Jaguar brake judder on the XK8 & XJ. Secrets of the XK8 ep82

[@briansmith6862]

Hi John. I get low speed judder as I'm slowing to a smooth controlled stop. This is on a 05 XKR with Brembos and the supersport suspension. So, you may find this interesting. Ray at Surrey Jaguar Centre, a renowned independent, told me there is absolutely nothing that can be done because it has nothing to do with the brakes at all, but the suspension. As you apply the brakes the suspension obviously twists around the moment of the axle and once it meets too much resistance it bounces back and the process starts all over again. This is why it only happens at low speed. At higher speeds there's always too much torque for the suspension to untwist itself. Apparently this is common to all cars with a double- wishbone layout, and the bigger the discs, the worse the effect. However, I agree with you about material transfer. I think the problem with warped discs was predominant in the XJS which had skinny discs and heat soak after any stop caused the discs to overheat and warp.

[@ToTheGarage]

Good point. its certainly possible and if the suspension or subframe bushes are worn its probable. But jags are all about power hidden by refinement, so it will not have done that from new, and therefore it is resolvable. (albeit, it may take a lot of patience and money to track down these issues) A. very good and interesting point though Brian. You really cant underestimate the value of a good independent Jag Specialist. Thanks for the recommendation and hi to Ray at Surrey Jaguar Centre👍 great to hear someone who thinks like an engineer.

[@hewyn1]

Wow, John, what an excellent video! I shall never look at my brakes in the same way ever again. I shall also try the ‘lift off’ method of braking too. Thank you for making me so much better informed. Cheers John!

[@ToTheGarage]

Kind words Nick. Thanks.👍

[@Dave-in-France]

Hi Nick, when driving an automatic with 'creep' and coming to a halt it helps if you slip the 'box into neutral, using the handbrake if required. Then pop it back into drive when departing. Some people will tell you that if you do this the oil pump in the 'box will not work and could cause damage to the 'box. This is 100% untrue. The gearbox oil pump is permanently operating whilst the engine is running.

[@hewyn1]

@@Dave-in-France That’s an excellent and little known tip. Many thanks, David! Cheers Nick

[@Dave-in-France]

@@hewyn1 Just to follow up on what I said earlier Nick and use of handbrake, I'm assuming you know that the handbrake comes off automatically when you drive off, you don't need to release it yourself.

[@t.alanblain6313]

@@Dave-in-France While you may be correct on certain more modern cars with electic/electronic handbrakes, I am fairly sure that that is not the case with the XK8. I have a 2004 and the handbrake is purely mechanical as I think it is on all XK8s.

[@titusteak6633]

Very interesting video, thanks. The existence of a warped disc may also be felt through the brake pedal very slightly pulsing rhythmically as you come to a stop. I encountered this many years ago on a car without ABS which was confirmed in a subsequent MOT.

[@ToTheGarage]

Thanks Titus👍

[@steveanderson735]

Thanks John , yes and also on my Mercedes 320 cls cdi on a 2007 3 litre automatic, the disc surfaces had got ridges on them so replaced all brakes with high performance Brembo vented discs and pads of a much higher quality Stopped the problem. Also more recently on my 2011 Jag XJ 3 litre twin turbo all round. (November 2020) although the car passed its MOT. I have been driving autos for about 10 years and I am now 54 and have always tried to lift off unless in an emergency stop situation. Swapped my Mercedes for the Jag XJ can say what a lovely car in appointment, driving and handling John. Great videos especially about Blu and Purdey. Thanks John.

[@stun9771]

@@steveanderson735 my understanding of disks getting ‘scored’ (developing ridges), is mainly due to badly worn brake pads, where the rivets that hold the braking pad onto the metal part of the pad fixing, wear through to the surface of the brake pad, and start cutting or scoring the brake disk surface...

[@bbhoustontx]

I make it a habit to take the disk's to an auto shop and have them resurfaced as part of the brake job along with new pads. They are usually cheap to have this done. Your explanation sounds right and makes me more conscious now. Thank you John I enjoy all your vids. Your the best!

[@alexanderthegreat6480]

Don't let the judah betray you ! ;) Thanks John, excellent video.

[@ToTheGarage]

Thanks

[@Dave-in-France]

Very good Alex, had me laughing out loud !

[@alexanderthegreat6480]

@@Dave-in-France me too. I'm still laughing about my stupid joke...

[@kevinetheridge8818]

Useful information as always. I remember being advised to lift off the brakes just before coming to a stop for a smoother drive. More comfortable for your passengers, no more ‘nodding heads’. You’ve just added a financial benefit. Thanks John.

[@ToTheGarage]

Great point! Cheers Kevin👍

[@noneofyourbusiness3356]

Had my xjr at the dealer twice to check this. Now I know what it is and how to fix it. Thank you My dealer is really good but their techs are young and probably don’t have experience in this issue. They will now.

[@ToTheGarage]

Glad it helped 👍

[@ccuk]

Great video John. I have a similar issue. When I got the car in February it had been sitting for a while and the break judder was bad. This quickly improved to a light judder. I will be trying your tip to clean them up - if not new breaks will be on the ever growing xmas list.

[@ToTheGarage]

Thanks for sharing

[@t.alanblain6313]

Thanks John. Another excellent video and again you've taught me something that I didn't know. I can definitely see the problem with 'hot stops', and while I have, in a manual car, prided myself on no jerking as the car finally stops, I am beggared as to how it is possible to do it on an automatic. It has been my pet hate since I began driving automatics.

[@ToTheGarage]

Its a challenge but good quality pads make it easier

[@geirfammestaddonski4835]

Thanks. I was looking to replace the almost new discs on my x308. I'll try this first 👍

[@ToTheGarage]

Let us know how you get on Geir👍

[@gerardbooth40]

Fantastic video John. Great to hear an experienced and knowledgable engineer’s opinion on a subject that has often puzzled me. That all makes so much sense and is definitely going to alter my approach to brake judder in future. BTW, the X308 passed her MOT with flying colours and no advisories 😃.

[@ToTheGarage]

Many thanks Gerard. So pleased to hear that the BBBig cat has cruised through test👍

[@ML-tr4md]

Hi John, have ever heard about Frozen Rotors. Those are cryogenic treated (and they don’t rust) and I did install 4 new rotors on my XFS 2017 with yellow stuff pads from EBC. They are amazing, never had brake so efficient. Next step will be to have those Frozen Rotors on my XK8..

[@terryc8164]

Interesting John, does make a lot of sense. Cheers.

[@ToTheGarage]

Thanks Terry

[@jonrickard4762]

I had juddery braking on my 2001 xk8 and had the discs changed which didn't solve the problem but what did solve it was a 5 min wheel alignment!!!

[@ToTheGarage]

👍

[@flyurway]

DA sander with 80 grit or coarser works good for cleaning up rotors.

[@ToTheGarage]

I may have to try out some restoration techniques Andork. I still have the rotors

[@hunty28]

Another great video, thanks John👍

[@ToTheGarage]

Glad you enjoyed it

[@stagnite2]

Hi John, another excellent and very informative video. I had this problem on my Jaguar S Type R which took me a while to resolve. In brief, if you have a steering wheel wobble which only happens when braking, jack up the front and spin both front wheels. If one produces an even shhhhhhhh sound from the pads touching the disc when spinning it, its OK. If one produces a shhhh shhhh shhhh in time with the wheel revolution, this is the one that has a problem. If you remove and rotate that disc on the hub by 144 or 216 degrees as it has five studs, and the wobble becomes worse, you have a bent hub which has deformed the disc so the wobble is now accentuated. If there is no difference, the disc is either warped or has those hot spots as you have described. After I fitted a new hub AND disc at the same time, the wobble disappeared. A bent hub will damage a disc in a few thousand miles. A repaired Alloy will give you an indication of a possible bent hub! Here is my rather long winded story of how I eventually cured my brake judder which may interest you and give you another angle to look at your problem. I am Stagnite on this forum. www.jaguarforum.com/threads/steering-wheel-wobble-when-braking.95239/

[@ToTheGarage]

An excellent write up Stagnite 2. I had not considered a bent hub. If my discs dot clean up in the next few weeks I will be swapping the discs and pads but will check the hub runout just out of interest

[@stagnite2]

@@ToTheGarage Ok John. Neville.

[@Therighteousone522]

Enjoyed that. Made sense john thanks

[@ToTheGarage]

Cheers Robert

[@josephpatricio851]

Very interesting, I’ve learned a lot. I’m in Canada and here when that happens the mechanics “turn” the rotors which is basically machining them. They can only do this so many times, is this common in Britain. By the way, the previous owner of my xk8 upgraded the rotors to drilled brembos. I’ve had the car for fifteen years and never so much as a shudder or vibration from the brakes.

[@ToTheGarage]

Hi Joseph Brembo's are awesome. (if expensive) Turning Discs is not a common thing in the uk (but does happen). Its far more common to just replace them

[@timshannon999]

Really interesting John. Didn’t know that. Many thanks. I see PJ is up on eBay now. Cheers, Tim

[@ToTheGarage]

Hi Tim. Thanks for the tip off I will take a look just to be nosy

[@noneofyourbusiness3356]

If the rotors are ported and slotted to reduce heat. Does this weaken them to any significant concern?

[@ToTheGarage]

Drilled rotors are more prone to cracking than un drilled ones. Groves that are not perfectly radial (aligned from centre to outer edge) Dont significantly weaken the disk. Thats why most grooved discs have groves that are diagonal or curved, to endure they dont line up with the relatively unsupported areas where the Venting inside the disk sits.

[@philcrowell7516]

Hi John, I'm in a bit late on this one, but I'm a potential XK8 owner and find your insights fascinating and very enjoyable. Just a quick question. Why do you think the material transfer is tending to be only on one side? Would this indicate a problem with uneven piston movement on each side? I'm not familiar with the caliper make up, but is this something worth considering in the mix of things?

[@ToTheGarage]

The callipers (unless you are luck enough to have Brembo's) are large single piston units. This tends to produce a slight imbalance with the 'dead side of the calliper slightly scrapping the disc and the live side slightly clearing it, so differing amounts of transfer is quite likely unfortunately

[@mistermikeanson]

Very educational - as always!

[@ToTheGarage]

Thanks mike

[@warishussain82]

Thanks for the info!!!! Changed my brakes on my x350 sovereign model and still feel some judder now I know what I'm doing hot stops!!!! Would love u to do the bonnet sensor on how to 'clean it !!!!

[@ToTheGarage]

Can you describe the 'Bonnet sensor' Waris? Bonnet open sensor?

[@warishussain82]

@@ToTheGarage that's the one mate!!! For some reason I get the bonnet open message, it come and goes I'm trying to figure out how to clean it!!! 😅

[@philip.aocallaghan4602]

Hi, i have a problem with xk8. i do not have dashlights no rev counter and it is stuck in park. I have looked at all of your videos and find them very helpful, but none really address this issue. or explain how to go about finding the issue that is causing all these problems. i know how to use the emergency release , but that does not fix the problem.. Can you offer any advice on this please...

[@Dave-in-France]

Having watched this I was prompted to say to 'er indoors that for owners of XK8's and X350/8's that watching your vids is a bit like have your very own mechanical tutor/mechanic - honestly they are just brilliant.

[@ToTheGarage]

Thank you David,. Much appreciated

[@Dave-in-France]

Hi John, as always a good watch on an interesting subject. One observation if I may? The 'witness marks' as you referred to them were predominantly on the inside of the disc; the piston(s) in the caliper meet with the inside of the disc; the piston(s) often seize within the caliper. Coincidence ? Discuss. Cheers Dave

[@ToTheGarage]

Hi David. Nice point. Yes I think I Agree. The piston is far more likely to seize or at least stick than the slider pin on its rubber bushes so the back is more likely to get the pad transfer. In reality is should not be much different though🤔

[@UdoIBress]

Very interested, i didnt know it. 👍

[@ToTheGarage]

Thank you Udo

[@colingordon4]

Cheers for this John, I don’t know which books you read to get this stuff from, but please keep reading them and sharing on your channel. This is by far the most useful resource I have found anywhere (and have I been searching 😀). This video really has answered a lot of my unanswered question for my juddering XJ sport premium. Cant thank you enough John 👍

[@ToTheGarage]

Thanks Cheeky Smurf.

[@johnwilliams4556]

Hi john. John here. I love when u say that. I need help with my license plate lights. Replaced them but still not working. Where is the fuse. Trying to find the problem. Please reply soon need inspection.

[@ToTheGarage]

fuse box in the drivers footwell. It will be the one that is blown😁. Sorry I don't have access to a fuse map at the moment (away from home) Someone else may be able to help though.

[@johnwilliams4556]

Thanks john. Car in the shop now can get your email.

[@johnwilliams4556]

Thanks john. Car is in the shop now.

[@lmachugh1810]

Judging by the pads the callipers are probably dirty and the pads are not sitting square in them

[@ODRModurol]

John, hot stuff and good information. Are you fitting new pads, assume you are if so which do you recommend? EBC? Thanks for another great video, regards Damian

[@ToTheGarage]

HI Damian. Thanks mate👍 I am trying to clean them up on the car with good braking technique at the moment. They are better but not good enough. So will probably end up swapping them. The pads will certainly be EBC. probably red stuff🤔. Discs will be re cut or replaced. Probably the latter as I don't know of anyone nearby who could do them on a quick turnaround.

[@ODRModurol]

@@ToTheGarage Look forward to watching those videos. Our Jaguars just keep giving, ha, ha, regards Damian

[@peteb3091]

Fantastic video, been following for a while, I've got a XJ 358 too, have owned it for roughly 6months now, I have now done nearly 10000miles in that space of time, due to work. I started to get brake judder a couple months ago, 30miles of my 70mile journey to work is on country roads and I do give the old girl a bit of stick, (usually over taking Land Rover defenders and such) so fast overtaking (60mph max...... Officer) then hard on the brakes very often. The discs and pads were fairly new when i bought the Jaaaag. As you said in the last part of the video I obviously have the same problem. So are we saying that the problem Is that the disc diameter/pad size is to small for the weight of our cars, and can't substantially dissipate the heat? What are your thoughts on the EBC drilled and vented discs? Thanks.

[@ToTheGarage]

I love EBC stuff though prefer a groove to drilled discs. I think that cooler disc would help but better pads more so. Im trying to restore my disks through driving a particular way. 1000 mikes into that experiment I have improved it but the judder has not yet gone away so new discs and pads may be on the new year list?

[@ulfsandblom6341]

What is that in your hand in the end of the video? Aluminum foile? Keep up the good work. Best regards Ulf

[@stevepitts7998]

I may be wrong Ulf but it looks like a stainless steel scrubber - the type of scourer you'd use to clean dirty saucepans (or contaminated brake discs) with.

[@ToTheGarage]

Ah well spotted. A stainless steel pan scrubber🤣

[@ToTheGarage]

Exactly Steve.👍It won't remove anything that has gone into the disc material, but will take off a small amount of transfer from the surface. Also good for pots and pans😁

[@stevewainwright669]

Very interesting. My experience is a little different though. Having driven a 2013 XF 3.0 for 100,000 miles and now a 2015 XJ 3.0 for nearly 90,000 I have been plagued with this issue and replaced 5 sets. A Jag specialist in the Midlands looks after my cars and only fits quality parts, pads and disks. The hot stop explanation is really interesting but at least twice my judder has started after a high speed hard braking without stopping. The last one happened at 130 mph in Germany when a lorry pulled into the middle lane (my lane) just as a Porsche came up on the outside lane at significantly higher speed. My only choice was a very hard brake, from 130 to 60 ish. Resulting in real bad brake judder immediately after. As most of my mileage is on motorways, hence few hot stops, I would be very interested in your view of my issues.

[@ToTheGarage]

Hi Steve its a really interesting one. If you hadn't said it was a Jag specialist I would have suggested they were using some really low quality pads and that despite the lack of a hot stop , you had just boiled the phenolic resin out of the pads.

[@stevewainwright669]

@@ToTheGarage Hi, I use Northfield Garage Jaguar Specialists, a guy called Ricky McCarthy who is well recommended on JDC and have no doubt he uses decent parts. I also don't know how cooking the pads can cause such terrible judder. To be honest, I drive many many motorway miles and I'm not heavy footed on the brakes and always try to consider wear, but over the past near 200,000 miles in 6 years, the brakes are the weakest link on otherwise bullet proof cars. That incident on an autobahn really shows there weakness in my mind.

[@Bezza1959]

Now you've got the 2 jags have you ever thought of measuring both centre consoles to see if the one from the x358 would fit the x100? That would be interesting to see !!

[@ToTheGarage]

I have not but my instinct is that the XJ is significant wider and Much taller🤔

[@Bezza1959]

Hi John. I sold my x350 in June this year because I missed my xk8. Now I'm back driving the best Jag ever made I DO miss some of the " creature comforts" of the xj, especially the touch screen, the heated seats & the heated front screen !! Wish I'd done some measuring to see if I could upgrade the audio system.