Brake fluid loss

[Martinez]

My brakes failed a while back whilst going down hill. Bit scary but just managed to stop. I topped up the fluid but by next day it was down again. In fact that’s been the the story ever since. I can’t see any signs of a leak underneath so I’m thinking it’s time to replace all the 20+ year old brake pipes and be done with it. 
I’ll be using copper brake pipe but what thread are the nuts ? Metric or imperial? ( I’ll guess metric )
Secondly, anyone have experience of replacing all the pipes ? Just looking for a few tips tbh
Cheers all

[geoff]

I'd double look / check all joints for a leak before undertaking ANY replacements !!

The metal pipes will be ok I reckon

I'd remove the wheels and look for leaking wheel cylinders / pistons

Memory tells me the fluid can be drawn into the engine for burning if the servo has a fault ??? ... memory not what it was or maybe it was a fault on older style vehicles ???

Pipe threads will be metric

[ItsGreen]

Most likely a rear wheel cylinder seal gone or a steel brake line rusted out. Either whip your rear wheels and drums off and have a look, or get someone to give it a pump while you have a good look round underneath - a bit of dry blue roll or kitchen towel can be a bit help.

I'm assuming it doesn't have ABS? If not, the rear compensator growing a rust hole can also be a candidate.

Dob't pump the brakes with the rear drums off or you will need a pair of cylinders.

[geoff]

^^^ with the drums off you will make a bit of a mess on the floor but the cylinder pistons and seals will easily reinsert, just ensure all is clean

[Cumbrian]

I replaced the brake pipes on my Mondeo recently so can offer a bit of advice should you decide to replace all or part of your system.

• Use copper nickel (CuNi) not copper pipe. Copper is softer than CuNi and easier to bend (but more likely to kink). It is banned in many countries (not UK) for brake pipes because it is prone to breaking when flexed. CuNi is the standard pipe material on nuclear submarines for good reasons.
  
• When cars are built the brake pipes are one of the first things attached to the body so they can be very long. When replacing them all sorts of things like suspension and engines get in the way. There is no rule which says you have to replicate the originals exactly; you can fit connectors and run the pipes wherever is convenient.
  
• Use a good quality pipe flaring kit. The cheap universal flaring kits are useless on CuNi or steel pipes. The type illustrated is not much more expensive but works well on CuNi and steel (I’ve tried it).
  
• If you’ve not made brake pipes before read up on the different types and have a few practice attempts. You don’t need pipe bending tools unless making very tight bends. Just bend the pipe gradually round something like your knee.
  
• If most of the pipe looks OK you can cut the rusty bit out and splice in a new section.
  
• Replace the flexibles at the same time.
  

[Martinez]

Hi all. Yes it’s copper nickel I’ll be using.
I’ve heard about master cylinder leaks into servo unit so it’s something I’ll check for. I’ve got a pro pipe flaring tool somewhere I inherited which you clamp in a vice. I’ll have to try n find it.
My brake pipes at rear didn’t look great last time I looked so I’m expecting one of those to have failed tbh. I’ll leave it for today as the neighbours get upset if I’m too noisy on Xmas day he he. Anyway, I’m off to the pub

[ItsGreen]

Good call all round!

Copper nickel (aka kunifer) is better than plain copper. I do tend to use plain copper though just because of price and availability. A bending tool is well worth having, but it is possible to bend the curves over an appropriately sized socket.

Personal preference is I generally do my flares on the vehicle so I can get the pipe lengths exactly as I want them. I use an in situ flaring tool (Laser 3434). About £60-70 worth, so probably not cost effective for a one off job unless you sell it after.

I don't like paying people to do a job I'm capable of doing, but, to be fair, brake pipes are use of those jobs that can be fairly cost effective to get a garage to do. Getting the car up on the lift, practice, and having a decent system to bleed the brakes can be a huge time saver.

Not saying any other way's wrong, this is just what works for me.

[RattyCortina]

Don't forget to put the fittings on the pipe before you do the second flair, and get them to the ends before you bend the pipe...