BRAKE SHUDDER ISSUE

[teebone]

I've had DBA 4000 series slotted rotors and bendix ultimates all round on mine for a couple of hundred kays and besides not having to worry about brake shudder I have far bettrer performing brakes than the lame standard ones. Much more bite and no noticable fade (in street use anyhow). For just over 1K fitted, it's a bargain and a great solution for those with troubles

Any problems with brake dust and squealing or graunching noises?

[teebone]

Just a thought, if you use non ford brake pads and they warp again, they may not cover under warranty cos they may say it was the after market pads that's caused the problem????

I love my car, don't get me wrong, but I'm not spending money on bits and pieces that arn't proven yet to solve the brake shudder issue.

You will know if they start doing it!

Mine have been done twice to the "permanent fix" std. First time quite a noticeable shudder thru the steering wheel under light to moderate breaking, which just doesnt feel like a new car should and was a bit disconcerting when trying to quickly scrub off 20km/h of speed on the freeway, whilst also going around a slight bend. 2nd time not as bad and thought the dealer wouldnt accept it but came back to pick up the car with brakes that feel as smooth as putting a knife through butter - for now anyway

[Guest cul08r]

Steering wheel shudder. A pulsating pedal is usually the symptom of faulty boosters and master cylinders. Shudder is the discs out of balance.

Andrew

[NT TURBO]

yeah I was gunna say the pulsating pedal is really all I notice some tramlining?

[ktford]

Just a thought, if you use non ford brake pads and they warp again, they may not cover under warranty cos they may say it was the after market pads that's caused the problem????

I love my car, don't get me wrong, but I'm not spending money on bits and pieces that arn't proven yet to solve the brake shudder issue.

You don't honestly believe Ford could deny this Models problem with shudder simply by teling someone that their aftermarket pas wad the problem, do you?

Scotty

[Guest dbasteve]

Hi,

Just reading through the posts I can not find anyone mentioning the symptons to brake shudder.

So if anybody can give some symptons as to the brake shudder

problem I can be prepared to notice what it is.

:banghead:  Joe

As a general rule

Disc runout = vibrating steering wheel only.

Disc thickness variation = Pulsating pedal at low speed plus steering wheel at high speed.

Pad material transfer = Jurking sensation at low speed (cyclic torque) and when the brakes warm up the floor (chasis) will vibrate and eventually the steering and pedal as it gets worse.

Time to stick my neck out......

With all the information we have now and plenty of discussions I beleive the problem is a pad material transfer issue. Why?

Most pads these days transfer a third layer onto the disc rotor. This is often the brownish color on bedded rotors. The pads actually brake on this layer which creates good friction as they are similar materials. The problem begins when there is even the slightest bit of run out (discs, hubs and bearings) and the pads do not retract adequately to clear the high spot of the run out. This is called off brake wear or off brake transfer in this case.

So the disc is rotating and the high spot on the disc from accumulated runout is touching the pad. The area of the disc touching the pad builds up with pad material to create an irregular thickness around the braking surface. Now you have DTV and pulsating pedal, floor (chasis) vibrations, and a shaky wheel. When the rotors get hotter the friction film gets tacky and the vibration (cyclic torque now) gets worse.

Why does it happen so quickly? The common form of DTV is created from wear which takes a while (around 10,000 to 15,000 km). This friction film was developed to reduce wear (I.E 150,000 3 year warranties) and it does. The problem is that it builds up much quicker (with run out) in the 3500km to 8000km time frame.

Supporting Evidence;

1. A new fleet of highly accurate on car brake lathes. Disc run out contributes to the problem but is not the only one. Therefore to eliminate all the runout accumulated in the bearings, hubs, and discs the discs must be machined on the assembly.

2. The pad shims to force the pads further away from the rotor. To stop the off brake material transfer.

3. The problem often dissapears when agressive non-transfering pads are fitted. Even without machining. DTV from wear doesn't not go away but DTV from material build up can be cut away with an agressive pad.

4. Slotted or X drilled rotors either prolong the occurance or eliminate it because they are agressive on the pads and reduce the transfer process.

Note: The amount of runout we are talking about here is only about 0.025 to 0.05mm.

The discs aren't warping guys.

You have a caliper that suits a very rigid axle assembly and an axle assembly that suits a caliper with more piston retraction. (seal roll back).

The shims may help but it's not a solution.

Please note: This is my own personal opinion and not an official document from the company I work for.

Regards

Steve

Edited 23/02/04 08:22 AM by dbasteve

[genebaby]

The Ford pads must be quite crap,as a few who went to slotted rotors but kept the OEM pads have got brake shudder back. Took longer to come back but it did.

I considered just changing the pads when I bought my car as I did not trust them but figured the benefits of better pads and slotted rotors together was worth it. It was. I have had a few quick stops lately and all is fine. Just on 5000kms now.

[Guest cul08r]

Thanks for that info Steve. Its ppl like you that help the bunnies like us get a better understanding of what the fault is. So, in your opinion, in your role with Coles in Alice Springs, is it allowable that we pay for our weekly groceries in $30 lots so we maximise the number of reciepts we can get for discount fuel? ie, If we buy $120 worth of groceries, we could get 3-4 reciepts.

Seriously, for spirited street use, would you recommend slotted rotors or slotted and drilled?

Andrew

[Geeseman]

Any problems with brake dust and squealing or graunching noises?

Some slight squealing under light breaking but nothing worth worrying about yet.

Apparently slotted and drilled make far more noise then just slotted. My installer has slotted and drilled on his AU and he doesn't think they are all that good because of the noise.

[Guest dbasteve]

Thanks for that info Steve. Its ppl like you that help the bunnies like us get a better understanding of what the fault is. So, in your opinion, in your role with Coles in Alice Springs, is it allowable that we pay for our weekly groceries in $30 lots so we maximise the number of reciepts we can get for discount fuel? ie, If we buy $120 worth of groceries, we could get 3-4 reciepts.

Seriously, for spirited street use, would you recommend slotted rotors or slotted and drilled?

Andrew

For spirited driving and towing the slotted discs are best as they can handle more abuse.

I'm actually from God's country too......Central Coast

Regarding the noise issue with cross drilled rotors; Yes they do make more noise than standard or slotted. The level of noise is directly related to the hardness of the pad too. We normally recommend Lucas brand pads for cross drilled if noise is an issue.

Edited 12/02/04 04:55 AM by dbasteve