Hi Guys, would really appreciate any thoughts. I have had issues with my front disks getting damn hot under heavy braking and that the peddle goes high / stiff, picks up a vibration, get a rumbling sound and just feels wrong.For example when playing up you cant lock it up even with full pressure from ones foot. Let the car cool for a little while and all is well again. The garage is stuggling to fix it as so far i have had two sets of pads and disks (different manufacturers)dot 5 fluid put in so it is not the obvious things. I am not loosing any fluid so i guess there is no air getting in. All started after a service!!! Wish i had not bothered…
Here is a shot in the dark:
The arm between the pedal and the master cylinder needs to be adjusted, you need to ensure that the master cylinder is able to return completely with 1 or 2mm of free play. I had this problem before and it took me a while to get to this cause. The system builds up pressure over time and eventually becomes so stiff that you can’t move the pedal.
There is a tiny allen key on the trunnion which you lossen and then turn the rod with a 10mm spanner, perhaps use some whiteout as a reference on the rod so that you can see you are adjusting in the correct direction. you will need to move the rod towards the pedal, i.e. into the trunnion.
Hope this helps, you might find that you need to adjust your throttle pedal for heel toeing again if this is the problem.
Jay,
What type of pads are you running?
The fact that you say your pedal gets high/stiff when things get hot (lets keep our minds out of the gutter now ) sounds a bit strange to me indeed.
The juddering certainly sounds like a pad problem but the pedal feel sounds like doggy fluid or a master cylinder problem.
Was is DOT5 fluid or DOT5.1 fluid that was used? DOT5 is silicon based and will not absorb water which is bad for you brake components, it is mainly used in show cars that don�t want to risk getting fluid on the paint.
It was 5.1 fluid, i have had both Green pads and genuine Lotus motorsport pads. I know neither are the best but they were fitted at no cost to see if this was the problem. It is definatelty heat related and if i keep my left foot on the brake gently whilst driving (naughty i know, but simulates the fault nicely and safely) but this can get the peddle shuddering within a few hundred yards. leave it for a few minutes all perfect
What you describe is typical of a disk (or disks) warping under heat.
If you have just uneve depositions the brake pedal would be juddering always, since it only happens when it’s hot, it’s the disks that are changing shape (warping) and then returning to the proper shape when cold.
The only way to get rid of this is to change them.
I understand that you’ve changed them twice, but you’ll just have to change them again. Many times the casting is wrong (uneven thickness) from new.
It happened to me, when I bought the car (new) within 2K miles I had 3 sets of disks and pads (yes MS like you say) and it was always the same.
They told me that if I changed to different disks the warranty would be void, but I had no option. Useless brakes with warranty? or good brakes without warranty? no brainer for me.
Mind you, I was not happy with the Hi-Spec disks that I got initially, sent them back to Hi -Spec and they sent another couple that (finally) were Ok.
BTW, don’t use Green Stuff, they are the ones that run the hottest, due to the resins they use.
Pagid RS4-2 are a safe bet.
Thanks for the help, the anoying thing is that although my origional disks were shot to pieces they never suffered form this problem. The issue only started with new disks so this would appear logical just makes you doubt yourself when you change disks and pads yet still retain the fault. Just have to drive slower!!!. Oh by the way should i be able to actually perform 3 or 4 emergency stops from 100mph or is this an unfair test?. Still get the problem under normal driving but this really shows the fault if you know what i mean.
Yes, I know.
Stopping 4 times from 100 mph is not asking more from the brakes than say, 10 laps at a track. So no, it’s not unfair.
Better disks will be the solution, you’ll see.
Yes, I know.
Stopping 4 times from 100 mph is not asking more from the brakes than say, 10 laps at a track. So no, it’s not unfair.
Better disks will be the solution, you’ll see.
But 3-4 emergency stops from 100 on fresh (non-heat cycled ) disks may be.
You may want to take it easy on the new iron once installed. Brake discs must be properly cycled to avoid warping.
Many many thanks boys, all appreciated and i now know i am not going mad!!!.
Any advise as to the best afterkmarket disks or are the AP racing lotus disks ok?
Who puts this site togoether anyway as it is god damn fantastic!!! All credit to those involved.
I had similar symptoms just after a brake service. The discs and pads were changed for new OE items and the problem occoured. I checked everything except the new items fitted as it seemed logical that because they were new it couldn’t be them !!!
The problem was the new discs fitted were warped, changed them and all was OK again. So i’d agree with Uldis that this is your first thing to check…
Yes, I know.
Stopping 4 times from 100 mph is not asking more from the brakes than say, 10 laps at a track. So no, it’s not unfair.
Better disks will be the solution, you’ll see.
4 stops from 100mph is 1 lap at the brake killer Hockenheim!
even the AP 295s could not take that in my S
I reckon its the 4 pots and 308mm discs from Lotus Motorsport for me next spring…
You need proper cooling.
or higher corner speeds