braking bad

[Mark1]

Yikes, have rounded off brake union nut on me 03 Brillingo! Had sprayed it a few times over the week with penetrating fluid aswell. Guessed it was a molegrip job but struggled with that (access).. Gonna have to maybe pop the bleed nipple out and possibly get a little medieval on it tomorrow.

If i do manage to loosen it off do you think i can use grips to tighten it back on to the new w/cylinder? Would save me a lot of trouble as can't envisage needing access again (famous last words) Another poss option is to cut through b/pipe and put a join in if i could bribe my mechanically minded but annoying neighbour to have a go, but have heard this could lead to an mot failure. Is it possible that where bp leads to the flexi rubber section slightly further up, is there a union there somewhere lurking under the rubber sheath? Then i could in theory just make a short piece of bp up (read order a piece made up) then do it without a join?

Oh sugar, could have done without this. Have a pair of new shoes, 2 wheel cylinders and a b/f reflush to sort out. Oh why didn't i let the garage do it. I never learn sob...

Should i set the blow torch to it to? Haven't tried this before but have heard it might loosen it. I'm also curious do you try to loosen it when heated up or should you wait till it cools down? Confused! Also bit concerned due to proximity of brake fluid. Oh hum. Any ideas advice appreciated guys?!


PS On a side note I'm already signed up to this forum but had forgotten my pw. requested for a pw reset but got no reply!
Fuming   So had to start afresh.

[ron]

My advice,for what it's worth,is to cut the pipe & remove the cyl with the stub attached.Renew the pipe from cyl to flex pipe.Do it properly,do it once.

[polar]

a bit of heat works and yes you could tighten it with mole grips.

If you do as Geoff says ^^^ you must flare the joint and not use a olive type coupler

[Mark1]

Thanks guys. Unfortunately haven't had time to try to tackle it today.

ron. Presuming you can order the length of bp already shaped with unions attached? Ebay? Or isn't it that straight forward?

polar. Read you should wait till it's cooled before attempting to undo nut, Is this right?

[polar]

No better when hot - someone is talking BS there Mark

[oilyrag]

If you do manage to move the pipe union it is likely to twist the pipe round with it and either weaken it or make it collapse - given that the brakes will fail if the pipe leaks in the future do as suggested above - clamp the flexible if you can and cut the pipe and remove the wheel cylinder and throw it away. Most small garages have a pipe flarer and will make up a new pipe for you for very little cost. BTW if the pipe you intend to heat is copper based it will be buggered by the heat and brake fluid is very flammable, so hardly worth the risk. Worth buying yourself a brake pipe spanner - not expensive - like a ring spanner with a gap in it.
Good luck!

[Mark1]

Yep. Blow torch a definite no no. Thanks guys.

[jj9]

It's your call as to whether the rounded off union is reusable or not, take into consideration is the brake pipe in good condition etc.

If the union is only just rounded and not chewed up badly it should be ok to refit. You could clean it up with a file and then you may get a spanner back on it.

If you plan on removing the bleed nipple to give better access wedge the brake pedal down an inch or two with a piece of wood up against the drivers seat, this isolates the master cylinder reservoir and stops the brake fluid running out, better than clamping the flexi hose as this can cause damage to them.  

Get the grips onto the union nut nice and tight, don't try to crack the union loose straight away, try bouncing the grips back and forth as if to tighten and loosen the union, do this with increasing force and most of the time they come loose without the need for heat.
A small Footprint pipe wrench or similar is good to crack the union free if you can get in with them as the more force you apply the tighter they grip the nut.

If you're successfully and you feel the union crack loose STOP. 

The union nut will more than likely be seized onto the brake pipe that passes through it so it won't spin, if you try to loosen it out of the wheel cylinder you will twist the brake pipe into a knot !  you will have to loosen the wheel cylinder from the drum backplate and turn the cylinder off the union nut!

Once you have the wheel cylinder off and the brake pipe free you need to un-seize the union so it will be free to spin on the brake pipe. Do this by heating the union and turning it back and forth and sliding it back up the brake pipe, you shouldn't need a lot of heat to free it off, when free use some oil so it gets between the union and the pipe.

You may get the odd small flash flame from the brake fluid but nothing major, it's normally the plastic coating that's on the brake pipe that starts to burn but again nothing major.

If all goes to plan you can now fit the new wheel cylinder to the drum backplate and fit the union nut into it easily, take care not to cross the threads as you fit the union.
When fitted best to put some paint or grease on the area of the pipe that was heated behind the union nut to prevent corrosion.

Good luck.

[dumdum]

If you do manage to move the pipe union it is likely to twist the pipe round with it and either weaken it or make it collapse - given that the brakes will fail if the pipe leaks in the future do as suggested above - clamp the flexible if you can and cut the pipe and remove the wheel cylinder and throw it away. Most small garages have a pipe flarer and will make up a new pipe for you for very little cost. BTW if the pipe you intend to heat is copper based it will be buggered by the heat and brake fluid is very flammable, so hardly worth the risk. Worth buying yourself a brake pipe spanner - not expensive - like a ring spanner with a gap in it.
Good luck!

If you've ever burnt brake fluid it's hardly very flammable as it's in a confined pipe and there's a small green flame at the end lol, it's not like it's petrol or alcohol! And as for copper bro gdamaged by heat, as long as you aim the heat at the the cylinder around the union (the bit you want to expand) the copper will be unscathed and just fine! In fact once the pipes out I'd anneal the end of the brake pipe with some heat so it softens up a little as you do with copper head gaskets (get them glowing cherry red before reuse so I'm not quite sure what a bit of heat is gonna do to a copper brake pipe??)

[pompeylewis]

Thanks guys. Unfortunately haven't had time to try to tackle it today.

ron. Presuming you can order the length of bp already shaped with unions attached? Ebay? Or isn't it that straight forward?

polar. Read you should wait till it's cooled before attempting to undo nut, Is this right?