Brake pipes

[TedAllen]

Paul and I have been having some email discourse over the last few days and one topic that has arisen is the subject of copper brake pipes. I restored my brakes about 10 years ago with pure copper pipes. Two years ago I suffered brake failure whilst returning from a local show. I was approaching a busy junction and the lights were on red with standing traffic. Fortunately there was nothing coming towards me and I swerved across the road into a hotel car park and slowed by switching the engine off. I have not yet investigated the cause as I felt it was time to come off the road and do some restoration jobs I had been putting off for some time. Paul mentioned that he had fitted pipes made of copper mixed with another metal...possibly Kunifer pipes ?
This brought to mind a tragic incident which occurred about 4 years ago on a local pelican crossing where a 12 year old boy was killed when crossing on the green by a car which failed to stop. The car was a Morris Minor traveller and this led to the usual calls for old cars to be banned from the road.
The following year I was at the Tatton Park show with the Javelin when I got chatting to a gentleman who turned out to be the father of the Morris driver. It transpired that the car had been fully restored and was in concours condition but the vehicle inspection after the fatal accident had discovered that one of the copper brake pipes had split suddenly along a seam. The driver was completely blameless but nevertheless devastated by the event.
So, what do other members, particularly sporting ones, think of these pipes ? I will re-post when I find out what happened to me.
I am fairly confident about mine, they are branded as 'Saville copper tubing' seamless 22 gauge, electronically tested and conform to 2 British standards. They have a wall thickness of .71mm and a safe working pressure of 3100 psi or 214 bar.
Lets hear from you technical lads and keep our cars safe
Ted

[Drummond Black]

AS I have made and fitted all my brake pipes on my Jowetts and vans for the last twenty years I must reply to Ted.

Original equipment brake pipes on all vehicles are steel with a plasticised covering to combat corrosion. They usually give good service for three to five years without any maintainence. However iuf used all year round the usual salt attacks them and surface rust and pitting occurs. With a modern vehicle you go to the dealer and get the same again. OR upgrade to reduce the corrosion aspect.

Running a fleet of merc vans over the years has giver lots of experience in brake pipe replacement. Brake pipe copper tube purchased about twenty years ago did in fact come both seamed and seamless. The seamless very quickly became the norm. I have had no problems over the years with self made pipes once I invested in a quality kit to make them up. If you are going to get a problem it will always be at the end if the flare has not been manufactured correctly. DO NOT MAKE THEM UP WITH CHEAP TOOLING. Your case in particular shows that he must have aquired old stock OR had it for years. Careful bending and routing is paramount to ensure safety. All clipe must have either a rubber or a soft plastic sleeve to prevent chaffing. Always use NEW ends. The number of people who reclaim ends and expect them to do a perfect job of sealing is still high. I try to obtain a min radius of two inches on copper and three inches on Kunifer piping.

The Jupiter is all done in Kunifer and the Javelin and my Rover 75 ( New model ) is done in copper.

L:ike Ted ( bless him ) I only use Saville seamless to BS 2871 PT2 C106 which is 3/16" O/D and .036" ( 0.91 mm ) wall thickness. Working pressure of 3100 PSI.

I have just finished rebuilding the Jupiter brakes and after 13 years on the road every connection unscrewed with ease to allow all the wheel cylinders to be replaced. No brake pipe replacement was required. I also fitted stainless steel bleed nipples with the point seal area. This disposed of the ball which seizes into the cylinder far too often.

So to conclude - I trust copper brake pipes but make them up with care and attention to detail..

[Drummond Black]

Unlike Ted I have only entered 64 posts. Well he must have something to do at midnight !!!!!!!!!! DB

[paul wilks]

and Drummond has just reminded me that this my 104th posting but probably 70 of them were about my b****y brakes- which I am STILL working on!

Paul

[Drummond Black]

I have been in the workshop all day reclaiming A large box of brake cylinders which have been building up for some years. Out of 22 cylinders I have managed to salvage 14 which can be safely used again, both front and rear. The cylinders I took off the Jupiter were the first to be rebuilt as they were in reasonable condition, only two were seized and heat freed the pistons out of the bores. One thing that I did notice is that the flair requirement for the brake pipe is different on the back as to the front. I will return to this point as it is the main point of this post. A visual check on condition of studs, 3/8 UNF threads for brake pipe ends and bleed nipple are made first and if OK then a detailed examination of the bore is then carried out. They all require through cleaning and I leave them soaking in petrol for few days before cleaning. Corrosion and hard dried fluid are always present but if you attempt to scrape the bore you will only damage the surface. They require to be polished to mirror finish to allow the new seal to work without leaking. I achieved this by the following method :

I put a length of 3/4 inch bar into the lathe chuck and wrapped a small piece of towel, which was soaked in T-Cut, round the bar and clamped the loose ends of the towel into the chuck jaws along with the bar. The lathe is set to about 200 RPM and the cylinder is slid onto the bar / towel. It takes about three of four minutes per cylinder to complete and the resultant finish is superb.

Clean in clean petrol and run a tap down the threads and final check with a pipe end fitting before assembling the cylinder with new seals. Ensure that the correct pistons are put into the cylinder(s) as the front and rear are different. I always asemble with Girling red rubberiod grease.

Now the main point of this post regards the type of final flare you require at the brake pipe ends to suit each cylinder. Most brake pipe kits have two dies in them Stage 1 and then if required Stage 2.

Stage 1 leaves the pipe flared and with the end of the brake pipe forming a cone.

Stage 2 then reforms the cone to end up with a cup effect.

It is imperrative the you carefully check the shape at the bottom of the threaded bore were the pipe if going to finally locate to see what end shape is required.

On the Javelin and Jupiter the short pipe joining the two front cylinders only require the brake pipe being formed to Stage 1, whereas the pipe at the rear cylinder requires being formed to Stage 2.

Hope the above helps. All the brake fittings I have came across on full hydraulic systems are 3/8 UNF and the hold down studs are 1/4 UNF.

Drummond

[TedAllen]

Thans for all that , Drummond, I use a good quality flaring tool, a Sykes Pickavant with dies for both imperial and metric in both stages.
I was particularly interested in your method of polishing, I think I will be stripping and checking the whole system over the winter months.
If you ever buy a Lada Riva, give me a ring, I have a supply of both male and female ends...the thread is like nothing we use over here !
Thanks for the blessing....good to see your grasp of the English language is getting better. What I do at midnight is no business of yours.....even if I do go out and prowl round the East end with a sharp knife cleansing the streets of loose women, although sometimes I'm content to stay in with the Jowetteer and a mug of cocoa !
Ted

[Keith Clements]

14. I had a new copper brake line burst on the Javelin. I think it was badly manufactured tube. OK I do have a servo fitted but?*!

http://jowett.org/jowettnet/dt/tech/bra ... brakes.htm


It was stock that Ben Shaw had used and was seamed!

[Drummond Black]

Keith - Seamed copper brake tubing was tabood by the trade about 20 years ago. Seamless is the only tube that can be safely used. Throw away any seamed . DB