I've sprung a bit of a leak in the union of the front hydro pipe. My plan is to disassemble and clean the union to (hopefully) fix the leak.

With the tappet chest breather, dual hs4s, fuel pump and radiator.. there isn't much room to access the bottom nut and was wondering how to best access it.

I was thinking of removing the radiator but didn't want to go through that trauma again (haha).

Probably just looking to confirm my suspicion the rad is the only way to properly get at the union.

I would remove the top steady. Why is it there anyway unless you have a rod change box?
They do nothing with a remote shift box.

Edit I think the radiator hose needs to come off the pump too, you should have access then.

Good luck with fixing the hydro pipe, I fixed my son's then it got another leak further back.
I have fitted nylon lines instead.

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DrMini- 1970 wasaMatic 1360, Mk1S crank, 86.6HP (ATW) =~125 @ crank, 45 Dellorto (38 chokes), RE282 sprint cam, 1.5 rockers, 11.0:1 C/R.

From your photo the leak looks to be above the mounting bracket, where the displacer hose attaches to the connector. It is not an uncommon place to leak.
Have you tried to get a spanner (3/4"AF) onto the hose's tail nut to nip it up slightly.
DrMini's advise will help a lot too, before you have to remove the radiator.

I've tried tightening the end of the hose but couldn't get it tighter (the bracket was starting to bend with the force)

I'll try removing the thermostat housing/engine steady and radiator pipe and hopefully there's enough space to turn a spanner.

Interesting that the engine steady isn't needed with a remote box. I thought it did, because it's a 1275. Also recall needing a top engine steady for a blue slip in the late 90s, when I installed a 1275 A+.. but that was a rod change

The extension housing on a remote box acts as a 3ft long torque arm.
That's why top steady isn't fitted.

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DrMini- 1970 wasaMatic 1360, Mk1S crank, 86.6HP (ATW) =~125 @ crank, 45 Dellorto (38 chokes), RE282 sprint cam, 1.5 rockers, 11.0:1 C/R.

Start with the easiest thing first.
Drop the pressure on that side by releasing the rear valve.
Jack up the body on that side a few inches to take the pressure off the bag.
Because its the highest point there wont be any fluid left in the hose.
Undo the hose fitting.
Check both sealing surfaces are smooth and not corroded.
Check for cracks in the fittings or threads.
Clean up the mating surfaces and put it back together and check for leaks.
Get yourself a hydro pump as you will need it



If the joiner is too rusty or cracked then you can buy new ones - Pt No 21A1524
You can access it better with the radiator out



If its the hose fitting leaking then the bag will need to come out and a new hose fitted to the bag. Suspension has to come out for this.

Awesome thanks all - now have a plan of action.

First step will be to make a hydro pump and then go from there.

You can safely release the pressurized fluid into a bucket.

Take off the dust cap from the rear left hydro access port.

Stick a rag over the valve and push a screwdriver into the valve nipple. It's just like a tyre valve.

Just be careful and make sure it's covered with a rag because the fluid is normally about 280psi.

At least you can make a start on it until your pump arrives.

Don't use a screwdriver it can bend the valve stem. Use the domed valve cap if you have one, if not the blunt end of a 3mm drill will do. Watch yer eyes, but it's not dangerous to do.

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DrMini- 1970 wasaMatic 1360, Mk1S crank, 86.6HP (ATW) =~125 @ crank, 45 Dellorto (38 chokes), RE282 sprint cam, 1.5 rockers, 11.0:1 C/R.

I've ordered the attached pump and schrader coupler online. Hoping to take it to Pirtek and get a T piece and extra ball valves installed, so that I can use it to both de-pressurise and pump up the system

Here is the one that I have.



Mine has a small bleed valve to drain the system.

Using that pump you can de-pressurise without any additional fittings.

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1986 Mayfair (998 auto), 1974 S, 1974 Van, 1972 PMG Van

Too many minis

I have a currently similar problem on my MKIII Cooper S except the leaky bit is under the connector (21A1524) where it joins the steel pipe fitting. One possible remedy in my case or yours might be to use a copper flare gasket at the hydro hose connection and/or the steel pipe connection in case the connection surfaces aren't too badly corroded:

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"You're not a true petrolhead if you've never owned a mini" - James May 2012 - TopGear

I cleaned and reassembled the hydro pipes, and keeping an eye on it. Haven't really driven it much, but I did notice a tiny weep after jacking up the front. I've got the pump now, so if it continues to be a very slow leak - its not a big deal to pump it up.

Thanks for the suggestion of the copper flare gasket.. I'll keep it in mind but not rushing to remove the radiator yet again haha

About the copper flare gasket, I forgot to mention that others elsewhere have suggested making the same type of washer/gasket out of lead material as it would be softer and more likely to seal up an irregular surface. Once I get mine apart I will find out how badly corroded the joining surfaces are and try the flare washer fix if possible. I will have to remove the rad, hoses and such as the leaky bit is below the connector and access to the steel pipe nut is more difficult. This photo shows the crowded area, similar to yours:
Here's the leaky spot:

A worse case scenario is that I'll need to replace the complete steel line or use the split bendable copper type to fix it. I have since acquired both types and a new 21A1524, but to properly replace the pre-bent steel item requires removing engine/subframes, a daunting task to say the least and I will avoid that in any way possible!
I hope your situation will continue to be nothing more than a minor nuisance at best!

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"You're not a true petrolhead if you've never owned a mini" - James May 2012 - TopGear