Jetstream brake upgrade

[Adrian W]

Something I have never understood is why do we get all of these niggly brake issues, A Ford GT has very basic brakes, one piece undrilled not slotted Discs, basic calipers, but it just stops and on track it goes on and on, keeps stopping, no fade and no judder, what did they get right that we are missing?

Edited by Adrian W on Tuesday 10th September 10:07

[markrichards]

I've got the semi-floating fronts, grooved rears and RS29s and have judder. Was quite bad on Sunday. Have been through 3 sets of discs / pads with new hubs etc and can't seem to solve it. Under very hard braking the judder stops, which is unusual. I'll get the rears skimmed while on the car as a final resort. Otherwise off to Matt for a final solution (not that I know what that is yet).

[Adrian W]

A bloke from AP once told me to look at the calipers as the ones Noble used were the cheapest available and not very rigid, and he felt they were the source of the problems.

[Metalman]

Rob_W said:

Did you just do front hubs etc. I had vibration issues for ages which I assumed were from the front and appeared with the slightest of heat and eventually thanks to the Dave B tracked it down to rear hubs, replaced them and then skimmed discs on car - perfect since then

Yes just the front, I'll do the rears over the winter then get the discs skimmed and fit new pads. It felt like the front that was giving me problems but after a few laps it did feel like the rear offside but I thought it was just my imagination.

[andygtt]

Adrian W said:

A bloke from AP once told me to look at the calipers as the ones Noble used were the cheapest available and not very rigid, and he felt they were the source of the problems.

yes cheapest calipers and a radial mount size that doesn't have a direct upgrade... if I get any issues in the future I will machine the uprights and stick a better caliper on it... I have about 10 pairs in the garage that would be better lol.

[Metalman]

markrichards said:

Under very hard braking the judder stops, which is unusual.

I noticed the same, judder on initial braking but seems to get better if you really stamp on the pedal.
I'm sure my inexperience is partly to blame but I tried braking as late, hard and little as possible. I'll also be getting some tuition next time.

[Adrian W]

Metalman said:

markrichards said:

Under very hard braking the judder stops, which is unusual.

I noticed the same, judder on initial braking but seems to get better if you really stamp on the pedal.
I'm sure my inexperience is partly to blame but I tried braking as late, hard and little as possible. I'll also be getting some tuition next time.

and you don't think this is knock-off?

[jl34]

blimey this is a confusing thread . 2 people say upgrading to semi floating discs stops the vibration, one person says it didnt work for him. Some say it might be the callipers. Some says pads (which i can't believe will make a jot of difference to the vibration)

Ive tried different pads, discs skimmed on the car and it made no difference and it's worse than ever on track. Far worse than that is nobody conclusively knows what the cause is ! i could spend over a grand and not make any difference whatsoever!

[Adrian W]

jl34 said:

blimey this is a confusing thread . 2 people say upgrading to semi floating discs stops the vibration, one person says it didnt work for him. Some say it might be the callipers. Some says pads (which i can't believe will make a jot of difference to the vibration)

Ive tried different pads, discs skimmed on the car and it made no difference and it's worse than ever on track. Far worse than that is nobody conclusively knows what the cause is ! i could spend over a grand and not make any difference whatsoever!

Yep,

However! I think that if you use it on the road (most of us do) glazing is a big issue, maybe caused by poor selection of disc material, you may find that deglazing the discs and pads regularly helps resolve this issue, that is why disc skimming seems so effective,

[wessexrfc]

GET THEM SKIMMED ON THE CAR!!!!!!

As I said I have had all your vibration issues, I've taken off wheels, redrilled the holes, blown out the dust, still the same, replaced the front discs with the groved type, still the same (mine are standard front floating). Then SWLC brought a skimming machine that skims the discs on the car and asked if I would like to try it out as they knew I had vibration issues, had it done as it wasn't expensive (about £70ish for the pair) and bingo, no vibration!!!! The issue to my mine is heat and as Adrian said a combination of different alloys could be exacerbating the problem.
You should know if its the front as, like mine the vibration was coming through the steering wheel as well as through the seat/chassis. When mine were bad and as others have said it really feels like brake fade and really takes away the confidence to brake late and hard!!!
Save a packet and try the skimming first, it worked for me!!!

[jl34]

As i said i had my discs skimmed on the car by a disc cut lathe in Worcestershire. Unfortunatley the vibration came back on track pretty quickly.

Im sure floating discs would help mask the problem if not absolutley cure it. Is it possible to modify our disc/bell setup to floating ?

[markrichards]

Agree that on car skim is the first step. I'll be off to SWLC as soon as I can. Hoping it's rears only in my case as I don't think you can easily skim the upgraded floating fronts.

[jl34]

Mark, did you also go for the Jetstream disc set up ?

[andygtt]

jl34 said:

blimey this is a confusing thread . 2 people say upgrading to semi floating discs stops the vibration, one person says it didnt work for him. Some say it might be the callipers. Some says pads (which i can't believe will make a jot of difference to the vibration)

Ive tried different pads, discs skimmed on the car and it made no difference and it's worse than ever on track. Far worse than that is nobody conclusively knows what the cause is ! i could spend over a grand and not make any difference whatsoever!

rather fortunately for me I've never suffered judder on my car so have never tried to solve it... as I said I have my views on the cause, but clearly there isn't just one single cause on all the cars, i've heard the uprights are often to blame and some have replaced the bearing a few times before it was solved.

As Adrian said it's not helped that the std setup is the cheapest it could be, but plenty have got the stock setup working effectively both on road and track... Im very pleased with the Jetstream setup I have now, I don't have judder, its nice on the road with no rattles or squeals and it has massive stopping power on track... basically exactly what I wanted.

[wessexrfc]

markrichards said:

Agree that on car skim is the first step. I'll be off to SWLC as soon as I can. Hoping it's rears only in my case as I don't think you can easily skim the upgraded floating fronts.

Very easy to skim the fronts as this is what they did for me.

[Mike Tuckwood]

jl34 said:

blimey this is a confusing thread . 2 people say upgrading to semi floating discs stops the vibration, one person says it didnt work for him. Some say it might be the callipers. Some says pads (which i can't believe will make a jot of difference to the vibration)

Ive tried different pads, discs skimmed on the car and it made no difference and it's worse than ever on track. Far worse than that is nobody conclusively knows what the cause is ! i could spend over a grand and not make any difference whatsoever!

It could well be there are a variety of problems and everyone is assuming its just one problem?

Floating or semi floating discs can be prone to vibrations, especially if not kept clean/free of road dirt and grit etc.
Discs can warp, we all know there have been hub and bearing issues reported. Pads can stick against discs when hot, particularly if cooling down laps are not carefully done or brakes left with foot on pedal when stationary with hot discs creating high spots.

Some of these issues are usually accompanied with pulsing through the pedal. So, multiple problems, some have managed to tie their specific problem to a suitable solution. For others, that solution won't work if it's a materially different cause?

I would be VERY surprised if it was the calipers contributing to these issues though!


Mike.

Edited by Mike Tuckwood on Wednesday 11th September 17:05

[Gadgeroonie]

I have been watching this thread with interest and it is difficult to work out the problem.

I suggest if somebody is about to track their car that they change the pads before there is a problem

I suspect a pad that is quite abrasive will prevent the disk/pad glazing and should prevent the problem

What pads have people tried that have not been associated with judder ?

Skimming the disks seems to reset the problem which may or may not reappear dependant on pad choice

Anyway that is how i see it

[Adrian W]

Mike said:

I would be VERY surprised if it was the calipers contributing to these issues though!


Mike.
]

You must know more than the man from AP then, I'll stick to keeping an open mind

[wessexrfc]

It is a minefield, but this makes interesting reading. Makes me question how skimming has worked for me, but it did. Wondering if skimming is squaring the mounting rather than the disc itself??
http://www.stoptech.com/technical-support/technica...

[Gadgeroonie]

that is a good article and confirms my thoughts

"In fact every case of "warped brake disc" that I have investigated, whether on a racing car or a street car, has turned out to be friction pad material transferred unevenly to the surface of the disc. This uneven deposition results in thickness variation (TV) or run-out due to hot spotting that occurred at elevated temperatures.power of the disc brake system."

http://www.stoptech.com/images/tech-white-paper-im...