BarryG Posted August 23, 2019 Report Share Posted August 23, 2019 I have owned my TR4A for about 4 years now. And last year I attended a garage inspection day organised by our group. This has resulted in a fair amount of work being done to the car. One of the smaller issues was that there was a fair amount of moisture in my Brake Fluid. I immediately replaced the brake fluid by running a litre of DOT 4 brake fluid into it, when finished I could see the bottom of the brake master cylinder ie clean fluid. Since then I have done about 750 miles and all of a sudden the fluid in the master cylinder resembles the bottom of the Thames, all muddy/dirty. So yesterday I ran another litre and a half through the system and was shocked at what came out. I have a jam jar where the bottom half is black and the top half is clear. I hasten to add that all during this time the brakes have always behaved themselves, worked fine every time and no sponginess. So somehow on the first attempt I could not have replaced ALL of the fluid - puzzled. Looking at the forum I see members mentioning the brake restrictor valve and what a waste of time it is, it seems that the best advice is to throw it away. Would I assume that this would be a simple case of removing the internal spring and seal? Could the restrictor valve be responsible for blocking off part of the system and some how I have freed this up by replacing the fluid twice? Has anyone else experienced this? Thanks Quote Link to post Share on other sites
stillp Posted August 23, 2019 Report Share Posted August 23, 2019 Looks to me as if you have one or more seals, or possible rubber hoses, breaking up. Yes, you can just ditch the internals of the restrictor valve, but I don't think that would explain the problem. I'd want to change all the flexible hoses and all the seals. Sorry. Pete Quote Link to post Share on other sites
Lebro Posted August 23, 2019 Report Share Posted August 23, 2019 +1 for rubber breaking up somewhere in the system. Bob. Quote Link to post Share on other sites
RogerH Posted August 23, 2019 Report Share Posted August 23, 2019 The rubber breaking up in the system doesn't really explain the crud in the master cylinder. This crud could simply be Aluminium being rubbed off the piston tube when pressing the pedal. The clutch suffers badly from this. However your jam jar does look like you have a rubber pipe issue. Roger Quote Link to post Share on other sites
Z320 Posted August 23, 2019 Report Share Posted August 23, 2019 (edited) Hi, I guess this is a mix of DOT 5 on the ground (was violet, is now black) and DOT 5.1 on top (was clear, is now dull). This mixes very bad and separates very fast. Shake it and see what happens. Ciao, Marco Edited August 23, 2019 by Z320 Quote Link to post Share on other sites
stillp Posted August 23, 2019 Report Share Posted August 23, 2019 Barry, how did you know there was moisture in your brake fluid? If there were visible drops of water then you must have had silicone brake fluid (DOT 5) which doesn't mix with DOT 4. Pete Quote Link to post Share on other sites
ctc77965o Posted August 23, 2019 Report Share Posted August 23, 2019 Hey Barry, as others have said, that jar looks like you have two immiscible fluids in your brake system (probably a silicone and a glycolether). Get a glass of clean water, use a teaspoon to get a drop of the top layer in your jar and drop it into the clean water...it should 'dissolve' into the water. Now decant the clear layer off your goopy jar (into another jar - eat more jam if you need to)...do the same with teaspoon to collect some of the bottom layer - does that dissolve in clean water? or does it float on top as a blob? In the meantime suggest you purchase master cylinder rebuild kits for both brake & clutch, as that blackness indicates something is degrading and contaminating the fluid. Quote Link to post Share on other sites
Peter Cobbold Posted August 23, 2019 Report Share Posted August 23, 2019 12 hours ago, Z320 said: Hi, I guess this is a mix of DOT 5 on the ground (was violet, is now black) and DOT 5.1 on top (was clear, is now dull). This mixes very bad and separates very fast. Shake it and see what happens. Ciao, Marco Dot5 (silicone) will float above glycol (Dot 4 or 5.1) Water will sink thtough the silicone and dissolve in the glycol. Mixing the two is bad for all rubber in the system, a bigger job that merely fresh fluid Peter Quote Link to post Share on other sites
Z320 Posted August 24, 2019 Report Share Posted August 24, 2019 (edited) 7 hours ago, Peter Cobbold said: Dot5 (silicone) will float above glycol (Dot 4 or 5.1) Water will sink thtough the silicone and dissolve in the glycol. Mixing the two is bad for all rubber in the system, a bigger job that merely fresh fluid Peter Hi Peter, a label next to the brake master in my TR4A told me silicone DOT5 was in there - and I changed over to DOT5.1 This is the bottle of what came out and made me believe on the ground is the silicone and on top DOT5.1 I might remember from the data sheet it should be the other way round.....? So it is time for a "good morning test" with this 2 brake fluids, the only both I had / have in use. And indeed you are right! Shame on me! I have been real surprised! The violet DOT 5 is on top, as you told it! What was my first thought? Never ever tell anyone anything that you have not checked yourself! But see what happened.... I shaked it..... And after two minutes to my own surprise this happened..... This is not to embarrass you, this is not at all what I expected, a surprising double turn in what I know or might think I know. But the story goes on the DOT4. Mixing... Shaking... Clear....? Needed more time to separate, about 10 minutes, this is the result! Only by the liquid level I guess DOT5 is still on top, as you expected, but lost all its colour? A very interesting start of the weekend with things I did not expect my own..... Ciao, Marco Edited August 24, 2019 by Z320 edit because of my bad english Quote Link to post Share on other sites
RogerH Posted August 24, 2019 Report Share Posted August 24, 2019 Hi Marco, that is astonishing. I have never seen that done before. So the only good test is adding water and seeing the results Roger Quote Link to post Share on other sites
Quicksilver Posted August 24, 2019 Report Share Posted August 24, 2019 Marco, that are interesting results, looking forward as Roger suggest, adding some water, and some rubber parts (sealings)....and shake. Marcel. Quote Link to post Share on other sites
Peter Cobbold Posted August 24, 2019 Report Share Posted August 24, 2019 (edited) 5 hours ago, Z320 said: Hi Peter, a label next to the brake master in my TR4A told me silicone DOT5 was in there - and I changed over to DOT5.1 This is the bottle of what came out and made me believe on the ground is the silicone and on top DOT5.1 I might remember from the data sheet it should be the other way round.....? So it is time for a "good morning test" with this 2 brake fluids, the only both I had / have in use. And indeed you are right! Shame on me! I have been real surprised! The violet DOT 5 is on top, as you told it! What was my first thought? Never ever tell anyone anything that you have not checked yourself! But see what happened.... I shaked it..... And after two minutes to my own surprise this happened..... This is not to embarrass you, this is not at all what I expected, a surprising double turn in what I know or might think I know. But the story goes on the DOT4. Mixing... Shaking... Clear....? Needed more time to separate, about 10 minutes, this is the result! Only by the liquid level I guess DOT5 is still on top, as you expected, but lost all its colour? A very interesting start of the weekend with things I did not expect my own..... Ciao, Marco Marco That means the blue dye in silicone Dot5 prefers to dissolve in water/glycol ( dot 4 or 5.1) Dot 5 and 5.1 should never be mixed. 5.1 is NOT a newer, better version of 5 Peter Edited August 24, 2019 by Peter Cobbold Quote Link to post Share on other sites
Z320 Posted August 24, 2019 Report Share Posted August 24, 2019 (edited) Hi Peter, thank you for this information, to be absolutly shure I made a test with more DOT5.1 und less DOT5. Shaking... Some minutes later DOT 5 (still on top) indeed lost all the violet colour to the DON5.1 (on the ground), amazing! So the two (not mixing?) fluids in Barry's cucumber glas could be DOT5 on the top and DOT5.1 on the ground? Text test is to mix DOT5.1 and DOT4.... Both are mixing immediately because they are both glycol based, only DOT5 is silicon. BTW: I do not use DOT 5 by conviction. Another look on the bottle with my old brake fluids perhaps is interesting: As we know now on the top is DOT5, lost all colour to the DOT 5.1 on the ground, between some "bubbles". Possibly this is water? Density due to datasheets I found at the internet: DOT4 = 1,04 gr/cm³ H2O = 1,00 gr/cm³ DOT5 = 0,96 gr/cm³ So water not fixed in the glycol fluid anymore should swim between both fluids? Ciao, Marco Edited August 24, 2019 by Z320 Quote Link to post Share on other sites
stillp Posted August 24, 2019 Report Share Posted August 24, 2019 12 hours ago, RogerH said: So the only good test is adding water and seeing the results Or you could pour some on your bonnet and see if the paint comes off. On second thoughts, might be better to use something other than your bonnet. Pete Quote Link to post Share on other sites
Peter Cobbold Posted August 24, 2019 Report Share Posted August 24, 2019 25 minutes ago, Z320 said: Hi Peter, thank you for this information, to be absolutly shure I made a test with more DOT5.1 und less DOT5. Shaking... Some minutes later DOT 5 (still on top) indeed lost all the violet colour to the DON5.1 (on the ground), amazing! So the two (not mixing?) fluids in Barry's cucumber glas could be DOT5 on the top and DOT5.1 on the ground? Text test is to mix DOT5.1 and DOT4.... Both are mixing immediately because they are both glycol based, only DOT5 is silicon. BTW: I do not use DOT 5 by conviction. Another look on the bottle with my old brake fluids perhaps is interesting: As we know now on the top is DOT5, lost all colour to the DOT 5.1 on the ground, between some "bubbles". Possibly this is water? Density due to datasheets I found at the internet: DOT4 = 1,04 gr/cm³ H2O = 1,00 gr/cm³ DOT5 = 0,96 gr/cm³ So water not fixed in the glycol fluid anymore should swim between both fluids? Ciao, Marco Marco, When you shake up dot 5 and 5.1 the huge surface area between the droplets allows the purple dye to migrate from the silicone to the glycol, which is where it prefers to be Technically it is called partitioning. https://www.quora.com/What-is-the-lipid-water-partition-coefficient-of-a-drug Dye partitioning leaves the dot5 clear Note that the dye deos not stain the silicone molecules, ther is no chemical attachment Partitong will happen slowly even without shaking uo the tow fluids. The dot 5 floats on the glycol as it is less dense,as in your table of SGs Water wont dissolve in silicone ( whis is why I use it) but is avidly absorbed by glycol, irreverisbly. The bubbles in the interface may be silcone droplets that have a contaminated surface preventing them from re-fusing with the bulk dot5. Traces of fat can do that, Peter Quote Link to post Share on other sites
Z320 Posted August 24, 2019 Report Share Posted August 24, 2019 Peter....., we lost Barry. Quote Link to post Share on other sites
rogerowen Posted August 24, 2019 Report Share Posted August 24, 2019 Yikes! I'm sticking to DOT 4! Quote Link to post Share on other sites
Peter Cobbold Posted August 24, 2019 Report Share Posted August 24, 2019 1 hour ago, Z320 said: Peter....., we lost Barry. Marxo, He'll be busy, strippimg out all the rubber in the system, flushing the pipes with meths, then drying with compreesed air. and rebuilding. Peter. Quote Link to post Share on other sites
keith1948 Posted August 25, 2019 Report Share Posted August 25, 2019 19 hours ago, Peter Cobbold said: Dot 5 and 5.1 should never be mixed. 5.1 is NOT a newer, better version of 5 Peter Yes I would echo the above advice from Peter. At a well known car/cycle shop they have Dot 4, Dot 5 and Dot 5.1 together on the same shelf. When I have asked the assistants about them I have been told you can mix them all which is absolutely wrong. I have also been told that 5.1 is a better version of the other two which is also wrong. You can use Dot 4 and Dot 5.1 in your braking system as they are ethylene glycol based. Dot 5 however is silicone based and should not be mixed with the other types. So if you have Dot 5 then only use Dot 5. Dot 4 is fine for road use and I have used it for years. The chemistry experiments are fascinating by the way. The same shop yesterday had never heard of a 2BA spanner. I spent about 15 minutes explaining to the assistant about metric, imperial, BA and Whitworth spanners. I could have been talking in a foreign language. Sign of the times! Keith Quote Link to post Share on other sites
rogerowen Posted August 25, 2019 Report Share Posted August 25, 2019 1 hour ago, keith1948 said: Yes I would echo the above advice from Peter. At a well known car/cycle shop they have Dot 4, Dot 5 and Dot 5.1 together on the same shelf. When I have asked the assistants about them I have been told you can mix them all which is absolutely wrong. I have also been told that 5.1 is a better version of the other two which is also wrong. You can use Dot 4 and Dot 5.1 in your braking system as they are ethylene glycol based. Dot 5 however is silicone based and should not be mixed with the other types. So if you have Dot 5 then only use Dot 5. Dot 4 is fine for road use and I have used it for years. The chemistry experiments are fascinating by the way. The same shop yesterday had never heard of a 2BA spanner. I spent about 15 minutes explaining to the assistant about metric, imperial, BA and Whitworth spanners. I could have been talking in a foreign language. Sign of the times! Keith Ha, ha. I was in a car shop yesterday and asked if they had straight 40 gear oil........they looked at me as if I was from Mars! Quote Link to post Share on other sites
ianc Posted August 25, 2019 Report Share Posted August 25, 2019 In these days of PC and LBGT, asking for anything "straight" could get you into serious trouble! Ian Cornish Quote Link to post Share on other sites
BarryG Posted August 25, 2019 Author Report Share Posted August 25, 2019 No you have'nt lost me - i'm still taking it all in. And thank you all very much for you input. Just a quick recap, when I bought the car some 4 years ago, the first thing I did regarding the hydraulics was to replace both front calipers as it failed its first MOT, owing to an unbalanced front brake reading something like 10% - 60%. So I would have thought that the rubbers in the brand new calipers should last for 4 years. At that time I replaced the fluid with DOT4. (I ran one litre through the system) As the Clutch was leaking I replaced both the slave and master cylinder and filled it with Silicone, the blue stuff. A few months ago I was told by a garage doing some work on the car that I had water in my brake fluid, no mention of a mix of Silicone and DOT 4, so again I replaced all of the fluid with DOT 4. Then a few weeks ago doing a regular inspection I noticed that the fluid in my master cylinder was a tad muddy looking. So at this stage I replaced the rubbers in the master cylinder and replaced the fluid with another litre of DOT 4. The only old rubber now that could be left in the system is the four flexible hoses at each wheel and the rear slave cylinders. The rear cylinders do look like new, I checked them when I first bought the car, the external rubber looks like brand new and the metal looks shiny clean as though they were both newly fitted by the previous owner (I cannot guarantee this of course). I think the route I will take is to replace all four rubber hoses, and yet another litre of DOT 4 and see how it goes. If there are still issues then I will replace the rear cylinders. This surely must resolve the issue as everything will be new. I have never put silicone into my braking system, so if there is any in the system it must have got past several changes of fluid. Quote Link to post Share on other sites
Peter Cobbold Posted August 25, 2019 Report Share Posted August 25, 2019 13 minutes ago, BarryG said: No you have'nt lost me - i'm still taking it all in. And thank you all very much for you input. Just a quick recap, when I bought the car some 4 years ago, the first thing I did regarding the hydraulics was to replace both front calipers as it failed its first MOT, owing to an unbalanced front brake reading something like 10% - 60%. So I would have thought that the rubbers in the brand new calipers should last for 4 years. At that time I replaced the fluid with DOT4. (I ran one litre through the system) As the Clutch was leaking I replaced both the slave and master cylinder and filled it with Silicone, the blue stuff. A few months ago I was told by a garage doing some work on the car that I had water in my brake fluid, no mention of a mix of Silicone and DOT 4, so again I replaced all of the fluid with DOT 4. Then a few weeks ago doing a regular inspection I noticed that the fluid in my master cylinder was a tad muddy looking. So at this stage I replaced the rubbers in the master cylinder and replaced the fluid with another litre of DOT 4. The only old rubber now that could be left in the system is the four flexible hoses at each wheel and the rear slave cylinders. The rear cylinders do look like new, I checked them when I first bought the car, the external rubber looks like brand new and the metal looks shiny clean as though they were both newly fitted by the previous owner (I cannot guarantee this of course). I think the route I will take is to replace all four rubber hoses, and yet another litre of DOT 4 and see how it goes. If there are still issues then I will replace the rear cylinders. This surely must resolve the issue as everything will be new. I have never put silicone into my braking system, so if there is any in the system it must have got past several changes of fluid. Hi Barry. Glad you're still here. I wonder if the previous owner used silicone and failed to mark the reservoir. If you still have the fluids in the bottle you photgraphed, take some of the clear upper layer and see if it mixes with water. If it doesnt its not glycol and is probably de-dyed dot 5. Brake system rubber may swell differently in glycol and dot5. and switching fluids may well shorten its life and reliability There was along thread a few years back when PaulAA dicovered his mechanic had topped up his dot5 with the "new version 5.1". He decided to replace all rubber components throughout. Peter Quote Link to post Share on other sites
harrytr5 Posted August 26, 2019 Report Share Posted August 26, 2019 Automec in Leighton Buzzard has told me most modern seals are no problem when using either DOT 4 Dot 5.1 or DOT 5 (silicone) Just flush out with the fluid you want to use. Reading the above and other sites I am not so sure. I have done it to mine in the past and had no problems (this is not an endorsement by the way) So confused! Using silicone for the last 25 years or so. Regards Harry TR5 Nutter Quote Link to post Share on other sites
RogerH Posted August 26, 2019 Report Share Posted August 26, 2019 (edited) Hi Harry, the silicone fluid is very very inert and would cause no damage to anything but the most delicate materials. The rubber used for DOT 3/4/5.1 is fine for DOT5. The issue comes when you switch fluids. Will a DOT 3/4/5.1 soaked rubber seal (or pipe) be happy to live in DOT 5 or vise versa. The base materials of the fluids may be OK with this but the additives may complain. So if you switch fluid then you really need to replace ALL rubber in the system and that includes the flex pipes. The only common fluid to stay clear off is Mineral oil - this will kill a conventional seal very quickly. Roger Edited August 26, 2019 by RogerH Quote Link to post Share on other sites
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