Anybody With The Brembo Setup; New Pads & Judder

[Loose Cannon]

Getting the car ready for the MOT I decided to fit some Ferodo DS2500 pads, partly because of good reports on the forums and partly because they are deemed to be fairly abrasive and might cheaply cure the brake judder that has been slowly getting worse (this has been a problem that has cropped up 2 or 3 times in the last few years, usually cured by some prolonged maniac braking but not this time).

On checking one of the discs the inner face seems to have faired quite poorly (only 4/5 surface area working, and a strange ridge in the middle of the face) whereas the outer face is fine. I have only looked at the drivers side side so far but shining a torch under to the other side the story looks the same.

Now I have seen this sort of thing before, where one face seems to be doing more work than the other, but usually on cars with sliding calipers. All 4 pistons slide in and out smoothly, and the little stainless steel guides are smooth with no corrosion visible underneath them.

One strange thing I noticed is that the disc looks very slightly offset within the caliper - this can't be normal can it? As far as I know the previous owners (including a certain Mr Baird) all had problems with judder and had at least the discs replaced, not sure about the calipers. Is there a chance they have been reassembled badly? The service note s don't show one but could there be a shim missing or something?

[Paul17764]

Getting the car ready for the MOT I decided to fit some Ferodo DS2500 pads, partly because of good reports on the forums and partly because they are deemed to be fairly abrasive and might cheaply cure the brake judder that has been slowly getting worse (this has been a problem that has cropped up 2 or 3 times in the last few years, usually cured by some prolonged maniac braking but not this time).

On checking one of the discs the inner face seems to have faired quite poorly (only 4/5 surface area working, and a strange ridge in the middle of the face) whereas the outer face is fine. I have only looked at the drivers side side so far but shining a torch under to the other side the story looks the same.

Now I have seen this sort of thing before, where one face seems to be doing more work than the other, but usually on cars with sliding calipers. All 4 pistons slide in and out smoothly, and the little stainless steel guides are smooth with no corrosion visible underneath them.

One strange thing I noticed is that the disc looks very slightly offset within the caliper - this can't be normal can it? As far as I know the previous owners (including a certain Mr Baird) all had problems with judder and had at least the discs replaced, not sure about the calipers. Is there a chance they have been reassembled badly? The service note s don't show one but could there be a shim missing or something?

Hi Mark, Cant Help with the problem but mine are exactly the same on my GT3, Noticed this today when getting ready for the MOT on Thursday. They were all renewed about 3000miles ago by the previous owner on the C service. Brakes have been fine, No Judder. Will see what thursday brings on the brake test. Regards Paul

[superdavelotus]

Silly question Mark, but have you tried spinning the disc without the wheel on to see if the is any buckle? It may be very slight so you may need a gauage to measure it.

I think you need to scim or at least flatten the rust off those discs.

If you can't be bothered then PNM and SJ do replacement discs for about

[wiseraven]

Persistent judder is often caused when the disks are fitted without checking the runout so they wobble slightly as the wheel is rotating. Once driven like this, the disks get hotspots and distort, so it ends up worse. If this is what's happened in your case, your only option is replacing the disks, because the localised heating has changed the microstructure of the disk.

I don't know what the specs are for the Brembo setup, but the maximum runout for the Toyotas is 6 thou at the front and 8 thou at the rear.

The manual has this to say:

Check the braking surface on both sides of the brake disk for scoring or corrosion. Replace if in doubt.

[Jonathan]

Also check the pads can move freely in and out :

http://www.lotusespritworld.com/EGuides/EM...rakeRefurb.html

This was a problem with mine, the in and underneath the wear strips they had furred up and caused the shims to buckle.

I took the shims off and 'lapped' them flat again and went to work on the caliper. I've had the brakes off again just this week and the pads slide around in there beautifully - runs like silk.

If it were mine I'd buy new disks, even the EBC ones are not that dear and they are fine if you ask me - take the whole lot off and got to sleep with it for a few nights until it was all nice and shiney again and put it back together with some TLC and enuf copper grease on the moving parts. It's clear the disks haven't been swept propperly - as someone mentioned they might need to be clocked to see if they are running true (usually shit under the bell / hat getting inbetween the diska nd the hub face).

If you fit the pads and the disk is up the swanny then you're gonna muck the pads up....then when you fit new disks you'll muck the disks up and so on. If you have issue - it's best to replace the lot and start from new..........imo.

[DanR]

Persistent judder is often caused when the disks are fitted without checking the runout so they wobble slightly as the wheel is rotating. Once driven like this, the disks get hotspots and distort, so it ends up worse. If this is what's happened in your case, your only option is replacing the disks, because the localised heating has changed the microstructure of the disk.

With hotspots and before buying new discs you could try this:

Find a quiet area and complete about 10 savage stops from 60-80kph to zero. If you get the discs glowing that's better. Then let them cool off naturally with only gentle braking for the next 30 minutes.

Doesn't always work but worth trying. Check runout and bearing play before doing this too.

[Loose Cannon]

At least it's not the only car affected! I will get hold of a guage tomorrow and check for runout. The discs have been skimmed once already (yeh yeh I know it's not ideal but there's always family stuff comes first) so any sign of trouble in that way and they'll have to be binned. I think I'll go with the EBC replacements but it's gonna hurt (currently also facing huge cambelt service on the missus' Alfa!)

The only thing that stops the inner pad sliding in smoothly is this unequal gap between the disc and the inside of the caliper - the outer pad has loads of room, I'll try to measure the difference tomorrow but it's way more than rust or crud buildup could cause.

Find a quiet area and complete about 10 savage stops from 60-80kph to zero. If you get the discs glowing that's better. Then let them cool off naturally with only gentle braking for the next 30 minutes.

I tried this as it has worked in the past, but not this time. I did so many emergency stops I felt physically ill like an astronaut on re-entry, and had to lie down for a bit! At least it proved the ABS worked 100%!

[Jonathan]

To be fair the inside pistons are still out a little bit, however there should be equal distance between the pads and the disk - when I checked mine not just this weekend they were perfectly symetrical, so what you're describing isn't ideal.

I wonder if the lathe was not set up correctly as well. I personally wouldn't turn disks but those who have would need to set the lathe up very accuratly to get the cut right - any small misalignment and it'll be out, then it'll thow the pads out and so on and so forth.

Just go without food for a week or something - beans and white bread for a month for the kids or something....it'll be worth it in the long run !

[superdavelotus]

Mark,

If cost is an issue then why go for EBC when you can get patten ones from SJ or PNM for

[Loose Cannon]

Mark,

If cost is an issue then why go for EBC when you can get patten ones from SJ or PNM for

[Glyn Harper]

My new PNM discs and bells seem to run slightly untrue, but they don't judder when I brake.. but they're brand new with new discs.. and even new hubs!

Anything I can do about this?

[superdavelotus]

Speak to Pete bout this and see what he says

My new PNM discs and bells seem to run slightly untrue, but they don't judder when I brake.. but they're brand new with new discs.. and even new hubs!

Anything I can do about this?

Hi Mark,

I think an appology is in order, I am sorry that I misled you, I didn't realise that everyone has put their prices up on discs. Found out that it's the manufacturer that is doing this. Even Sj have put theirs up to

[Loose Cannon]

Dave

It's wierd, I priced all this stuff up last year but never got around to it due to family circumstances (illness, death, you name it). Since then everythings gone up by about 20%!!

[Dave Ledwitch]

Hi Mark.

Sorting Brake Judder was the first thing i did when i got my GT3. it was awful. I found a local engineering firm that had a setup for refacing disks, cuttin both sides at the same time. Cost me

[Loose Cannon]

Hi Dave

Not wanting to regrind a second time I plonked some new EBC plain discs on; sorted. The Ferodo DS 2500 pads seem pretty good so far although not the quantum leap I was hoping from the regular street Ferodos fitted before; maybe that will change as they bed in??

Yes the allen-headed disc retaining screws were a nightmare last time and got really chewed up, so I bought some new ones from the Lotus dealer but found they were the wrong parts! I cut a slot in them to use a large screwdriver next time.

I am sure all these problems are caused by lack of use. From now on whenever it goes out I'll try and remember to include a bit of sustained heavy braking regardless. Looking at the rear discs and it's the same story. They have never been ground so I'll get them done and slap on the new pads that have been sitting on the shelf since last year. No doubt the rear wheels will come off the same way as the fronts with a block of wood an a mash hammer - turns out the mechanic who had it last year cleaned off all the copperslip and tightened the wheelnuts to the point of rounding!

[superdavelotus]

Glad you got your car sorted in the end. Are you going to use EBC for rears too? Makes sense I suppose...

[Loose Cannon]

I haven't seen any listings for the rear discs, EBC or otherwise. Probably just get them cleaned up. The car sailed through the MOT today but the rear brakes performance was the only thing that was marginal. Again not a hard job, just need to find some time after the 'sprit has finished filling in for the family shopping trolley.

Front brakes are getting better all the time BTW:-)

[Jonathan]

SJ or SW Lotus do the rears - I've got them on both cars.

As long as the system is maintained and cleaned (as per service intervals) there shouldn't be a prob, you shouldn't have to stuff the brakes in at all to keep them going.

I've had my EBCs on for 2 years now, I hardly ever brake hard (if you read the road you dont need to brake much) and they're fine, hardly any wear on them.

The only negative thing about them is the lack of surface area means a stronger pedal - I doubt the slots / dimples really do much on the road other than look nice.