stvaughn Posted May 12, 2019 Share Posted May 12, 2019 Is anybody having any issues with using DOT 5 brake fluid with brass sleeved cylinders? I have been told that they are not compatible. Link to comment Share on other sites More sharing options...
Bloo Posted May 12, 2019 Share Posted May 12, 2019 I can't quite answer your question. I do know that the main source of brass sleeved cylinders was (and possibly still is) White Post Restoration. As I understand it, White Post do not condone the use of DOT5 fluid under any conditions, and will void the warranty if you use it. There have been long threads about DOT5 fluid in the past, and this is the first time I have heard of incompatibility of the fluid with the metal itself. Frankly I doubt it. I have heard of brass (harmlessly) discoloring the fluid as it wears. I don't think that is exclusive to DOT5 though. I really don't know, but I would bet he just got sick of babysitting people who could not get DOT5 bled properly. It is very tough to bleed. Certainly not a job for anyone who lacks patience or has a short temper. 2 Link to comment Share on other sites More sharing options...
Frank DuVal Posted May 12, 2019 Share Posted May 12, 2019 No metallurgical reason for DOT 5 to not be compatible with brass. There are brass parts in most all brake tubing systems!😉 I have not had any brass lined cylinders that I know of, but have run DOT 5 in cast iron, aluminum and stainless steel cylinders. Never an issue.👍 I do know some people just cannot bleed a system properly. I saw a guy help another person (who had no experience doing it) bleed their brakes. This guy sat behind the wheel and pumped the brake pedal like it was a machine gun! The firewall actually moved!!!!!! This is a sure way NOT to properly bleed brakes, and get air trapped in the DOT 5 fluid. I'm sure this idiot was taught by a prior idiot, so they are out there!😲 2 Link to comment Share on other sites More sharing options...
Ben Bruce aka First Born Posted May 12, 2019 Share Posted May 12, 2019 I am not understanding why dot5 is any more difficult to bleed than any other. One is bleeding the AIR, not the fluid. Ben Link to comment Share on other sites More sharing options...
auburnseeker Posted May 12, 2019 Share Posted May 12, 2019 3 hours ago, Ben Bruce aka First Born said: I am not understanding why dot5 is any more difficult to bleed than any other. One is bleeding the AIR, not the fluid. Ben The problem is if you don't do everything nice and slow, it froths up mixing the air into the fluid in little bubbles that you need to let settle out. Usually do it all then let it sit and do it again the next day. It will come out eventually and you will never touch it again so it's worth the extra cost and effort up front. I don't notice any difference in it's characteristics once it's in the system as far as compress ability or boiling, though I don't drive race cars, which is where I guess people notice differences under extreme conditions. 1 2 Link to comment Share on other sites More sharing options...
Bloo Posted May 12, 2019 Share Posted May 12, 2019 Put some DOT5 in a jar, and then pour some more in as if you were topping a master cylinder. Look closely. There will be some bubbles. Look closely, they are very small. Now, watch how slowly they come to the top. It can take hours. Every time you add more fluid to the reservoir, theres more bubbles. Every time the master cylinder expels some air, more bubbles. They are almost too small to see. They get sucked back into the system when you bleed it. It can be very frustrating, particularly if you don't understand what is happening. Some brands work better than others. 20 years ago, I liked Johnsen's. I don't know what is good now. 1 Link to comment Share on other sites More sharing options...
JACK M Posted May 12, 2019 Share Posted May 12, 2019 12 hours ago, Frank DuVal said: I'm sure this idiot was taught by a prior idiot, so they are out there!😲 And they breed. Link to comment Share on other sites More sharing options...
stvaughn Posted May 12, 2019 Author Share Posted May 12, 2019 2 hours ago, auburnseeker said: The problem is if you don't do everything nice and slow, it froths up mixing the air into the fluid in little bubbles that you need to let settle out. Usually do it all then let it sit and do it again the next day. It will come out eventually and you will never touch it again so it's worth the extra cost and effort up front. I don't notice any difference in it's characteristics once it's in the system as far as compress ability or boiling, though I don't drive race cars, which is where I guess people notice differences under extreme conditions. I understand the slow part but is there any reason to pump more than one time between bleeds? Link to comment Share on other sites More sharing options...
auburnseeker Posted May 12, 2019 Share Posted May 12, 2019 (edited) You only want to pump enough to build pedal and do it slowly. I paid around $100 for a gallon from Kanter over 20 years ago. That stuff seemed to work well. The newer stuff seems to create more bubbles has a bit more body to it, where the older stuff was thinner. That might be some of the difference. Edited May 12, 2019 by auburnseeker (see edit history) Link to comment Share on other sites More sharing options...
Frank DuVal Posted May 12, 2019 Share Posted May 12, 2019 (edited) No there isn't. (reason to pump several times). Unless you do not get a "pedal" with the first push, but you should, even if it is low pedal, you can open a bleeder. It has been a while since I used the two person, one push pedal method. Mostly I use a Mighty-Vac to suck fluid out of the bleed screw. Sometimes I have had to apply PTFE tape to the bleed screw threads to get a seal. Other times I use the one-man-brake bleeder shown in so many shop manuals: Rubber hose and bottle. Then if it is a cowl mounted master, I use the gravity bleed, remove master cylinder cap, open a bleed screw, wait for gravity to force the fluid out. Do the next screw, or do all 4 at once. This method works well when filling a dry system, like when all new parts and filling with DOT5. Edited May 12, 2019 by Frank DuVal (see edit history) Link to comment Share on other sites More sharing options...
ply33 Posted May 14, 2019 Share Posted May 14, 2019 (edited) FWIW, I usually work alone in the garage and I've never had luck with the Mighty-Vac style brake bleeding kits. And the pump and hold the pedal method is definitely not a one person job. So for about $20 I picked up a small garden sprayer (on sale), a Schrader valve and stuff to make a master cylinder cover adaptor specific for my car. The resultant home made pressure bleeder made it real easy to get the little bit of air out that I was never able to achieve with other methods. The key part in using the garden sprayer as a base is don't use the built-in pump as that forces air into the bottom of the container and will create bubbles in your DOT 5 fluid before it ever gets into the master. I use the Schrader valve mounted on the sprayer body above the fluid level to pressurize the bleeder. If I recall correctly, I regulated it down to somewhere around 15 PSI on the tire chuck when bleeding the brakes. Too low and you don't get enough fluid. My guess is too high could create a real mess when the cheap plastic garden sprayer parts gave way. So I just bumped up the PSI a little at a time until I got enough flow at the wheel cylinders to flush out the bubbles. Edited November 20, 2020 by ply33 Gramar (see edit history) Link to comment Share on other sites More sharing options...
stvaughn Posted May 14, 2019 Author Share Posted May 14, 2019 Sounds like a home brew Motive pressure bleeder. Motive makes an adapter to fit the fill hole on my master cylinder. What kind of master cylinder do you have? Mine is a Lockheed with a top bolted on with 6 bolts. Not sure it will hold pressure. Taking your idea a step further, use the pump from a one gallon sprayer in a 2 1/2 body and you wouldn’t even need an air compressor. I just need to find out if it will work with my type of master cylinder. Link to comment Share on other sites More sharing options...
ply33 Posted May 14, 2019 Share Posted May 14, 2019 12 hours ago, stvaughn said: Sounds like a home brew Motive pressure bleeder. Motive makes an adapter to fit the fill hole on my master cylinder. What kind of master cylinder do you have? Mine is a Lockheed with a top bolted on with 6 bolts. Not sure it will hold pressure. Taking your idea a step further, use the pump from a one gallon sprayer in a 2 1/2 body and you wouldn’t even need an air compressor. I just need to find out if it will work with my type of master cylinder. Mine is a fairly early Lockheed with six bolts holding the top cover on. The vent on the cover is 1/2" pipe threaded, so my adaptor simply gets me to the pipe thread. The adaptor is brass and I soldered a tube extension on it to have the fluid come out at about the height I wanted the reservoir level. Regarding leaking: There is a paper gasket between the cover and the body and there are little copper washers on each cap screw holding the cover on. It doesn't hold much pressure before it leaks around the cover bolts, but it doesn't do too bad with 15 PSI. And since I am using DOT5, the leakage doesn't act as a paint remover. I guess you could use a pump from a 1 gallon sprayer in a 2.5 gallon body. But that would have meant buying two sprayers and ending up with a much larger device to store, etc. Since I have an air compressor it seemed logical to me to simply put a Schrader valve into the upper part of the reservoir body. Link to comment Share on other sites More sharing options...
JACK M Posted May 14, 2019 Share Posted May 14, 2019 On 5/12/2019 at 10:45 AM, stvaughn said: I understand the slow part but is there any reason to pump more than one time between bleeds? I never pump between bleeds, open the bleeder helper pushes down slowly then close the bleeder. Let the pedal up and wait a few seconds. Repeat until no air the close bleeder as the helper is pushing. Always start at the wheel furthest from the M/C. 1 Link to comment Share on other sites More sharing options...
Bhigdog Posted May 14, 2019 Share Posted May 14, 2019 1 hour ago, JACK M said: I never pump between bleeds, open the bleeder helper pushes down slowly then close the bleeder. Let the pedal up and wait a few seconds. Repeat until no air the close bleeder as the helper is pushing. Always start at the wheel furthest from the M/C. Buick and Olds (GM) says start nearest first. Chrysler says start farthest. Your results may vary, I guess......................Bob Link to comment Share on other sites More sharing options...
Frank DuVal Posted May 15, 2019 Share Posted May 15, 2019 If I do two person bleeding, it is person at wheel shouts "step", person behind wheel steps, person at wheel loosens bleeder, person at pedal shouts "floor" when pedal is on floor, then person at wheel tightens bleeder and shouts "up" for the pedal to go back to the up position. Repeat several times at each wheel. Start closest or furthest, your choice, the brakes do not care. On a solid rear axle vehicle, left to right makes little difference in length from master. Want to refine this? Try: 1.Have person at wheel put finger over bleed screw after opening it and leave it there, with finger pressure. Acts as a one way check valve. And you can feel the air bubbles push past your finger. Continue until no air bubbles are felt. 2. Go ahead and set up as a one man bleeder, rubber hose on bleed screw, other end in bottle (with an inch of fluid in there), but still have helper push pedal. Now you can see bubbles in the bottle. Or, use Tygon tubing, and you can see bubbles in hose!👍 Stop when no bubbles are seen in the fluid. 3. If the correct size is available, buy those one man bleeder bleed screws. Just like I hear stories of DOT 5 not working for people, I hear the Mighty Vac does not work for people. I've used one for over 30 years, drum brakes, disc brakes, since I work alone most of the time, even back in my shop days.I have had to "seal" air leaks around bleed screw threads at times due to sloppy fit. Usually use PTFE tape. Attach hose to Mighty Vac, other end to supplied reservoir. Attach hose from supplied reservoir to bleed screw (having already broken screw loose, snugged closed). Pump Mighty Vac to 25 or so inches of Mercury, open bleed screw and listen for rush of fluid/air into reservoir. Close bleed screw at about 5 inches of Mercury. Pump back to 25 inches, repeat. Look in supplied reservoir for bubbles in fluid. Repeat until no bubbles, checking on master cylinder level, do not want to run it dry, as then you have to start over! 😲 1 Link to comment Share on other sites More sharing options...
Spinneyhill Posted May 15, 2019 Share Posted May 15, 2019 One man bleeding: use a clear hose on the bleeder and make sure it loops upwards before going below the bleed nipple to the jar. Then slowly press and release pedal (3 times for me then a refill) and run around and close the bleeder. No air can get in if the hose goes upwards and is properly sealed on the bleeder. Link to comment Share on other sites More sharing options...
JACK M Posted May 15, 2019 Share Posted May 15, 2019 11 hours ago, Frank DuVal said: I have had to "seal" air leaks around bleed screw threads at times due to sloppy fit. Just about always. Link to comment Share on other sites More sharing options...
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