Pagid RS4-2s pad build up / vibration

[rich83]

Cool. I emailed them.

To be honest thats probably the only time they have been that hot.

[Johnsy]

just out of interest how many cool down laps do you do?

[rich83]

What? On the road? 

[greygti]

I've just fitted the AKS / vagbremtechnic 345 mm DB9 kit with pagid RS4-2 blue pads and so far so good .....I'm just off to touch a large piece of wood

[tony_danza]

Bed them properly.

Taken from Pagid's info, but essentially the same as I do on any pad:

WHY BEDDING?
To transfer a layer of friction material onto the brake disc (rotor) faces to achieve maximum performance.
To stabilize compressible materials to avoid a spongy pedal.
To boil off volatile elements in the friction compound in order to have the initial green fading during bedding and not during the race.
To align the pad surface with the brake disc (rotor) surface to have full contact.
If pads do not get bedded properly and / or used too hard right out of the box will likely lead to pad glazing. Pad glazing is a condition where the resins in the pad crystallize on both, the pad friction surface and the brake disc (rotor) surface, resulting in poor stopping performance, brake judder and vibrations. Also rapidly escaping volatile elements and moisture from the resin would seek an immediate escape route out of the friction compound, creating small fissures that would lead shortly to cracking and chunking.

RECOMMENDED VEHICLE BEDDING IN PROCEDURE
1. BREAKING-IN
(creating a perfect contact-pattern between rotor and brake pad surface)
10 stops with low pressure and low temperature from 150 km/h (90 MPH) to approximately 80 km/h (50 MPH). Distance between each brake stop approximately 600 – 800 meters ( 600 to 800 yards).
 
2. HEATING-UP
(Warm up in order to initiate some core heat in the whole brake system)
A sequence of 5 stops with medium to high pressure from 180 km/h (112 MPH) to approximately 60 km/h (37 MPH) with maximum acceleration between the stops. After the last stop cool down for 3 minutes with the speed preferably not higher than 100 km/h (62 MPH).
 
3. RECOVERY STOPS
3 to 5 stops with low pressure from 150 km/h (90 MPH) to approximately 80 km/h (50 MPH). Distance between each brake stop approximately 600 – 800 meters ( 600 to 800 yards).

Then drive home and leave them to go stone cold.

[tony_danza]

Rich, is the spacer part of the bell, or on top of it? I don't understand why two different metals would be butted up against each other in the first instance, they have conflicting properties when subjected to heat. If the latter, then it's ok.

To also note, as in the first post by the OP. J hooked, Slotted, Grooved or whatever pattern you like don't stop pads sh*tting themselves all over the disc and causing judder.

[rich83]

Without spacer


Better pic to show the spacer (ignore caliper... they were sh*te so came off)


As mentioned before... braking from 60-0, causes no vibration and the stop the car incredibly quickly. Its just when over 90-100 (which to be honest isnt very often)

[patpong_pete]

Without spacer


Better pic to show the spacer (ignore caliper... they were sh*te so came off)


As mentioned before... braking from 60-0, causes no vibration and the stop the car incredibly quickly. Its just when over 90-100 (which to be honest isnt very often)

Hi Rich can i ask what make and size of spacer thanks for reply

[rich83]

H&R 8mm Hubcentric

[xjay1337]

They wont have warped... 2 piece discs. Jay is on single piece discs, so as we have the exact same issue I'm 10000000% sure it defo the pads/pad deposit.

Yea i have non floating 340mm tts ebc usr discs
Same calipers and pads as rich

I suspect rich drives his car harder than mine (hes a lunatic from the midlands)
Without sounding like a bellend know it all
 i fail to see how ive overheated pads designed for racing with 95% road use (my normal commute is 5jcts  on the motorway lol) and one trackday. Which was possing with rain anyway so not going flat out anyway :-)

They have never faded,  never sat on the brakes after stopping etc. I know about looking after brakes. Alex did all the bedding in and he was gone a good 10 minutes and my car was umm well used when it came back so i have every confidence in him bedding them in.
I may try running through the bedding in process again for what good it wont do.


I phoned alex when i was at the trackday and he was helpful saying it sounded like pad buildup/deposit also.

As i said in the other thread im going back to alex for some more modding and when I'm there as long as its ok with him,  i will whack on some new discs and pads and new fluid  (only just over a year old anyway). It is always in the back of my mind when I'm out for a drive so best remove that.

Cheers for input tony but while the rs42 is a good pad in terms of cost / performance across temp ranges and life (ive got like half the pad left still) i think they are are quite finicky and can (note i said can not are) be problematic for some cars / set up / conditions.

[rich83]

Dude I am from Yorkshire. Clown! 

[xjay1337]

Dude I am from Yorkshire. Clown! 

Yes but you have such a priveleged upbringing you sound like any other southerner. You live in the midlands. You are a midlander.

[tony_danza]

Jay, if they weren't bedded in properly from the start, you didn't need to overheat them to have them melt their resin all over your disc. Normal operation will do that and you'll have the "glazing" mentioned above in Pagid's info. You've a solid mounted caliper, so even a few thou of deposit can feel like the car is trying to shake itself apart.

10 minutes in the middle of the day (assuming the space and lack of traffic required), unless he's based on an airfield isn't really enough to bed them correctly IMO and what you've got is the result of that failure to boil all the resin out. Any pad you buy will suffer the same problem if you fail to do it likewise... Unless you go for a fully sintered one, like a Carbon Lorraine.

Take the car out at night on a quiet length of bypass etc and warm the brakes with some general use, then do 5 60-20 stops, drive for a mile, do 5 XXX (ahem) to 30 stops, giving it full beans back to XXX after - you should feel the brakes fading, this is correct. Drive for a few miles, doing some more small stops to cool them gently, rather than quickly. Arrive home and leave them to go stone cold till morning.

This should be enough to remove the build up and any remaining resin in the pads.

If it does take a set of new pads and discs to resolve, then be mindful of doing the next set properly.

[xjay1337]

Ok man, I'll try that.
Again i didnt go with alex as otherwise he'd have had to lock up etc.
There is a bypass 2 minutes from Alex's unit so i assumed he went on that. That being said i cant be sure Alex did it correctly other than trusting him.

I will do as you suggest and see how it goes :-)
 Think it may also be a good idea to sand the discs down  (both sides).

[tony_danza]

I don't mean to sound like I'm having a pop at Alex, I'm sure he gave it a good go and maybe to a method he's used on a different type of pad that worked ok.

Some are, as you say, more temperamental than others and need a very defined bedding to stop problems.