Unseizeing brake unions ..

Post by **JustinMinor1000** » Fri Mar 10, 2006 11:08 am

All of the (two year old) brake unions seem totally siezed ... all soaked in WD40 to no obvious effect ..

Any tips ?

Post by **Alec** » Fri Mar 10, 2006 12:32 pm

Hello Justin,

I don't know if it is steel or brass unions, but for steel, Plus gas is a much better fluid to use.
Get the best fitting spanner you can, ideally a proper flare spanner is best. (An open ended ring spanner is my best description)

Alec

Post by **simmitc** » Fri Mar 10, 2006 2:35 pm

Not much help when already seized, but on re-assembly use copperease or similar on the threads and tube, but keep the end and innards of the pipe clean. Since adopting that practice I've never had a problem.
Once seized then sometimes a sharp tap on the well fitting spanner works better than constant pressure. It's still best to have a spare pipe ready just incase the old one twists - once it does then it's weakened and shouldn't be used.

Post by **rayofleamington** » Fri Mar 10, 2006 3:34 pm

If you grerase them, make sure you don't overtighten!
with lubricated threads it will be extra easy to flare the end of the flare nut, making it impossible to use twice.

Post by **bmcecosse** » Fri Mar 10, 2006 4:09 pm

Best to burst the pipe - and then you can get a good ring spanner on it. Spot of heat from a gas torch may be needed too.

Post by **JustinMinor1000** » Fri Mar 10, 2006 7:35 pm

ARRGH .. Well .. I ignored all the advice .. fortuantly it is only one outboard union that didn't respond to the ring spanner treatment.

With one side in a vice and the second (sacrificial joint) in a pair of overstressed mole grips. I felt it give and thought all was well ..

No .. it had of course sheared ..

Hi ho hi ho it's off to the parts car we go ..

Post by **bmcecosse** » Fri Mar 10, 2006 7:38 pm

Told you to use some heat!

Post by **JustinMinor1000** » Fri Mar 10, 2006 7:42 pm

bmcecosse wrote:Told you to use some heat!

I know

just shoot me and be done with it ..

Post by **bmcecosse** » Fri Mar 10, 2006 7:47 pm

Never mind - maybe would not have come out anyway - was it front or rear ?

Post by **JustinMinor1000** » Fri Mar 10, 2006 8:11 pm

bmcecosse wrote:Never mind - maybe would not have come out anyway - was it front or rear ?

It was rear .. I made a rather silly mistake .. the nearside cylinder was siezed and (in my opinion) very badly fitted and knowing they had both been done at the same time I assumed that the other side would be the same, and that the best course would be to change them both.

As the nearside one had a new rubber boot and the unions were all free(ish) I bought the parts on that basis .. New cylinders/pipes/copper washers.

What i didn't do was to dismantle the other side .. assuming they would be the same ..

They wern't .. 30 year old rubber boot almost perished seised in union etc etc .. My guess is that the other side the boot fell to bits when they dismantled it so it had to be replaced this one stayed together ..

So it's more new bits tommorow ..

It could have been worse! The three way union could have been siezed ..

Post by **bmcecosse** » Fri Mar 10, 2006 8:45 pm

And it's the one with the unusual threads. New cylinders are best bet - they will then last for many years. I keep a bit of slack in the handbrake cables so the cylinders get some movement when the brakes are used. MOT lad always grumbles - I explain why it's like that - he's happy.