| Author | Message | |||
     Robert Noel Reddington Frequent User Username: bob_uk Post Number: 89 Registered: 5-2015 |
factors that govern when brake fluid should be changed are generally restricted to water content. However copper content dissolved in the fluid is of concern. 200 parts per million is the limit. How this effects copper or cunifer pipes I could not find out. Also a race car guy told me that once brake fluid has boiled its no good. | |||
| Randy Roberson Grand Master Username: wascator Post Number: 432 Registered: 5-2009 |
If boiled means that it had water in it which turned loose during hard braking, that is one obvious fault. Another; when glycols are overheated they start to decompose and become acidic. Another problem. I suppose glycol has a boiling point as well. Does it start boiling first or decomposing due to heat first? I don't know. Something in the fluid, like water, could damage the copper. So could acidic products of decomposition. | |||
| Robert Noel Reddington Frequent User Username: bob_uk Post Number: 99 Registered: 5-2015 |
I have found out about copper. Brake fluid [DOT3]. Before 1969 didn't have a inhibitors to stop corrosion of copper. The inhibitors wear out. The fluid attacks the copper. Copper ions then go looking for iron ions. Which corrodes ferrous metals. Its been identified at 200 ppm as being the max before corrosion starts Also the corrosion causes oxygen ions to aid the rust. Race guys say they have boiled brake fluid that is only hours old from a foiled sealed container. Once boiled I am not sure what happens to the fluid that makes it unusable. Bearing in mind that corrosion is not an issue with race stuff. Because they change brake fluid every race. | |||
| David Gore Moderator Username: david_gore Post Number: 1636 Registered: 4-2003 |
"The inhibitors wear out. The fluid attacks the copper. Copper ions then go looking for iron ions. Which corrodes ferrous metals." Bob, I think you have got this back to front. Remember the school science class experiment of copper plating a steel object [usually a nail] in a container of Copper Sulphate solution. The Copper/Iron electrochemical reaction causes the Copper to plate the surface of the iron. A similar process would have occurred in brake systems containing Copper and Iron components especially once the fluid began to absorb moisture from the atmosphere; the uninhibited DOT3 brake fluid would preferentially corrode the copper components and this would then plate the iron components. The iron does not corrode as it is being protected by the cathodic protection from the anodic erosion of the metallic copper. | |||
| Robert Noel Reddington Prolific User Username: bob_uk Post Number: 101 Registered: 5-2015 |
Yes I checked and I have got it back to front. Is this copper plating damaging any thing. Will spool valves and pistons get bigger. | |||
| David Gore Moderator Username: david_gore Post Number: 1642 Registered: 4-2003 |
Not really, the plating is very thin as well as very soft and would wear away very quickly on moving parts. | |||
| Omar M. Shams Grand Master Username: omar Post Number: 474 Registered: 4-2009 |
A small request please: For the benefit of those who don't know the personalities on this forum, may I respectfully request that we give this "dot" thing its proper name? Also do the moderators have the tools to retrospectively do a "find and replace" of previous threads that repeatedly reference "dot" to give it its proper name? For the record, my understanding is that "dot" is brake fluid. How someone from outside the small group of regular users of this forum is expected to pick up on it appears to be a challenge to me. | |||
| Brian Vogel Grand Master Username: guyslp Post Number: 1383 Registered: 6-2009 |
Omar, I'm inclined to agree, particularly when it's not abbreviated as DOT3, DOT4, or just brake fluid. The lower case dot is simply a diminution of the Department Of Transportation designation, which always has a number that goes with it. Of course, there is the whole "learning from context" and "you have to deal with jargon" thing in any area. Brian | |||
| Geoff Wootton Grand Master Username: dounraey Post Number: 761 Registered: 5-2012 |
I agree with Omar. There are several users who do not speak English as their first language. So impeccable is their written English I doubt most of us realize this. It must be a lot harder for these users to gain meaning from context. There is also the problem of jargon used in the trade. Most of us are enthusiasts who have never heard some of this terminology. "Windy gun" is a good example. So, my vote is with Omar. Geoff | |||
| Robert Noel Reddington Prolific User Username: bob_uk Post Number: 102 Registered: 5-2015 |
Point taken. I shall refrain from using Dot and use brake fluid. I have never understood why the word fluid is used. Fluid means gas or liquid. Automatic Transmission Fluid. Is really oil. Brake fluid is hydraulic oil. Instead of engine oil -- engine fluid. Maybe the word fluid is used to make the stuff sound exotic. Many moons ago a guy wanted brake fluid and brought autobox fluid instead. He thought that fluid is fluid. I repaired his brakes after - Renault 25. Moderator's Comment: This is one that slipped past me as I normally refer to R-R/B brake fluid as RR363 when related to Silver Shadows, mineral hydraulic fluid for Silver Spirit and later models and DOT3/DOT4 for all other makes [except certain Citroen models of course]. Have appropriately edited the title and relevant posts. Thank you Omar for bring this oversight to my attention | |||
| Bob Reynolds Prolific User Username: bobreynolds Post Number: 270 Registered: 8-2012 |
The use of the term DOT is particularly misleading when talking about Shadows, as they don't actually use DOT! | |||
| David Gore Moderator Username: david_gore Post Number: 1643 Registered: 4-2003 |
Bob, I think Bob was talking generally about brake fluid used in non-R-R/B vehicles - RR363 for Silver Shadows is known to be a blend of DOT3/DOT4 and a modified castor oil. The castor oil is specifically added to be a lubricant for the high-pressure pumps which have very fine tolerances for the piston and bore to minimise fluid leakage past the piston as there are no oil seals as per the normal practice for hydraulic system piston pumps. | |||
| Robert Noel Reddington Prolific User Username: bob_uk Post Number: 106 Registered: 5-2015 |
Problem solved I shall call Shadow brake fluid RR363. and normal cars Dot 3/4. As Dave said RR363 is Dot brake fluid blended with castor oil. My RR363 tank says Dot on the label. Anyway your wish is my command. I tend to forget that Grease Monkey English is difficult for other first language speakers. Dot is easy to write. | |||
| Jan Forrest Grand Master Username: got_one Post Number: 809 Registered: 1-2008 |
Aren't all gasses and liquids actually fluids no matter what they are formulated to do? It's even been proved by experimentation that many solids, if separated into discrete particles, can act similarly to fluids. Examples include flour, grain, sand, soft soil and even huge boulders in a land/rock slide. Snow has little difficulty in flowing around obstacles during an avalanche - until it stops which is when it sets almost as hard as concrete! | |||
| David Gore Moderator Username: david_gore Post Number: 1648 Registered: 4-2003 |
"Aren't all gasses and liquids actually fluids no matter what they are formulated to do? It's even been proved by experimentation that many solids, if separated into discrete particles, can act similarly to fluids." Pedant's Corner: Harking back to my university days when I had to do a subject called momentum, heat and mass transfer due to its relevance to mineral processing and metal refining, a fluid was referred to as being a substance that had no fixed shape and which would always move when subject to eternal pressure. Accordingly gases and liquids conform to this definition but solids do not as their size and mass may be such that they could have a fixed shape and not always move/change shape when subject to external pressure. A "suspension" of fine solid particles in a liquid or gas can but not always exhibit the properties of a fluid and would not categorised as a fluid for this reason IMHO. | |||
| Robert Noel Reddington Prolific User Username: bob_uk Post Number: 137 Registered: 5-2015 |
Yes all liquids and gasses are fluids. Solids in dust form behave like fluids. And an ignition source can make behave like a gas. Explosion in a custard factory. Saw dust is deadly. A few years back a saw dust extractor build up a static charge. It went bang and fell off the wall. Chains can behave like a fluid. I noticed this watching a ship drop anchor. They say that hitting water at 60 mph is like hitting concrete. I saw a mud and rock slide on tv it looked like a river. Fluid dynamics is a whole subject on its own. Starts off easy to understand then its my brain hurts. Imagine dry sand flowing. Then up the scale to large rocks I suppose any thing can flow. A good example is aluminium extrusions. I used to work for Fairy Nuclear. They made magnesium alloy finned tubes inside which they put radioactive stuff at the power station. A large hydraulic ram forced the alloy through a die and the alloy flows like a liquid. Amazing to watch. Bit like a play doe machine for grown ups. | |||
| Jan Forrest Grand Master Username: got_one Post Number: 817 Registered: 1-2008 |
Swaging is the term for what you saw at Fairy. It's a common way of changing the shape of metals; In 'drawing' (thinning wires) drawing it is caused by pulling the item through the die, while swaging is performed by pushing it through. | |||
| Robert Noel Reddington Prolific User Username: bob_uk Post Number: 173 Registered: 5-2015 |
It was dangerous because of the magnesium. Oil was used for cooling and lubrication. The combination was lethal if it caught fire. Never did though. The extrusion ram had mega serious force. One could feel it though the floor. I saw a film about making copper wire and it's surprising the speed the copper is drawn through the die. The copper billet moves slow but the wire goes fast. Rists cables Ltd. | |||
| David Gore Moderator Username: david_gore Post Number: 1655 Registered: 4-2003 |
Pulling material through a stationary die is known as drawing and it is often a puzzle for observers who cannot work out why the thinner output section doesn't break from the applied tension. The physics involved is quite complicated and is explained in the following document for anyone who is interested:
Pushing metal through a stationary die to change its dimensions and shape is known as forward extrusion and pushing back with a ram along a stationary die is known as backward extrusion. The best known products manufactured by forward extrusion are the diverse shapes of aluminium architectural and structural sections. Metal toothpaste tubes and aluminium drink cans are made by backward extrusion. Deep drawing is a variant of forward extrusion where a flat sheet of metal is pushed through a stationary die whilst being held back by applied pressure to transform its shape. Common items produced by deep drawing include stainless steel sink bowls and laundry tubs. My most difficult but rewarding deep drawing problem involved the manufacture of the first implantable sealed Titanium cases for heart pacemakers made by Teletronics when two of our stainless steel customers who were recognised experts in producing difficult deep drawn products were approached to see if they could make the very deep and narrow draw required for the desired shape. Much testing and scrap metal was involved until a successful technique was developed involving the use of an extreme pressure lubricant. https://en.wikipedia.org/wiki/Deep_drawing Pedant's Corner: Swaging usually refers to an alternative metal forming process similar to forging using movable or rotating dies and a stationary workpiece. It is sometimes used in the metal tube industry to refer to the wire drawing process used to correctly size the tube or reduce its diameter. | |||
| christopher carnley Unregistered guest Posted From: 86.173.13.57 |
A far cry from the wire drawing of the16&1700,s that went on around here.Involving a pierced wortle plate, hand wound drums, and lots of child labour to scour the scale from the hardened wire . It went to the needle and pin "factories" as seen in Denis Diderot, "Encyclopedie", (Message approved by david_gore) | |||
| David Gore Moderator Username: david_gore Post Number: 1657 Registered: 4-2003 |
Christopher, Using drums to pull the wire through the die is still used today, the only difference is the drum is driven by an electric motor instead of by young children often from a nearby home for orphans and abandoned children who were paid a pittance much to the benefit of the wealthy factory owners. Children from poor families were also involved in child labour under atrocious conditions. | |||
| Jan Forrest Grand Master Username: got_one Post Number: 820 Registered: 1-2008 |
Swaging soft materials (eg. lead and soft copper alloys) can be performed by hand powered machinery. A lot of home reloaders of bullet heads use it to finalise the sizing of hand cast slugs. In this case the die is fixed and the slug is forced into it. |
Drawing