Hard braking - Keeping her straight
- Thread starter R60BBA
- Start date
I think you're going to end up chasing your tail on this and replacing half the car without proper diagnosis.
If you've done the obvious and checked for disc & pad wear, even contact on discs ie no missed parts in sweep, tyre pressures correct, tyre wear left to right wheels even. All checked on front and rear and done your brake testing on different surfaces, such as a big car park, then I'd take it to a station with an MOT style brake tester and that will in 2 minutes to confirm or eliminate all brake issue. You can then either repair or focus on all the more complex stuff of bushes, alignment, suspension, damaged parts, etc.
IMHO it's nothing to do with calipers sticking as this replicates at all speeds nor collapsed lines as that gives mushy or no brakes. Lollipops are possible, but part 3 first
If you've done the obvious and checked for disc & pad wear, even contact on discs ie no missed parts in sweep, tyre pressures correct, tyre wear left to right wheels even. All checked on front and rear and done your brake testing on different surfaces, such as a big car park, then I'd take it to a station with an MOT style brake tester and that will in 2 minutes to confirm or eliminate all brake issue. You can then either repair or focus on all the more complex stuff of bushes, alignment, suspension, damaged parts, etc.
IMHO it's nothing to do with calipers sticking as this replicates at all speeds nor collapsed lines as that gives mushy or no brakes. Lollipops are possible, but part 3 first
cj10jeeper said:
Thanks for this, it was quite an insightful read.
Tbh I was planning to replace the discs, upgrade to Red stuff pads and Goodridge lines w/ fluid change next month anyways as I will be taking the car to the Nurburgring in May.
I guess I may have to bring this service sooner. If I still have problems after then I will look at bushes and other suspension components. But I would probably discuss this with my mechanic first before spending £500...
Okay so after calling around I’ve got a few quotes for replacing discs, pads, lines, sensor and fluid.
Interestingly Will at TWG did not recommend using EBC Redstuff pads nor Goodridge lines, stating that the pads have poor bite and the lines can leak. Instead he recommended using Ferodo DS2500 pads and HELL lines. (I presume he notified this to me because TWG provide a 1 year warranty on all work done by them and so need to be satisfied that the parts they fit are up to standard.)
Anyone had any issues with EBC Redstuff? Or should I take his advice and go with the Ferodos.
(I believe the difference in price between the 2 pads is roughly £100).
- Munich Legends - £700 :? but £220 if I don’t change lines
- Evolve Automotive - £327
- TWG Automotive - £200
- BMS Leatherhead - £180
- ETA Motorsport - £250
- Birds BMW - £350
Interestingly Will at TWG did not recommend using EBC Redstuff pads nor Goodridge lines, stating that the pads have poor bite and the lines can leak. Instead he recommended using Ferodo DS2500 pads and HELL lines. (I presume he notified this to me because TWG provide a 1 year warranty on all work done by them and so need to be satisfied that the parts they fit are up to standard.)
Anyone had any issues with EBC Redstuff? Or should I take his advice and go with the Ferodos.
(I believe the difference in price between the 2 pads is roughly £100).
HEL lines are excellent and can.be supplied in any colour
Just a further update.
Did some more testing today and noticed that the offside rear is stepping out a bit under hard braking, which is making it harder to keep her straight. (Thus, this is the fulcrum of the problem methinks).
It’s almost like it goes into a mini slide before I have to catch it again, and align correctly. Kind of like torque steer but whilst braking if that makes sense.
I tried braking hard at speed on different roads and got more or less the same results. However I noticed that it only happens from 70mph upwards, if I brake hard at 40/50/60mph there are no issues.
When I parked up I had a look at my discs and noticed that the offside rear has a groove/cut on the top (see attached) but none of the others seem to have this.
Was wondering if this could be causing the problem?
I’ve booked the car in with BMS Leatherhead for its brake upgrade in a couple weeks.
Did some more testing today and noticed that the offside rear is stepping out a bit under hard braking, which is making it harder to keep her straight. (Thus, this is the fulcrum of the problem methinks).
It’s almost like it goes into a mini slide before I have to catch it again, and align correctly. Kind of like torque steer but whilst braking if that makes sense.
I tried braking hard at speed on different roads and got more or less the same results. However I noticed that it only happens from 70mph upwards, if I brake hard at 40/50/60mph there are no issues.
When I parked up I had a look at my discs and noticed that the offside rear has a groove/cut on the top (see attached) but none of the others seem to have this.
Was wondering if this could be causing the problem?
I’ve booked the car in with BMS Leatherhead for its brake upgrade in a couple weeks.
Attachments
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1CDCC5C6-5A09-4DC2-9008-F8F18F99EE58.jpeg -
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3FD44C19-0BF4-4F53-AE6B-1FB733161F14.jpeg -
65E0979F-850E-4BEC-A98D-510104E5803D.jpeg
Ed Doe said:
I did the 12 and 6/ 9 and 3 o’clock check and there was very minimal play. I’ll get BMS Leatherhead to inspect the bushes for reassurance but they seem fine.
The car had a fresh set of tyres and full alignment last month so it can’t be that.
At least you’re narrowing it to a possible rear brake issue
I thought those machine marks are factory balancing of the disc? Perfectly normal though
Your pulling left is you compensating for the brake induced rear steer. My instinct is a rear brake refresh will fix it so hold on until this work is done and see the results.
I thought those machine marks are factory balancing of the disc? Perfectly normal though
Your pulling left is you compensating for the brake induced rear steer. My instinct is a rear brake refresh will fix it so hold on until this work is done and see the results.
That machined indent on the edge of the disc is definitely factory balancing. To be honest with you although there is a fair bit of metal left in them I don't think those discs look in particularly brilliant condition 
I'd fit some new discs and pads and bet it makes a world of difference ! I fitted new Brembo discs and pads all round on mine a few weeks ago as I was having all sorts of issues with the MTEC/Red Stuff combo I was running. Now the Brembos have bedded in the difference is night and day....much, much better !
I'd fit some new discs and pads and bet it makes a world of difference ! I fitted new Brembo discs and pads all round on mine a few weeks ago as I was having all sorts of issues with the MTEC/Red Stuff combo I was running. Now the Brembos have bedded in the difference is night and day....much, much better !
R60BBA said:
I use DS2500 on my RS4 and they are a very effective way of stopping 1800kg from enormous speed (with the OEM Brembo BBK). I've not taken it on a track but it stands up to very hard use on country lane blasts.
I use EBC Bluestuff in my ///M and I've found them perfect for track and road use. Previously I used Yellowstuff and found I could overheat the pads on tight technical tracks.
patriot66 said:That machined indent on the edge of the disc is definitely factory balancing. To be honest with you although there is a fair bit of metal left in them I don't think those discs look in particularly brilliant condition
I'd fit some new discs and pads and bet it makes a world of difference ! I fitted new Brembo discs and pads all round on mine a few weeks ago as I was having all sorts of issues with the MTEC/Red Stuff combo I was running. Now the Brembos have bedded in the difference is night and day....much, much better !
What was wrong with your Mtec/Redstuff combo if you don’t mind me asking.
Hi R60,My threepenneth on this is listen to Ducklakeview,as those front lower wishbone bushes may not appear worn and may be entirely passable at m.o.t.but upgrade them to a polybush and this eliminates the horrible braking wander that ruins these great cars.Then when the polybush bug bites,do change the rear trailing arm front bushes next to tighten things up nicely.Don't be put off the Redstuff pads,as mine have been excellent in every way for the last 20 thousand odd miles,plenty of meat still on them and have not carved into the discs as I expected.There is no discernable wear lip at the disc edge yet so I recommend them and will buy again when the time comes.The only negative I found was the bedding in time being rather longer than usual.Good luck with however you go
R60BBA said:patriot66 said:That machined indent on the edge of the disc is definitely factory balancing. To be honest with you although there is a fair bit of metal left in them I don't think those discs look in particularly brilliant condition
I'd fit some new discs and pads and bet it makes a world of difference ! I fitted new Brembo discs and pads all round on mine a few weeks ago as I was having all sorts of issues with the MTEC/Red Stuff combo I was running. Now the Brembos have bedded in the difference is night and day....much, much better !
What was wrong with your Mtec/Redstuff combo if you don’t mind me asking.
Red Stuff pads are superb but they just completely overwhelmed the Mtec discs and put that much heat into them the NSF and OSR warped. Had them skimmed on the car and a new set of pads and same again ! Had this combo on 2 previous but different cars and the same happened. Once bitten twice shy so maybe I should've known better than to try them on the Zed. I have my doubts that this would have happened with a better quality disc like the Brembos.
jack07 said:Hi R60,My threepenneth on this is listen to Ducklakeview,as those front lower wishbone bushes may not appear worn and may be entirely passable at m.o.t.but upgrade them to a polybush and this eliminates the horrible braking wander that ruins these great cars.Then when the polybush bug bites,do change the rear trailing arm front bushes next to tighten things up nicely.Don't be put off the Redstuff pads,as mine have been excellent in every way for the last 20 thousand odd miles,plenty of meat still on them and have not carved into the discs as I expected.There is no discernable wear lip at the disc edge yet so I recommend them and will buy again when the time comes.The only negative I found was the bedding in time being rather longer than usual.Good luck with however you go
Thanks for your input buddy.
I will get BMS to check the bushes when I put her in for brake service. But if the problem goes away after the brake service then I will change the bushes when required.