BRAKE SHUDDER ISSUE

[RESPEC7]

bolt was completely gone.

[RESPEC7]

Edited 19/08/10 08:27 AM by RESPEC7

[RESPEC7]

got these today... will see how they go..

they should suit my driving styles as I dont give my brakes a super hard time

[Snailracing]

Haya all, I haven't read the entire post but I thought I better add my 2 cents. The problem most of people experiencing brake shudder isn't the sole result of the discs alone. Nor will just any machining fix the problem.

The actual problem lies with lateral run-out (Disc Wobble). If a disc is taken off a car and machined off the car with either a bench lathe or similar you should get the two sides parallel to each other but what happens when the disc is put back on the car? Does this actually fix the lateral run-out? What happens if the problem doesn't lie in the disc? What if it's in the hub? All you've done is spent money and not fixed the problem. Even worse, What if you spend lots of money on replacement discs, but not fixed the problem still, you get annoyed for starters.

On most modern cars the min. spec. For lateral run-out is .002" (Nissan is even less) and anything more than this could be felt at the brake pedal as shudder. .002" is not much thicker than a human hair!!! (Human hair is about .0071") and more than that and as the disc is turning it passes through the caliper and bumping one pad, and then the other. As this happens the disc and pads slowly get worn until you get Disc Thickness Variation. This means that the rotor will be two different thicknesses at different points (I.e. 12 o'clock and 6 o'clock).

So how do you fix it?

Use an on car Brake Lathe! The market leader is one called a Pro-cut. They’re made in the US and they are the OEM approved tool for the likes of Ford, GM, Nissan, Daimlar/Chryslar, Subaru and more.

Pro-cut have the added advantage of being self adjusting on the newer models so the operator doesn't have to adjust for LRO (lateral run-out), and it guarantees the end result is less than the required .002"

So if you do have brake shudder, Find a workshop that does have a Procut On car Brake Lathe, Make sure they use it on car, and get your car done by them! Problem solved

Out of interest EBC Brakes (Googling them, their big) recommend that their rotors must be machined on car when they are installed new on to a vehicle and will not warrant them without this done.

There are some great videos on Youtube that explain this better than I do, so have a look yourself.

[discostig]

Mine have started to get bad, I'm using the DBA4000 slotted's and QFM pads. Had shudder with stock discs too.

On car machining sounds good! I'm concerned it is due to not cleaning enough rust scale off the hubs when I mounted the discs in the first place. Haven't given the brakes a big work out, some big stops at the drags but not to a halt and baking them while stationary. Feels dangerous when stopping from anything above 80 :( Surely affecting my stopping distance too.

[Snailracing]

Your right -SteveR- replacing your discs with the DBA4000's would not have fixed the issue if there is still run out with in the hubs. Ever since modern vehicles shifted from have a single hub/disc combo with tapered bearings (which could basicly self adjust with their inhearent free play) to the big single roller bearings (with almost no self adjustment) brake shudder is a problem which is increasing problem. Couple that with cost cutting/using cheaper materials for the hubs and it's amazing that the problem doesn't effect more people (It's only due to modern technoligy and excellent CNC machining that the problem it more wide spread).

Not machining the discs, or machining them off car is a bit like putting new tyres on your mags but not balancing them.

To watch a Pro-cut in action have a look at this-

And to see lateral run-out and what does look at this-

[Anchor]

I went new hubs when I installed the front discs. Only cost me $66 each.. Well worth it imo as its a sealed bearing unit.

I've absolutely raped my brakes since installing, to the point of boiling the brake fluid twice and having smoke coming off.. Still no shudder. Slight squeel though but I can live with that.

[discostig]

That's good to know as well, new hubs aren't much. Would it be worth doing as mine are 100,000kms old?

[Snailracing]

Not a bad idea but will they have any less lateral run out than the ones you are replacing???

[B_L_W_N_B_A]

this may answer some questions

Australian Ford Forums - One reason why the BA shudder keeps coming back !

reason why the BA shudder keeps coming back !

G'day , after an exhaustive day with the Nolethane gurus as well as Geoff Murray from Redranger and Steve Borg from TRW Australia, I now have a much better understanding of my car (BA) the BF/FG and the VE front and rear geometry and the factory suspension shortcomings...

I started a thread how to change out the hydraulic castor bushes here www.fordforums.com.au/showthread.php?t=11306516

Now one thing I couldn't explain was why they stopped my brake shudder , my best information out of today is the bush when it fails moves around a heck of a lot and over time even though the wheel is mounted to the rotor and then onto the hub it creates wear points on the face of the rotor called "DTV" Disc Thickness Variation .....

Oh well we just give the rotor a skim and no more problems Right ?

Until next time.... I machined my rotors 5 x times before I purchased slotted rotors and the shudder came back !

It became so random and sooo annoying I wouldn't let my girlfriend drive it anywhere.. I changed the front bushes and the shudder dissapeared straight away....

I couldn't explain to anyone why the bushes created shudder if someone had just had their rotors machined and the situation appeared fixed ....

Only for 5000-7000kms or so only to return ..

Fact , if you replace your front bushes as well as fresh rotors/pads and wirebrush the mating service on the hub you will NEVER get that 'SHUDDER' again.....

Ford went to great lengths to explain to us via tech bulletins , how to line up the yellow stud with the date stamp on the rotor / how to torque the wheel nuts correctly ( NEVER use a rattle gun ) so as not to warp the rotor/ and most importantly to keep the mating surfaces free of rust/debris to insure perfect roundness for pad contact...

If you follow the correct procedure for maching the rotor and the problem comes back , then it is time to look elsewhere...

I have finally fixed mine "Hallelujah".

I know I have probably forgotten something because my head is ready to explode with information ... But I hope this sheds some light on our front end , these are essentially Taxis and absorb everything we throw at them but the FPV's are wearing these bushes out much faster and the Brembo's seem to mask the problem because their quality of manufacturing is so high they dont produce DTV very readily ..

Thanks for reading and please change your Hydraulic Castor Bushes.. The difference in having precise control of your front end is amazing ..cheers.

Daz..x..