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MG Midget and Sprite Technical - Kad callipers
| When I rebuilt the brakes I fitted 4 pot Kad callipers and drilled discs,when running the engine in they seem very capable,today I decided enough was enough time to turn up the boost on the turbo!when braking from high speeds I got a lot of brake fade so I was wondering if there are any discs out there that are vented or thicker as the Kad callipers can take thicker discs or should I go for larger diameter discs and would the Kad still fit? |
| Rob Newt |
| Is this fluid fade or friction material fade, or both? What fluid is in the system and how old is it? What is the compound of the pads and how large are they? How heavy is your car? |
| Daniel Thirteen-Twelve |
| Daniel I would think friction fade as the fluid is brand new dot 4. Running greenstuff pads (500 miles)in the Kad callipers you use Metro Turbo pads. The only thing that has not been replaced on the brake system is the m.c.I wonder if this is not doing its job as it should, I still have a bit too much travel in pedal even after bleeding lots(with eezibleed)??? No servo fitted.. |
| Rob Newt |
| m/cyl cannot cause fade; I'd target the pads, greenstuff are IMO a triumph of marketing over performance. |
| David Smith |
| I had KAD Calipers fittes and could not get not get enough movement to lock the wheels (its as if it needs a larger bore M/C to displace more fluid) so gone back to standard calipers, until I can solve this problem. |
| K Harris |
| Chuck away the Greenstuff pads and run Mintex 1144 or 1155 Alternatively give Hawk Black pads a go... |
| James Bilsland |
| So I now think it could be a combination of too mutch travel in the pedal and cra##y green stuff pads,Mintex pads on order and this brings me to the question is there a m.c. with a larger bore to cope with the 4 pistons,Kad told me I would not need to change m.c. bit if you think about the extra volume the 4 pistons use it must need a larger m.c.?? |
| Rob Newt |
| I'm tempted to give the blackhawk ones a go as well, though for my mgb calipers. Also thinking about some disc vent ducting, has anyone done this? |
| Brad (Sprite IV 1380) |
| That would be my guess, Rob. With the MC now pumping fluid to four slave cylinders vs. two... even if they're smaller... the ratio between master and slave is now different from stock, suggesting that you'll need a larger MC to restore the ratio to something like original. With the current setup, you've got a greater "squeezing" force, but at the expense of increased pedal travel. Cheers, -:G:- |
| Gryf Ketcherside |
| master cylinder/caliper mismatch will not give fade and any problem you have should have manifested itself straight away and not just under 'press on' conditions. Try a change of pads first, then look at the master cylinder if you still have problems... Every racer I know who has started with EBC Greenstuff has soon graduated onto other pads when they realise how poor they are... |
| James Bilsland |
| On a side note on M/C's who supplies larger M/C that fit in a standard pedal box ? |
| K Harris |
| My racer has a standard pedal box and Wilwood master cylinders (as supplied by Rally Design). Not a straight swap, but not a complicated mod either... HTH JB |
| James Bilsland |
| K Harris Have you spoke to Kad to see what they say,I have have spoke to them today and they still say that the Kad callipers were tested with a standard m.c. with very good results,they were very helpful and seem to agree that green stuff are useless,does a frogeye m.c. have the same bore as a rwa 72 midget? P.s.whats the K stand for?  |
| Rob Newt |
| nop an original frogey MC (the combined one) is a 7/8 bore the "72 should have a single 3/4 bore MC. there is an 3/4 bore combined mc fitted to the early disc brake cars (until "67) i have a new 7/8 combined mc as a (wrong)spare if anny one is intrested am comming to silverstone soon |
| Onno Könemann |
| no, the frog m/c was designed for use with DRUM brakes. Do you know if you have the original Frog m/cyl or possibly the slightly later Mk3 Sprite / Mk2 Midget 1098cc m/cyl which works with discs? Did you go direct from drums to the KAD stuff or was the car already on discs? |
| David Smith |
| What James and David said is correct. Likewise the reason I didn't ask about the master cylinder is because is has no bearing on brake fade. If the master / slave ratio is incorrect you get a soft pedal with lots of travel or a hard pedal with no travel. Which you get depends on which way around the bias is correct. According to the book 'The MG Midget and A-H Sprite High-Performance manual' by increase the slave (caliper sizes/more of)you'll have a soft pedal with longer travel. But this has nothing to do with fade. New DOT 4 ought not to fluid fade so it's down to the limitation of the friction material to cope with the heat and how fast the discs can shed the heat. The Spridget disc even if drilled and vented will always struggle to cope with a lot of braking torgue which is why the Peter May kit using the Spitfire disc is so popular - its bigger and thicker so copes better with heat (sheds faster). You haven't mentioned the weight of your car. The heavier the car the harder the brakes have to work. You haven't said how fast you were going but if you are hitting 90 - 100mph and regularly lugging it down to 60mph (The bracknell ringroad 'experience') you'll start to get fade even with better pads. Mintex once told me it was impossible to fade M171 in road use I didn't bother to argue with them but switched to the Peter May big disc conversion. On Peter's kit I have yet to be able to turn AP Racing Green heat indicator paint to any other colour - it remains green. |
| Daniel Thirteen-Twelve |
| I spoke to KAD ages ago as the calipers required spacers being made up so the disk was centered in the caliper. They also said a standard M/C would work but clearly it doesn't ( I'm using a 1500 dual line M/C) as I have far too much travel (only just passed MoT brake test on the rollers) and I have checked that no air is in the system, hence reverting back to standard calipers and they work fine. The K stands for Ken. |
| K Harris |
| Update changed the m.c. tonight for a new standard bore as it was the original,slight improvement but now seems very good if I give it a couple of pumps on the pedal before slamming the brakes on,I have pressure bled the system 3 times and no more air seems to be in there. under normal braking seems fine. Daniel The car has not been on a diet yet,so not a light car by any means. Mintex pads should be with me Wednesday,so I will give that a wirl and if still no joy there will be a nice pair of Kads on fleabay ! |
| Rob Newt |
| ""but now seems very good if I give it a couple of pumps on the pedal before slamming the brakes on"" But why should you have to pump it ? no good in a emergency !! hence why I changed back.. |
| K Harris |
| I have never had any joy with the 1500 dual circuit master cylinder - it always seems a complete pig to bleed and you always end up with excessive pedal travel. I have a single circuit .750 Wilwood Master cylinder on my B car with 4 pot Wilwood calipers and standard (possibly 1500?) rear slave cylinders. It works fine with no excessive travel. One day when I have time I will fit the Wilwood balance bar pedal box that I had on my last car... Rob - if you need to pump the brakes before they work OK then you still have air in the system... |
| James Bilsland |
I'm no expert but can't see any mention here of ensuring the rear drums are correctly adjusted. If not sorted it might help a little vis a vis pumping. Eggs Granny etc. |
| Gavin Rowles |
| I've had the KAD calipers for a couple of years with standard (1275) m/c and mintex pads. Work fine for me with no problems at MOT time, possibly a little overbraked now. Seem to remember if you work out the piston area standard/ KAD they are the same give or take. And yes adjusting the rears makes a big difference. David |
| d brenchley |
| rob if you ever want to get rid of them just say it i'll be glad to take them of you hands. since i hope to switch to a seperated mc system with balance bar that won't be a problem. |
| Onno Könemann |
| Thanks for the comments,very helpful. Back brakes all set up and bedded in. After driving back from south mids classic car meet I have come to the conclusion there must still be some air in there somewere (i thought I new how to bleed brakes)and a change to Mintex should do the trick. I now have a rather greater problem !! on the M42 doing about 70mph the bonnet catch came undone also ripping through the safety catch due to the speed and the wind DOH !!! BO@@OCKS,bonnet slammed into the windscreen,managed to pull off onto the hard shoulder,lucky to be alive ! So Onno how do you fancy a free car with the Kad callipers  |
| Rob Newt |
| Your very lucky, you were able to get on the hard shoulder. I had this happen in my old BGT after a MoT (tester never shut the Bonnet firmly) its a trouser filling moment, glad your OK. |
| K Harris |
| The Same thing happened to Bill in Lara. He had a similar crease in the front valance. |
| Gary Lazarus |
| Bloody hell that's a lucky escape. I'd be gutted to pick up damage like that - hope you get it sorted OK. |
| Jordan Gibson |
| ACK!!! I've had my bonnet catch come loose once, but the safety latch held until I got stopped. Very unnerving. Will you be fitting bonnet pins after you fix the damage? |
| Trevor Jessie |
| Tough break, Rob! Sorry to see that, and I hope you can get it put right ASAP. -:G:- |
| Gryf Ketcherside |
| rob bring it to MG Live then i'll take it off your hands ;) lucky that your windscreen held up a friend of mine had the same when he forgot to lock one of the bonet pins on his twincam racer of cours the front one.... he was lucky to only have damage on the bonet. |
| Onno Könemann |
| Cheers folks Cant beleive that its happened to so many other people,makes me feel a tad better now. Now the dust has settled I remember my other half saying "ouch that was a big pot hole" about a minute before it happened,so my guess is the pot hole dislodged the bonnet from the catch and the wind did the rest. So pot holes dont just wreck tyres!! Insurence accesser coming round Friday,that will be interesting.. Seems like I know how to show a girl a good time, stick a bonnett in her face at 70mph,were laughing now ...just.... |
| Rob Newt |
| "Seems like I know how to show a girl a good time, stick a bonnett in her face at 70mph" Thanks, Ill remember that one Rob! Have a date comming up in two weeks and first impression should be lasting isnt it? LOL!!!! |
| Arie de Best |
| Whoa! A date! How come it's two weeks away? Does she need that long to put her slap on? Or maybe it takes a while to do a full body shave. |
| Tarquin |
| A new better Master clyinder, with multiple bore sizes and vary inexpensive.... over lucas ???? Why of course...I belive there is one. but it means crossing over to the dark side of the force and turning your back on lucas and his jedi ways Now that Bill Young has (almost) crossed over to become "Darth Spridget" soon the whole world of spridget will come to know the power of the dark side and the end of lucas and his jedi master clyinders will finally be with in my grasp, and its Damnation forever! Feel the force under your foot...you cant resist the power of the dark side http://www.tiltonracing.com/content.php?page=list2&id=22&m=b PLUS http://www.tiltonracing.com/content.php?page=list2&id=13&m=b Prop...The true power of the black hole midget is revealed. |
| Prop |
| >>>>>>>>>>How come it's two weeks away? Does she need that long to put her slap on? Or maybe it takes a while to do a full body shave. <<<<<<<<< It takes a while to find a good sheep shaver http://www.sheep101.info/shearing.html Prop |
| Prop |
| Interesting Rob, after reading this thread I contacted the KAD distributor in the US about calipers for my Midget and their man said that on his Mini the 4 pots worked great but did increase the pedal movement a bit. I think the Mini uses a bit smaller bore master cylinder than the Midget though, so with a Midget the difference should be very small. I guess since Prop's dubbed it "Darth Spridget" I'll have to repaint it in black when I install the new brake masters.  |
| Bill Young |
| LoL. Id be leary of painting it black, with all the cofs, and other enviromental contaminates in paint, it could give it an astmatic breathing condition...LOL was it seven entrprise you contacted.... Im guessing its the soild gold pistons they use that makes them so incrediable expensive Prop....Kad calipers, I didnt even pay that much for my car. |
| Prop |
This thread was discussed between 11/04/2010 and 15/04/2010
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