Technical Brake pipe fittings

[adamsdad]

Hi
Looking to change the rear flexi hoses on my sons Punto (2004 1.2 8v active), got under the car today and the male fittings screwed into the ends of the flexi's and the retaining clips are rusting nicely and won't come undone, I can probably get them out with mole grips or similar but I don't want to go there just yet. Assuming I'm going to have to replace at least some of the steel pipes (either the full lengh or cut and join a new piece in) can someone confirm the fitting and pipe size, I think it's standard 4.75mm pipe with 10mm thread DIN fittings and DIN flares? I wanted to confirm then I'll make sure I've got everything I need before I start, bleed nipples seized as well so will probably turn into a full rear brake overhaul. Thanks Steve

 

[jackwhoo]

@Pugglt Auld Jock

 

[vexorg]

You are unlikely to be able to flare a steel pipe, usually you need copper from end to end unless you have a machine to flare it.

If you need molegrips then it's time to start replacing them with new.

 

[RedAbarthMTA]

Personally I would opt for Kunifer ( Cupro Nickel ) a copper alloy that is easy to work and unlike steel does not rust. Why oh why do they still insist on using steel? I know, it rusts and we have to pay to replace them, but surely in something as important as brakes manufacturers would change over to kunifer pipes and silicone flexibles?

 

[chris3234]

Personally I would opt for Kunifer ( Cupro Nickel ) a copper alloy that is easy to work and unlike steel does not rust. Why oh why do they still insist on using steel? I know, it rusts and we have to pay to replace them, but surely in something as important as brakes manufacturers would change over to kunifer pipes and silicone flexibles?

Cost and quicker to assemble when the pipes are all pre made steel won't bent back out of shape when working with it unlike cooper especially on a large run that is common on the OEM pipes

 

[RedAbarthMTA]

see you're thinking like a manufacturer not an enthusiast With a little effort you can get the runs as straight as you like. If I can do it with Kunifer, so can you.

Cost and quicker to assemble when the pipes are all pre made steel won't bent back out of shape when working with it unlike cooper especially on a large run that is common on the OEM pipes

 

[adamsdad]

Any pipe I replace will be copper not steel, I may chase the pipes back to a joint and replace from there depending on the route and access, or I may cut into the original steel and flare that then use a shorter lengh of copper to get to the flexi, obviously I won't be putting back anything that needs mole grips to undo, that will be the last resort once I've got the bits I need to complete the job, they would only be used to get the old pipes off if necessary. Anybody confirm the pipe and fitting sizes? Thanks

 

[chris3234]

see you're thinking like a manufacturer not an enthusiast With a little effort you can get the runs as straight as you like. If I can do it with Kunifer, so can you.

I'm talking about why manufacturers use it not why you'd use it at home for home use copper is far better bute it's far too easy to bend for use on a factory' assembly line where the lines are shipped from the manufacturer

 

[judderbar]

Anybody confirm the pipe and fitting sizes? Thanks

I have a brake cylinder, ABS unit with cut pipes and front hoses I can measure if you get really stuck for needing this information.

 

[adamsdad]

Hi
Thanks for the reply (thread seems to have been hijacked) I've gone with the 10mm thread and standard 4.75mm pipe as per my first post, hopefully be OK. Thanks Steve

 

[jackwhoo]

Hi
Thanks for the reply (thread seems to have been hijacked) I've gone with the 10mm thread and standard 4.75mm pipe as per my first post, hopefully be OK. Thanks Steve

Did you go for m10 with a 1mm pitch? Which is typical fiat. Yes to 4.75mm pipe. Yes to DIN flares.

Sorry for delay was hoping Jock would leap in with answers.

 

[adamsdad]

Hi
Yes, that's what I've gone with, thanks Steve

 

[vexorg]

I've gone with the 10mm thread and standard 4.75mm pipe as per my first post

I have seen ABS units in other cars that have more that one thread size.

And it'll be 3/16" pipe, imperial still rules in pipe world no mattery how hard they try. I'll bet your flaring tool has 3/16 on the former.

 

[adamsdad]

The pipe I have is marked up as 4.75mm, which I thought was unusual as most pipe/tube uses imperial measurements, however 3/16 is 4.76mm so I don't foresee any issues. Thanks Steve

 

[adamsdad]

Just checked and my DIN flaring tool is marked up as 4.75mm

 

[Pugglt Auld Jock]

Did you go for m10 with a 1mm pitch? Which is typical fiat. Yes to 4.75mm pipe. Yes to DIN flares.

Sorry for delay was hoping Jock would leap in with answers.

Sorry for not getting onto this sooner but I was starting to dismantle the light display I rig up every year to the front of the house and it's damned cold up here today so I fell asleep on the couch after I'd finished! Anyway, I just caught up with this now.

As everyone has already said, yes it's 4.75mm pipe and normal "standard" metric tube nuts as sold just about everywhere. On longer runs I like to use Kunifer because it holds it's shape much better but on short runs, like along suspension arms I tend to go for copper as it's easier to bend into complex shapes. Kunifer has a higher bursting pressure than copper and it's interesting to note that copper is banned for use on brakes in the US and many other countries - UK being one of the few exceptions. Having said that I've used it for many years and never had a problem.

The biggest problem doing this sort of job is if you need to cut off the end of the front to rear pipe - due to corroded fittings or pipe perhaps - which leaves you with the problem of pressing a flare into the original fit steel pipe so you can install a connector and short extension to get you back to where the flex hose connection is. Very few DIY (cheaper) flaring tools will look at steel pipe. I recently bought a DIN flaring tool which claims to be able to do this and I made a post/thread about it which I'll now try to find. If I do I'll post a link here.

 

[Pugglt Auld Jock]

While I'm trying to find that thread about the flaring tools you might find this interesting: https://www.fiatforum.com/threads/straightening-new-brake-pipe.486934/

 

[Pugglt Auld Jock]

I haven't found that thread yet but the DIN tool I bought was this one: https://www.ebay.co.uk/itm/161353061492?epid=22017019790&hash=item2591645474:g:raEAAOSwOMVgLpNW
I haven't yet needed to use it on steel pipe - it claims to work on steel pipe - but it produces very nice flares on copper.

 

[Pugglt Auld Jock]

I've now thoroughly confused myself as to what I'm trying to find but I think it's this thread: https://www.fiatforum.com/threads/whats-made-you-smile-today-part-ii.290396/page-547#post-4596412 The bits about the new DIN flaring tool are about half way down the thread.

 

[adamsdad]

Hi
That appears to be the same flaring to that I have, I've used it before on steel with no problems (just remember to put the nut/fitting on before you flare the pipe), seems a good tool. I'll either make up a short lengh to get to the flexi or i'll follow the line back to a factory joint if there is one, should be enough available pipe to get a joint quite near the flexi's hopefully to the rear of the fuel tank (don't want to get involved removing the tank). Thanks Steve