommended for severe-duty applications like hauling, requiring greater pressure on the system to get the same stopping power as under regular driving conditions.
Bottom Line:
Rotor quality (metallurgy) is elusive, with very little, mostly no meaningful information available. Price is the quality indicator. Not a good yardstick.
 

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Discussion Starter · #10 ·
Nice info on pads ...not sure I'd buy the braking system temps arguments as presented ... ultimately the same amount of energy is absorbed whatever the type of pad.

That heat has a low resistance path to dissipation from the rotor surface and through the wheel bearings to chassis parts. It has a higher resistance path through the pads and the small metal tabs on the ends of the pads to the caliper and the small metal ring of the piston.

The difference in braking performance of the pad types is how well they can grip the rotor surface and how much they cope with the heating and cooling cycles. Ceramic pads are capable of more aggressive braking .. The RATE of heat generation is higher with ceramic since they'll stop you quicker, so short term the pads and rotors will get hotter faster. Instantaneous temps will go up and then dissipate mostly through the rotor. But those instantaneous heatings will be harder on fibrous metallic pads than ceramic pads hence why the friction material will transfer off the fibrous pads and glue itself onto the rotors.

Remember that early pads were fibre asbestos ... the asbestos kept a lot of the heat on the rotor to prevent the fibre material from burning and reduce the amount of heat getting to the hydraulics.

So if you drive in an aggressive environment ... i.e. city driving ... then ceramic pads will provide more efficient braking for longer as long as the thermal characteristics of the rotors can cope!

I don't think they'll have much benefit for the DGC driver!!!! (Although the 5th Gen DGC can easily spin its wheels from a standing start due to Low Gear being remarkably low!!)
 
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