Testing fluid lines before fluid?

So, how do i test all my lines and fittings before i actually finish? Id like to make sure no leaks before continuing assembly. Brake and fuel. So wjen i go to put fuel and fluid in, im not having to chase stuff and fix paint, etc.

Theres a lot of fittings and leak points in the brake and fuel lines.

Perhaps air pressure or vacuum? Like testing coolant seals, have a pump with a gauge to see if they hold pressure.

Yes, you'd think that with a bit of air pressure and a soap bottle, you'd be able to check everything. 

I feel your pain  cause I just went through this with the Healy .  I considered making a pressure vessel that screwed on to the two brake lines that went into the master cylinder. Use some flex lines out of the pressure vessel so that it can be used in other applications.

In the end I just rolled the dice and it was another vindication for buying this kind of line flaring tool:

Whole car re-plumbed, zero leaks. First time ever had that happen. Only downside is that it only does 3/16 lines.

That is what I was thinking,  but needed to poll the audience. 

Guess i have to finally fix the compressor 

I visit the local hydraulic hose shop pretty much weekly for my job and they have a test rig that's just shop air, a valve, pressure gauge and a million adapters. As long as you can get your hoses to adapt to npt you can get an airline fitting to connect to it?

Your options are pretty much air pressure or vacuum.  Personally, I've built miles of plumbing over the decades and, while I can't claim I've never had any leaks, I think the time spent leak testing would have drastically exceeded the minimal amount of time I've spent repairing the few leaks that I've had.

I don't think vacuum is the answer. If I recall, the seals on the brake system have a taper that uses internal pressure to push the seal against the cylinder surface. Vacuum would collapse the seal.

Please tell me there's a good reason for gas line fittings in the passenger compartment. And please put a line clamp on the brake line to the right of the pedal where the line appears to be rubbing on the edge of the sheet metal recess in the firewall.

NOHOME said:

I feel your pain  cause I just went through this with the Healy .  I considered making a pressure vessel that screwed on to the two brake lines that went into the master cylinder. Use some flex lines out of the pressure vessel so that it can be used in other applications.

In the end I just rolled the dice and it was another vindication for buying this kind of line flaring tool:

 

Whole car re-plumbed, zero leaks. First time ever had that happen. Only downside is that it only does 3/16 lines.

You are absolutely right. Buy good quality tools for brake and fuel lines and You don't have to worry about leaks. 
   Here in Minnesota brake and fuel  lines take a real beating due to the salt we put on our roads.  If we had to test them before putting them on changing brake lines would go from a 30 minute job to a ;3 hour job and few could afford it. 

Brake lines, not really.  You are not going to have anything that makes as much pressure, so you may as well just use brake fluid.

Fuel, I do the same thing, because fuel is easier to find than air bubbles or smoke.

NOT A TA said:

Please tell me there's a good reason for gas line fittings in the passenger compartment. And please put a line clamp on the brake line to the right of the pedal where the line appears to be rubbing on the edge of the sheet metal recess in the firewall.

Reason for the fuel lines in the passengers compartment is that due to the nature of the tube frame there is no way to run them that they do not become a drag and pinch hazard. What you don't see in this picture is the aluminum sheets that close out the interior and protect the fuel lines from the top side. I am still in the process of making the brake lines and none have been secured at this time. All will be secured with P clamps at appropriate points and lined with the brake line armor because nycop tends to Dent easy. Is there something I'm not thinking through fully? I ask so I can learn before making more expensive mistakes

My concern is GAS LINE FITTINGS in the passenger compartment. Protected fuel lines don't bother me but the potential for a leak at fittings is MUCH higher than straight tubing.

Best bet is a mity vac and a bottle of snoop or soapy water. That doesn't mean they'll hold 2k psi but about as good as a precheck as you will get.

So, i fubard the lines on final bends. And i have far too many leak points and failure points for comfort now that im standing back and looking.

Plan b time.