timb2117 Posted October 5, 2020 Share Posted October 5, 2020 Just thought I'd share fitting of Jack Webb big brake kit to an imperial sv roadsport. I chose them after advice on the forum and Caterham were struggling at the time with Covid supply chain.Supply was super fast and email response likewise from Jack - V helpful - only thing I needed extra was part number 77209f braided lines from caterham (wish I'd known at time as I would have ordered together.)Took hub off and re greased bearings too took about 2 hours per side including a major clean up- one hassle was the copper sealing washer for caliper end was a touch big and off centre so didn't seal first time I bulked the thread up with a bit of PTFE tape so it centred perfectly and cinched up well.Bleeding dead simple and pedal feel and power much nicer than the old 15 year old Girlings. I have retained the original master cylinder after reading the threads on here and it seems A1 and a quality bit of kit..... Now for the track acid test. Link to comment Share on other sites More sharing options...
Wrightpayne Posted October 5, 2020 Share Posted October 5, 2020 They look very similar to Canley Classics offering for the Herald / GT6. Link to comment Share on other sites More sharing options...
timb2117 Posted October 6, 2020 Author Share Posted October 6, 2020 I was advised that they were the same. Most impressive was the bolt on bolt off nature of them really an easy match up to the hubs and no difference in lining up (which is just as well because the steering rod end joint has barely 2mm clearance to disc!) Link to comment Share on other sites More sharing options...
K7 VCT Posted October 6, 2020 Share Posted October 6, 2020 Glad to hear they are as described and working well Link to comment Share on other sites More sharing options...
John Vine Posted October 6, 2020 Share Posted October 6, 2020 ...the copper sealing washer for caliper end...Are you sure the washer is required? I would have thought the convex end of the 1/8” BSP to M10x1.0 adaptor would self-seal in the caliper.JV Link to comment Share on other sites More sharing options...
Guy Lowe Posted October 6, 2020 Share Posted October 6, 2020 Not sure that using PTFE tape on brakes is good engineering practice. Link to comment Share on other sites More sharing options...
John Vine Posted October 6, 2020 Share Posted October 6, 2020 Re #6:I agree. But it won't be needed when the OP removes the washer and relies on the adaptor for a seal.ETA: Re-reading post #1, I think the OP used PTFE simply to centre the washer rather than apply it to the thread of the adaptor. But it won't be needed anyway.JV Link to comment Share on other sites More sharing options...
timb2117 Posted October 6, 2020 Author Share Posted October 6, 2020 Yeah totally agree ptfe is ok for taps but that's it :)Its only role was to get the pesky washer to line up centrally and stay that way as I tightened it up. I had already checked re the sealing with Jack as a an engineer this end queried the practice and validity, he works on v8 supercars and warned me that they get up to 700lbs of pressure - he cannot even press the brake pedal hard enough with both feet! Link to comment Share on other sites More sharing options...
John Vine Posted October 7, 2020 Share Posted October 7, 2020 The point is that you don't need the washer at all. It just happens to be in the hose pack that CC supply, just like the packs for the flex rear hoses.JV Link to comment Share on other sites More sharing options...
John Vine Posted October 7, 2020 Share Posted October 7, 2020 Re #9:Apologies, I think I've got my fronts and rears mixed up. Looking at my AP 4-pots, there is indeed a washer between the adaptor and caliper body. I assume the Jack Webb calipers are the same.But I'm still puzzled why the washer should be a slack fit over the adaptor.JV Link to comment Share on other sites More sharing options...
aerobod - near CYYC Posted October 7, 2020 Share Posted October 7, 2020 Usually there is an undercut of the thread to ensure the adapter mating surface is flat beyond where the thread ends, this means that the washer inner diameter is no smaller than the thread outer diameter, but the undercut diameter is less than the thread root diameter. This is why the washer can move around in the undercut, but normally it shouldn't move much off centre if it starts concentric to the adapter to begin with when tightening. Link to comment Share on other sites More sharing options...
timb2117 Posted October 7, 2020 Author Share Posted October 7, 2020 What he said :) ha ha. Many thanks James that is exactly it, wish the washer were tighter but it isn't for that reason. The ptfe tape is essentially redundant in terms of sealing the washer doing all the work.I would have been a bit happier with a more substantial mating surface but am guessing thats the point its small therefore under high torque, hence does the job. Jack said it has been done for a long long time by Caterham like this so I suspect whilst we all have our own incarnations of this brake kit they all use the same principles/ washers.thankyou all I appreciate the attention to detail. Link to comment Share on other sites More sharing options...
timb2117 Posted November 6, 2020 Author Share Posted November 6, 2020 Ok got a few road kms and one track day in, reliable but with the supplied ferodo's do squeal a bit coming to gentle stop, however good stopping power, but the rears are still doing more work.I am going to pop in a valve to the brake line to rear, just as it goes into the tunnel under the bonnet then I can tune out the backs a bit- I am not super feeling on the set up so will fit/ test then forget, without the need to fettle in cab, mid track session. Link to comment Share on other sites More sharing options...
Simon.Rogers Posted November 10, 2020 Share Posted November 10, 2020 Don't do it! The rear is under braked.Pedal feel will change to zero and be pants.Particularly with the big brakes you need more aggressive pad in the rear to try to balance things out. Link to comment Share on other sites More sharing options...
Area Representative Richard Price Posted November 10, 2020 Area Representative Share Posted November 10, 2020 "but the rears are still doing more work" timb2117,What makes you say that?As Simon says, I'd be very surprised if you need LESS rear braking after fitting big fronts!What pads do you have front and rear? Additionally, what type and size tyres are you running. Link to comment Share on other sites More sharing options...
timb2117 Posted November 11, 2020 Author Share Posted November 11, 2020 Hi Richard I know it sounds odd but -The rears prior to (and after) fitting of the bigger fronts easily and by far heat up more than the fronts, also under aggressive "test" braking the rear locks up sooner.Sorry not sure about the rear pads but standard caliper, tyres toyo proxxes r888 and wheel size 205/45 r16. - I realise they're big but came on the car and I can get enough heat into the nearly new soft tyres on track for them to work well.Front pads are the ferodo "race"that came with the brake set up.....Any thoughts Link to comment Share on other sites More sharing options...
ECR Posted November 11, 2020 Share Posted November 11, 2020 When I fitted big brakes many years ago and changed to Mintex 1144 pads all round, I found that the rears locked up even more than with standard fronts. I deduced that the weight transfer to the front was unloading the rears and causing this. Link to comment Share on other sites More sharing options...
timb2117 Posted November 11, 2020 Author Share Posted November 11, 2020 I understand however on "normal' cars the front still locks first, and I think makes it more controllable, do hope I have not upset the balance too much. Link to comment Share on other sites More sharing options...
John Vine Posted November 11, 2020 Share Posted November 11, 2020 Re #18:...on "normal' cars the front still locks first...And 7s too. The IVA examination in the UK specifically tests for this, and if the rears do lock first, the car will fail.JV Link to comment Share on other sites More sharing options...
ScottR400D Posted November 11, 2020 Share Posted November 11, 2020 Looking at it simplistically, and ready to be corrected, if you significantly improve the front you’ll increase the rate of weight transfer and provoke rear locking by taking the weight off the rear. Improving the rear in proportion will maintain the rate of transfer and balance and keep things in order? Link to comment Share on other sites More sharing options...
ECR Posted November 11, 2020 Share Posted November 11, 2020 Assuming you're not locking the rears in the first place (which I was).... Link to comment Share on other sites More sharing options...
ScottR400D Posted November 11, 2020 Share Posted November 11, 2020 Which could be made worse by improving the front braking, for similar reasons as I suggested? Link to comment Share on other sites More sharing options...
Area Representative Richard Price Posted November 11, 2020 Area Representative Share Posted November 11, 2020 "Front pads are the ferodo "race"that came with the brake set up.....Any thoughts"It would be helpful to understand exactly what front pads you are running. Both DS2500 and particularly DS3000s require some heat in them to work effectively (with DS3000's working best when the discs are glowing red hot!)If you have a standard pad in the rear, but a competition based pad in the front, you may well have brakes that work from cold in the back, but not the front. If its a track only car, and you know that, then that's not a problem, where as you build heat, the balance will improve, but, for a road car, that is not very safe....You comment that the rear brakes get hot. That is not unusual, and, in itself, not as much a problem as a characteristic. Quite a lot of the available stopping power of our cars actually comes from the rear brakes, but, on standard cars, the discs are solid and cooling is poor. By increasing the disc and pad size, and adding vented discs that dissipate the head better, you exaggerate the temperature imbalance between front and rear.In an ideal world, the brake sizes would be specified so that heat built up and was dissipated at the same rate on both axles. However, there is not "one size fits all" solution to suit all 7's. Overall weight, weight distribution, along with tyre sizes and and compounds all affect that "ideal". ECR's car have a heavy Vauxhall XE in the front, where the 'Busa car that I've driven this year has a vastly different dynamic......I'd really want to fully understand exactly what you have before making any other change.For optimum braking performance, front to rear balance is paramount. To that end, I've been running a modified pedal box with dual master cylinders and a bias bar to enable adjustable front/rear balance for the last ten years. Link to comment Share on other sites More sharing options...
Area Representative Richard Price Posted November 12, 2020 Area Representative Share Posted November 12, 2020 Oops.It's just been pointed out to me that my opening statement in the above post did not make sense,....I've just edited it to correct it.If you look at the chart below, you see that DS3000s have close double the stopping power at 500°C that they do when stone cold (note that the chart starts at 150°C, but road cars will often be braking from stone cold).Additionally, DS3000s are at their optimum between 500 and 700°C (that is in the range where the discs are glowing red hot)In contrast, a typical standard pad will work at its best from cold, typically getting worse the hotter they get.So, if you have different pads front and rear, whatever front/rear balance you cold is unlikely to be what you have warm, and different again when hot. https://www.ferodoracing.com/products/car-racing/racing-brake-pads/ds3000/ Link to comment Share on other sites More sharing options...
7 wonders of the world Posted November 12, 2020 Share Posted November 12, 2020 I can confirm that despite what the graph says...... DS3000 do work very well from cold, far far better than the previous 1144's and maintain a consistent feel as they warm up to.Expensive but a very good material. Link to comment Share on other sites More sharing options...
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