Wilwood brake judder

[justinsane]

Hi guys,
I've had my Wilwood front BBK on for about 7 months now and approx 10000km (6000 miles)
I have the BP-20 pads and my car is pretty much a city commuter and yesterday was the first time I really took it above 80mph on this BBK. I tracked the car prior to this on stock brakes but these Wilwoods have never seen track/autox use.

Yesterday I was on the highway and even pressing the brake lightly I could feel pretty noticeable vibration through the steering wheel but around town <40mph there's never been any issue. I can brake fairly aggressively from 50mph and it will brake straight with no steering vibration whatsoever. I didn't try braking hard >80mph

I don't think it's a wheel balancing issue as there's no noticeable vibration just cruising along at 80mph, only under braking.


Here are the pics of my driver's/passenger's side rotors.
Passenger's side is the clean one that looks pretty normal, driver's side has that uniform line going down the middle.

I've read that if you throw an aggressive pad on there it'll take off uneven deposits, I have some Hawk DTC-30's that I can experiment with to test this theory but wondering if it could be something else. I also read that a few hard braking stops from 60-10mph would also help.

I get that vibrations may be amplified at speed but weird for there to be no issues under 60mph and noticeably vibrate over 80mph. The feel of the vibration is similar to an unbalanced or non-hubcentric wheel that wasn't torqued evenly

I will be tracking the car in 2 weeks and going at speeds around 110 mph on the front straight so there is probably need for concern.

 

[Joszer]

Do the rotors feel smooth? Have you tried Mic'ing the rotors to make sure that they're the same thickness all around? I've had my Wilwoods for about 11000 miles, and with 2 rebuilds, and 5 track days, and my only issue is that I am starting to get a stress sqeeze/sqeak sound everytime i depress the brake pedal at at stop.

How hard are you pressing the brake at 80 mph? does the car veer off to any particular side when your hands are off the wheel? My best guess is that one or more of the pistons are not engaging as much as the others which is probably making the pads wiggle under stress. Pop your wheels off and check to see if all the pistons are making contact with the pads. If they aren't you could always rebuild them with new seals. ~$25 at Summit.

I'll do a 80 mph stop on my way home from work and will report back to see if mine do the same.

 

[justinsane]

I'm just barely touching the pedal and it's vibrating, it doesn't pull in any direction in particular.
At city speeds when I come to a stop I can feel slightly inconsistent brake pressure
I just went out and did a few hard stops on the highway to bed in my new rear Ferodo pads which might have helped the fronts as well
I'm going to try again with moderate braking at 80mph tomorrow and see what happens

 

[Joszer]

I just did a hard 90 mph stop with my car, no shakes at all. I got the Spec37 rotors and the BP-20 pads

 

[justinsane]

Did you always run the Spec 37 rotors?
I'm planning to get new rotors but I'm not sure which bolts to get
The one in the installation manual says 230-11934 "5/16 -18 x.75 Torx"
but that part # seems like it's out of stock
There is another part # 230-0233D "5/16-18 x .75" which is an allen key bolt with what seems like the same thread and comes in a package of 8 and I'm curious whether I can run those instead. I would imagine they are intended for brake rotor application as well since they come from Wilwood in a package of 8

 

[Joszer]

They should be the same, as they bolt up to the same hub.

 

[RAAMaudio]

Sounds like you got the brakes a bit warm and stopped and held your foot on the brakes causing pad transfer on one spot on the rotors which is the primary cause of what you are describing.

Did you do a bed in process?

Did you get them warm and stay on the pedal?

Generally rotors do not warp, it has happened but far more often it is pad build up.

Usually it can bet fixed with some steel wool and brake cleaner but sometimes rotors need to be turned.

 

[Joszer]

Sounds like you got the brakes a bit warm and stopped and held your foot on the brakes causing pad transfer on one spot on the rotors which is the primary cause of what you are describing.

Did you do a bed in process?

Did you get them warm and stay on the pedal?

Generally rotors do not warp, it has happened but far more often it is pad build up.

Usually it can bet fixed with some steel wool and brake cleaner but sometimes rotors need to be turned.

Couple hard stops with the DTC-30 pads should do the trick. I ran the DTC-60's at the track and it shredded my rotors clean of all prior brake material left from my previous wilwood pads.

 

[RAAMaudio]

I have done that before as well, even with a relatively stock car on street pads, does not always work but usually does but if not then I have been able to take care of it with cleaner and the steel wool.

I have had one set of rotors turned in 47 years and hundreds of thousands if not a million miles of driving, that was before I knew better.

Even mildly grooved rotors do not need to be turned or replaced, the pads wear to fit them easily enough.

The majority of work done at brake shops is not needed, just making money by charging for things that just a set of pads will fix in many cases or cleaning up the rotors with some hard stops or cleaner and steel wool.

 

[justinsane]

Threw on the DTC-30's...
Such an awful street pad haha

Definitely feels better after having them on a few days

 

[westcoaST]

I'm running the polymatrix pads on the street. No dust, no squeaks, a really good pad with great stopping power. Just a tap on the brakes is needed now to stop the car.

 

[lukits01]

I had the polymatrix-E on brand new rotors that worked perfectly fine when new.
After a few track days, especially the first week after abusing them on the track, they would squeal very loudly.

So I swap out them out with BP-10 for street use. Absolutely silent now.
When the pad was new on used rotors, they would vibrate under light braking.
After a few hundred miles, the vibration went away.

Threw on the DTC-30's...
Such an awful street pad haha
Definitely feels better after having them on a few days

Hey justinsane, just wondering, in what way are they awful street pad?
I have DTC-30 on order for use as track pad, but was considering just leaving them in on the street too.

 

[justinsane]

With the DTC-30 after about half an hour of driving my front wheels are grey,
there's very poor cold/initial bite and the feel is inconsistent because they get grabbier as they warm up
I haven't had too much squeal with them but they do make a loud grinding noise, even when you're just coasting and off the brakes.

 

[Spectral Necrosis]

Hi guys,
I've had my Wilwood front BBK on for about 7 months now and approx 10000km (6000 miles)
I have the BP-20 pads and my car is pretty much a city commuter and yesterday was the first time I really took it above 80mph on this BBK. I tracked the car prior to this on stock brakes but these Wilwoods have never seen track/autox use.

Yesterday I was on the highway and even pressing the brake lightly I could feel pretty noticeable vibration through the steering wheel but around town <40mph there's never been any issue. I can brake fairly aggressively from 50mph and it will brake straight with no steering vibration whatsoever. I didn't try braking hard >80mph

I don't think it's a wheel balancing issue as there's no noticeable vibration just cruising along at 80mph, only under braking.

View attachment 5141 View attachment 5142
Here are the pics of my driver's/passenger's side rotors.
Passenger's side is the clean one that looks pretty normal, driver's side has that uniform line going down the middle.

I've read that if you throw an aggressive pad on there it'll take off uneven deposits, I have some Hawk DTC-30's that I can experiment with to test this theory but wondering if it could be something else. I also read that a few hard braking stops from 60-10mph would also help.

I get that vibrations may be amplified at speed but weird for there to be no issues under 60mph and noticeably vibrate over 80mph. The feel of the vibration is similar to an unbalanced or non-hubcentric wheel that wasn't torqued evenly

I will be tracking the car in 2 weeks and going at speeds around 110 mph on the front straight so there is probably need for concern.

I probably have about 2000KM on my Wilwood BBK form 2J. Plain rotors and PolyE pads. They where fine for about two months and then all of a sudden over three days became basically unusable due to vibration in the steering wheel. This again is only at speeds above 50KM/hour. If I brake super hard it also goes away or if I’m at parking lot speeds. I never track the car or anything or drive all that aggressively in terms of brake use. Had Ford dealer put them on because I was busy and brakes are better done by someone with experience.

Took it back in for diagnosis and they say my rotors are warped. This is impossible so I asked for runout and thickness measurements. All in spec they say. They say there’s no deposits either. But I need new rotors.

Any ideas? Did the DCT-30 Pads end up doing the job for you?


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