Davey
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Resident Tyre Nerd.
Posts: 2,203
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Sept 30, 2022 15:22:22 GMT
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I am starting to get at my wits end with this. For reference I am a qualified technician and have all the tools in the world but i cannot seem to fix this, i hope someone has at least an idea. Background: I am getting a wobble through the steering wheel under what can only be described as "Medium" braking. Brake lightly - Nothing, Brake firmly not much. Problem seems to get worse when the brakes are hot and gets to the point of trying to pull the steering wheel out of your hand. 2010 Jaguar XF, has the chonky "S" front brakes rotors somewhere north of 300mm and huge callipers that look twin pot but aren't. Car has had new disks and pads front and rear, temporarily better perhaps? Front callipers both rebuilt completely. New pistons, seals, sliders the works. Front hubs have been wire brushed to the point of being shiny..... Several times! New rear wheel bearings (Unrelated to this issue but worth noting I think?) New front lower arms, uppers had been replaced not long before I bought the car and the issue was already present then. New rear arms, lower and upper. Brake fluid replaced. These is some talk on the Jaguar forums of pad material transfer. I have gone through every iteration of brake bedding and cleaning process outlined, i have sanded visible pad marks off the discs everything i can possible think of.. Some seem to lessen the issue but its never goes away completely and it always ends up as bad as before. I have tried to rule out the ABS by pulling the fuse and again maybe a little change but nothing perceptible. Having rectified all the cars little foibles and making it the ideal daily driver (Its not even that thirsty 40+ mpg on a run!.) this just ruins the whole thing. Anyone have any ideas before I take it down to the local industrial estate and have my own burning man festival. Pictures of said glamorous pain in the backside as penance.
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K11 Micra x3 - Mk3 astra - Seat Marbella - Mk6 Escort estate - B5 Passat - Alfa 156 estate - E36 compact Mk2 MR2 T-bar - E46 328i - Skoda Superb - Fiat seicento - 6n2 Polo - 6n polo 1.6 - Mk1 GS300 EU8 civic type S - MG ZT cdti - R56 MINI Cooper S - Audi A3 8p - Jaguar XF (X250) - FN2 Civic Type R - Mk2 2.0i Ford Focus
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Sept 30, 2022 15:52:31 GMT
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Just an idea (I'm no expert on these) have you tried getting the brakes warm enough to the point where the wobble happens, and then doing a run-out check on the wheels and discs? Something expanding to the point it's causing the fault? (He says sounding like I know what I'm talking about 😁)
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Davey
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Sept 30, 2022 15:58:11 GMT
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Just an idea (I'm no expert on these) have you tried getting the brakes warm enough to the point where the wobble happens, and then doing a run-out check on the wheels and discs? Something expanding to the point it's causing the fault? (He says sounding like I know what I'm talking about 😁) Unfortunately for me and my scorched fingers. Yes. Absolutely stone dead 0.
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K11 Micra x3 - Mk3 astra - Seat Marbella - Mk6 Escort estate - B5 Passat - Alfa 156 estate - E36 compact Mk2 MR2 T-bar - E46 328i - Skoda Superb - Fiat seicento - 6n2 Polo - 6n polo 1.6 - Mk1 GS300 EU8 civic type S - MG ZT cdti - R56 MINI Cooper S - Audi A3 8p - Jaguar XF (X250) - FN2 Civic Type R - Mk2 2.0i Ford Focus
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adam73bgt
Club Retro Rides Member
Posts: 4,866
Club RR Member Number: 58
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Sept 30, 2022 16:25:04 GMT
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What brand of discs and pads have you fitted? If the discs have measured as having no run out then it's unlikely they could be affecting things too much but if they're cheaper pads they might be causing some odd behaviour.
I used to work in brakes engineering at JLR but unfortunately that generation of XF was slightly before my time so I can't give any direct insight 😅
Is the suspension, bushes, steering all in good condition also? Could be something triggered by the brakes but amplified by something else in the system
Edit: sorry had skipped over the bit where you said new suspension arms fitted!
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Last Edit: Sept 30, 2022 16:26:10 GMT by adam73bgt
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Sept 30, 2022 16:34:56 GMT
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Cant be a lot of help but could it be something in the steering like the rack loose?
If were having a barby Ill bring the sausage!
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Sept 30, 2022 16:44:38 GMT
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Have you tried a different compound of pad material or different manufacturer. The fact heat makes it worse and there is no disc run out suggest pads in some way.
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Needs a bigger hammer mate.......
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Davey
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Sept 30, 2022 16:48:18 GMT
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Currently brembo discs and pads all round. Brand new uniroyal rs5s all round. Has previously had bosch and pagid pads.
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K11 Micra x3 - Mk3 astra - Seat Marbella - Mk6 Escort estate - B5 Passat - Alfa 156 estate - E36 compact Mk2 MR2 T-bar - E46 328i - Skoda Superb - Fiat seicento - 6n2 Polo - 6n polo 1.6 - Mk1 GS300 EU8 civic type S - MG ZT cdti - R56 MINI Cooper S - Audi A3 8p - Jaguar XF (X250) - FN2 Civic Type R - Mk2 2.0i Ford Focus
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Davey
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Sept 30, 2022 17:00:49 GMT
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What brand of discs and pads have you fitted? If the discs have measured as having no run out then it's unlikely they could be affecting things too much but if they're cheaper pads they might be causing some odd behaviour. I used to work in brakes engineering at JLR but unfortunately that generation of XF was slightly before my time so I can't give any direct insight 😅 Is the suspension, bushes, steering all in good condition also? Could be something triggered by the brakes but amplified by something else in the system Edit: sorry had skipped over the bit where you said new suspension arms fitted! Apparently similar issues with the x260 if thats any more your time period.
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K11 Micra x3 - Mk3 astra - Seat Marbella - Mk6 Escort estate - B5 Passat - Alfa 156 estate - E36 compact Mk2 MR2 T-bar - E46 328i - Skoda Superb - Fiat seicento - 6n2 Polo - 6n polo 1.6 - Mk1 GS300 EU8 civic type S - MG ZT cdti - R56 MINI Cooper S - Audi A3 8p - Jaguar XF (X250) - FN2 Civic Type R - Mk2 2.0i Ford Focus
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Davey
Posted a lot
Resident Tyre Nerd.
Posts: 2,203
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Sept 30, 2022 17:01:41 GMT
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Cant be a lot of help but could it be something in the steering like the rack loose? If were having a barby Ill bring the sausage! I had thought it could be rack related but i cant make anything move at all. Even mountings to subframe seem brand new.
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K11 Micra x3 - Mk3 astra - Seat Marbella - Mk6 Escort estate - B5 Passat - Alfa 156 estate - E36 compact Mk2 MR2 T-bar - E46 328i - Skoda Superb - Fiat seicento - 6n2 Polo - 6n polo 1.6 - Mk1 GS300 EU8 civic type S - MG ZT cdti - R56 MINI Cooper S - Audi A3 8p - Jaguar XF (X250) - FN2 Civic Type R - Mk2 2.0i Ford Focus
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stealthstylz
Club Retro Rides Member
Posts: 14,839
Club RR Member Number: 174
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Sept 30, 2022 17:23:04 GMT
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Could it be something stupid like the ABS been overly sensitive on one side, pulsing one brake might cause a steering wibble. On hard braking when it's working on both it'd go away.
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Sept 30, 2022 17:27:21 GMT
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Also have you swapped the wheels front to rear? Had a discovery on a while ago with odd pulling/ vibration problems OSF tyre was 120psi! Not suggesting that you wouldn't have checked pressure, but is one tyre going out of shape/ delaminating? Really clutching at straws here 😟
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adam73bgt
Club Retro Rides Member
Posts: 4,866
Club RR Member Number: 58
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Sept 30, 2022 17:31:04 GMT
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What brand of discs and pads have you fitted? If the discs have measured as having no run out then it's unlikely they could be affecting things too much but if they're cheaper pads they might be causing some odd behaviour. I used to work in brakes engineering at JLR but unfortunately that generation of XF was slightly before my time so I can't give any direct insight 😅 Is the suspension, bushes, steering all in good condition also? Could be something triggered by the brakes but amplified by something else in the system Edit: sorry had skipped over the bit where you said new suspension arms fitted! Apparently similar issues with the x260 if thats any more your time period. Yeah I was there for x260 although I was more on the LR side of things. X260 had all new brakes compared to x250 (and I think a fair bit of the suspension bits were different also) so might not be the same issues. I think the pad material deposition issues are related to lower copper content pads that came in due to legislation on metals from brake dust getting into waterways (sounds like a stretch I know). Copper is quite a good lubricant so you take some out of the compound and you can see more issues with juddery brakes etc. (That's about as far as my knowledge of pad material science goes, it's a bit of a black art!) Aftermarket pads should be a bit of a lottery really, considering the amount of refinement development that goes into an OEM brake system but 9 times out of 10 they'll be absolutely fine, the R90 standard that aftermarket (and OEM) pads have to meet is quite a low bar compared to the standards the OEMs work to. Brembo pads should be ok though, and if you've tried a couple different brands and are seeing the same issue, the problem may well lie elsewhere
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Davey
Posted a lot
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Posts: 2,203
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Sept 30, 2022 19:03:47 GMT
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Could it be something stupid like the ABS been overly sensitive on one side, pulsing one brake might cause a steering wibble. On hard braking when it's working on both it'd go away. Tried running the car with abs fuse pulled and no real difference other than being able to easily lock the rears. Had a similar thought as it makes an audible abs test noise on startup but apprently this is fairly normal.
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K11 Micra x3 - Mk3 astra - Seat Marbella - Mk6 Escort estate - B5 Passat - Alfa 156 estate - E36 compact Mk2 MR2 T-bar - E46 328i - Skoda Superb - Fiat seicento - 6n2 Polo - 6n polo 1.6 - Mk1 GS300 EU8 civic type S - MG ZT cdti - R56 MINI Cooper S - Audi A3 8p - Jaguar XF (X250) - FN2 Civic Type R - Mk2 2.0i Ford Focus
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Davey
Posted a lot
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Posts: 2,203
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Sept 30, 2022 19:05:46 GMT
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Also have you swapped the wheels front to rear? Had a discovery on a while ago with odd pulling/ vibration problems OSF tyre was 120psi! Not suggesting that you wouldn't have checked pressure, but is one tyre going out of shape/ delaminating? Really clutching at straws here 😟 I am also clutching so anything is worth a shot. Every wheel has been on every corner. Brand new tyres in last 3 weeks and no change. Pressures all set and reset to 34psi. Have tried running higher and lower to no avail. Had a small wheel balance wobble before the new tyres which obviously wasnt helping but that is now completely gone.
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K11 Micra x3 - Mk3 astra - Seat Marbella - Mk6 Escort estate - B5 Passat - Alfa 156 estate - E36 compact Mk2 MR2 T-bar - E46 328i - Skoda Superb - Fiat seicento - 6n2 Polo - 6n polo 1.6 - Mk1 GS300 EU8 civic type S - MG ZT cdti - R56 MINI Cooper S - Audi A3 8p - Jaguar XF (X250) - FN2 Civic Type R - Mk2 2.0i Ford Focus
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Davey
Posted a lot
Resident Tyre Nerd.
Posts: 2,203
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Sept 30, 2022 19:06:55 GMT
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Apparently similar issues with the x260 if thats any more your time period. Yeah I was there for x260 although I was more on the LR side of things. X260 had all new brakes compared to x250 (and I think a fair bit of the suspension bits were different also) so might not be the same issues. I think the pad material deposition issues are related to lower copper content pads that came in due to legislation on metals from brake dust getting into waterways (sounds like a stretch I know). Copper is quite a good lubricant so you take some out of the compound and you can see more issues with juddery brakes etc. (That's about as far as my knowledge of pad material science goes, it's a bit of a black art!) Aftermarket pads should be a bit of a lottery really, considering the amount of refinement development that goes into an OEM brake system but 9 times out of 10 they'll be absolutely fine, the R90 standard that aftermarket (and OEM) pads have to meet is quite a low bar compared to the standards the OEMs work to. Brembo pads should be ok though, and if you've tried a couple different brands and are seeing the same issue, the problem may well lie elsewhere This makes a lot of sense. I may try some OE bits and see how i get on. If not then maybe something more aggressive. Ebc yellows or mintex m1155s perhaps.
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K11 Micra x3 - Mk3 astra - Seat Marbella - Mk6 Escort estate - B5 Passat - Alfa 156 estate - E36 compact Mk2 MR2 T-bar - E46 328i - Skoda Superb - Fiat seicento - 6n2 Polo - 6n polo 1.6 - Mk1 GS300 EU8 civic type S - MG ZT cdti - R56 MINI Cooper S - Audi A3 8p - Jaguar XF (X250) - FN2 Civic Type R - Mk2 2.0i Ford Focus
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Sept 30, 2022 19:10:47 GMT
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Did you have the issue before the calipers were rebuilt?
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mk2cossie
Club Retro Rides Member
Posts: 2,953
Club RR Member Number: 77
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Sept 30, 2022 19:32:59 GMT
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Who rebuilt and serviced the braking system on it?
As we have had issues at work with some people using copper slip or red rubber grease on slider pins. The trouble with using either of those, is that neither likes heat and becomes more resilient to just sliding nicely.
The other problem is pad material transfer from braking to a halt, and then holding the vehicle on the foot brake for too long
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dog
Part of things
Posts: 47
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Sept 30, 2022 19:53:48 GMT
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Double check and rebalance your wheels a weight might have dropped off. After a run use a lazor temp gauge on all the discs and check the temps match up with each other. Make sure all the caliper pistons and sliders are free and comparable with the others, we have seen a few LR with slightly overheating brakes that have caused a judder. Check the condition of your shockers, you may have one that is slightly weak condition. Check all the suspension bushes loaded, not on wheel free.
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Last Edit: Sept 30, 2022 19:54:16 GMT by dog
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Sept 30, 2022 20:56:52 GMT
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Isolate each wheel brake in turn ( clamping hoses etc ) to locate where the defect exists and then check that area for defects.
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Sept 30, 2022 21:03:14 GMT
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Have you replaced the track control arms on the front? Or just the lower arms?
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1988 Mercedes w124 superturbo diesel 508hp 1996 Mercedes s124 e300 diesel wagon 1990 BMW E30 V8 M60 powered! 1999 BMW E46 323ci project car
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