use a standard length spanner and just got really tight. thats how i do mine
Battling with my newly completed brake system, it seems to leak at most of the unions. Flares were carefully made with a good quality tool, used a pipe cutter not a saw on the pipes and carefully checked for swarf etc. How tight should the unions be? I know this is a bit like ' how long is a piece of string ' because you cannot get a torque wrench on there only short open ended spanners. Is it a case of max force - I am not particularly strong. Also what are the possible defects in the flares and or unions I should look for. Any advice appreciated.
go for FT (fucking tight)
use a standard length spanner and just got really tight. thats how i do mine
Have you done the correct flare? Sometimes you need to do a double flare depending on what your attaching to
I too would say the flares are wrong.
As above, need correct flare shapes.
Even when using a mini pipe cutter I always use a file to make sure there is a clean cut on the pipe before flaring. Make sure that you are using the correct male and female dies. imperial flares are different to metric as well as single or double although I have seen imperial flares on metric fittings being done without any leaks. Doing the fittings up FT is plain stupid as you run the risk of stripping the threads on the nuts etc . Can't remember ever having any leaks in nearly 50 years in the trade
Are you using the correct unions? Are they long enough to squish the flare before bottoming out? Is there a gap between the underside of the hex and
the bit it's screwing in to? Is it the correct thread?
I've never had to swing on a brake union to get it tight enough to hold fluid! Usually, you feel the union touch the flare and then another half
a turn will pinch it enough to hold it.
As the guys have said above, I also have made my own pipes for years, and still "dress" the flare with a file to clean up any burrs
ive never had every one leak massively, and If I did, would never make one again!
but any small weep, just nipped up with a spanner,
FT will not work, brake unions are not strong, you will strip the threads,
steve
Thanks for the input so far. I am using the CBS flaring tool which forms male ( bubble ) flares and double female flares. I am not sure whether these are SAE or DIN spec or indeed something else. I did not find them difficult to form and was happy with the quality otherwise I would not have used them. Still not sure how I could have gone wrong. Most of my hardware is generic mostly from CBS I think but I have some flexis with Aeroquip fittings.
I was unsure so i just nipped it up. I pressurized the system using a ezzibleed and you couldhere the leaks bleeding the air out
I made all my flares with a cheapo tool, I did have one union which did weep and further tightening made little difference. I think if you have the same problem redo the flare. I found it best not to put excessive pressure in creating the flare but spanner the flare up in a spare union mounted in a vice and brake fluid for lube.
quote:
Originally posted by johnH20
Thanks for the input so far. I am using the CBS flaring tool which forms male ( bubble ) flares and double female flares. I am not sure whether these are SAE or DIN spec or indeed something else. I did not find them difficult to form and was happy with the quality otherwise I would not have used them. Still not sure how I could have gone wrong. Most of my hardware is generic mostly from CBS I think but I have some flexis with Aeroquip fittings.
If you have metric fittings you should have DIN flares but generally using an SAE flare in a DIN fitting or vice-versa won't cause
problems provided the flares have not been formed undersize.
Officially all DIN standard flares should be convex not a concave-convex double flair BUT in the real world car manufacturers use them in
female fittings particularly in pipe to pipe splice joints and connections to some brake hoses.
A concave-convex DIN flare won't seal where a simple convex DIN dome flare is required and vice-versa.
So it looks either you flares are not generously enough sized or you are using double flares where single should be used.
Interesting comment British Trident. I have read that one should NEVER use single flares on high pressure ie brake systems. I am obviously not an expert so not sure how to treat this info.
quote:
Originally posted by johnH20
Thanks for the input so far. I am using the CBS flaring tool which forms male ( bubble ) flares and double female flares. I am not sure whether these are SAE or DIN spec or indeed something else. I did not find them difficult to form and was happy with the quality otherwise I would not have used them. Still not sure how I could have gone wrong. Most of my hardware is generic mostly from CBS I think but I have some flexis with Aeroquip fittings.
quote:
Originally posted by johnH20
Interesting comment British Trident. I have read that one should NEVER use single flares on high pressure ie brake systems. I am obviously not an expert so not sure how to treat this info.
For anybody buying a brake flaring tool the best one under £100 is the PowerHand on car tool which sells under different brand names for under £40. It is a really solid precisin tool unlike the red handled tool sold by CBS (also Sealey) it makes nice DIN flares.
Franklin tools make a nice flaring tool which will make good flares on steel pipe so Kunifer etc is no problem , available for metric or imperial so make sure you get the right one. I use one if I ever need to replace rusty pipe sections on the car using a joiner
quote:
I have read that one should NEVER use single flares on high pressure ie brake systems.