torque for master cylinder bolt

ironbuttjohn

ironbuttjohn

Member
What is the amount of torque used on the bolt on the back to the '48 master cylinder? This is the one that holds the brake lines on.
 
I believe he's talking about the 1/2" threaded banjo bolt that holds the brass distribution block on the back of the cylinder. I don't know the torque. I just use a suitable sized spanner (wrench) and make sure it is tight.

Sometimes you need to use judgement and develop a feel.

Mart.
 
If copper washers are new, they should be annealed soft. If they are old, they need to be annealed. It's best to use new but you can heat them up red hot and quench them in water to anneal them. It doesn't take much torque to get a seal. Hollow banjo bolts break easily so snug them good and see if they leak. Tighten until they don't leak within good reason. That's about the best I can say.
 
The other thing that is easy to break is the brass fitting when screwing in the brake light switch. I had a hell of a time sealing the one on my 49. Never thought to anneal them first.
 
Rotorwrench has it down. Aircraft spark plugs use copper washers, and we kept a supply of annealed ones for each job. Trainees got to do it. Newc
 
For annealing copper, rub some hand soap on the washer. Heat it up and when the soap blackens or turns to soot, you have the right temperature. Copper can either be air on water/oil quenched and with keep the anneal, softness, either way. Water quench will remove the black oxide.
 
glennpm said:
For annealing copper, rub some hand soap on the washer. Heat it up and when the soap blackens or turns to soot, you have the right temperature. Copper can either be air on water/oil quenched and with keep the anneal, softness, either way. Water quench will remove the black oxide.
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Thanks! I was just going to ask!
 
Well, the torque is a bit less than what you used last time then.

Sorry couldn't resist.

Mart.
 
So are you saying new copper washers from the parts store such as from Dorman that are described for brake lines need annealing? I thought they would be ready to use since they were described for brake lines?
 
zuburg said:
So are you saying new copper washers from the parts store such as from Dorman that are described for brake lines need annealing? I thought they would be ready to use since they were described for brake lines?
Click to expand...
Only used washers should be annealed in order to re-use.
 
51 MERC-CT said:
Only used washers should be annealed in order to re-use.
Click to expand...

Depends. I get my washers at NAPA and they are hard as rock. Not sure if they are Dorman or what.

Got to watch out too, our chinese brothers are putting out copper-coated washers, not clear what's underneath.
 
I don’t have an acetylene torch. Can it be done with a small propane torch like plumbers use to solder copper pipes?

Now I have seen posts that say you don’t need to anneal new washers. The ones I have used show the rings pressed into the copper gasket from the brass block after tightening, but it still leaks. Also, there are no rings on the master cylinder body where the banjo bolt threads in so no rings will be crushed into the copper gasket on the M/C body side. I assume this is normal? So far, I can’t tell if it is leaking on the M/C side or the brass block side of the copper gasket.

Any other ideas to eliminate these leaks? I’ve been fighting this for weeks now.
 
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