[Callsign_Vega]

I've noticed in my car in sig that there seems to be a good 1 inch + of pedal movement before any real braking happens. This leads to my big feat sometimes also pressing the accelerator pedal at the same time I am braking. Is it possible to adjust the system so that more brake pressure is exerted closer to initial pedal pressure?

 

[forkmeupscotty]

1"+ of dead zone in your brakes??? That's not supposed to happen..???
... bleed the brakes....?


Usually, people put pedals covers to put gas pedal _closer_ to the brake pedal (for easier heel and toe), but maybe you can use it to get them farther apart since they are adjustable.
The brake pedal height can be adjusted at the pedal box by adjusting the brake pushrod length... but I don't think you're asking for that..

 

[realrundell]

My car has had a similar issue since I bought it in '08. I have bled the brakes, checked for pad knockback and have even modified the system with front calipers on the rear(not for that issue) and the pedal has remained consistent. There is a bit of take up before any braking occurs, although on mine it puts the brake pedal just right for heel/toe. The only thing I can figure is that the brake pedal pushrod ajustment is off. If I remember correctly, there are some quite old threads addressing this adjustment. I haven't bothered to change mine because I like the the level of engagement for my tastes.

 

[Callsign_Vega]

Ya, I will have to look into maybe this adjustment. I just bled the brakes, and had no air bubbles etc. Could there be air in the ABS system from maybe a previous owner that doesn't come out? I remember reading something about a scan tool needing to be used for the computer to do something to the ABS module to get air out.

I wouldn't say that first inch is completely dead, it starts to brake lightly but any real brake pressure doesn't happen until the brake pedal is pretty much even with the throttle. The car does have a AP Racing BBK on all four corners, not sure if that has anything to do with it. (Higher volume?) I would just love the brakes to engage a bit earlier in travel and be more precise.

 

[realrundell]

It is possible that there is air in the ABS HCU, but the pedal would be more likely to have a soft/mushy feel. It is interesting that you have the AP BBK on all fours. There may very well be a master cylinder issue with the increased caliper volume. If the pedal is consistent and firm, but just has an unacceptable amount of take up, I'd be inclined to think that you do not have an air issue. You may want to research the possibilty of a master cylinder with a larger psiton to match your BBK kit. I don't have any personal experience with that particular setup. An substantial increase in caliper piston area can most definitely contribute to a long pedal stroke.

 

[realrundell]

Just thought of something else...(I'm a little slow, age you know), double check that none of the brake pads have any substantial taper wear. That causes pad knock back every time you let up on the pedal and will increase the pedal stroke as well. That's just one reason to never allow pads on a track car to wear beyond half way.

 

[Callsign_Vega]

Ya, the car does stop extremely quick with that 4-point BBK and 888's with a constant road contact patch. Just seems like the major gripping is at the very bottom of the brake pedal and comes all at once. I guess it's hard for me to tell if there is air somewhere, as I have not driven another S2 to compare it with to see if it feels "mushy" or if its normal. The braking pressure between top and bottom definitely isn't linear, although I don't think most cars are.

I just painted the calipers so I had the pads out, they looked good and symmetrical without any obvious tapering. If there was air in the ABS, is there any way of fixing that at home? I don't exactly have a Lotus scan tool or dealer anywhere near me to pop into to do that ABS air bleed procedure (if there is such a thing)...

If the BBK required a larger master cylinder, I would hope I would have found some info but couldn't find any info as to one being recommended.

 

[Callsign_Vega]

I just did a test with the car off. At rest, the brake pedal appears to be about 1.5" or so extended out from the throttle. Pumping up the brake with the car off and when the pedal becomes "firm", with a decent amount of pressure the pedal goes to about even with the throttle pedal.

Could anyone with a S2 do the same thing and see how much the pedal travels on theirs before it gets real firm? I think that may rule out under-sized master cylinder and should only indicate an air problem if other peoples brake pedals don't move as far.

 

[RichardNHCooper]

A while ago I put my old front calipers on the rear but soon removed them as the pedal travel was too long with the 4 pots up front.
This may be an option.
Simply Sports Cars -Lotus Big Brakes master cylinder- Lotus

 

[Callsign_Vega]

Hm, interesting. I have this 4 piston caliper kit on all four:

AP Racing 4 Corner Big Brake Kit for the Lotus Elise and Exige

Sounds like my "long" pedal could be simply due to an undersized stock master cylinder then eh?


EDIT: plus each of my calipers have inside and outside bleeders, so I shouldn't need to do the flip caliper upside-down to get rid of air trick eh?

 

[realrundell]

Ok, just came in from the garage. With all vacuum depleted from the booster, my brake pedal stops just about even with the throttle. The pedal at rest is about the same measurement as yours. It sounds like the pedal in my car is pretty much the same. Having said that (just to confuse matters), I have driven other Elise's that have a pedal that is right at the top. Once again this brings me back to the pedal pushrod adjustment.

 

[oldmansan]

Hm, interesting. I have this 4 piston caliper kit on all four:

AP Racing 4 Corner Big Brake Kit for the Lotus Elise and Exige

Sounds like my "long" pedal could be simply due to an undersized stock master cylinder then eh?

No. I have the same BBK and they engage very quickly (stock master cylinder). When transitioning from another toy to my Lotus sometimes I grab a bit too much brake and the results are instant. Sounds like your brakes weren't installed correctly or you need to bleed them properly.

EDIT: plus each of my calipers have inside and outside bleeders, so I shouldn't need to do the flip caliper upside-down to get rid of air trick eh?

Calipers with inside and outside bleeders don't need any special treatment other than proper bleeding. This is basic stuff. Anyone telling you to do the "flip caliper upside-down to get rid of air trick" is just screwing with you. After that do you they tell you to go hunt a snipe?

San

 

[Callsign_Vega]

Ok, just came in from the garage. With all vacuum depleted from the booster, my brake pedal stops just about even with the throttle. The pedal at rest is about the same measurement as yours. It sounds like the pedal in my car is pretty much the same. Having said that (just to confuse matters), I have driven other Elise's that have a pedal that is right at the top. Once again this brings me back to the pedal pushrod adjustment.

Hm, interesting. So sounds like I don't have a trapped air problem then.

No. I have the same BBK and they engage very quickly (stock master cylinder). When transitioning from another toy to my Lotus sometimes I grab a bit too much brake and the results are instant. Sounds like your brakes weren't installed correctly or you need to bleed them properly.

When you mean "engage very quickly", how much do you have to push down on the pedal to get 100% clamping force and the pedal doesn't move further?"

As for bleeding the brakes properly, I use a Motive pressure bleeder, did the clutch first, then the calipers, all with the new fluid coming out and no air bubbles. Not sure what else could be done...

 

[oldmansan]

When you mean "engage very quickly", how much do you have to push down on the pedal to get 100% clamping force and the pedal doesn't move further?"

As for bleeding the brakes properly, I use a Motul pressure bleeder, did the clutch first, then the calipers, all with the new fluid coming out and no air bubbles. Not sure what else could be done...

I met a friend at a canyon road. I offered to let him drive my Lotus Exige S. I warned him about the brakes being touchy. He touched the brakes nearly sending us through the windshield and proceeded to kill the car. He immediately decided he didn't want to drive the car. They were that touchy.

As I said already, when I transition from another toy to the Lotus I find that the brakes are extremely sensitive and engage quickly. Having too much pedal travel has never been an issue.

I had my brakes installed by professionals that are very meticulous, VSA Motorsports. Allen is very good.

The fact you were even entertaining flipping your calipers upside down to bleed air tells me you aren't qualified to bleed brakes. I have to wonder what else you may have missed. I'm honestly trying to be nice.

San

 

[holmz]

Narrow shoes are also worth a mention here.

 

[Callsign_Vega]

I had my brakes installed by professionals that are very meticulous, VSA Motorsports. Allen is very good.

The fact you were even entertaining flipping your calipers upside down to bleed air tells me you aren't qualified to bleed brakes. I have to wonder what else you may have missed. I'm honestly trying to be nice.

I only mentioned flipping the calipers upside down as that is posted all over brake threads in this forum. It may make sense for the OEM calipers, but not for the AP Racing ones that have dual bleeders per caliper. Also, realrundell seems to have almost exactly the same amount of take-up on the pedal as mine. One mans "touchy" is another mans "spongy". Completely subjective. My car stops so fast that it could "send you through the windshield" too, just with more pedal travel than I would like.

Not sure what is up with the attitude. I've been working on/building cars for 20+ years, just because my brakes have more travel than I would like doesn't mean the brakes weren't bled right. It's also hard to take advice from someone who had to have a shop install something as easy as a BBK and not do it himself. :huh:


On another note for those that have mentioned the larger MC, quote from the SSC Big Bore MC: "This large bore brake master cylinder significantly reduces pedal travel and increases brake force at the pedal. If you've upgraded to larger front calipers you probably have a soft, long travel pedal now. This master cylinder is the solution you've been looking for."

That is interesting, as not only are my front's larger, but also the back. Getting this larger MC could only help, but it may be a clam-off job looking as how tight it is in there. I wonder on the price too if this is an actual specific MC, or one used on another car that costs $200 and price tripled as its sold on Lotus vendors sites. That stuff happens all the time.

 

[oldmansan]

I only mentioned flipping the calipers upside down as that is posted all over brake threads in this forum. It may make sense for the OEM calipers, but not for the AP Racing ones that have dual bleeders per caliper. Also, realrundell seems to have almost exactly the same amount of take-up on the pedal as mine. One mans "touchy" is another mans "spongy". Completely subjective. My car stops so fast that it could "send you through the windshield" too, just with more pedal travel than I would like.

Not sure what is up with the attitude. I've been working on/building cars for 20+ years, just because my brakes have more travel than I would like doesn't mean the brakes weren't bled right. It's also hard to take advice from someone who had to have a shop install something as easy as a BBK and not do it himself. :huh:


On another note for those that have mentioned the larger MC, quote from the SSC Big Bore MC: "This large bore brake master cylinder significantly reduces pedal travel and increases brake force at the pedal. If you've upgraded to larger front calipers you probably have a soft, long travel pedal now. This master cylinder is the solution you've been looking for."

That is interesting, as not only are my front's larger, but also the back. Getting this larger MC could only help, but it may be a clam-off job looking as how tight it is in there. I wonder on the price too if this is an actual specific MC, or one used on another car that costs $200 and price tripled as its sold on Lotus vendors sites. That stuff happens all the time.

I had the shop install my brakes while the clam was off and they were doing the Laminova, radiator, puller fans, thermostat etc. I don't have as much time as I used to.

I have Stoptechs on my other toy and the APs are far touchier. Nothing spongy about them and no excessive pedal travel.

I think you'd be wasting your money on the larger MC. VSA preps race cars and they never even suggested a different MC. Give Allen at VSA Motorsports a call. I'm sure he can help you out.

VSA Motorsports | Lotus Service and Prep

San

 

[realrundell]

I've searched and searched and I cannot find the thread that explains the brake pedal adjustment! I think I would hold off on spending any money on a master cylinder and first attempt adjusting the pedal pushrod. It's a quite a squeeze, but there is a locknut on the rod where it threads into the clevis. A quarter to half turn makes a fair bit of change. Maybe you can get the height exactly where it is comfortable for you. I know this was a popular subject around seven/eight years ago when this was EliseTalk.

 

[oldmansan]

I've searched and searched and I cannot find the thread that explains the brake pedal adjustment! I think I would hold off on spending any money on a master cylinder and first attempt adjusting the pedal pushrod. It's a quite a squeeze, but there is a locknut on the rod where it threads into the clevis. A quarter to half turn makes a fair bit of change. Maybe you can get the height exactly where it is comfortable for you. I know this was a popular subject around seven/eight years ago when this was EliseTalk.

I know Allen at VSA did some adjustments on mine to minimize brake pedal travel. That's why I suggested the OP contact him.

San

 

[sturgeongeneral]

I also have the 4 corner Big Brakes. Stops on a dime!! It sounds like you need a brake and clutch fluid flush and adjust the MC rod length. Mine are right there and very quick to react.