Brake pedal

[MARTIN993]

My pedals used to be perfectly aligned for heel toe…

However, i've found that when brakes get hot there is more travel in the brake pedal meaning that heel toe becomes difficult (as the accelerator pedal is too high).

Anyone else experienced this?

Do i need to adjust them?

[Grubbster]

You can adjust the pedals a bit to achieve the best compromise which may help but not really solve the problem. Or you can try to improve the braking system so the pedal doesn't go long (bleeding them, better fluid, check for leaks, fit the uprated master cylinder etc). If it is a fairly new car it's probably got the latest standard master cylinder which is know to be less than perfect (it used to be a Girling one which was quite a bit better) - in the Academy it was commonplace to see people frantically bleeding brakes in the pits Also the newer rear callipers are known to leak sometimes so check these.

[MARTIN993]

Thanks Grubbster.

How often should the brakes be bleed?

Or should this just be done when the pedal goes long?

Brakes were hammered on track today (pads / disks are new and plenty left on).

Thanks,

Martin

[Grubbster]

In theory once bled correctly they shouldn't really need to be done again, but if there is a problem with the system that allows air to enter then that's when bleeding is necessary. On the newer cars the master cylinder can fail slightly and start to let fluid pass the seal inside (this is what happened on 2 of mine). Any connections or nipples not fully tightened (but take care not to break anything!) can allow a little air in. do you know how old the fluid is? Brake fluid can absorb moisture over time and this can lower the boiling point of the fluid and lead to a long pedal when the brakes are hot. So if your fluid is more than a year old then it's worth replacing it before doing anything else (cheap to DIY). On my big power K I run the caterham big front brakes and a standard master cylinder, I get a slightly long pedal on track at times but not enough to worry about too much - but I am planning to fit the uprated AP master cylinder soon.

[KRL]

I plan to upgrade the M/C at some point due to this issue. My brake pedal is fine during normal road use and can heel and toe with out issues. However when on track after the brakes heat up I get a lot more travel preventing me from being able to heel and toe.

This is the same despite numerous brake bleeds using high quality fluid. So as Grubbster says I think the best solution is to upgrade the M/C.

[framerateuk]

MARTIN993 said:

My pedals used to be perfectly aligned for heel toe…

However, i've found that when brakes get hot there is more travel in the brake pedal meaning that heel toe becomes difficult (as the accelerator pedal is too high).

Anyone else experienced this?

Do i need to adjust them?

I've had this exact problem myself. I was ok on most trackdays (where I wasn't so familar with the track), but on my local track I found the brake pedal needed to be pushed significantly further by the end of each session and as you say it makes heel and toe very difficult.

I had the brake fluid swapped at my last service and the problem has been completely sorted. We didn't know how long the fluid had been in there for, but we replaced it with some DOT5.1. I really need to get myself an EZBleed so I can do it myself....

(I'm already running the AP front brakes and upgraded master cylinder).

Edited by framerateuk on Thursday 12th June 09:23

[Camoradi]

Gents, thanks for the info above.

I've experienced a small leak from master cylinder when fluid gets hot.

Is this product http://caterhamparts.co.uk/product.php?id_product=... the uprated master cyclinder you refer to, and if so is it a straight swap or do brake lines need modification?

thanks

Kevin

[KRL]

Yep the link you posted is the uprated A.P. M/C

WRT to your standard M/C leaking. It might be worth fitting this:
http://caterhamparts.co.uk/product.php?id_product=...

My standard M/C was leaking during track use (fast cornering) from the cap and this race cap fixed it.

[framerateuk]

I've had a small leak on mine also (only a couple of drips over a whole trackday), but I've replaced it with the race cap (which I had fitted before, but I guess it was just worn) and it's been dry since.

http://caterhamparts.co.uk/product.php?id_product=...

[Camoradi]

That looks worth a try then

and cheaper

and easier to fit

thanks a lot

K

[KRL]

Make sure you keep your old M/C cap for the MOT. Some stations may fail the car if it has the race M/C cap fitted due to it having no brake fluid level sensor.

[Camoradi]

KRL said:

Make sure you keep your old M/C cap for the MOT. Some stations may fail the car if it has the race M/C cap fitted due to it having no brake fluid level sensor.

Yes that did occur to me, but thanks for taking the trouble to post it

[framerateuk]

Is that a requirement? I can't say I've ever noticed a sensor in the cap on my Megane, though I'd admit to not really looking for it before.

Edited by framerateuk on Thursday 12th June 16:36

[MARTIN993]

Thanks all,

reassuring to hear it's a fairly common issue.

Will see if they need a bleed.

Cheers,

Martin

[KRL]

framerateuk said:

Is that a requirement? I can't say I've ever noticed a sensor in the cap on my Megane, though I'd admit to not really looking for it before.

Edited by framerateuk on Thursday 12th June 16:36

I believe so yes but it is obviously down to the station doing the test.

Taken from here - http://www.motester.co.uk/mot-information-for-moto...

Brakes – Warning indicators

Electronic parking Brake (EPB) warning device must not be indicating a malfunction
ESC warning lamp must be present, working and not indicating a fault
ESC Switch must not be insecure or faulty
A brake fluid warnimg lamp must not be inoperative or illuminated
Class (v): Electronic braking system (EBS) warning device must not be inoperative or indicating a fault
ABS and ESC components and associated wiring/switch checked for presence and condition