Mobile Mike Posted October 6, 2021 Share Posted October 6, 2021 Hi enthusiasts,I hope you can help. I recently purchased a 2016 Caterham SV 420R from Caterham South. I have taken it out on 1 track day. There was a brake fluid leek. Unfortunately this has hit the paint work and caused some considerable damage. I took the car back to Caterham and they have told me it is common for fluid to leak out of the cap when the car is being driven hard and that there is no "Broken Part" that would lead to a valid warranty claim. This to me sounds unlikely. Do these caps leak brake fluid, and should I put up with this as an explanation, or is this a defect and I should be insisting that the warranty rectifies the damage to the paint work?Thanks in advance for your consideration.Mike. Link to comment Share on other sites More sharing options...
Mark w Posted October 6, 2021 Share Posted October 6, 2021 The standard caps can leak a bit on track .Best to change it for the AP bellows type .It means you loose the brake warning light if the fluid level drops but at least you dont get spillage . Link to comment Share on other sites More sharing options...
OldAndrewE Posted October 6, 2021 Share Posted October 6, 2021 See this threadCaterham 620s - Brake warning light coming on under acceleration | Lotus Seven Club (lotus7.club) Link to comment Share on other sites More sharing options...
Mark w Posted October 6, 2021 Share Posted October 6, 2021 https://caterhamsuperlight106.wordpress.com/tag/ap-racing-brake-master-cylinder-cap/This is the type Link to comment Share on other sites More sharing options...
Wrightpayne Posted October 6, 2021 Share Posted October 6, 2021 Caterham 'race' cap.....https://caterhamparts.co.uk/master-cylinder/914-brake-master-cylinder-cap-race-no-float-switch.html Link to comment Share on other sites More sharing options...
ScottR400D Posted October 6, 2021 Share Posted October 6, 2021 Just do this. First track day in 2015 mine spilt fluid. I had to respray the top of the side panel. Fitted this and it's been fine since. And I get to keep the low level switch.Sorry about the orientation. It's fine anywhere else but whatever I do here it turns the image Link to comment Share on other sites More sharing options...
MattB Posted October 6, 2021 Share Posted October 6, 2021 For info, the current owner's handbook (dated 2017) states on p26:"NOTE: For track use, cars fitted with uprated brake master cylinder must use race cap to avoid any leaks"MattB Link to comment Share on other sites More sharing options...
ChrisC Posted October 6, 2021 Share Posted October 6, 2021 I combine the tried and tested shop towel with motorbike brake master cylinder socks, even with the race cap fitted. https://caterham420detailedbuildblog.co.uk/2020/09/11/finishing-touches/ Link to comment Share on other sites More sharing options...
7 wonders of the world Posted October 6, 2021 Share Posted October 6, 2021 If using the race bellow make sure you remove the plastic baffle and seal from the new cap otherwise it will neither seat correctly or fully tighten Link to comment Share on other sites More sharing options...
GulfSeven Posted October 6, 2021 Share Posted October 6, 2021 That's interesting.I found mine quite hard to seat and tighten, but had advice elsewhere that you just had to be careful not to overtighten.I didn't think to try and remove the inserts from the cap. Are you sure that's required? Wouldn't Caterham supply it without those if that was the case? Link to comment Share on other sites More sharing options...
7 wonders of the world Posted October 6, 2021 Share Posted October 6, 2021 The baffle is only there to deflect fluid ejected as you release the brakes, however the bellow now does this, likewise the seal is redundant as the lip of the bellow is also the new seal.The detail is on the AP site, give me a few minutes and I will try to find the linky, Link to comment Share on other sites More sharing options...
7 wonders of the world Posted October 6, 2021 Share Posted October 6, 2021 Here you go:https://apracing.com/race-car/actuation-products/fluid-reservoirs/bellows-diaphragms/small-size-cp2709-156 Link to comment Share on other sites More sharing options...
GulfSeven Posted October 7, 2021 Share Posted October 7, 2021 Thanks! I shall refit mine then! Link to comment Share on other sites More sharing options...
Support Team andy_harries Posted October 7, 2021 Support Team Share Posted October 7, 2021 I was told that this is a typical issue with the standard fluid cap - another club member told me that after the first time on track in his Academy year Caterham did a brisk trade selling 'race caps' for the fluid reservoir as so many leaked. You lose the brake fluid sensor as the cap doesn't have the links, but on the plus side the paint work is saved Link to comment Share on other sites More sharing options...
GulfSeven Posted October 8, 2021 Share Posted October 8, 2021 #12 Thanks.Having refitted it without the baffle and the seal it certainly screws down further. You still have to be careful not to overtighten though. Link to comment Share on other sites More sharing options...
Area Representative Geoff Brown Posted October 8, 2021 Area Representative Share Posted October 8, 2021 The problem with my 2013 R400D is not hydraulic leakage from the brake MS cap but from the 5/8" Willwood clutch MS cap. The rubber seal tends to snag up if wet with fluid so on tightening it slips & progressively becomes damaged every time it is refitted.The answer is to ensure that the MS body lip & cap seal are as dry as possible before refitting.If replacement is necessary don't go to CC at £23.20 (part ref 300B0043A) go to www.rallydesign at £8.31 part ref 330-1-15081. Link to comment Share on other sites More sharing options...
7 wonders of the world Posted October 8, 2021 Share Posted October 8, 2021 Dry the cap and seal then lightly apply a small amount of RRG goes up a treat then Link to comment Share on other sites More sharing options...
Guy Lowe Posted October 8, 2021 Share Posted October 8, 2021 Not pretty but it works, I also have the race cap underneath. Link to comment Share on other sites More sharing options...
AG2728 Posted October 8, 2021 Share Posted October 8, 2021 Might not impress a fussy scrutineer though Link to comment Share on other sites More sharing options...
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