THSCC Forums

I put the same compound I used to run on my (former) 93 RX-7 on my wife's Jetta. Bedding them on new rotors I was surprised how quickly I got them to fade. I don't ever recall getting fade on the Mazda. I know the Jetta weighs about 300 lbs more, but since the RX-7 had well more than double the horsepower they would work well enough.

Could it be that the rotors & pads get cooled more on the track? Or will it only be worse than what I was getting during the bedding? I did several medium near stops from about 40. Several from about 60. Several from about 80.

I flushed the fluid and bled them. The pedal never got mushy.

I can think of three factors that could be at work here.

1 weight balance, the Jetta has more weight bias toward the front end and will do more braking with the fronts percentage wise than the RX-7.

2 brake size, I would guess the RX-7 has bigger brakes.

3 weight you mentioned that.

_________________
George Bright Member # 141
One of the youngest of the old farts.
Yes I voted against you joining the club.

Yes the VW's are slightly smaller at 11.3 in versus the Mazda's at 11.6 inches. I think it is the combination of handicaps. Well I don't intend to track it more than a couple of times so I'll just have to exercise restraint and practice driving within the car's limits.

That quick initial fade is a side effect of you bedding them in. Nicholson once told me, when bedding pads (this is the unscientific method) to basically stop hard with them until they fade, then park the car.

Sounds like job done to me.

_________________
Karl S.
2014 Baby, 2014 House, 2013 Ford Focus ST, 2013 BMW 328i, 1994 Mercedes E320
(Insert passive aggressive signature line here)

Matt, any time you bed in brakes, you should get fade, that's part of the process.

I think more than anything, it's the repeated stops without much cool-down time. It's one of the reasons places like CMP and VIR South are so hard on brakes, lots of successive stopping.

Some other factors might include brake ventilation... you probably had more airflow in/around the RX-7's brakes. Are you sure too on the weight? I would think a Jetta (especially if it's a newer Jetta) would weigh significantly more than a 3rd gen RX7... I'm usually wrong though.

What pads/compound are we talking about here? You said the pedal never got mushy, so it sounds like you're getting a dead-pedal... which could be a by-product of out-gassing from the pads. Less-likely would be that you managed to glaze them over.

Hopefully out resident brake guru will notice this thread and expunge some wisdom upon us.

_________________
Stacy King
Midlife Crisis Participant

Its an '01 jetta mk4. The pads are carbotech xp8. They are squealing much more than I recall on the Mazda.

Sounds like green fade. Did this happen while bedding or on track?

During bedding. So does green fading toast them? I have not punished the pads since bedding them.

Completely normal for Carbotech pads.



No. It is, in fact, EXACTLY what you want to have happen.