Amjad Posted August 19, 2014 Share Posted August 19, 2014 I'm guessing this is my MC that's failed/failing? Did half of my 4 hour track session at JF2 with a little air in the system, would this have caused the MC to fail? Pulled in, bled system and it was way better. Did the second half of my session fine, but found that leaving Donington my pedal was pretty soft! Got a mate to jump in when I was bleeding so I'm not sure if he was pressing pedal a bit too hard at the time? Gonna check pads aren't just low but I would think that low pads, after giving more pedal travel than usual would still give a firm pedal towards the end of the travel? The pedal just stays soft at the moment Any help is much appreciated! Amjad Quote Link to post Share on other sites
turbo Grant Posted August 19, 2014 Share Posted August 19, 2014 Just give it a good pressure bleed. Release the bleed nipples when someone is inside pushing the pedal down. Then lock it back up before they relise the pedal. Works a treat that way. Quote Link to post Share on other sites
WallaceGlanza Posted August 19, 2014 Share Posted August 19, 2014 Getting rid of the ABS will sort it, brakes feel much better without! Quote Link to post Share on other sites
mikey4410 Posted August 19, 2014 Share Posted August 19, 2014 Maybe the trackday has caused a few issues somehow.bleed thoroughly and that should make it better.and yeah abs sucks balls Quote Link to post Share on other sites
morgey Posted August 19, 2014 Share Posted August 19, 2014 Theres a possibility the fluid behind the pistons has boiled creating air in the system again.A quick bleed should sort it.I was told that you should bleed your brakes after every track day becuase of this. Also it keeps fresh fluid in the system Quote Link to post Share on other sites
Keri-WMS Posted August 19, 2014 Share Posted August 19, 2014 My understanding is that once brake fluid has boiled it needs changing because it can retain gas bubbles, and it will also boil in future at a lower temperature (!!) and that it is also APPARENTLY more compressable even excluding the bubbles! So a full flush is a good idea if you've ever boiled your brakes. Quote Link to post Share on other sites
DavidAshton Posted August 19, 2014 Share Posted August 19, 2014 My pedal has gone quite soft since my short 20 minute track session, not sure they would have survived a long session. It strange though as they were perfectly fine on track and when I parked up, went to drive home and they were softer. Hoping a bleed will bring them back in. Quote Link to post Share on other sites
morgey Posted August 19, 2014 Share Posted August 19, 2014 My thoughts would be You'll have air circulating when driving, as soon as you park up the cooling would stop and cause excess heat which might in turn cause the issue. Quote Link to post Share on other sites
Amjad Posted September 17, 2014 Author Share Posted September 17, 2014 Cool, thanks for the advice fellas! Sorry I haven't been on in a while, car has been the same but I've gotten used to it. Will have to try a fresh bleed and fluid replacement when I get a chance! So much for Gulf "Racing" brake fluid lol Oh and I don't have ABS Quote Link to post Share on other sites
MARC MOSS Posted September 17, 2014 Share Posted September 17, 2014 Flush it through and Go get some synthetic dot 5.1 from opie oils mate I bet any money as already said you have boiled the fluid behind the pistons, I have done it many times on track and this fluid will help although after a hard day on track it will still feel like the pedals shit. That and when you have bled the system pump the pedal up as hard as poss with the engine off and force it down over night when it's at it's hardest as it will force the remaining air from the fluid.. Trust me Quote Link to post Share on other sites
daniel_g Posted September 17, 2014 Share Posted September 17, 2014 Cant beat a good brake & clutch bleed sesh lol. Quote Link to post Share on other sites
Amjad Posted February 12, 2015 Author Share Posted February 12, 2015 Just a quick update, I bled the system at Xmas and it improved things, but still felt "off". Got a bottle of ATE Type 200 (thanks ID-Workz!) and flushed 900ml through the system after extracting as must as I could with a syringe from the MS. And it's pretty much back to normal! There's a slight bit of travel before the brakes engage but I guess that's pads running low? Flush it through and Go get some synthetic dot 5.1 from opie oils mate I bet any money as already said you have boiled the fluid behind the pistons, I have done it many times on track and this fluid will help although after a hard day on track it will still feel like the pedals shit. That and when you have bled the system pump the pedal up as hard as poss with the engine off and force it down over night when it's at it's hardest as it will force the remaining air from the fluid.. Trust meMarc can I just run through what you've said to make sure I've understood it correctly?I've replaced all the fluid now so that's cool. To get the last bit of air out if there is any:-Pump pedal until it's hard, leave it overnight-In the morning, just bleed a little from each caliper in case there's air left? Quote Link to post Share on other sites
AdamB Posted February 13, 2015 Share Posted February 13, 2015 When you come off track did you put the handbrake on at all?That will boil also the fluid so when you come off track just leave the car in gear rather than putting the handbrake on. Quote Link to post Share on other sites
Amjad Posted February 13, 2015 Author Share Posted February 13, 2015 I was aware that you shouldn't apply handbrake after pulling in so I'm pretty sure I didn't Quote Link to post Share on other sites
Calum122 Posted January 28, 2017 Share Posted January 28, 2017 Yeah that's interesting I am getting this problem after fitting new brakes. Seems to bleed fine, then once the engine is running the pedal goes all soft. I did notice I was using Brembo DOT 4, then saw the mastercylinder cap specify DOT3 but that shouldn't matter right. I have recently rebuilt the rear calipers and needed to put in a rear line. But I was sure to bleed these lines and test them before I started on the fronts. Do I need to go around each caliper even though I am only replacing the fronts. Quote Link to post Share on other sites
AdamB Posted February 3, 2017 Share Posted February 3, 2017 I would recommend to bleed all 4 corners You can just gravity bleed them also. Quote Link to post Share on other sites
dan106 Posted February 4, 2017 Share Posted February 4, 2017 Did you have the handbrake on when you bled them? I did when I changed front calipers and I have a soft pedal now, haven't managed to fix it yet mind Quote Link to post Share on other sites
Calum122 Posted February 4, 2017 Share Posted February 4, 2017 Yes I did as a matter of fact Dan. I guess I never thought about taking it off... Can't see why this would make a difference though? I'm using a vacuum pump to remove the fluid, rather than pumping the pedal. But maybe I didn't. I will bleed all the corners. If I can sort this, then that would be really awesome. Cheers lads Quote Link to post Share on other sites
dan106 Posted February 5, 2017 Share Posted February 5, 2017 I'm not sure how it would make a difference but I'd definitely re bleed them with it off just to be sure, hoping this will fix mine aswell lol Quote Link to post Share on other sites
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