wxywb021254 Posted June 25, 2021 Share Posted June 25, 2021 Hi there, I have had my 420s for a few months now. One thing I am not sure is brake. It just does not give me the feeling that I am used to have in other cars. Maybe I am not used to non-boosted brakes? My car is 420s w/ standard brake MC and 4 piston calipers w/ original pads (good condition). I flushed the brake fluid with new ones recently but the pedal feeling before and after is the same. And I check there is no leak A few questions: 1. Sometimes, when I hard brake, the rev goes up. I think I didn't accidentally press the gas pedal... Anything can cause this? To my understanding, our cars have non-boosted brake, so the booster, rev thing is not here? 2. For normal brake, it feels fine and actually, we don't need to brake too much in these cars... But to brake hard, I really need to press the pedal really really hard, and it never locks up. Although I never got the pads to high temp and I am on Toyo R888r. Is this normal? I am in AZ and I don't know any other 7 owners... So hard to find another one to try out... 3. From what I understand, upgraded MC won't help on this and it will make the pedal even harder to press? Any suggestion? Thanks in advance! Link to comment Share on other sites More sharing options...
sf4018 Posted June 25, 2021 Share Posted June 25, 2021 1. I'd been fighting that for a while where the right foot presses on the gas pedal little when braking (I have super wide feet). I would hazard a guess the same thing is happening for you. If you have the stock gas pedal add a spring return, that'll help you feel it better. Also narrow footwear or even race shoes may be worth a shot. Last resort modify the gas/brake pedal. 2. The brakes for me take a little warming up to work fully, once warm you can lock the wheels up, but it does take more force to operate than typical cars do, it just takes a little getting used to. They may need bedding in too. 3. No idea. Link to comment Share on other sites More sharing options...
Pokey Posted June 25, 2021 Share Posted June 25, 2021 From my limited experience with a relatively new 420R: 1. Odds on you are finding both pedals as it is really easy to do. Happens to me all the time when I mess up my heel-toe technique which is essentially what you are doing on accident. 2. My 420R took a lot of force to get the brakes to bite out of the box. Bedding the pads changed that, they bite now just fine, albeit still take a fair amount of pressure. At this point any improvement would take a different pad compound, but I've no issue locking up the wheels at speed so am happy. 3. I'll defer to those more knowledgable, but will say that if your master cylinder is functional than I would focus my efforts elsewhere. If you haven't bedded your pads I'd start there. Link to comment Share on other sites More sharing options...
CarlB Posted June 26, 2021 Share Posted June 26, 2021 I do not have a 430R, but I have some general comments. You should absolutely be able to lock the brakes. I suspect your pads are glazed and sanding the rotors and pads and bedding them again should fix it. Pad material builds up on the rotors and a light sanding will remove it. I do not know what Caterham supplies for pads, but pads have different coefficients of friction. and different operating temperature ranges. Racing pads do not work until they get hot. As pads get better at stopping they also work in a narrower range. Bedding procedures also become more important. They are not inexpensive but I really like the Porterfield vintage race car pad compound. I use it on my Caterham and my MINI. It is has a very high coefficient of friction. A smaller diameter master cylinder will make the brakes easier to push. For the same force on the brake pedal you will be applying more force pushing the brake pads. The disadvantage is the pedal will travel further. You still need to move the same amount of brake fluid to move the caliper pistons. Link to comment Share on other sites More sharing options...
wxywb021254 Posted June 27, 2021 Author Share Posted June 27, 2021 Thank you for your advice! I guess I need more experiments then. I did notice when brake warms up, it grabs better. But I can hardly get them warm on street... Link to comment Share on other sites More sharing options...
Kitcat Posted June 30, 2021 Share Posted June 30, 2021 My Caterham has a brake balance/bias adjustment mechanism. So I can dial in more front or rear grip. I have never had a problem locking them up. In fact Croc has posted a video of my car engulfed in tire smoke after locking all 4 wheels up in order to avoid his careening, ill-handling ‘65 Mustang at NJMP:). Something is amiss with your Cat as it should be easy to lock the front brakes. I agree with CarlB’s assessment. I’d be nervous driving it in its current condition. Hope you get it resolved, keep us posted. Link to comment Share on other sites More sharing options...
wxywb021254 Posted June 30, 2021 Author Share Posted June 30, 2021 54 minutes ago, Kitcat said: My Caterham has a brake balance/bias adjustment mechanism. So I can dial in more front or rear grip. I have never had a problem locking them up. In fact Croc has posted a video of my car engulfed in tire smoke after locking all 4 wheels up in order to avoid his careening, ill-handling ‘65 Mustang at NJMP:). Something is amiss with your Cat as it should be easy to lock the front brakes. I agree with CarlB’s assessment. I’d be nervous driving it in its current condition. Hope you get it resolved, keep us posted. Thanks. I haven't brought the cat on track yet so not sure about how the brakes perform when hot. But all the observation I had was on street and i used almost no brakes on street so I would say they are very cold... And actually I am not sure what pads are in the car right now... Will test with pads warmed up more and get back. Link to comment Share on other sites More sharing options...
Croc Posted June 30, 2021 Share Posted June 30, 2021 1 hour ago, Kitcat said: In fact Croc has posted a video of my car engulfed in tire smoke after locking all 4 wheels up in order to avoid his careening, ill-handling ‘65 Mustang at NJMP:). @KitcatWould you mind? Its not ill handling. Its just grip constrained when at the limit and I was hanging on by my fingernails to stay ahead of you. Link to comment Share on other sites More sharing options...
Kitcat Posted June 30, 2021 Share Posted June 30, 2021 In fairness to Croc and his Mustang, he was trying to get it to do something it was never designed to do (turn....:)). 1 Link to comment Share on other sites More sharing options...
wxywb021254 Posted June 30, 2021 Author Share Posted June 30, 2021 9 minutes ago, Kitcat said: In fairness to Croc and his Mustang, he was trying to get it to do something it was never designed to do (turn....:)). Oh. Mustang turns. Just need some crowds as bait. Link to comment Share on other sites More sharing options...
CarlB Posted July 1, 2021 Share Posted July 1, 2021 Let me be clear. If you can't easily lock the brakes at hot or cold don't drive the car. There is something wrong. If it takes a long time to slow down from 60 MPH and the pedal effort is high you might have racing pads or pads that were not bedded correctly. Link to comment Share on other sites More sharing options...
wxywb021254 Posted July 12, 2021 Author Share Posted July 12, 2021 Update: the brake does lock up if I press hard enough using R888Rs. So I may be just not familiar with cars without brake booster. And I can notice, with a bit temp the brake grabs significantly harder. So maybe the pads are kinda race pads. Link to comment Share on other sites More sharing options...
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