Guest 72 blue Posted February 18, 2006 Report Share Posted February 18, 2006 Im in the process of replacing the master cylinder on my tr6,i am considering using silicone fluid is this superior to regular dot 4 fluid or am I better using dot 4 for regular road use Quote Link to post Share on other sites
ianhoward Posted February 18, 2006 Report Share Posted February 18, 2006 There has been a good amount of discusion on this subject - if you perform a search in the forum you will find plenty of good reading!! Trouble seems to be that there do not seem to be any definitive answers! It's all down to personal preference... You pays your money and takes your choice Brgds Quote Link to post Share on other sites
Don Elliott Posted February 19, 2006 Report Share Posted February 19, 2006 In 1990 when I finished the restoration of my TR3A, I put in silicone fluid. I had changed all the hoses and rubber seals at the time. The only problem I had was in 2001 when I spent 2 weeks in the Rocky Mountains (10,000 to 12,000 ft altitude) and we bled the brakes to get the pressure back. I've driven 87,000 miles with silicone fluid and never had any other complaints. Don Elliott, Original Owner, 1958 TR3A TR Register Member since 1987 http://mysite.wanadoo-members.co.uk/trebor/don3a_big.JPG Quote Link to post Share on other sites
DaveR Posted February 19, 2006 Report Share Posted February 19, 2006 I have used Silicone Brake Fluid in our Gitfire for 11 years. After 7 years the seals went soft, feels like air in the system. I replaced the seals and all has been ok since. When I replaced the seals cylinder bores were found to be in excellent condition mainly I feel due to the use of Silicone. One of the reported disavantages to using Silicone has been fluid compression, feels as if there is air in the system. The only time I found this to be present was when the seals were defective i.e. soft. Just my own findings, the stuff work for me. Quote Link to post Share on other sites
foster461 Posted February 19, 2006 Report Share Posted February 19, 2006 I'm going to do this conversion this summer. I have read all the info and I think the benefits outweigh the potential issues. My main interest in silicone is to avoid future paint damage after I refurb the engine compartment and servo which along with the inner and outer bulkhead have all suffered from brake fluid leaks/spills. Stan Quote Link to post Share on other sites
Les Pettitt Posted February 19, 2006 Report Share Posted February 19, 2006 I changed to silicone, copper pipes and stainless steel flexibles several years ago and have had no problems at all. I think the brakes are better than before. The pitting in my old cylinders made me determined to change to silicon. I guess water got into the old fluid but this was probably my fault as I never changed it. No such problems with silicon. They work perfectly straight away after a winter lay up whereas I always had problems when using the old fluid and had to pump the brakes to get any feel to them after a few months of non use. Quote Link to post Share on other sites
jonlar Posted February 19, 2006 Report Share Posted February 19, 2006 Hi 72blu, as Ian says this has been covered before, try these: http://www.tr-register.co.uk/forums/index....653&hl=silicone http://www.tr-register.co.uk/cgi-bin/ib3/i...t=ST;f=5;t=5265 http://www.tr-register.co.uk/forums/index....wtopic=3423&hl= Quote Link to post Share on other sites
Richard Crawley Posted February 20, 2006 Report Share Posted February 20, 2006 Been running silicone for nearly 3 years now since total restoration. No problems on initial fill & bleed of the system at all, pedal action feels reassuringly good & brakes work fine. I would certainly replace all the seals before switching over & using braided hoses helps to avoid any sponginess in the pedal. Quote Link to post Share on other sites
Guest 72 blue Posted February 20, 2006 Report Share Posted February 20, 2006 Thanks for all of your comments this forum is invaluble for reasurance at times I shall try silicone and braded hoses thanks again Quote Link to post Share on other sites
Terry Pruce Posted February 21, 2006 Report Share Posted February 21, 2006 I had converted to silicone and found it rotted my seals. So now use Lucas 5.1 fluid ( for over 6 years ) which is not aggressive to paint work. I think other 5.1's are also much more gentle on paint than the 4dot's but have no specific evidence to support this. Quote Link to post Share on other sites
Andy Moltu Posted February 21, 2006 Report Share Posted February 21, 2006 In 1990 when I finished the restoration of my TR3A, I put in silicone fluid. I had changed all the hoses and rubber seals at the time. The only problem I had was in 2001 when I spent 2 weeks in the Rocky Mountains (10,000 to 12,000 ft altitude) and we bled the brakes to get the pressure back. I've driven 87,000 miles with silicone fluid and never had any other complaints. Don Elliott, Original Owner, 1958 TR3A TR Register Member since 1987 http://mysite.wanadoo-members.co.uk/trebor/don3a_big.JPG I'll concur with Don's experience - I have had no problems other than at altitude - high in the Alps. Silicon fluid, repeated braking and altitude lead to a soft pedal. However I've never, ever had problems with soft pedal at sea level in spite of similar repeated heavy braking. When I go to the Alps next I'll put regular brake fluid in but will happily revert to silicon after. (Doesn't strip your painwork when it leaks) Quote Link to post Share on other sites
jean Posted February 21, 2006 Report Share Posted February 21, 2006 Terry, I was convienced that DOT 5.1 is more or less the same as DOT4, clycol based, but has a higher boiling point. Im almost sure that it eats paint at the same rate won't challenge it. Jean Quote Link to post Share on other sites
raydrink Posted February 26, 2006 Report Share Posted February 26, 2006 The other major benefit is that Silicone fluid does not take up water. Every winter one piston in each of the rear slave cylinders on my Stag rusted solid, even though the car was used throughout the winter, albeit rarely. Expensive in new cylinders. I put Silicone in and the problem's gone away. Ray Quote Link to post Share on other sites
marvmul Posted February 26, 2006 Report Share Posted February 26, 2006 If altitude can cause spongy pedal when using silicone brake fluid, I suppose the only explanation is that small or microscopic air bubbles stay in the brake lines and pumps? Perhaps the brake pedal is a little spongy at sea level too, but the driver get accustomed to it and it is only noticed when it get worse when driving in the mountains. When silicone brake fluid was 'invented' (was it first used in the army?), it must have been very interesting to racing people, because the boiling point of SBF was higher than the best brake fluid of that time and it seems that the reason why SBF was not succesfull in racing may well be the bleeding problem. In racing, bleeding is often required because of changing of brake system components, and bleeding should be perfect in one go. Quote Link to post Share on other sites
Roger H Posted February 27, 2006 Report Share Posted February 27, 2006 Although this may have been covered in previous links, it may be worth checking out this site for brake fluid and other info http://www.afcoracing.com/tech_pages/fluid.shtml Quote Link to post Share on other sites
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.