Just bought new rotors. With them came instructions on how to break them in. Talked about jamming on the breaks at 40MPH but not stopping. Then 50 mph... jamming them on hard... to 10mph.. etc etc etc. Repeat 10x.

Is this really necessary?

I installed new pads too.

Thanks very much,

SirJag

 

That Sounds really quite dangerous! I wouldn't like to be behind you on the public road if you were doing that!!! That all sounds a bit silly to me, I suggest you do the normal thing and drive at a leisurely pace for a 100 miles or so and allow yourself extra distance for braking.

Jamming on brakes and other antics is what causes discs (rotors) to become warped which will result in uncomfortable braking. Just take it easy and all will be well.

S.

 

It sounds as if the new pads and rotors need to be tempered--and then completely cooled down. If the instructions said to follow such a procedure, I'd just do it.

My new Wagner semi-metallac pads came with the same instructions--and it just took me a 3-4 miles to complete the stops.

 

Here some interesting articles about brakes:
StopTech : Balanced Brake Upgrades

In particular for this subject:
StopTech : Balanced Brake Upgrades

Personaly I always follow the instructions, and find of course a road where I can perform the procedures...

 

As usual, Avos brings factual valid information!
And why is it that folks always question what the manufacturer of something says to do? Maybe folks here know more than the brake manufacturer. the engine manufacturer, the transmission manufacturer, and so on BUT I DOUBT IT!

 

+1
roger that!

 

My thoughts are with Stu on this, here's a "factual" paragraph from EBC, probably the largest supplier of performance pads and discs in Europe - bare in mind if you install them incorrectly, slamming on will wreck both pads and discs.....

1. How to bed in your new brakes
Drive your vehicle steadily within the first 300-400 miles of road use only using the brakes violently in case of emergency. During this time use the brakes lightly and intermittently to achieve a matching between the pad and rotor which we call break in or bed in.
The speed with which perfect brake in will have occurred depends on how often the brakes are used. If you drive on a freeway or motorway and do not use your brakes for miles at a time, break in periods will be much longer. Using the brakes with caution during their early life will extend their wear life and greatly reduce the chances of rotor vibration or “shimmying” as it is known in the States. During the bed in time the pads will only contact the disc on a limited area until tiny irregularities in machining or misalignment of the pads against the rotor have been removed. You can easily see how far you have progressed with bedding in your new brakes by looking through the wheel spokes and evaluating pad contact. The rotor should look shiny and smooth across its surfaces from outside to inside in all areas of the rotor. If you have purchased EBC gold zinc or black zinc coated sport slotted rotors, all of these coatings should have been visibly removed across the entire braking area of the rotor. Break in times on European vehicles is usually considerably longer than on Asian or US built vehicles because of the design of the brake system. European vehicles use a “taller” brake pad and may tend to contact on the outer edges of the rotor first and gradually contact more towards the centre of the axle over the first few hundred miles. After you are confident that the pads and discs are perfectly mated, use the brakes on a quiet and safe road 5-6 times at medium pressure bringing the car from 60mph to 10mph. Drive the vehicle for a few miles to allow the brakes to cool and repeat this procedure. During this final break in a brake odour will almost certainly appear and this is perfectly normal. This is known as green fade where the surface resins within the pad finally cure and burn off.

This bed in procedure is for STREET driving only. For race use bed in please see notes inside the package.

It's always good to see both sides of the coin.
Original text and more info here,
http://www.ebcbrakes.com/troubleshooting.shtml

 

I've just read Stop-Tech's bumpf, they use alloy caliper adaptors.....they use two piece calipers.....and, they say their calipers are the stiffest amongst competitors without naming names....they were suppliers of US touring cars in 2003 t0 2005. Not once do I see F1, WRC, BBTC, ALMS, LMP etc, of which would give me confidence in their products, for once I'm doubtful of Avos' information source. Now if it were Alcon, AP Racing or EBC I'd pay close attention, but Stop-Tech, and the way one man's opinion are written doesn't look good to me.

 

SirJag bought brake pads. they came with instructions. Why would you try and follow some other manufacturer's instructions. If you don;t think the guys who made the pads know how to bed their pads, buy someone elses pads.

 

are you addressing me? are you telling me to not comment? who are you, the technical director of this website, if you have more to add than "follow the instructions" I'm all ears, I'm at the very least adding to the discussion raised by the OP. It sounds like a how-to-warp discs instruction to me. But what would I know.....I guess you're also telling Avos the same thing, seeing as his post if from another manufacturer.

I'd like to know the make of both pad and rotor. Then I may add to the instructions. In the link I have supplied it gives reasons to why bedding in processes are necessary, and the OP's inferred question is to justify this bedding action. Spark, do yourself a favour and consider the question asked, this is supposed to be a helpful site for owners of X308's. Not to pour scorn on suggestions and alternatives. If this is the case, this forum looses members, including me.

 

Actually he bought both discs and pads. What we're trying to say is play it safe. It doesn't matter who makes the things all we're saying is watch out you don't get rear ended. The dodge with slamming on, especially in an X308, is it could set off any number of sensors including fuel cut off.

At the end of the day it is up to SirJag what he does with his brakes, he asked because he himself obviously doubts the logic of slamming on repeatedly. The point of arguing and trying to snipe each other is nil, but I happen to know that Sean B is a mechanic and teacher of physics. He has been working around Jaguars before he could walk, he has an XJR and an E Type in his garage. His Dad is a highly respected Jaguar restorer who is highly sought after by those in the know. I myself am also an educated and qualified mechanic and am also a professional Driver, who's family's motor racing involvement goes back since before WW2. So again I'll just say it's up to SirJag who to listen to.

 

Sean:
In fact, I was not addressing you in the specific. But who says YOU are not to be disagreed with? My point was obviously not as plain as I meant for MY OPINION to be. That is, if something comes with directions, you should follow them. You obviously disagree, so I was indirectly referring to you, I suppose.

I am using "you" as we Americans do while we destroy the English language. I suppose a properly educated Englishman would use the word "one" as in the case of the "one" who buys a product; you, Sean, me, Ross or whomever.

Anyone can do anything they want, but it seems to me that if you (one) buy(s) a product that you (one) believe(s) is a reliable product, then taking the suggestion of the manufacturer is much superior to getting opinions from me, Ross, you, Sean, Avos, or anyone else. If the product comes with no instructions, then finding out how similiar products are used from general concensus might very well be a good idea.

So, no, I only consider my opinion superior in that I suggest deferring to those most likely to make a valid recommendation- the ones who built the product.

That said, I personally have never bought pads with bedding instructions and I have tried both methods over the years, and ultimately I believe the ones I have babied for the first miles ultimately had less shimmy, fade or other problems. But, I would bet that asbestos, organic or ceramic pads potentially behave entirely different from each other.

And I do value your imput quite a lot, so I am sorry I offended you.

 

The statement is contradictory.

Stu wanted nothing to do with rapid stops.

But, the final part of the EBC procedure is the same as the same as the procedure Stoptech recommends that Avos linked to and Sparkenzap seconded. It is also how Brutal fixes deposits on discs, except he has to apply the brakes because he does it in a parking lot.

The key element in the procedure is the use of the rolling stop to prevent rotor warp/deformation/bending/whatever.

Most of the tech articles at stoptech are very well written, and written by someone who is very obviously an expert in the field. Given a choice between a professionally published article targetted at a subject and a random opinion on a forum ... the article wins.


++

 

Well, now that we are back on technical issues, I have read, but never validated myself with a indicator, that most street use rotors that are thought to be warped are actually suffering from a transfer of lining material affecting the braking surface. This material transfer affects the friction chracteristics unevenly and makes a condition like sliding your finger along a wet countertop. It would be pretty hard to warp a piece of metal the size of a Jaguar rotor witrhout it getting very hot and holding it in a strain.
Brakes on race cars glow red for many hours, something I am absolutely sure the brakes on my Jaguar will never do. I assume brake materials, both cast steel and pads, change characteristics at those temperatures much more than at normal brake temperatures. So what race brakes do is only marginally important for evaluating street brakes.

 

The reason the car is not completely stopped during the break in procedure is to avoid transfer of pad material, as Sparkenzap mentioned, not the fabled 'rotor warp'.

 

@ SirJag, Good practice to do the following, build up the faces of both the new pads and rotors until full contact across both faces - then do your rolling stops - I've not debated the stop procedure, just queried the right out the box stops, I know the R1 equipped cars appreciate this 'go easy' approach initially, then the burn in, green phase of the repeated stops (but not dead stops of course). If rushed, squeal because of pad deposits (or glazing), and a wobbly feeling in the wheel. I've actually had new discs skimmed 5 thou to hurry this process, and it works a treat.
"European vehicles use a “taller” brake pad and may tend to contact on the outer edges of the rotor first and gradually contact more towards the centre of the axle over the first few hundred miles"

@ plums, I'd never fit aluminium caliper adaptors to a road car, that spells disaster. (EN31/21 steel with a nitrile coating for road cars) none of this is covered in the stoptech articles I've looked at, I'd not like to try and cover 100k miles with aluminium, even aero grade. The other concern is the statement made about how two piece calipers are superior to monobloc, that alone made me whiskers twitch, wrong, totally wrong. Maybe something for you to read about.
I'm assuming Stu thought from SirJag's statement, to just go out and do these stops with the new brakes fitted, with no mention of the safety aspect, are you having fun with me? I'll make myself clear, I agree with Stu that to fit new pads/rotors, tear off up to 60mph and slam on to 10mph x 10 doesn't sound safe. I hope SJ gets back to clarify what the manufacturer states on finding a quiet flat long road to do this burn in process. Even better he supplies the full instructions!
@ Ross, you mention ceramic, these are a different animal to the organic compounds - I'm still wondering what SirJag has fitted?? all pads are different, so following the instructions is totally the way to go, BUT when it's posed as a question the way SirJag has put it, it does need questioning, with valid ways of carrying out the process of bedding in. This may sound contrived, but it's the inference of the OP's question, and the inferred manufacturers instructions that I debate along with Stu, it just sounded the incorrect way of bedding Ate Jaguar pads and discs, maybe just for pads, but not both. I hope I am clear on this. This is the reason I joined the party, I'm into brake systems and maximizing the performance. The most important aspect of a vehicle, and one of the least considered.

btw we cool (a US term, one would find, if one was Prince William!).

 

Sean:
yeah, man. we cool.