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Brake line - St/Steel braided hose for 223 rear wheel.


I would appreciate some help: I would like to replace the existing brake line assy to the rear wheel. I was thinking that a siingle line from the master cylinder to the rear wheel (as per motorcycle convention) would be a useful simplification. As to why - well the existing assy is quite corroded etc and is on the winter list. However I do not know the thread sizes used in the citroen brake system.


Membership No. 1887J

Re: Brake line - St/Steel braided hose for 223 rear wheel.

I've had a similar s/s braided brake hose set up for years - no leaks, no fractures, no spongy brakes.

The thread size is not, amazingly,M7. It's a plain vanilla M8 x 1.25. Unfortunately M8 is an off size for brake banjos - M10 is the norm. So - because the fittings are off size they are a bit more expensive.

Venhill and others on eBay sell suitable fittings and brake line. They are expensive so you might as well splash out on stainless - BZP fittings are a waste of money in the end.

The difficulty is getting them to seal on a master cylinder and wheel cylinder designed for the Citroen system of tube nuts and rubber seals. Copper washers help but the main issue is that the castings are rough just where you need them to be dead smooth. The first choice is to have them milled flat (taking care to ensure the milling is done to a perfect 90 degrees in relation to the bolt axis). The other way is to take a fresh stanley knife blade, coat the sealing surface with engineers blue and careful scrape it smooth and flat. Coat and scrape several times and use the blue dye to reveal low areas. Carry on until the dye comes off completely on te first pass. Don't let the scrapings get in the cylinder. This method works very well if you are careful and change the blade often. It also has the advantage that it can be done with the parts en situ

Braided brake lines are easy to make up. You can buy special tools to cut the lines cleanly and insert the olives without spiking you fingers. They are not really necessary (if you're near Chester you can drop in and I'll make the line up for you). There's a really good explanation of how to do it on the link below;

The other alternative is to have swaged ones made up by one of the many companies who do this - but be sure of measurements and fittings as mistakes will be expensive.

Of course, I should make it clear that there's absolutley nothing wrong with the standard 2CV part. But we're not talking about standard 2CV's are we?

Re: Brake line - St/Steel braided hose for 223 rear wheel.

BTW - I understand that there were some master cylinders and wheel cylinders in early cars and/or DOT 3 systems that used M9 and M7. I've never come across one but to be on the safe side it's best just to run a regular M8 bolt into the inlets to confirm exactly what you have before you spend any money on fittings.

Re: Brake line - St/Steel braided hose for 223 rear wheel.

Hi Geoff,

Many thanks for the response. I have since checked out various websites and was suprised to learn (as you say)the pipe nuts are M8 x 1.25 for M/Cyl, calipers and brake cylinders. I have also learnt my M/Cyl resivoir thread is a single circuit Ami LHM type with a M10 x 1.50 thread to attache the resivoir. But as you note it is the sealing any fittings into the above. Mind you maybe the careful application of an epoxy or studlock type sealant may do the job!! After all once the fitting is in place you would never want to remove it. The hose would screw onto said fitting.I think I would stay with the conventional citroen pipes for the front (easy access) and just fit the braided hose for the rear wheel drum brake. I will check out E Bay as suggested - thanks for the offer of making the lines, but as I live nr Shaftsbury Dorset it would be a long run!

Cheers, Steve

Membership No. 1887J

Re: Brake line - St/Steel braided hose for 223 rear wheel.

Steve - No problem having a hardline to the front brakes and a braided one to the rear. I've used a braided pipe to the front brakes because it is easier to route out of the way. I find it is best to use a standard Citroen hardline between the calipers though.

I would recommend using the scrape flat & copper washer method of getting a seal on the master cylinder and wheel cylinder surfaces. It is very easy to do and the fittings are so expensive that you wouldn't want to risk loosing one due to problems getting it off. Also, it is better to make the entire line up off the vehicle so that things can be "clocked" correctly.

Are you sure that your single circuit Ami LHM master cylinder actually has M10 outlets? The reason I say this is that I have a brand new boxed one sitting here in the workshop and it most definitely has M8 x 1.25 outlets. It is the only Ami LHM single circuit M/C listed by ECAS on their website and the notes on the page confirm that the outlets are M8 x 1.25.

I have had all the outlets milled flat for use with banjos - it's for sale in the classifieds because I no longer have the car I was going to use it on. There's also a new Reservoir (M16 thread).

It may be that your M/C does have M10 outlets, some do, but I can't see an Ami single circuit LHM one with anything other than M8 listed on any of the internet sellers.

Just realised you were referring to the reservoir mounting thread and not the inlets - my bad.....

Re: Brake line - St/Steel braided hose for 223 rear wheel.


Wires crosed! Yes the actual outlet ports are m8 x 1.25 - the resivoir mounting port is M16 x 1.5 (as per the ECAS web page). Varifocals playing tricks on my eyes!

I will have the master cylinder & resivoir - email me confirming P&P.

Perfect timing!

Membership No. 1887J