Guest Posted July 4, 2014 Share Posted July 4, 2014 Hi, I just got the high ratio brake pedal in an attempt to fix a spongy feel to the pedal. Endless attempts to bleed the brakes were also performed. Anyone nows if the high ratio pedal is supposed to fit a 2012 academy 125 sigma car? Even thought the pivot seems to fit the master cylinder attachment point is smaller and it also seems to be slightly off centre with the master cylinder, was it presumptuous to assume a straight swap? Link to comment Share on other sites More sharing options...
Stationary M25 Traveller Posted July 5, 2014 Share Posted July 5, 2014 If the system is spongy, you have air in the fluid, or a faulty master cylinder. A different pedal won't solve that. I recall a local Sevener fitting a new pedal and something had to be drilled out to make it fit ... albeit to a slightly older car Link to comment Share on other sites More sharing options...
Leadership Team SLR No.77 Posted July 5, 2014 Leadership Team Share Posted July 5, 2014 As Ian says, keep bleeding! The ratio change is not enough that you're going to feel you've suddenly gone from spongy brakes to solid, less travel yes. Stu. Link to comment Share on other sites More sharing options...
elie boone Posted July 5, 2014 Share Posted July 5, 2014 you can have a spongy feel if the disc's are worn and the pads don't fit perfectly the "worn" patern Link to comment Share on other sites More sharing options...
Grubbster Posted July 5, 2014 Share Posted July 5, 2014 unfortunately many people seem to experience spongy brake problems in the newer cars including me (and lots of others) in the Academy last year. Since Girling stopped making the master cylinders the one that replaces it isn't very good (I had 2 fail, 1 only lasted an hour on track). On top of this the remanufactured rear callipers are also prone to leaking. If you can find an old style Girling master cylinder (there are still a few new ones around I believe) this might help, or fit the uprated model instead. Back to the question though - I know that a lot of the roadsporters have fitted the high effort pedal to their ex academy cars so it must be possible but I don't know how hard it is to do. Link to comment Share on other sites More sharing options...
CB Posted July 5, 2014 Share Posted July 5, 2014 According to Caterham the high effort pedal was designed for the old chassis but fits with some "fettling" (I got one of the teams to do mine). Why they can't update it to directly fit the chassis they have been selling for years is somewhat beyond me.... Edited by - CB on 5 Jul 2014 11:14:31 Link to comment Share on other sites More sharing options...
Guest Posted July 5, 2014 Share Posted July 5, 2014 Thanks everyone, no end to the knowledge on this forum, after some fiddling decided to work harder on bleeding the brakes, to install the high effort pedal I would have to grind down the support where the pedals pivot bolt is, making this a non reversible change, as don't know if I would like the pedal seems a risky move, will either try to return or sell it on. Shame that caterham does not have this sorted as even if the pedal went in it would be too close to the accelerator. Link to comment Share on other sites More sharing options...
Z3MCJez Posted July 5, 2014 Share Posted July 5, 2014 To be fair to Caterham, I think they went updated master cylinder instead of high effort pedal to achieve the same thing ... Jez Link to comment Share on other sites More sharing options...
Leadership Team SLR No.77 Posted July 5, 2014 Leadership Team Share Posted July 5, 2014 And it all goes to show that you'll get a better ratio of responses on Blatchat than Pistonheads Stu. Link to comment Share on other sites More sharing options...
myothercarsa2cv Posted July 6, 2014 Share Posted July 6, 2014 Caterham told me for ages it was normal. Got a second hand girling and Lo and behold all my issues went away. Now I've got some time I'm going to strip down the old one and see what went wrong. P.s. I fitted a high effort pedal to my 08 metric chassis no problem when I thought it would improve things. Not sure it has but it shortened the stroke considerably. Drilled an extra hole for the brake mc as it was a little too extreme... Edited by - myothercarsa2cv on 6 Jul 2014 11:05:01 Link to comment Share on other sites More sharing options...
Grubbster Posted July 6, 2014 Share Posted July 6, 2014 I think I know what goes wrong with them John. There is a hole that allows the fluid into the cylinder, when you apply the brake the internal seal passes that hole then the pressure can build up and operate the wheel cylinders. It appears that as the seal passes the hole it catches and is damaged (possibly even being pushed up into the hole slightly IYSWIM) and once there is a tiny bit of damage to this seal you can't maintain a steady pressure as the fluid passes the seal. In short it is not a great piece of engineering . . . . If you find something different it'd be good to hear Link to comment Share on other sites More sharing options...
ChrisC Posted July 6, 2014 Share Posted July 6, 2014 Does the current race master cylinder upgrade have the same design? Link to comment Share on other sites More sharing options...
myothercarsa2cv Posted July 6, 2014 Share Posted July 6, 2014 Quoting Grubbster: I think I know what goes wrong with them John. There is a hole that allows the fluid into the cylinder, when you apply the brake the internal seal passes that hole then the pressure can build up and operate the wheel cylinders. It appears that as the seal passes the hole it catches and is damaged (possibly even being pushed up into the hole slightly IYSWIM) and once there is a tiny bit of damage to this seal you can't maintain a steady pressure as the fluid passes the seal. In short it is not a great piece of engineering . . . . If you find something different it'd be good to hear I believe there was talk at some point of shimming it to reduce this effect, but damned if I know how you'd do that! I'm not that brilliant an engineer, Ian James will attest to that Link to comment Share on other sites More sharing options...
Guest Posted July 8, 2014 Share Posted July 8, 2014 On the off chance that I need to go on the AP brake upgrade path sooner, is there a part number for the AP master cylinder? or any place to get other than CC? Link to comment Share on other sites More sharing options...
Terry Field Posted July 16, 2014 Share Posted July 16, 2014 Keeping it simple, it is possible that you are not bleeding the brakes properly through no fault of yours. If you are using the brake up / brake down process, it is possible to draw air back into the system as you release the brake pedal. Invest £20 or so on an Ezibleed system which pressurises the system and you can then be sure that you are not sucking air back in. Terry Link to comment Share on other sites More sharing options...
Z3MCJez Posted July 16, 2014 Share Posted July 16, 2014 On a 125bhp car you do not need bigger brakes. You need properly functioning ones. The race MC doesn't require new calipers/discs (unless you want them to look bling) and are more than capable of overcoming even slick tyres. Jez Link to comment Share on other sites More sharing options...
Guest Posted July 16, 2014 Share Posted July 16, 2014 Thanks for the reply I already invested on a eazybleed but will probably invest on the ap mc to be on the safe side, Agree that for 125bhp upgrading brakes would be unecessary, the only valid reason to upgrade the rear brakes was to avoid this bleeding issue, this should not be this hard... oh well.... Link to comment Share on other sites More sharing options...
James.S Posted July 17, 2014 Share Posted July 17, 2014 I'm really fussy about brakes, took me forever to find the perfect set up. You will sort your problem with the uprated MC and high ratio pedal. We use a different fluid and pads as well but this is more for fade. Mine are rock solid, no sponge, no fade and no dead zone. Speak to CC midlands or one of the caterham races teams. Good luck, j Link to comment Share on other sites More sharing options...
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