Brakes shuddering

s.patete, Jan 8, 9:14pm
I have a 98 EL Falcon, about 12-18 months ago it received new brake discs courtesy of Pit Stop (previous owner) and it had a shudder straight away.I told him to take it back but as he was days away from his wedding he never did.I purchased the car not long after and just put up with it as it wasnt too bad.Over the last 8 months it has got worse and I want to get it sorted.My first thought is warped discs because when you slow to a stop you can feel it lurching at even intervals.When braking at 100ks its down right scarey, the whole car shakes.I had the front calipers rebuilt 6 months ago and it didnt change it at all, was told at this time pads are half worn.
Is there anything else that could cause it!
Cheers in advance.
boxersrus, Jan 8, 9:29pm
I'm a girl here, but a taxi driver. And only driven BA & BF Falcon's. When I get that shudder in the brakes, my mechanic grinds either the pads or the rotors. Not sure which. I hope this helps.
s.patete, Jan 8, 10:05pm
Yea was going to get discs machined but i dont want to spend the money if thats not the problem.
s.patete, Jan 8, 10:09pm
Just had a quote 180+gst for both discs machined and new pads, I guess ill start there and hope it goes away.
boxersrus, Jan 8, 10:13pm
EEEk. I must have a super friendly mechanic. You shouldn't need new pads unless they are worn. Do you own the GTO on your profile. My first real car was a GTO.
tonyrockyhorror, Jan 8, 10:40pm
Disk machining is usually a waste of time, long term, for warpage. It's probably just the cheap nasty rotors Pitstop would have put on. I really can't fathom why people keep going there.
s.patete, Jan 8, 10:59pm
Yes that was my GTO sold about 3 years ago and still regret it but hey thats life might own another one day. Pads were half worn at last wof 6 months ago and I assume they will be taking a hiding with warped discs, does the price seem excessive Ive never had this done before.
Tony, do you think I should just opt for new discs!Yea Pit Stop especially the one in Palmy is utter crap.
tonyrockyhorror, Jan 9, 12:02am
If it were me, I would spend a little bit more and go for new rotors after confirming they are the problem with a DTI. If they have little runout, start looking for worn suspension components.

The pads could be reused as they aren't likely to be grooved given the rotors were new. that's if they were actually brand new.
ceebee2, Jan 9, 4:32am
New rotors and definitley NEW pads.do not refit used pads to brand new rotors.
a.woodrow, Jan 9, 4:35am
Why not! If they are in good condition, half worn or whatever there isn't any need to replace. Its something you can make a call on when you have them out and can inspect.

ETA - when I first started out in the trade I was taught to avoid replacing pads and rotors together if possible as they didn't bed in as well on new rotors
tonyrockyhorror, Jan 9, 4:36am
The rotors the pads are on now are not 18 months old. The pads will be fine to be reused. It's not like they're putting pads off a grooved rotor onto a new one.
alan1111, Jan 9, 4:55am
I specialise in brakes at work. First thing to do is measure rotor thickness.If ok get them machined via a oncar brake machine Fords/Holdens as they are notoriously bad for shudder and doing of car cant garantee. Then if me would be putting new pads in preferbly Bendix.Lube the caliper slides and problem should be gone.I would be charging around $280.00 yes you can get it cheaper at Pit Stop etc but they will be using the cheapest pads they can find.
peejeles, Jan 9, 5:01am
i put new aftermarket rotors on my ba. no more issues. the ford ones are shit. dont even bother machining them. you will be back at the garage in a few months.
tonyrockyhorror, Jan 9, 5:10am
People should read the OPs post more carefully.
unbeatabull, Jan 9, 5:40am
If you specialise in brakes at work you should know the pushrod clearances on the PBR systems particularly Fords have a too low tolerance from factory in 90% of cases and cause the brake shudder due to the brakes never being fully 100% released as there is always a little pressure on them ;)
sharchew, Jan 9, 5:52am
Put a new set or rotors on it
peejeles, Jan 9, 6:50am
and not ford ones. get decent ones.
turton, Jan 9, 7:02am
i had my front disks machined last year at mag n turbo, cost was $40 per disk (on a 97 lancer).
alan1111, Jan 9, 7:10am
$25.00 inc gst we charge for of car machining each.
ceebee2, Jan 9, 8:54pm
So your telling me grooved disc pads do.BS
s.patete, Jan 9, 9:11pm
Just to clarify:
The calipers were rebuilt 6 months ago.
The rotors were brand new roughly 18 months ago unfortunately by Pit Stop by previous owner so Im unsure what ones they used.
The pads were half worn at the time the calipers were rebuilt 6 months ago.
They only shudder under braking, when coming to a stop you can feel the car lurching at even intervals as the wheels rotate, at 100ks when braking the steering wheel and brake pedal shakes and vibrates pretty violently.
Car also needs a wheel alignment, whether this would contribute at all Im not sure.
ceebee2, Jan 10, 1:32am
Definitley "out of true" rotors. A crude way to check is to remove the front wheels, hold a ball point pen against outermost shiny part of the disk and get someone to slowly turn the disk, I would say by that shuddering it is way out of "true"
Using a DTI gauge is the preferred method of checking rotors. .004" inch is the max. from memory which isn't much.
PS =You may need to refit the wheel nuts to ensure the rotors are tight.
unbeatabull, Jan 10, 4:50am
Far quicker way is just to check it on a rolling road, anything more then a variation of about 10 will be felt on the road.

If W/A is way out it could also contribute a little, but it won't be the main cause of the shudder.

And I'd imagine Pit Stop would of fitted some cheap rotors. Get Brembo or another suitable brand - BNT stock them.