Mk1: Trackdays and warped front brake disks - fact of life ?

[BenF]

I've just bought another set of front brake disks for my Trackday Mk1 in preparation for Elvington in a few weeks time. This will be the third set I've had for the car, after about six or seven trackdays.

Which got me thinking - has anyone found any solutions to preventing teh front brake disks warping on a Mk1?

For reference, I've got a Mk1a which I've fitted Mk1b brakes and disks to after I warped the MK1a disks. Its had new front balljoints and the wheels are always torqued up with a torque wrench.

I've also cut away the shroud at the back of the disk to help improve airflow. I'm using standard MrT brake pads as suitable for a MK1a (but they also fit the MK1b calipers)

One thing - I did have a chat with my local MrT and it appears they have three different part numbers (ie pads) for different years of Mk1 - I'm wondering if MrT was experimenting with different friction compounds to reduce warping?

[Icsunonove]

Ben,

All I can say is I've got Black Diamond discs all round (drilled and grooved discs on the front and grooved only on the rear). They seem to handle trackdays really well. Are yours standard?

Tom

[Lauren]

Ben,

All I can say is I've got Black Diamond discs all round (drilled and grooved discs on the front and grooved only on the rear). They seem to handle trackdays really well. Are yours standard?

Tom

Ben's are standard, yes.

How many trackdays have you done in yours though Tom?

I'm getting vibration from mine after the Ring under braking, though i'm not overly worried about it as its easy to drive round it at trackdays. Sometimes the vibration can ease off once you get the brakes up to temp.

Stock discs are only around £50ish per pair so cheap enough to replace as consumables if needed.

[Icsunonove]

Good point Lauren (it's only 3 I think) 2 Angelsey and 1 Cadwell

[BenF]

Hmm, the brakes at the moment are grooved Black Diamond efforts, and I've just placed an order with Brakes International for another pair of standard disks - they're not expensive at £55ish a set, but I was just wondering if I was missing a trick

The brakes do get hard use on trackdays, but I'm not a manic late-braker - I've been tending to brake a little earlier and more gently to protect the disks.

Doing Anglesey I had no problems at all, but it is a circuit which isn't too bad on brakes. Donnington had a few big stops on the circuit and half way through the day there the brakes were vibrating.

I've been using the car on the road, and for 'normal' driving they're fine - its only when you push on and get the discs hot that you notice the vibration when you're braking hard.

Are there any Mk1 Challenge regulars out there that have any advice ?

[kaiowas]

There's always Paul Woods big brakes conversion to consider as an alternative...

http://www.mr2mk1club.com/Bigbrakes.html

[lodgeman]

the st 165/185 277 vented disc and caliper either single or twin fit the mk1 without having to do any mods- all you have to do is drill some holes in the discs for correct pcd

[Speedy]

big brakes conversion

Bah, you'll just end up overbreaking the car, much too much stopping power for the weight and engine power

The slug was ok after swapping out the front disks after the tumble-dryer-on-heavy-spin which was donington park, haven't had any trouble with them since (was fine at Mallory Park, was fine at Bruntingthorpe), make sure that all the calipers are nice 'n free, and just warm them up and down gently. Might want to check the rears are free and easy, so that the fronts aren't doing too much work?

Usual rules apply (just incase any trackday novice is reading), try not to use the brakes on a warm down lap - and really do a warm down lap, use the engine to slow the car down in the pits/paddock and leave it in gear with the handbrake off (or use the chock, if you've got one).

<afterthought>
I wonder if it's something to do with original suspension components aggrevating the situation...
</afterthought>

[DoM]

Hi Ben,

It's a pain isn't it! I've had the same problem with all my MK1's and now with the Teg! I was begining to think it was just my driving style!

I found the SC worked best with standard disks and pads, the black diamond disks & pagid pads I had on the N/A were the worst - the steering wheel used to vibrate like crazy. It's true that you can drive through it, it's just really disconcerting when the steering wheel is bouncing up and down in front of you!

Have you tried removing the dust shields or adding some cooling ducts? I don't know if this would have any effect, I guess it might help a little.

I haven't heard of anyone who's managed to cure this on a MK1, though Lauren's seemed pretty good in Germany. It would be interesting to hear what set up the MK1 challenge cars use.

Dom

[Mk1 Turbo Powered Steve]

Hi Ben,

It's a pain isn't it! I've had the same problem with all my MK1's and now with the Teg! I was begining to think it was just my driving style!

I found the SC worked best with standard disks and pads, the black diamond disks & pagid pads I had on the N/A were the worst - the steering wheel used to vibrate like crazy. It's true that you can drive through it, it's just really disconcerting when the steering wheel is bouncing up and down in front of you!

Have you tried removing the dust shields or adding some cooling ducts? I don't know if this would have any effect, I guess it might help a little.

I haven't heard of anyone who's managed to cure this on a MK1, though Lauren's seemed pretty good in Germany. It would be interesting to hear what set up the MK1 challenge cars use.

Dom

I must admit that my sc judders,under hard braking.It doesn't worry me!
Haven't a clue what's
on there as thay are still the ones that came with the car when it was imported.
You get used to it but there again mine hasn't been on the track since i have owned it.

[superchargedsam]

Just go big brakes on the front and learn to use them properly as I dont know why people are so opposed to them, sure the wieght of the car is biast to the rear but in a straighline (and lets face it your never gonna brake in a MK1 hard when off line as it aint gonna help you) all the wieght is transferred forward so let the brakes and suspension do the work then back on the gas to drive the corner. I have a bike that weights in at a shade under 200kilos and will pull between 170 and 185 real speed (not what the speedo tells you) and this runs twin 320mm discs with 6 pot calipers on each disc, now I am fully aware you cant normally compare a bike to a car but in this case a fairly similar layout as the engine is well behind the front contact point although not as far away as the MR and again you dont really wanna be hangin on the brakes around the corner as u really need to scrub the speed well before shifting the weight of the bike or your gonna lose the front end just like in the MR. By going large brakes on the front for track use you can use these to your advantage by being able to brake very very hard and then back on the power quickly while the large discs allow the heat built up to disapate better, if you had this set up and were really worried about overbraking the front then buy a 2 way bias valve form any decent motorsport place then work out how to plumb it in so you can shift some bias to the back and this can in most cases be done on the fly so as you learn the track you know where it is and isnt needed. Large brakes on the front are never going to be an overkill if used correctly and if your suspension and all relavant parts are up to the job and your tires can also cope. It many cases its worth investing in your brakes over engine mods as braking later can be more benificial and a cheaper way of getting lap times down as an engine mod to give you the same efffect coming out of a bend could be 10x the cost of the brake upgrade in some cases. Anyway these are my opinions as this is how I see it and having upgraded front brakes on most vehicles I have owned I have never found you can overbrake especially in a straight line and the only time I have warped discs is on my GT4 after a very hard thrash across the cotswolds and the GT4 is a very heavy beast anyway and it can brake easily mid corner and with the four wheel drive you can soon be back on the power to compensate any problems the brakes have caused. Another option is discs from Godspeed who make his own ones up to your spec and he did some for my NA and they were amazing and were cross drilled and grooved and never ever had any fade or any vibrations issues. The first thing to do is get some decent braided lines on there to help as u will be suprised how spongy the original lines can be especially if very old and then replace with some DOT 5 fluid as well. Also learn to do some cadance braking as this can allow you to brake just as hard while keeping temps down and reducing the risk of lock up. Everyone will have thier own opinion on braking and how it can be done and what you can and cant do but try as many options as you can and see what suits you as everyone will approach it differently, my stlye is very heavy late braking which is why large brakes suit me as I can hang on them hard then come off them completely, others may use a gradual braking approach or full on cadance braking so the options are vast and you will need to find what suits your stlye.

[Blokey]

...are you sure it's brake disk warping...? I know it's an old thing to say but they're big lumps of metal - are you sure they're warped...?

I've had a few times when I feel steering wheel wobble/brake pedal vibration that's in time with the wheels turning while braking on track days. I replaced the pads and this went.

The vibration I describe above was only there when the disks were hot - once they cooled down (even between sessions) they were fine again until I heated them up. Different pads and this went away.

Could it be part of the disk becomes more sticky than the rest when it's hot so the brakes grab more when that part of the disk passes the pad - so it feels like the disk is warping but it's actually fine....?

It would be interesting to get a run-out dial, take the car out on track and blatt it then bring it in and look for run-out.

I would wonder if it's worth considering the vibration may be from braking efficiency changing between different parts of the disk...? Perhaps something that's minor when it's cold becomes major when it's hot?

Could it even be the grain of the metal in the disks....? http://www.metal-mart.com/Dictionary/dictletg.htm#I7


B.

Edit: Correct my carp spelling.

[Speedy]

Could it be part of the disk becomes more sticky than the rest when it's hot so the brakes grab more when that part of the disk passes the pad - so it feels like the disk is warping but it's actually fine....?

Or the calipers aren't properly releasing due to the (non)sliding pins?

[BenF]

big brakes conversion

Bah, you'll just end up overbreaking the car, much too much stopping power for the weight and engine power

The slug was ok after swapping out the front disks after the tumble-dryer-on-heavy-spin which was donington park, haven't had any trouble with them since (was fine at Mallory Park, was fine at Bruntingthorpe), make sure that all the calipers are nice 'n free, and just warm them up and down gently. Might want to check the rears are free and easy, so that the fronts aren't doing too much work?
<afterthought>
I wonder if it's something to do with original suspension components aggrevating the situation...
</afterthought>

Ta - I've spent some time checking all the brakes on the car, and the rear disks and pads were also done at the same time that I did the front Mk1b brake conversion - all the sliding pins etc were checked/ regreased, and were in good order.

Suspension - yes, hands up its the original 20 year old stuff as far as I can tell, and one of the shocks is a little rattly but still works fine - but I can't see how that would relate to warped disks? FWIW, the car also has had an aligment after I did the steering rack end balljoints and the lower front balljoints.

I'm not sure if that info helps though !

[BenF]

Hi Ben,

It's a pain isn't it! I've had the same problem with all my MK1's and now with the Teg! I was begining to think it was just my driving style!

I found the SC worked best with standard disks and pads, the black diamond disks & pagid pads I had on the N/A were the worst - the steering wheel used to vibrate like crazy. It's true that you can drive through it, it's just really disconcerting when the steering wheel is bouncing up and down in front of you!

Have you tried removing the dust shields or adding some cooling ducts? I don't know if this would have any effect, I guess it might help a little.

I haven't heard of anyone who's managed to cure this on a MK1, though Lauren's seemed pretty good in Germany. It would be interesting to hear what set up the MK1 challenge cars use.

Dom

I must admit that my sc judders,under hard braking.It doesn't worry me!
Haven't a clue what's
on there as thay are still the ones that came with the car when it was imported.
You get used to it but there again mine hasn't been on the track since i have owned it.

Juddering - there's none on the road for 'commuting' driving, its only when you're working the brakes hard doing backroads that you notice it.

For trackdays, you can brake through it, but it is a bit distracting and probably worst of all taking away the steering 'feel' as you're turning in.

I'm currently tempted to try some late Mk1b pads from MrT to use with my brake disks that turned up yesterday from Brakes International, and see if MrT sorted the problem.

[Speedy]

I was thinking more along the lines of tired components unable to restrict the vibration in the same way as newer (or firmer) suspension parts..

Can't do the front wheel bearings any good anyway.

[BenF]

It would be interesting to get a run-out dial, take the car out on track and blatt it then bring it in and look for run-out.

I would wonder if it's worth considering the vibration may be from braking efficiency changing between different parts of the disk...? Perhaps something that's minor when it's cold becomes major when it's hot?

Hmm, I'm tempted to get a run-out dial, just as another gadget to have in my toolbox

I've got the previous sets of disks to hand so it wouldn't be difficult to check them.

I know other cars also suffer from warped front disks (eg Modern Evos) so it looks to be a generic thing - but all credit to MrT, the Mk2 and Roadster don't seem to suffer from warped disks on track.

[Icsunonove]

Ben, I can supply you with templates to get an accurate picture of the warp on the disc if you want. See below:





It turned out to be my hub that was bent, here's how I fixed it:



Tom

[MartG]

Anyone tried these disks ?

http://cgi.ebay.co.uk/Cross-Drilled-Mk1 ... dZViewItem

[DoM]

I don't know if it is actually the disks warping, or just the excessive heat causing something to wobble (Thats about a technical as I get).

I had it first on a MK1 N/A, changed the disks/pads/brake fluid - made sure I bedded them in properly and still had the same problem. Tried pagid pads & grooved disks, again the same problem!

Changed the car to MK1 SC, the same problem again!

Changed my car to the ITR, still the same bloody problem!!

I've just changed disks, pads and brakefluid to a reccomended set up - no confidence in it curing the problem!

I could live with having a bit of brake fade, but these vibrations drive me nuts!

Dom