18 replies to this topic

[Visible_Potato]

Currently starting to bleed the brakes on a 1963 Austin Mini. New rubber brake hoses have been installed, but I am using the original pipes. There hasn't been brake fluid in the system for 20+ years. 

 

When I compress the pedal, brake fluid leaks out between the union and the pipe. This is on the front left of the car where the brake pipe connects to the hose. I cannot tighten the union any further despite using quite a bit of force. The pipe can wiggle a bit within the union and when pulling the pipe up it seems to seal properly. Is there some sealant I should be using or anything else I should be doing to get it to stop leaking???

 

How it looks after drying with a rag:

 

Then after compressing the brake pedal:

 

 

[cal844]

Is the flex on the correct side, they are handed

[crossthread]

From your picture it looks as though the head of the union has bottomed out on end of the flexi pipe. Caused by over tightening of the union and crushing the flair on the end. They don't need to be too tight. This is no criticism of you , it happens over the years. 

Personally I wouldn't use that metal pipe anyway, it looks badly corroded. Change it and carefully check all the other metal pipes. 

[alpder]

Sealant can't (and mustn't) be used on brake pipes. If you're new to this and at all unsure it'd be best to get some first-hand assistance from someone experienced who can get you started, because brakes are so important.

 

Given the rusty state of that pipe, and that your system is most likely single-circuit (so a failure anywhere in the system means you lose your footbrakes totally) you might do better to replace all pipes. Here in UK a complete set of cunifer pipes can be had for about £60 including, from at least one reputable ebay seller, a colour-coded fitment chart. Someone in NZ can probably point you to a local similar seller.

 

If it's been fluid-less for 20+ years then chances are the system is shot anyway - seals dried out, cylinder bores rusted, and rusty crud floating about with risk it'll get into moving/sealing parts. So it may be a case of replacing the whole system from master to slaves.

 

If you do choose to buy replacement pipes it's best to avoid copper. They're widely available and cheap but there are lots of posts on here about copper (iffy and even illegal in some jurisdictions) vs cunifer (slightly more expensive but won't let you down).

Edited by alpder, 29 January 2026 - 11:00 AM.

[nicklouse]

As stated the hoses are handed. The deeper drilling is for the banjo side. If you put it on the other side is can not seal.

[stuart bowes]

^ definitely worth double checking, I would have got mine the wrong way around as well if I hadn't just happened to have seen a post on it literally that same day purely by chance

 

the difference isn't immediately obvious, if you're using the goodrich ones at least one of them had a marking on, OSF or NSF, whichever it was (can't remember)

 

(not meaning to detract from the various good points made by Alpder as well though)

Edited by stuart bowes, 29 January 2026 - 12:12 PM.

[Midas Mk1]

That pipe is knackered, with brakes if in doubt,  seek a professional. I'd check all brake lines if there hasnt been fluid in there for 20 years.

 

 

Andddd that the unions all have the correct flares.

Edited by Midas Mk1, 29 January 2026 - 02:39 PM.

[Ethel]

The pipe does look a bit crusty, follow it round the front of the subframe. It could well be worth taking the opportunity to replace it

[Spider]

If I have read your opening post correctly, you've re-fiffed original style rubber flex hoses. These are not 'handed' however some of the stainless braided hoses are, so you need to watch out for that, as the other guys have said.

These fittings seal on the flare of the pipe, the tube nut 'presses' the flare down in to the seat, When they are right and done up, these is a small gap between the hex of the tub nut and the fitting on the flex pipe. If there's no gap, as yours one is, then something is quite wrong. The flare on the pipe hasn't been made properly or is damaged or I've had the odd flex hose that the drilling was too deep on.

Take it apart and post up some photos.

[Visible_Potato]

If I have read your opening post correctly, you've re-fiffed original style rubber flex hoses. These are not 'handed' however some of the stainless braided hoses are, so you need to watch out for that, as the other guys have said.

These fittings seal on the flare of the pipe, the tube nut 'presses' the flare down in to the seat, When they are right and done up, these is a small gap between the hex of the tub nut and the fitting on the flex pipe. If there's no gap, as yours one is, then something is quite wrong. The flare on the pipe hasn't been made properly or is damaged or I've had the odd flex hose that the drilling was too deep on.

Take it apart and post up some photos.

 

Thanks everyone for the helpful replies. This is correct, I have used rubber hoses and they appear identical. These are the exact hoses I used: https://www.classicm...hose-drum-brake.

 

It makes sense that there should be more of a gap between the top of the tube nut and fitting of the brake hose, as this is how the other pipe joints are. On this one it has to be tightened this far for the pipe not to be able to move up/down in the tube nut. Even then there is a small bit of movement which I assume is what causes the leak. I fitted the other hose and the fitting is just as deep. It could definitely still be an issue with the tube nut and the flare, but I feel like the depth of the fitting on the pipe is not helping?

 

[68+86auto]

Your flare nut has been overtightened and therefore flared out. That'll be your issue. The non threaded section at the end should be parallel.

 

Both hoses will look the same. They must be measured to notice the difference. If they are different, the fault usually appears on the drivers side due to the banjo bolt bottoming out before the washers are compressed. Replacing the hard line should fix your problem though.

Edited by 68+86auto, 30 January 2026 - 04:35 AM.

[Spider]

While the original flare has been over tightened at some point, it still should seat, albeit, the tube nut would sit lower, but not bottom out and have the pipe loose.

Have you got your old hose to check the new ones against ?  If you have a 3/8" Bleed Nipple (twin leading shoe front brakes ?) you can also use that to test the new hose with. It should bottom on the seat before the hex of it comes down on the hose end.

It's a bit hard to say for sure in the (metal) pipe needs replacing, it's marginal at best but will soon need replacing. Since you have it apart, and yr hands are already covered in that wonderful Brake Fluid, it would be a good call to replace the pope at this juncture.

For test purposes only, you can file back the flared end in the tube nut to bring it back parallel again.

[DeadSquare]

While the original flare has been over tightened at some point, it still should seat, albeit, the tube nut would sit lower, but not bottom out and have the pipe loose.

Have you got your old hose to check the new ones against ?  If you have a 3/8" Bleed Nipple (twin leading shoe front brakes ?) you can also use that to test the new hose with. It should bottom on the seat before the hex of it comes down on the hose end.

It's a bit hard to say for sure in the (metal) pipe needs replacing, it's marginal at best but will soon need replacing. Since you have it apart, and yr hands are already covered in that wonderful Brake Fluid,

 

it would be a good call to replace the pope at this juncture.

For test purposes only, you can file back the flared end in the tube nut to bring it back parallel again.

 

Poor old Pope, he's hardly had time to unpack.

[Ethel]

That Kiwi suppliers also lists the pipe. Alternatively, you might find a local garage that can make one up for you (be sure it has 3/8unf unions). You could also get a flare tool, roll of Kunifer & unions to make your own - it'd pay off in the long run.

[Spider]

 

it would be a good call to replace the pope at this juncture.

 

Poor old Pope, he's hardly had time to unpack.

 

Given there's a risk of Brake Failure here, perhaps that's not such a good idea !