Want to upgrade front brakes - help please

[johnmckenzie]

I'm on my 4th set of front discs on my 4.5 and getting a bit ticked off as these are now juddering badly. Looking at the disc surface there are dark patches here and there that look as if pad material may be being deposited. That would explain the juddering as I imagine that the friction co-efficient of the clean surface will be different to that where deposits have taken place leading to "grabbing". I'm using EBC Green Stuff pads.
I suppose I could get them cleaned off by light grinding or a quick skim but I suspect it will just come back again.
Has anyone any experience with alternative discs whilst retaining the standard AP 4 pot calipers (dont want the expense of changing these). I'm thinking particularly of cross drilled and slotted discs in an effort to minimise deposits and keep the heat down a bit more. Any comments would be appreciated.

Regards

John McKenzie

[ByronTVR]

John,
The EBC Green Stuff , are too hard pads and they are 'working' in high temperatures, that's why they worn your brake disks...
Slotted disks are a good upgrade

ByronTVR

>> Edited by ByronTVR on Saturday 30th November 19:04

[DuncanM]

I don't drive a cerbera but Greenstuff are notoriously shyte!

I am surprised that you are running them.

The redstuff are a much better pad or try Mintex 1155's or Ferodo DS2500's.

My friend went through 3 sets of greenstuff before demanding his money back because of problems with them.

They are actually quite a soft compound hence the deposits on your discs.

Duncan

[ro_butler]

John,

I would ring Joolz, the opinions here seem conflicting in nature. I know Joolz was working on some brake upgrades and certainly knows all the issues with them as many of his clients are regular trackday attendees (which is where you will encounter the majority of brake problems such as fade, warping etc.)

Failing that WilliamBall or DannyLT seem to have a fair amount of experience with brakes and can probably share their experience with you.

Good Luck

Rob.

[snap]

John

Have you called Peninsula, they do upgrades for all Tivs I dont know what options are available on a 4.5 but surely some different pads and discs x drilled to get the heat out would be a good start
I run Greenstuff and have found them to be very good but recently chaged to ferodo 2000 which i do find easier on wear

[monkeyjunky]

First step has to be to bin the pads, as has been mentioned Green Stuff has a reputation for eating disks. Jooles would be worth a call as IIRC he is working on some discs (1 inch larger diameter) that retain the same calipers.

I've gone for Mintex 1144's on mine and they are superb both road and track.

[williamball]

Green stuff are not really up to it. Mintex 1144 are certainly better, but Ferodo DS3000 are the best I've tried for track day/road. The DS3000, in theory, shouldn't work too well when cold - ergo the DS2500, and when I fitted the 3000s I was worried I might have gone 'too far' for a pad for the road. Got to report no real problems on cold though. Maybe the first stop of the day on a really cold morning leaves a little to be desired, but overall they work fine, and just get better and better the hotter the brakes get. Packet says 'competition use only' or something of the like, so don't say I said to fit them. Only real downside is that they are seriously noisy - but I actually like that, as it sure clears a way though slower traffic

Mine being a 4.2 I don't have all the same disk options you have, but I saw the Joolz-supplied disks that went on Julian Rowntree's 4.5 [Scotland] and they looked absolutely superb.

Also, if you've got adjustable shox [or just sha66ed springs], make sure the car isn't sitting too low. I didn't realise at first just how important the ride height was in getting airflow to the brakes. My car was running very very low for a while, and although it handled just fine, the brakes were forever cooking. I lifted that car by an inch or so [still lower than standard] and most of the serious overheating problems went.

WB

[beej]

Upgrading the front brakes on a 4.5 is easy - you just fit the vented and crossdrilled version from the Tuscan S - straight swap, and cheaper too. Unless, of course, you already have these fitted and you are looking for even more stopping power?

There is a long thread on this some time back where I related my woes with the factory's intransigence over liability for these discs warping/picking up pad material.

Not sure I follow Byron's comment about Green stuff being too hard? Surely he means too soft?

As for all the recommendations on pad material - the only way to check is try. I don't know if Pagid do a pad for the AP caliper but the Caterham guys absolutely swear by them.

[joospeed]

there's an excellent upgrade for the 4.5 cerbie for half the cost of std TVR fitment. I don't like ferodo pads other than ds3000 for serious track use. Mintex 1144 or 1155 are my faves in the ap caliper. Don't run x-drilled discs cos of cracking issues under hard use. grooved discs are the way to go.
Joolz

[joospeed]

beej said: Upgrading the front brakes on a 4.5 is easy - you just fit the vented and crossdrilled version from the Tuscan S - straight swap, and cheaper too. Unless, of course, you already have these fitted and you are looking for even more stopping power?

There is a long thread on this some time back where I related my woes with the factory's intransigence over liability for these discs warping/picking up pad material.

Not sure I follow Byron's comment about Green stuff being too hard? Surely he means too soft?

As for all the recommendations on pad material - the only way to check is try. I don't know if Pagid do a pad for the AP caliper but the Caterham guys absolutely swear by them.

Don't be fooled into thuinking the tuscan S brakes are an upgrade, they most certainly are not, they crack very quickly and the rotors have vanes which aren't handed so one disc runs hotter than the other, they are very heavy and you can only get them in 322mm diameter. they are cheap but you pretty much get what you pay for here ... only to be considered if you are on a limited budget. there's far better discs to be had.

[ByronTVR]

beej,
the EBC green stuff pad material have Kevlar fibres
1) That's why it is working on higher temperatures,
2) That's why it warns the brake disks faster.

ByronTVR

[beej]

Thanks Joolz. I didn't know that. Must say I haven't had any cracking problems with mine - despite some serious work outs at a track or two but I will definitely keep an eye on things. So are these new alternative discs made by AP?

[johno]

I have driven a 4.2 with Joolz new disks and Green Stuff pads both on track a couple of times and down through France. I must say the new disks were a big improvement over the old ones.

I cannot comment on varying compounds for Cerberra's but I will say the only set of Green Stuff pads I owned I soon got shot off. Crap.

I ran my S on Pagid Fast Road/Track Pads after recomendation from a friend who works for a race/rally supplier. They were superb. I will be changing the Griffith pads to Pagid aswell.

As for DS3000's. I have a friend who runs them on his Wedge (4.3BV & 300 genuine horses), noisy as hell but the stopping power is phenomenal. He also reckons that cold they are up to the job and do not suffer as badly as other softer track day/fast road use pads he has used.

[johnmckenzie]

Thanks for all replies so far. Latest update on the brakes - any ideas anybody??. The problem with judder has only ever occured with heat in them. When cold they work cleanly with no judder. As soon as they are warmed up a little the judder is pretty bad and gets worse the hotter they are.
I took off the discs, cleaned off the slight traces of pad material (only a micron or so)and mounted them on a platern. Then set up a dial gauge and measured the cold run-out - bu**er all!!. Discs then heated slowly in an oven to 300 degrees C and run out measured again. Aha - two high spots appear on one and three on the other - all around 4 thou!.
Methinks the problem has nothing to do with pads at all!!!!!. Disks are warping when they get hot.
I seem to remember a thread a long time ago discussing warping that pointed to a web-site where a "learned" gentleman said that disks rarely (if ever) warp other causes should be sought for judder! - obviously not so learned after all!
So, any ideas peeps? - Do I consign these disks to the bin (along with 3 previous sets) or can I do something to salvage them? There is very, very little wear on them (only 9000 miles old many of which were motorway miles), no wear grooves and visually are in great shape. I wondered if grinding them would help - or what about hot grinding? Can that be done - the theory being that if the high spots can be made to appear at somewhere around operating temperature then these could be ground off. Of course, that could give a reverse problem of cold judder but that would be easy to live with.
Help!!!!!

Regards

John

[williamball]

You have fairly common Cerbera brake symptoms. I also disputed the 'disks don't warp' theory on previous threads, as I have had mine measure initially with no runount, and with 8tho [I think] after a track day. I had then skimmed and they've lasted quite a few thousand miles since, but the are starting to go again after the last track session. Skimming the disks is pretty cheep [at least mine were], so its worth a go.

There is a previous thread where I mentioned the costs etc. A few months ago now, and the old grey cells aren't up to remembering much else.

WB

[beej]

Guilty. It was me that started (at least one of) the other threads(s) about discs warping.. the vanes pointing the wrong way etc etc. The Carroll Smith's (is that his name?) article made very interesting reading and his arguments were compelling but despite following the bedding in advice I am back to the same problem again after just 3000 miles.

Exactly as you describe - acceptable when cold, juddering as soon as the discs warm up - and if it follows last time's form, it will just get worse and worse. Haven't measured the run out this time but last time it was 4thou on one disc and 3thou on the other. Enough to be really annoying.

Are we doomed to a life of skimming every 3k miles?