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Discussion Starter #1
Recently had a local very reputable shop swap out brakes lines and flush the system. When I returned to the track yesterday I noticed in left hand turns the dash brake light comes on (not abs light). I checked the fluid level and everything seems fine there.

The bigger problem is my brakes are seizing. I was not able to complete the last 2 sessions as a result. I felt a vibration in turn 9 (Sonoma Raceway) so I pitted to take a look and found nothing. Went back out the next session and it was gone and all was good. All the sudden I felt the same vibration exiting 6 after a few laps. I slowed through the esses with a hand up and by the time I got into the paddock the brakes were dragging enough that I had to fight to get back to my pits. I almost did not make it all the way. After she sits for 20 min it is like it never happened.

Near the end of last year I had felt the same vibration in turn 9 time towards the end of a couple track sessions. I thought I had picked up some debris from the track since it was a hot day but found nothing when I pulled in. I am thinking the new lines have now shown me a problem that I had before - now just worse since the brake lines are not flexing.

I am thinking a bad master cylinder? Not letting the brake fluid back into the reservoir? Not sure about the ABS module or how that might play into things. Final info: 2005 Elise, stocks calipers, CL6 brakes pads, Blackwatch Racing 2 piece rotors and brake lines.

Any thoughts and suggestions?
 

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FYI: The dash brake light can be the alignment of the switch in cap on top of the reservoir.

The rest of your problem - I don't know, but ALL your brakes at once sounds like unrelieved pressure as you've surmised.
 

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I found it on a thread here on Lotustalk. I'll search. I can attest that a 90 degree change can stop the intermittent light. Use Google search as it is faster.
 

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Here is a picture. I didn't clean mine, just rotated the black part of the cap to a different orientation. Of course make sure you have a full reservoir. This won't solve your big problem, though.
 

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Tell me more about the "vibration" - was it in the pedal like ABS or the entire car? Also are you saying that it was hard to get back to the paddock because effectively all the brakes were "on" - meaning pressure to the pads so they were pressing on the rotors?

I've definitely had my light blink during a track day and find that as others have said if I clean the sensor at the tank it clears it up (until it gets dirty again). I've also had my ABS light come on at various times (and confirmed ABS wasn't working) but as I don't want ABS anyway I've never cared. I have had my pedal go hard, ala "ice mode" but I think different from what you describe here.

I too think it's something with pressure in the system, I can't see how lines or calipers would cause this unless you had some physical obstruction somewhere in the system (doubtful to me).
 

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What color is the brake fluid after that track event? If the pads were riding on the rotor too much, as they would be if the hand brake was mis-adjusted, then the fluid will be black and full of bubbles.

Since you didn't mention a soft pedal, I'm going to assume that the problem is that you were going over the temperature limit for the pads and their friction was increasing with the increasing heat and the bad material was fusing to the rotor, causing the vibration and then a sticky feeling.

How do the pads look?

If your sliding surfaces for your pads were sticking, or the front pistons or rear caliper slides, then you should have also had a soft pedal from boiling the fluid.

I had something similar with my brakes, started off fine, then started to groan, then vibrate, and then the friction levels went through the roof, and the pads felt like they were fusing to the rotor. Once they cooled, everything was fine until they got hot again in the next session. Turned out the pad material was too soft and rated for a lower temperature than I was reaching.

A change of pad material, along with proper bedding in, or brake cooling ducts might solve it.
 

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Discussion Starter #10
Thanks uncle sam - I will play around with this and probably clean it as well. As you stated - 2 different problems.

Tell me more about the "vibration" - was it in the pedal like ABS or the entire car? Also are you saying that it was hard to get back to the paddock because effectively all the brakes were "on" - meaning pressure to the pads so they were pressing on the rotors?
The vibration came from the rear of the car, felt exactly like a wheel was out of balance. Nothing in the pedal itself - hind sight tells me it was the rear brakes overheating. When it did it sooner on the track I had the entire system heat up and yes, all 4 brakes were engaged. When I got to the paddock there was so much pressure on the rotors I almost did not make it back to my pits. When I turned the car she stalled and I had to force her to move the last 15 feet with throttle and clutch.

So far someone has suggested front pistons are sticking from brake dust and rear calipers need to be rebuilt. I just installed wavy front pistons - stainless steel I believe - and installed fresh seals at the same time. Rears are still stock.
 

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Discussion Starter #11
Vulcan Grey:

I have not had a chance to check the fluid at the caliper yet. The peddle was never soft. I have had this happen now with 2 different pad compounds, Pagid Blacks, and CL6's. I am not fast enough to over heat the pads although my ego flinches when I admit that ;)

What you are describing is exactly what I am experiencing. Although I would doubt that a stock elise with Toyo 888 with over 6 track days on the tires is capable of that much heat in the brakes when I was not even pushing it. Just bouncing around the track at a nice pace in order to setup my Nitrons to a base line.
 

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Hmm, not to beat a point to death, but are you sure both front and rear brakes were dragging? The reason I ask is there, obviously, could be different root causes for your issue. As far as all four dragging; the first things that come to mind would be- contaminated fluid(should be ok if they were just flushed) or a misadjusted brake pedal pushrod. If it's just the rears, I would want to double check the rear caliper adjustment using the proper procedure per the workshop manual. If the rears are misadjusted or the park brake cable is misadjusted, the rears can drag and overheat to the point that they vibrate and can literally bring the car to a stop. I'm not saying that either of these are your problem, but worth a look.
 

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Discussion Starter #14
realrundell: I do not think you are beating a point to death at all. Just backing up what others have said. After reading your post I am not 100% confident that it is all 4 brakes. Considering the fronts have been rebuilt and what a number of people have said I think I will take apart the caliper and replace the crank the seals and the pins and hardware.
 

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Hey Ziyad ... assume you're running with stock brake setup and have a rear parking brake?

Some suggestions:
1. Pictures of the parking brake adjuster cable
2. Remove the ABS fuse and do some testing, ABS can mask brake problems somewhat
3. Pictures of the rotors (all 4)
4. Rear tire rotation after you set the parking brake and release, excessive friction?
5. It does sound like the rear piston isn't screwing back and/or wasn't screwed back all way when the new pads were installed ... this piston "screws" back it doesn't just push back and it needs to be screwed ALL the way back prior to install of new pads.

It's been a while (3-4 years) since I've had ABS, a rear parking brake, and the rear caliper setup ... so trying to go from memory. But without seeing more, #5 seems to be the issue IMHO.

Cheers, Rob.
 

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Agree with Robains, check the easy obvious stuff first. Especially the rear parking brake mechanism.

Though in my case I have all 4 calipers with 4 pistons, full race Brembos with vented titanium pistons, and fully floating rotors, and no parking brake!

My calipers had also been recently rebuilt with new seals, the pedal stayed firm, and the pads are on loose simple slides that cannot bind, but it still felt like the car was getting difficult to move. Like the brakes were on, and the pads were glued to the rotors.
 
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