# Heavy shuddering when braking at freeway speeds in 5000tqa



## highme (Sep 7, 2001)

Hey all,
I just picked up my 5000TQA on Sunday and the only thing that's not aesthetic that needs my immediate attention is this braking issue I have.
The car stops fine, but when cruising @ freeway speeds to having to slow down significantly it shakes like an epileptic at a rave. 
I purchased the car from a guy that owned his own shop in Maine, and then worked at Matrix here in Portland,OR for the past few months before moving to Hawaii on Monday. So the car is in pretty good shape for an east coast car with 236k on it. I plan on giving him a call or dropping him an email to see what he thinks it is, but I wanted to let him get settled in Hawaii before I start harrassing him. 
He said he recently replaced all the parts on the rear brakes, and it has what look to be somewhat new Zimmerman crossdrilled rotors up front. The ABS ecu isn't attached, and I have the "brake pads are low" warning light in the middle of my console. 
I know that the car has not had the steering rack replaced yet, but when I checked with a couple of buddies they seemed to think that wouldn't be the cause. 
The most logical suggestion I've gotten so far is control arm bushings need replacing. 
Anybody else have any ideas for me?
thanks


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## PerL (Jan 9, 2001)

*Re: Heavy shuddering when braking at freeway speeds in 5000tqa (highme)*

I'd say that the brake discs (front) have a throw in them, since you only experience this when you brake. New discs (and pads) should cure this problem.


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## gidrew (Mar 28, 2004)

*Re: Heavy shuddering when braking at freeway speeds in 5000tqa (PerL)*

i agree, sounds like some warped rotors to me.


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## jaredpgh (Jan 18, 2005)

*Re: Heavy shuddering when braking at freeway speeds in 5000tqa (gidrew)*

If the warping isnt too bad, you can have the rotors trued on a brake disc lathe, which is most likely cheaper than entirely new rotors.


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## gidrew (Mar 28, 2004)

*Re: Heavy shuddering when braking at freeway speeds in 5000tqa (jaredpgh)*

Very true, But from the "heavy shuddering" he is getting i would guess that they are warped.


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## jaredpgh (Jan 18, 2005)

*Re: Heavy shuddering when braking at freeway speeds in 5000tqa (gidrew)*

thats true gidrew. I say take it to a shop and have them measure the runout. If its within spec of the lathe, just cut 'em. If not go with some slotted rotors.


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## StormChaser (Jan 3, 2000)

*Re: Heavy shuddering when braking at freeway speeds in 5000tqa (jaredpgh)*

Agreed except for the slotted comment. Slotted/drileld rotors are pointless, cost more, and are potentially dangerous...plus they warp easier. But if you're all about bling-bling looks...got for it.


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## StormChaser (Jan 3, 2000)

*Re: Heavy shuddering when braking at freeway speeds in 5000tqa (duandcc)*

Oh, one more th...check the torque on the lug nuts...if they are over torqued or unevenly torqued, it can warp the rotors...relem and reinstall tightening properly to the correct torque specs. Then drive for a couple of weeks...many times the warp will work it's way out...


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## mgyip (Dec 15, 2000)

*Re: Heavy shuddering when braking at freeway speeds in 5000tqa (duandcc)*


_Quote, originally posted by *duandcc* »_Agreed except for the slotted comment. Slotted/drileld rotors are pointless, cost more, and are potentially dangerous...plus they warp easier. But if you're all about bling-bling looks...got for it. 

Drilled rotors (unless they're factory cast) are merely for looks. However slotted rotors work quite well at dispersing hot gases under heavy braking. I'm not sure where you get the "potentially dangerous" statement from however - they're not any more or less dangerous that standard vented rotors. In fact they're safer since they allow venting of the brake gases which results in better brake performance. If I was allowed to use slotted rotors, I'd have them on my racecar in a heartbeat but alas, Improved Touring doesn't allow for any brake mods other than pads








Turning/truing rotors may work but if the warping is as bad as described, replace them - it's less headache overall. FWIW Ford won't warranty front rotors on my truck until they've been turned by the dealer - the reason they warp in the first place is b/c they're too thin to properly dissapate the heat generated by braking. Turning them only exaserbates the problem by making the rotor that's too thin to work properly even thinner








And for bling-bling, drilled/slotted rotors may be part of the package but you ain't **** unless you have painted calipers too


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## StormChaser (Jan 3, 2000)

*Re: Heavy shuddering when braking at freeway speeds in 5000tqa (mgyip)*

Outgassing by brake pads is pretty much a thing of the past unless you are running total junk pads. Even good old Mintex redbox is pretty much gas free even when pushed very hard...that's why I say slotted and/or drilled is just for looks. As for being dangerous, I say they are because lots of the slots are cut into the rotors not cast in. If they are cast in, they are fine, but cut in really weakens the rotor, making it more susceptable to crakcing and even total failure...there was a TT that had one EXPLODE on a track a few years back, destroyed a lot of the suspension.


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## mgyip (Dec 15, 2000)

*Re: Heavy shuddering when braking at freeway speeds in 5000tqa (duandcc)*

You're right - a properly bedded pad should not outgas at all as this should be taken care of during the bedding process. The slots also serve to move heat (in the form of a gas) and pad material away from the pad/rotor under heavy braking. Many race pads incorporate this in their design with an air gap in the pad itself to promote better air flow. 
For street use, slotted/drilled rotors are nothing more than bling-bling. In a race application, give me ANYTHING that will make my car stop better and more consistently. I've never had a rotor explode on the track (thankfully) although I've see it happen to fellow competitors. My rotors develop tiny heat cracks after one session along with a nice bluish colour from the burnishing.


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## mrdub27 (Mar 25, 2002)

*Re: Heavy shuddering when braking at freeway speeds in 5000tqa (mgyip)*

well just my $.02 but the shudder at highways speeds sounds to me like it could be a bearing ,tie rod or balljoint issue.... does the car pull hard when braking or seem to pull to one side..?
If it was the rotor then you'd get a severe pulse back thru the pedal and would pulse back at slow speeds too.. would feel like a mild abs pulse..on the foot.. I would also suggest checking the upper mounts for the struts too ..















Good luck


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## highme (Sep 7, 2001)

Thanks for all the input folks. I swapped out the rear rotors a couple of weekends ago and although they were grooved pretty heavily, replacing them didn't fix the issue. Due to my 4000 not liking all the attention being given to it's new sibling, it started acting up (in the rear brake department as well) and has taken up what little wrenching time that I had. 
Hopefully I'll be pulling the 5000 into the garage for some love in the next week or so, I plan on replacing most of the front suspension wear parts when I do so. Sounds like a good time.


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## mrdub27 (Mar 25, 2002)

*Re: (highme)*

Umm if it's a heavy shudder i would suspect wheel bearing issues to be honest.. under braking they can cause a shudder and also a slight pull too.. check them out.. also consider is the ABS working.. older abs units felt horrible when they were working properly.. I hate the ABS on my 87 5000Q i usually turn it off anyway ..


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