NOT EASILY SOLVED garage to make up Kunifer brake pipes

[Little Dog]

I responded in a bit of a rush last night, I was cooking at the time. The info I provided explains my reservations. However I think your question relates to the thread on the male union and how it connects with the female?
All of the male unions I fit have an unthreaded section at the end. The only female thread I have to refer to looks like it has been drilled for fluid flow, drilled out for tapping and to form the flare seat and then tapped finishing with a plug tap. The thread does not quite reach the bottom and there is is very short unthreaded section before the flare seat. The unthreaded portion of the male unions is probably there to stop the male thread bottoming out on the thread runout and uncut portion of the female thread before the flare is fully compressed.
As to why your new male unions have the unthreaded section under the head I can't say; I've only ever seen bleed nipples machined like that. Will they bottom out before the flare is compressed? I can't tell but you need to check it out.
Did a bit of checking on my components:
The total depth of the female component is around 11mm with 9mm threaded
The total length of the male component under the head is 11mm with 9mm threaded
Fit the flare hand tight then fully tighten and the flare compresses a further 0.6 mm, the final compressed height of the flare is around 2.5mm
Do the sums and I have about 6mm of male and female thread engaged. The male thread stops about 3mm before the bottom of the female thread so can't bottom out then there is a further 4.5 mm including 2.5 mm of flare when the two components are torqued up. it all works but the 6 mm of engaged thread was a bit of a suprise.
Your connectors would be a bit close at 0.5 mm from the end of the female thread but with 8.5 mm of thread engaged. Bosch female threads may have different dimensions.
After all of that perhaps the easiest thing for you to do is to fit one and see if you get a finished flare height of 2.5 mm? Or Drimel off the flares and do it all correctly?

 

[Alan_uk]

Thanks Phil @philward I need to digest what you just written and take measurements before trying. Will try to find time today but I'm very busy until then end of Monday.

As to why your new male unions have the unthreaded section under the head

Well spotted!

Thanks for your continuing help.

Alan

 

[Alan_uk]

Hi Phil @philward After a busy w/e back to the A2. I tried to 1. take more measurements of the nut and hose union and 2) compress the pipe into the hose. Measuring depth in the female hose was difficult, hence the circa figures.

I tightened to finger tight and at that point the threaded section had just disappeared. I then tightened 1/2 turn with spanners in each hand. This was probably the maximum I could do in the hand (i.e. not a vice). There appears to be slight marks on the pipe nipple where it seated.

As the nut has an internal funnel at the end then the pipe end does not get fully compressed into a mushroom.

Here is the uncompressed other end

What do you think?

Regards
Alan

 

[Little Dog]

Hi Alan @Alan_uk I have tried to replicate what you have been sold.


1 You definitely have SAE flares. I have had to use a UNF recessed fitting (yours may be metric but I can’t find a supplier of metric recessed fittings in size M10*1)

If you have UNF fittings they twist in the female metric thread as the 1/2 turn from finger tight is applied. Very dangerous.

I got the same result as yourself with a ring of contact on the flare

What you should have, ISO DIN

The convex flare matches perfectly the concave seat in the female thread resulting in metal to metal contact across the face of the flare.

I would not fit your pipes to my A2.

Sorry

Phil

 

[Alan_uk]

Hi Alan @Alan_uk I have tried to replicate what you have been sold.

You definitely have SAE flares. I have had to use a UNF recessed fitting (yours may be metric but I can’t find a supplier of metric recessed fittings in size M10*1)
if you have UNF fittings they twist in the female metric thread as the 1/2 turn from finger tight is applied. Very dangerous.
I got the same result as yourself with a ring of contact on the flare
What you should have, ISO DIN
I would not fit your pipes to my A2.
Sorry
Phil

Thank you for going to all that work Phil, much appreciated. No need to say "sorry" - safety if important.

I will now decided whether to go back and get them replaced (100 miles / 4 hours round trip) or get them made locally. Cutting off the old nipples should not make a significant shortening of the pipes.

I hope this thread is a lesson to other A2 owners as more need to get custom made pipes made whether steel of copper-nickel.

 

[Little Dog]

Cutting off the old nipples should not make a significant shortening of the pipes.

You will lose about 5mm each end. What could be a show stopper is the position of the first bend. You need enough straight pipe to clamp the pipe in the split die / clamp.

Red dimension looks too short, black is definitely too short:

 

[Alan_uk]

I did find a classic car restorer who made some but the flares were wrong. Seeing as I gave them a picture of my requirements I invoked "not as specified" and got a refund. I think they deal with mainly British cars and probably use non-metric on European cars and get away with it and the owners are non the wiser.

But the brake pipes are hopefully now solved as a member here has kindly offered to make them up for me

 

[tnpali01]

Just taken my TDI 90 for its MOT and whilst it passed , there was an advisory on brake pipe corroded , covered in grease or other material near side rear . looking at it its starting to go like in photos in one of the earlier posts.

Its no where near like this , Ive been told it doesnt need doing now, but will do. I dont wanna take a chance and would like to get this done asap. Now having crawled underneath , why is it always raining it looks like I need to do two pipes ? which are attach to a bracket? on the rear suspension arm. I dont want to do this work myself and would entrust it to MOT garage to supply and fit the correct parts. Before I do I would like to confirm is the only option to have these made up or is it that a made up pipe better than from Audi ? Does the original pipe have some form of sleeve on top ? Also what are ball park costs for making up and fitting these pipes. ? Should I get both sides done at same time? the other side I have been told is OK.

 

[Alan_uk]

Hi. First I need to change the title of my post as whilst I found a company (2 actually) who made them for me, I was not happy with them. Both had the wrong flares, although the 2nd was better. To answer your questions:

1. Audi pipes are no longer available, even from Audi Tradition in Germany (who wont post to the UK)
2. The original pipes are coated, it seems to be a type of plastic.
3. I was looking for Copper-nickel pipes that wont rust, but they are softer.
4. The first company, a pipe specialist (cars and other hydraulic pipes) charged £50 although they quoted £80 to start with. They did offer to redo them but I lost confidence, especially after visiting their premises.
5. The second, a up market car restorer, charged £111. When I said I was not happy they refunded in full. They said they restore German cars like Mercs and had no problems fitting their flares (i.e. I was too fussy). In their favour I suppose the softer copper will deform and seat better than a steel flare).

Fitting costs I don't know. Provided the flexi hoses are OK and and the nuts to them come undone easily (and the nuts to the brake cylinders) then perhaps an 2 including bleeding the system. But they may well not come undone. I was using an old axle as a donor and I could not undo the nuts to the brake cylinder. I've seen comments that the brakes need stripping down and the cylinders replaced, along with ABS sensors which likely to be corroded in as well. So the costs could mount up.

Also the old pipes are needed to make a pattern, so the car is off the road and occupying a ramp in the garage while new ones are made up. Obtaining the copper nickel piping is no problem. Plenty of sellers on ebay etc. and they are in coils so easily posted. The A2 pipes are thinner than most cars I was told.

I did find some local firms but they disputed the need for a metric flare or didn't have the right metric tools. Other companies said they don't make them up regularly but had the tools somewhere and would have a go. Others refused to make them up as a matter of policy - safety - and always recommended manufacturer's pre-made pipes.

In the end someone did make them for me as a favour - I paid him - but it took him a number of goes to get the flares OK and if too many don't work out then the whole pipe is too short and has to be thrown away for another length.

This is going to be a more common problem going forward. Perhaps others have had better luck or just accepted what the garage offered/did.

Good luck.

 

[Alan_uk]

I've just read @rotifer post on rust proofing his A2's rear axle and in the photos it looks like he has fitted new pipes.

 

[Deleted member 20348]

Hi,
I make my own brake lines.

You could have a go at the near side short one?

If you get it wrong so what, your learning a new skill. Be kind to yourself.

@Little Dog has done a excellent write up on brake lines.

The three ideas I have behind doing my own work.

• A excuse for new tools (not that I need one)
• learning stuff
• Garage labour charges

Give it a go if you have a question ask away.

I'm no expert, I used the wrong flare tool in first attempt but after being alerted to my mistake I kept going and put the mistake right.

All the best however you decide to proceed.




Edit
As you can see in the picture I have only basic tools.
I used a small flat file from the chainsaw tool box kit to chamfer the outside diameter of the cut pipe. I didn't have a reamer to hand for the inside diameter so I used the edge of a small screwdriver. (I know)
Once you made up the pipes before you fit them blast them out with a can of brake cleaner or the airline to get rid of copper shards.

The one on the left is not great as the pipe has too tight a turn which may have restricted the flow.
I can always have another go to perfect it.

Edit 2

Hand-Held Brake Pipe Flaring Tool DIN, 4.75mm

Established in 1919, Draper Tools is a supplier of quality trade, professional and diy tools. Check out the massive range of tools available from one supplier.

www.drapertools.com

 

[Howey]

Just taken my TDI 90 for its MOT and whilst it passed , there was an advisory on brake pipe corroded , covered in grease or other material near side rear . looking at it its starting to go like in photos in one of the earlier posts. View attachment 119549 Its no where near like this , Ive been told it doesnt need doing now, but will do. I dont wanna take a chance and would like to get this done asap. Now having crawled underneath , why is it always raining it looks like I need to do two pipes ? which are attach to a bracket? on the rear suspension arm. I dont want to do this work myself and would entrust it to MOT garage to supply and fit the correct parts. Before I do I would like to confirm is the only option to have these made up or is it that a made up pipe better than from Audi ? Does the original pipe have some form of sleeve on top ? Also what are ball park costs for making up and fitting these pipes. ? Should I get both sides done at same time? the other side I have been told is OK.

That brake pipe is absolutely fine, simply apply a bit of grease and it will last for years!

 

[tnpali01]

That brake pipe is absolutely fine, simply apply a bit of grease and it will last for years!

Are Garages just covering themselves by adding advisories. ? Would the original pipes be steel hence corroded. The way im reading the advisory the tester is not expecting a pipe to have grease on it . surely the grease is good as it would prevent corrosion .

 

[Howey]

Are Garages just covering themselves by adding advisories. ? Would the original pipes be steel hence corroded. The way im reading the advisory the tester is not expecting a pipe to have grease on it . surely the grease is good as it would prevent corrosion .

Yeah the tester is just covering their back to avoid any potential issues, a bit of grease on anything prevents corrosion and keeps things like brand new!

 

[tnpali01]

I am going to have to get a garage to do this when i work out exactly what needs doing and the most cost effetive way of doing so. What im unsure of is whether the outer coating is all thats perished and the pipe is still fine , or without the outer coating the pipe is likely to fail soon. Maybe I need to take it to another garage for a second opinion?

 

[Deleted member 20348]

If the outer coating (plastikote) has gone then that's game over the line is in decline.

 

[tnpali01]

I am going to get the line replaced , just need to work out how.

 

[bix]

That brake pipe is absolutely fine, simply apply a bit of grease and it will last for years!

Exactly my rear brake pipes ends are exactly the same for last 10 years and there is a lot of layers of waxoil, copper grease, rust proof paint which I'm renewing every year.

Depends on which MOT tester I go to some will mark it same as on your certificate "covered in grease or other substance" other MOT testers don't mark it at all. I would leave it. It's not rusty or damaged the end of the pipe is just stripped from that black plastic coating when someone was replacing the cilinder. You can see the marks on the pipe when they were wrenching it out.

 

[Little Dog]

Once you made up the pipes before you fit them blast them out with a can of brake cleaner or the airline to get rid of copper shards.

This is very important and I somehow missed it from the how-to. You will be surprised at the amount of muck that comes out.

How-to updated.

Edit, I missed it because i intended to create a pipe bending how-to. I blow out when the pipe is fully formed.

 

[Little Dog]

Hand-Held Brake Pipe Flaring Tool DIN, 4.75mm

Established in 1919, Draper Tools is a supplier of quality trade, professional and diy tools. Check out the massive range of tools available from one supplier.

www.drapertools.com

View attachment 119593View attachment 119594

You may need to experiment at step 3.3. I'm convinced these tools are designed for steel pipes which I suspect have a different wall thickness to Kunifer. To get the flat on the DIN flare you may need to stop winding before the setting tool is fully home. Measure with a feeler gauge, apply it each time and look forward to perfect DIN flares.