Morris Minor Owners Club

Hello all, as above really. I changed out the complete braking system last year- grumpy front disc conversion, all new Automec kunifer pipes, new rear cylinders on existing backplates and drums (both refurbished), remote filler reservoir and new genuine master cylinder (rubber bit removed). I decided to go with silicone brake fluid but I've always had a soft(ish) pedal and on checking the connections found a small weep from the nearside rear which stopped when I nipped it up. It took a while to notice a drip from the captive bolt on the gearbox cross member, looking inside the chassis rail there was brake fluid present. I nipped up the side exit brake nut, but still weeping.The rear inlet is dry.
I'm wary of tightening it further. I'm prepared to strip this connection down, and refit with a new copper washer. Is there any thread sealant that could be used to guarantee a fix on this joint?
Any other suggestions for a suitable fix gratefully accepted.
Bill

You won’t strip the thread with an ordinary length brake pipe spanner unless you resort to gorilla tightening. If it still weeps even when rather tight it’s possible there’s some dirt on the flare seat or the flare is damaged or not seating properly. In such circumstances it won’t stop just with more tightening. Try to nip it up tight and if that doesn’t work take it apart. Examine the flare carefully and if damaged replaced the pipe. When reinstalling the pipe, push the flared end of the pipe fully home and then push the fitting in and tighten. Sometimes, especially when the is a bend near the end of the pipe, the flare does not seat properly. Kunifer is considerably harder than copper pipe and more torque is needed to get the pipes to seal properly.

I had very slight weeps on both front brake pipes where they join the flexible hoses. It was just a little moisture but it did take quite a lot of force to get them both to seal completely. More force I must admit than I was entirely comfortable with but it was completely successful.

You mention the copper washer. The banjo on the MC has 2x copper washers, 1 on either side of the banjo. To save using new washers you can anneal and reuse the old ones if you wish.

Stephen

You're right, Stephen. I've just drained the system and undone the nut. No visible damage to the swaged end and threads look ok, however, I can now see one part of the problem. The hole in the chassis rail is off centre with the banjo bolt, thus not permitting full access to the hex head, even with the correct brake nut spanner. I don't remember this when I put it in. I can only conclude that the banjo bolt is missing the front copper washer, an oversight by me during initial installation, as this would help centralise the outlet. It looks like master cylinder out time! Oh what fun! I'll change all the copper washers while I'm at it. I may drill out the hole to a bigger diameter, just in case, as it may have always been like this.
Bill

Good news that you've found the problem and looks like you're well on your way to a successful outcome!

Stephen

One point: threads on any brake hydraulic parts are not there for sealing anything. The seal will always be metal to metal.

Yes thanks for pointing that out. It's over a year since I did the brakes and I posted the question without fully thinking it out. A bit of frustration on my part, as a couple of unrelated small niggles seem to have appeared at once. I'm happy to receive advice on anything minor related as I'm still learning on my first and only minor.
I will remove the master cylinder today and fit new banjo bolt washers, as I have some in stock. I did originally anneal the existing ones (as Stephen had mentioned), which may be part of the problem. I'll also dismantle the pipe to the 3 way tee to give it a good looking over. If the thread on both ends is the same I may reverse the ends on refitting. Any damage and it'll be a new pipe.
Once again thanks for letting me bend your ears!!
Bill

I find the pedal travel a bit "long" with a disc conversion, a slightly bigger bore master is needed, anyone found one?

or would a bored out and resleeved to a larger size be possible?

Are yours servo assisted? I have marina front discs with servo and pedal travel is normal. Is your free play at master cylinder adjusted correctly?

yes marina discs and a servo,
they work well but jumping out of something more modern (even a landrover) I seem to have a long pedal,

all bled etc,
will check free play,

Same here regarding pedal travel, but I don't have a servo, in fact I'm not sure if you can have a servo with silicone fluid ( I'm sure I read this somewhere).
My modern car has super sharp brakes, so the difference is very noticeable. When I reassemble the brakes with the new pipe and new washers it may improve as it's now apparent that there was a leak at the master cylinder. Hope that's not your problem as lying on a cold garage floor in these temperatures is no fun!

You can use a servo with Silicone fluid but you cannot use an ABS braking system. It is said that it can be more difficult to bleed a brake system that is using Silicone brake fluid. I have never noticed any issue with brake bleeding but I don't have a servo. Long pedal travel could be master cylinder pushrod adjustment or brake shoe adjustment. If it is long pedal travel and a spongy feeling it is air somewhere. If it is long pedal travel and the pedal creeps slowly towards the floor there is a leak. ESM gave me a tip for detecting small leaks: jam a piece of wood between the brake pedal and the seat and leave overnight. If the piece of wood has fallen out there's a leak. My brakes which are drums all round, no servo and Silicone fluid are as good as I could reasonably expect in a car of its age. The pedal does not have a long travel and is firm. I actually have larger than standard front drums, 9" and the braking is good enough that the real issue would be the grip of the narrow tyres on the road. I would be looking for air in the servo in the circumstances stated in the posts above.....

Stephen

bobtail4x4 wrote: ↑Sun Oct 26, 2025 6:33 pm yes marina discs and a servo,
they work well but jumping out of something more modern (even a landrover) I seem to have a long pedal,

all bled etc,
will check free play,

You can not compare the brake feel with a modern car which have high assistance levels and abs. They also use pendulum pedals direct to mastercylinder, not through the floor via linkage. You would be better comparing with another minor or you maybe chasing a non existent problem

as time goes on, I am getting used to it, but swapping between cars, takes a second or two the first time I stop,

fortunately I live on a private lane, so the first stop on a morning is there,
still have to think where the indicator is,
my scimitars are on the right, others are on left,
jump in modern and indicate with wipers.....