Hi,

I have a 2005 BA XR6 with 80,000km on the clock. I purchased this car 2 months ago and i have a few minor issues that i hope some people can help with.

When i got the car i replaced the front with new rotors and new bendix general CT pads. The rear disc surface looked ok, so i only replaced the brake pads with also the bendix general ct, as well as bleed the whole brake fluid with super dot 4.

After driving for a week i realised i still get brake shudder when im on a highway doing 80-110km/h and i brake. So i got the rear discs machined and tried to resurface the pads a tad by sanding it on a flat surface as spare parts shop was closed and i needed to drive the car that night.

I still would get brake shudder so the following day i replaced the brake pads again with brand new bendix general ct. It has been 2 weeks now and i can still feel brake shudder. My vernier measured 15.38mm thickness all round after i got the rear rotors machined...so i know its well above the minimum 14.60mm.

Now when i look at the rear discs and observe the pad contacting surface, it seems like only 80% of the disc rotor is being contacted by the brake pads in the rear.
I am using Bendix General CT 1376DB, im certain it is the correct model but the pad surface design is smaller in width than the actual rotor width so it only provides 80% contact... i am thinking this could be a possbile cause to the shudder????

Can anyone shed some light on this issue for me, i would assume the brake pad should be contacting 100% of the rotor surface not just 80%.

appreciate your help,
Ron

pads don't cause brake shudder, warped discs, or misaligned discs do.
when u put ur new discs on get some sand paper and clean off rust and crap from the hub so u have a clean face to put ur discs on.
If u want to do it properly use a dial indicator and measure run out, position the disc on the hub at various positions with the least runout. .005" is max
Don't do ur wheels up too tight, 80ft/lb per nut

I had the same prob with my 2003 ba xr8 but in the front,i thought its was because my rims were buckeld but closer inspection revield rotors were the prob.replaced them and now drives perfect,so maybe look at doin that i would ring burson maybe up to you mate good luck.

fatnsticky n youngboss,

I checked the the wheel nuts...they were too tight..so i did them at 80foot pounds with the torque wrench, though i still feel shudder from 80-110km.

When i changed my brake pads i did clean the surface from rust and sanded it down, this also allowed the rotor to slid on easier.

I will purchase brand new rotors this weekend and see if that eliminates the issue. I hope it does.

Considering i just bought brand new pads 2 weeks ago and placed them on a freshly machined rotor, i assume there is no need for me to purchase new pads again when i buy new disc rotors....correct?

appreciate the help guys

Is the shudder through the steering wheel? If so, it's the fronts. The stock front rotors were notoriously soft and warp easily. We have an RTV that was shuddering, I checked the runout with a dial and it was indeed very warped. Replaced with aftermarket rotors (DBA slotted) and the shudder is gone.

Front Rotors were replaced when i just bought the car. I do see your point though, i might check all the steering components in detail this weekend to make sure its not something else causing the issue. I will probably still go ahead and still change my rear rotors, that way i can narrow it down knowing i have changed all rotors and pads to news.

cheers

BA brake shudder was a very common problem. I reccommend you get rid of the undersized stock components and fit an upgrade kit from FTG Auto Salvage. Basically BF XR8/XR6T brakes all round, 322x28mm front rotors (up from 298x28mm rotors) with larger calipers and 328x26mm vented rear rotors (up from 303x16mm solid rotors) with larger calipers. I've been nothing but impressed with this set-up.

dad had that in his ba fairmont, wouldnt of had much more than 10,000kms when it happened. but think it was something to do with the abs, was under warrenty so not sure.

What front rotors did you put on?

sorry to hijack thread, but thought i would post in here rather than starting a completely new thread.

i have a 96' ef fairmont and get what i would say is the same problem as this.
when i first bought the car it had this problem..i thought it was possibly wheel balance/alignment so i got this done first..the problem disappeared for awhile, or atleast was not as noticeable.
between 80-100 i get a shudder/vibration through the steering wheel.
approx. 2months ago i got new tyres put on the car and once again another balance/alignment which showed that everything was out again?
the problem seemed to disappear again for a short time but came back maybe after 1-2 weeks if that!
also im guessing this will be related but when im braking ofcourse i get the shudder and when braking at slower speeds it feels as if the pads are on the disc and then off again..causing a sort of hop if that makes sense? :S
so if i was to replace the front rotors with some new ones im hoping this would solve the problem??

thanks for any help!

Hi i had the same problem i got new front wheels,rotors,wheel allinment and problem solved..

Hope I am not to late. Had this problem on mine and what I did was remove the rotors and cleaned the surfaces between the hub and rotor with a wire brush to remove all the crap that had built up. Then I cleaned them both with carby/brake clean. Not had a problem since.

Ok,

As it stands, my car now has brand new RDA standard front and rear rotors and new bendix general CT brake pads. The hubs have been cleaned spotless. I no longer get brake shudder when braking from 110km/hr but i now have brake shudder from 60-80km/hr.

This is doing my head in, i assume runout does not need to be checked when using new brake rotors on a cleaned hub?

Are there any solutions or ideas you guys have to help me eliminate this brake shudder issue?

can slightly worn outer edges of a tire cause the shudder?
I might put my ED fairmount 15" wheels on my XR6 to try and eliminate tires/mags as an issue.

Appreciate the help, as of right now im clueless on what to do.

yes u should do a run out check even with new rotors. Have u done a runout check on ur hubs.
Definately shudders only when braking and not driving?

fatnsticky,

I have not checked runout on the hub or the rotors as i do not have the instrument to do so.
Where can i purchase an elcheapo version from and how much do they go for?

Yes, only shudders when im braking. i can feel slight brake shudder as well as the steering wheel shudders. Can the Brake Dust Covers also be causing an issue?
If there is excessive runout, how can i fix it if i have new rotors already?

Cheers

EDIT: after some youtube videos i found out that if i have incorrect run out it can be fixed by using a correction shim. Is this correct? because i can not find any place online that sells the shims.
I found an ABC run out gauge tool for $75 online. will this too do or can it be bought cheaper elsewhere.