[PeteA]

Usually my make of choice for both pads and discs…..may try a good ol’ Italian Decoke of the brakes if you get my drift. Failing that, slide pins out for a good clean. Failing that, Pagid discs and EBC red pads. Detest any brake or steering feedbacks…!

I've tried that going down a very steep hill near us after getting up some good speed several times.. suffice to say that it's probably not worth the waste of fuel BigKev...

And yes, I did make sure that I drove for a good few miles afterwards to make sure that everything cooled down before using the brakes again..

 

[xf_phil]

Looks like clean the NEW slidies,but at less than 10k…?

Did you clean the caliper brackets and lubricate them with MolyKote Cu-7439 ( on the part where the pads contact the caliper brackets )?
I suspect the slide pins are a bit of a distraction, as they're in rubber anyway, so how hard can they seize, where as the pads can properly seize to the caliper brackets.

 

[BigKev]

Ears of pads smeared with wee bit of Ceratec and location got a wee scrape out.

 

[xf_phil]

Ears of pads smeared with wee bit of Ceratec and location got a wee scrape out.

I know a lot of mechanics do that, but my theory is that if you put the corrosion protection on the ears of the pads rather than the caliper bracket, then it only protects the bit of the bracket that the pads are currently in contact with, then the bit of the bracket closer to the discs where the pads should slide corrodes before the pads have worn, so when they get there it's already rusted again and they then jam.

5 months in with Mintex discs, and pads, so far no brake judder, hoping I didn't just jinx it with that statement

 

[BigKev]

I've tried that going down a very steep hill near us after getting up some good speed several times.. suffice to say that it's probably not worth the waste of fuel BigKev...

And yes, I did make sure that I drove for a good few miles afterwards to make sure that everything cooled down before using the brakes again..

Aye……buenos shoutos, Pete……went oot and tried anyway……gallon of fuel down the drain……did not work.

 

[cutlea01]

Strange how the XKR nor the F-Pace suffer with brake judder despite using a single piston caliper at each corner, the same as the XF. I suffered intermittent judder on my XF, under gentle at speed breaking, very annoying. Next day, gone.

 

[OzXFR]

Strange how the XKR nor the F-Pace suffer with brake judder despite using a single piston caliper at each corner, the same as the XF. I suffered intermittent judder on my XF, under gentle at speed breaking, very annoying. Next day, gone.

I thought a 2011 XKR had the same brakes as a 2011 XFR, that is 380 mm fronts and 376 mm rears, and the 380 mm fronts are twin piston.

 

[cutlea01]

I thought a 2011 XKR had the same brakes as a 2011 XFR, that is 380 mm fronts and 376 mm rears, and the 380 mm fronts are twin piston.

Yes, you are correct, the XKR has a twin piston sliding front caliper. But being single sided and therefore sliding is of a similar design principle to the XF. Brake judder is (so far) unknown on the XKR (and F-Pace).

 

[hamedhbb]

As you remember I changed brake discs and pads on all 4 corners and it did improve significantly but not as much as I was expecting. (Not as smooth as other cars I owned)
However, I was in a tyre shop last weekend because one of my tyres torn due to excessive toe. (I was too optimistic that changing an upper control arm won’t need wheel alignment).
Asked them to check all 4 wheels again for any buckles. They said they are all acceptable but when I asked them to see for myself. One of them had a buckle around 8-10mm that could be even seen over the rubber. Another 2 were around 3-5mm.
non are obvious until you hold something against it and rotate it fast. That could be the acceptable range for the industry is different to what XF needs.
These were people who could straight alloy wheels if needed.
Haven’t addressed it yet but having changed almost everything, I think there is another variable for brake judder on XFs which is the alloy wheels. Mine has a Hydra 20” with not much rubber to protect it. Wondering what wheels other people who have judder problem use.
Wondering if the alloy material would be different for different power ratings even if sizes are the same?

 

[PeteA]

I too have Hydra's Hamed, and my wobble/shuddering varies as it wants too. I have long held the belief that it's buckled/bent wheels causing the problem in origin, possibly even the accumulation of two wheels causing the issue hence it's coming and going for no seemingly good reason, i.e. 'in phase' or 'out of phase' causing the differences in severity.

 

[hamedhbb]

I too have Hydra's Hamed, and my wobble/shuddering varies as it wants too. I have long held the belief that it's buckled/bent wheels causing the problem in origin, possibly even the accumulation of two wheels causing the issue hence it's coming and going for no seemingly good reason, i.e. 'in phase' or 'out of phase' causing the differences in severity.

Totally agreed Pete. The guy said as long as it balances you shouldn’t have problem. But the truth is if wheels have a slightly shorter radius at buckle point, the torque that brakes should overcome is slightly less at that particular moment.

 

[xf_phil]

The tyre will flex considerably though, and it's the variation in radius of the tyre rather than the wheel that's in contact with the road, and considering that the contact patch is also squashed by the weight of the car where the tyre meets the road I'd have thought the variation in torque applied would be insignificant. Maybe there is some sort of harmonic vibration set up by the distortion.

I guess as you've been chasing this a while you will have already checked the run-out when fitting the discs, interesting advice from Mintex on that, to try the discs in a different orientation if the run-out is too great. Actually their leaflet tells you to rotate it 1/4 turn and try again, which isn't gonna end well for a 5 stud wheel
I suppose you could use that technique to find which of the 5 positions gives the least run-out.
Have you tried having the new discs skimmed on car?

So far I've only run into the judder once, when the car had been stood for long periods in lockdown, I could see a newly broken rust spot between the caliper bracket, and one of the pads when I changed them, so certainly looked like a pad seizing to the caliper bracket was the cause in my case, so I was careful to lubricate the entire contact area where the pad will slide on the caliper bracket during it's life, no more trouble so far, but then I only have 19" wheels not being an S model so less likely to have distortion I suppose.

I've been wondering if taking the wheels off is to be avoided, as every time you remove the wheel the disc is no longer firmly clamped to the hub ( I doubt those pressed nuts can stop them moving ), so if it shifts slightly corrossion between the disc, and hub could cause more runout.

 

[Philayl]

Just out of curiosity has there been any notice on whether it occurs more or less depending on the wheel diameter, for instance does it happen less on 18" wheels than on 20" wheels? Phil

 

[BigKev]

Had to read back to Cutlea’s post re. this being an intermittent ocurrence, and, contrary to previous posts can assure youz I am of sound mind, nearly. Relevance….? Had a forty mile round trip today, more than usual for me recently, and not even once did this brake/steering wheel shimmy finommynon manifest itself.
Really……what TF goes on here…? Goes from prominent to zero in a couple of days…?

 

[PeteA]

Had to read back to Cutlea’s post re. this being an intermittent ocurrence, and, contrary to previous posts can assure youz I am of sound mind, nearly. Relevance….? Had a forty mile round trip today, more than usual for me recently, and not even once did this brake/steering wheel shimmy finommynon manifest itself.
Really……what TF goes on here…? Goes from prominent to zero in a couple of days…?

Sounds about right too me.. I can go for days without experiencing it (first three days last week 550 miles no problem) next day came and went several times during 80 miles...

 

[cutlea01]

My experience exactly in my old XF. I gave up worrying about it, it didn't affect the braking performance, just the overall enjoyment of the car. Put it down to a trait of the vehicle. Though I would on occasion look forwards to driving the XKR, the brakes are judder free and more powerful (unsurprisingly).

 

[hamedhbb]

The tyre will flex considerably though, and it's the variation in radius of the tyre rather than the wheel that's in contact with the road, and considering that the contact patch is also squashed by the weight of the car where the tyre meets the road I'd have thought the variation in torque applied would be insignificant. Maybe there is some sort of harmonic vibration set up by the distortion.

I guess as you've been chasing this a while you will have already checked the run-out when fitting the discs, interesting advice from Mintex on that, to try the discs in a different orientation if the run-out is too great. Actually their leaflet tells you to rotate it 1/4 turn and try again, which isn't gonna end well for a 5 stud wheel
I suppose you could use that technique to find which of the 5 positions gives the least run-out.
Have you tried having the new discs skimmed on car?

So far I've only run into the judder once, when the car had been stood for long periods in lockdown, I could see a newly broken rust spot between the caliper bracket, and one of the pads when I changed them, so certainly looked like a pad seizing to the caliper bracket was the cause in my case, so I was careful to lubricate the entire contact area where the pad will slide on the caliper bracket during it's life, no more trouble so far, but then I only have 19" wheels not being an S model so less likely to have distortion I suppose.

I've been wondering if taking the wheels off is to be avoided, as every time you remove the wheel the disc is no longer firmly clamped to the hub ( I doubt those pressed nuts can stop them moving ), so if it shifts slightly corrossion between the disc, and hub could cause more runout.

Yes I have been through of that. When I installed the new discs the runout on disc was within spec. 0.02mm fronts and 0.05 rears. Before I skimmed the rear hubs runout was 0.2mm.

I understand what you say about rubber but you could see that on rubber and the rim edge.

p.s. I don’t have brake judder now but it is not as smooth as feeling on other cars. Specially if I hit the brake pedal suddenly.

 

[hamedhbb]

I did fix the buckle on the wheel and brought it down to 1mm. Considering I didn’t touch anything else, it massively eliminated the brake judder. I guess the remaining is due to the pad build up on the disc surface. I will report back if stays like this.

 

[hamedhbb]

Ok I could feel the judder for the first time after repair of the wheel on a 200miles motor way. I am now thinking maybe the piston is not retracted properly and touching the rotor which will make considerable amount of heat on a motorway. It’s smooth again after getting out of motorway.

 

[JonR]

When I first bought my XF S nearly 4 years ago it had brake judder from high speed but I thought no problem, I’ll fix that. Ahem. It’s taken up till now to fix 😂.
3 years ago I replaced all 4 discs with Brembo aftermarket ones and used EBC red superstreet ceramic pads.
But I’ve since had other problems with this car that the brake judder was a minor blemish and ignored. I could write a book on DPF systems and split inlet manifold covers…
When being TÜV‘ed this April I was advised to replace the front lower control arm inner bushes as they were worn and splitting. That’s another story with an independent workshop I used in England but they finally got the job done and tracked and trued all 4 wheels. Brake judder gone. Completely.
I can now brake hard from 250 km/h with no judder at all. Very happy.
Now onto the next job. Another oil leak from the recently replaced inlet manifold covers or related pipework…I should have paid the Jaguar labour rates (€4000) and got the job done properly rather than getting an independent garage do it for £1000 and have loads of trouble afterwards. Rant over.