Paul H Posted September 13, 2021 Report Share Posted September 13, 2021 Planning to change the Clutch and Brake Fluid , it’s 4 years old and the cheap tester reads 3 to 4 % The only issue is the new unopened bottle says the same 😱 or worse What to do ??? Paul Link to comment Share on other sites More sharing options...
johny Posted September 13, 2021 Report Share Posted September 13, 2021 Drive it😆 Link to comment Share on other sites More sharing options...
Pete Lewis Posted September 13, 2021 Report Share Posted September 13, 2021 this may just be a the calibration of the tester i guess you could warm some fluid to dispel any moisture and re test but if the sealed new is showing the same as the used then time to question its accuracy Pete 2 1 Link to comment Share on other sites More sharing options...
Paul H Posted September 13, 2021 Author Report Share Posted September 13, 2021 How often should we change Dot4 Paul Link to comment Share on other sites More sharing options...
NonMember Posted September 13, 2021 Report Share Posted September 13, 2021 I always reckoned that two years was about right for DOT4. I use DOT5 though, so I don't really know. Link to comment Share on other sites More sharing options...
dougbgt6 Posted September 13, 2021 Report Share Posted September 13, 2021 Be careful "warming" DOT4, it's far more flammable than petrol. I would take the new stuff back to where you bought it. Doug Link to comment Share on other sites More sharing options...
daverclasper Posted September 13, 2021 Report Share Posted September 13, 2021 2 hours ago, dougbgt6 said: I would take the new stuff back to where you bought it. Only if your sure it's dodgy? Link to comment Share on other sites More sharing options...
PeteH Posted September 13, 2021 Report Share Posted September 13, 2021 Change DOT4 at least every 2 years, even on well used vehicles. I experienced loss of braking due to "fluid boil", on a 9tonne R-V once!. It is a definite "brown trouser" moment!. As for your New Fluid showing "iffy". I would suspect the tester?. I`ve recently done my `06 P-107, because I had no idea when it was last done. I treat myself to a Vaccuum kit to speed the job up single handed. Pete Link to comment Share on other sites More sharing options...
Pete Lewis Posted September 13, 2021 Report Share Posted September 13, 2021 we had to continually sample trucks with DOT4 as storeage times could be Looong the moisture content over a year was really alarming all down the the breathing via the reservoir cap vent with ambient temperature changes when its hot air is expanded and expelled then overnight its cooled and drawn back in thats where the moisture enters and the flluid absorbs it its the moisture content that boils off in a hot caliper and you loose the pedal its not the fluid boiling just the water and whilst tootling round the lanes probably wont get hot enough but a fast dash down countisbury in devon or hardknott in the lakes and brown trouser rules will be evident a change every 2 years is the industry standard yes petrol on a hot exhaust will fizz and vapour up , wont ignite but brake fliuid will be an instant fire Pete Link to comment Share on other sites More sharing options...
johny Posted September 13, 2021 Report Share Posted September 13, 2021 I never understood why cars dont have a rubber bellows arrangement like motorbikes to keep the fluid away from the air. Its just a folded membrane clamped in place by the reservoir lid that seals the fluid but still allows its level to change. The air above it is then free to enter and exit as normal.... Link to comment Share on other sites More sharing options...
PeteH Posted September 13, 2021 Report Share Posted September 13, 2021 23 minutes ago, johny said: a rubber bellows arrangement like motorbikes Racking my brain to think where I had seen that arrangement. BMW R100RS.👍. There is a similar system on (some) US R-V`s with the Power Brake Boost system too, Did`nt prevent the issue with the R-V though!! Pete Link to comment Share on other sites More sharing options...
johny Posted September 13, 2021 Report Share Posted September 13, 2021 Seems to be pretty standard on bikes but maybe thats because the reservoirs they use are small - not much smaller than a standard Triumph one however,,,, Link to comment Share on other sites More sharing options...
Pete Lewis Posted September 13, 2021 Report Share Posted September 13, 2021 who can now visualise a reservoir under the bonnet with a condom over the lid !!!! pete Link to comment Share on other sites More sharing options...
dougbgt6 Posted September 13, 2021 Report Share Posted September 13, 2021 If it saves money, why not? And condoms will always save you money, in the long run. Doug 2 Link to comment Share on other sites More sharing options...
Badwolf Posted September 13, 2021 Report Share Posted September 13, 2021 These ideas come..and go. Yes I know. Close the door on your way out. Link to comment Share on other sites More sharing options...
johny Posted September 14, 2021 Report Share Posted September 14, 2021 8 hours ago, dougbgt6 said: If it saves money, why not? And condoms will always save you money, in the long run. Doug Sod the money, its those horrible boiling brakes I want to avoid! Link to comment Share on other sites More sharing options...
Peter Truman Posted September 14, 2021 Report Share Posted September 14, 2021 No fun running out of brakes due to boiling, it happened to me in the early 70's in the Mk2 Vitesse crossing the St Goddard Pass and doing battle with a Alfa, he finely nailed me coming down on a straight section. I limped into Como and after booking into the hotel I took the car to the RR garage next door to get the brakes and steering sorted, left the car with them overnight they changed the brake fluid and bled the brakes, and welded a bolt onto the sheared U bolt that holds the rack, they wouldn't change me, saying they'd get it back on the next Rolls service! The owner asked who won, I told him the Alfa on the way down, I'd held him off all the way up and most of the way down the pass, he said I hadn't tried hard enough, he'd taken the Vitesse home overnight and was very impressed with it's easy revving good torque and roadholding, great car for driving the alps. I then dropped a UJ in the tunnel at Monte Carlo, being a smart arse, well the GP had only finished a week earlier, and I gave the car some real wellie when I entered the tunnel, now that repair did cost me a lot, only a UJ, but the Frenchie garage in Nice charged 50quid! Link to comment Share on other sites More sharing options...
Chris A Posted September 14, 2021 Report Share Posted September 14, 2021 2 hours ago, Peter Truman said: Frenchie garage in Nice charged 50quid! That's the Riviera for you 🤑 Link to comment Share on other sites More sharing options...
Patrick Taylor Posted September 19, 2021 Report Share Posted September 19, 2021 So can you change to Dot 5 simply by putting it in the reservoir and bleeding it through? I have a dim memory of needing to fit new seals throughout first? Link to comment Share on other sites More sharing options...
dougbgt6 Posted September 19, 2021 Report Share Posted September 19, 2021 Depends how old your seals are. DOT4 "lubricates" the seals, DOT5 doesn't. so older seals may appear fine until you pour the DOT5 in. Here is an excellent piece on choosing brake fluid. Selecting+Brake+Fluid.pdf (squarespace.com) I didn't change my clutch seals when I swapped to DOT5 and it works fine, although had to be bled 3 times over 3 or 4 days to get the air out. Douh 2 Link to comment Share on other sites More sharing options...
Badwolf Posted September 19, 2021 Report Share Posted September 19, 2021 When I went over to D5 I changed all the rubbers. Then the clutch master cylinder leaked. Down the pedal, all over the footwell. Modern rubber spares!!! Pah!! Good thing other rubbers aren't as useless?...or are they???? Link to comment Share on other sites More sharing options...
Pete Lewis Posted September 19, 2021 Report Share Posted September 19, 2021 from past history makers like girling/lockheed offered no warranty on hydraulic components using Dot5 even though it was approved on certain military contracts we used it on .the lack of moisture absorption helps vehicles in long store. i was just a firm NO !! one thought following Dougs post about lubrication DOT5 does not seep past the seal lip so the bore continually runs dry so its a win some loose some Link to comment Share on other sites More sharing options...
dougbgt6 Posted September 19, 2021 Report Share Posted September 19, 2021 52 minutes ago, Pete Lewis said: from past history makers like girling/lockheed offered no warranty on hydraulic components using Dot5 even though it was approved on certain military contracts Yeh, the Buckeye Triumph guy says that, he put it in his TR6, but not his moderns because it invalidates the warranty. And you shouldn't use it on ABS brakes. Doug Link to comment Share on other sites More sharing options...
Patrick Taylor Posted September 19, 2021 Report Share Posted September 19, 2021 3 hours ago, dougbgt6 said: And you shouldn't use it on ABS brakes. That's OK -Bond didn't fit ABS to the Equipe, although it may have been possible to buy Bond-branded Hush Puppies with vibrating soles to achieve the same effect (this story will be confirmed on April 1st)😁. However, they were the first car manufacturer to fit a breakdown warning triangle to their cars... Link to comment Share on other sites More sharing options...
Pete Lewis Posted September 19, 2021 Report Share Posted September 19, 2021 8 minutes ago, Patrick Taylor said: first car manufacturer to fit a breakdown warning triangle to their cars... were they tempting fate ??? Pete Link to comment Share on other sites More sharing options...
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