Brake Shudder

[boost69]

Guys I know this topic has been covered but I cant seem to permantly solve my brake shudder problem.

I have the DBA 4000 slotted rotors and Bendix Ultimates allround... all bushes etc are OK...have even cleaned hubs but problem still keeps comming back.

Can anyone recommend someone in Sydney that knows their stuff so that I can take my car to and permantly solve this annoying problem.

[ZAP]

You may find it is your driving style.

Are you a left foot braker ?

Do you drive the car hard then park it ?

The shudder is gerenally caused by warped disks.

You havegone with the correct solution, so I am thnking more towards the driver

[4DZILR]

I know that if you dont clean the hubs before installing the rotors, it may cause a slight variation in rotor wear causing a possible warp in the rotor.

I had them replaced with dba cross drilled and slotted 5000 series.. with bendix pads I made sure the hubs were clean with a wire brush.. if I did, I could see a mm of rust on the hub which could of caused a brake shuddur (rotor warping)

hopefully your rotors arnt that bad, did u install them yourself?

[EvilDaifu]

You may need to change your calipers out as well. I had bad brake shudder and did 3 things:

1. Swapped out to dba 4000 slotted rotors.

2. Changed the brake pads to Race Brakes RB24s

3. Balanced the front tyres (there was not brake shudder but the steering needed steadying at high speeds).

I could have gone the calipers as well - but didn't want to go down that path and thankfully didn't have to as my brake shudder disappeared after steps 1 and 2 above. But changing out the calipers from the OEM PBRs to something else would have been my next step.

[Wenier]

It most likely isnt a warped disc. It will probably be an uneven deposit transferred onto the disc which will be causing your problem. As someone said if you give it a hard time then park up or stop with ya foot on the brake for a bit it can transfer this deposit to the disc.

I managed to sort my standard brakes out from the shudder by giving it a really hard time so they got hot and cleared the deposit off then allowed them to cool before stopping.

[Smoke them tyres]

Fit poly bushes in the UCA's would be a good start.

When you say the bushes are "ok", are they the std ones? How many KM does the car have on it?

This may be of some help.....

http://www.fordxr6turbo.com/forum/index.php?showtopic=55451&st=90&gopid=1022789#entry1022789

Let us know how you go.

Edited 08/07/10 12:31 PM by Smoke them tyres

[XR6TWolf]

I've fixed this problem several times.

On my BA I founds a nice set of APs cured it and provided somewhat superior stopping at the same time. Pricey way to stop shudder though.

I fitted a set of Znoelli slotted and dimpled rotors (front) and slotted (rear) to a friends BA turbo a few months back. Replaced front hubs at the same time as cost was not much more than a set of pads and considering the originals had close to 100000km on them it seemed logical. We went this way due to the lack of availablily off the shelf of the DBA product here in NZ and the inflated pricing compared to that in Australia.

Since then the car has done 15000km including 2 track days, one of which had rotors glowing and it still stops dead straight with not an ounce of shudder.

There are two things I think are too easily overlooked in the ongoing brake shudder conversations.

1. The weight of the Falcon means the standard brakes are inadequate. Add high quality rotors, decent pads and they will do a lot better. (In my view there is little point in bothering if you are not going to pay attention to the various suspension components that hold the whole thing together)

2. The vast majority of BA/BFs are now moderate to high km cars. I've seen 100000km examples with 20" wheels, lowered suspension, Bilsteins or better, DBA rotors and fancy pads yet nobody had thought to replace some relatively inexpensive suspension bushes. Try finding a 100000km BA with factory bushes still in place and take a long hard look....they will be rooted.

Now think about it....if you are getting 0.5mm movement in an inner bush then the outer end of that arm is going to flop around like a cock in a sock. The slightest shudder or vibration is going to magnify.

The other big issue I have found is the impact of big, heavy wheels. They may look sexy but they represent massive rotational mass and consequently cause elevated pain to brakes.

I've seen two IDENTICAL cars...both factory spec, both one the same tyres, both with the same rotors and pads. One had cheapish 17 x 9s on it and could get no better than 4 laps before brake fade set in. The other had Volk TE37s, still 17 X 9 and could stay out all day without fade. Sure, it was probably right on the edge but it was the most graphic demonstration of the impact 3 or 4 kg of rotational mass can have that I have ever seen.

[rockafellqeinstien]

Boost69, How long does it typically take for the shudder to come back after you machine or replace the rotors.

DO you see hot spots on the rotors? On my stock ones I could see shinny hot spots in the middle of the contact area the whole way around - In my case I am sure it wasnt warped but these "spots" causing me issues.

Regarding the bushes, I think the worst they could do is magnify an existing problem otherwise new rotors would shudder also.

I went with cheap rda slotted and have almost 10,000 km of hard kms since replaced at 100,000 and no shudder yet. but at least they only cost me $400 which wasnt that much more than machining.

I think the bedding in process could have something to do with starting the shudder problem. I did it exacty per the article in one of the shudder threads and all is good (something like 8 firm but not 100% slow downs from 80kmph - no stoping and then easy for 300km). I have done some 200kmph stops and all fine although the brake smell is very noticable

[XR6TWolf]

Regarding the bushes, I think the worst they could do is magnify an existing problem otherwise new rotors would shudder also.

That is my point entirely. What is often measurable as truly miniscule runout on a rotor is magnified many times over.

Talking to Race Brakes NZ a while back they also commented that a great many of the BAs they have done have had pretty bad glazing issues which wont be helping the issue. Obviously something easily sorted with slotted rotors.

[boost69]

Guys I just got my front DBA 4000 slotted rotors machined again on Saturday the mechanic had a look at the bushes and nothing seemed broken and there was no excessive play anywhere though im still not certain how thorough you have to be to pinpoint any problem...we still kepped my Bendix Ultimates and obviously for now the shudder is gone...

The car is totally stock wheels etc...guys I probably need a to go to a workshop that knows our cars inside out...I would love to go to a mechanic for once that can put my car on a hoist and diagnose the cause of my recurring shudder...even if he tells me my driving style is causing it etc...

If you guys know anyone in Sydney let me know...as I even got Aron Franklin who was the DBA sales rep to meet up with me a few month back and go over the car...and he blamed the rust scales on the hub...so I cleaned the hubs and skimmed the rotors and sure enough the problem came back...then another mechanic told me that the dba rotors are not what they are cracked up to be and he has seen heaps warp...even the Bendix Ultimates have been to blame for my shudder.. apparently far too harsh on the disc etc...every one blames everyone else...DBA blames the installer the installer blames DBA etc...and im left in the middle with my rake shudder problem...

I expect my shudder to start comming on slightly by the end of the week as I do about 500kms a week...

Thanks for the input though guys I value any opinions or advice...