Old M39 M809 series: brake and air lines identical?

[Robo McDuff]

I was looking at one of the scrapyards for my missing fixed brake line. Found something I thought would fit, then noticed it actually was an air line. Were they the same in strength and diameter?
The line I am looking for is 0.39 inch (10 mm), from the slave cylinder to the distribution point.

 

[162tcat]

Air line and brake line aren’t interchangeable! Air is likely copper which would rupture as brake line. Head to the auto parts store to buy steel brake line and rent the flairing tool while you’re there.


Sent from my iPhone using Tapatalk

 

[Robo McDuff]

The problem is, I am living in the Czech Republic. All the brake lines available here - or in most of Europe - are either 8 mm (all person cars) or 12 mm for larger vans. I can get 10 mm from one of the Dutch scrapyards, but only as a roll of 50 m ($$$), while I only need 50 cm.

Are copper lines not strong enough? One option I was considering was to use 10 mm copper gas line if I could not find anything else.

 

[Ajax MD]

No, copper is not strong enough, nor corrosion resistant.

 

[Robo McDuff]

Thanks, I will check it out once I am at my truck, hopefully tomorrow.

 

[Robo McDuff]

I was buying some things to repair the air system, and came across a 50 cm hydraulic flex line suitable for a working pressure of 150 bar (2200 psi) and a burst pressure of 200 bar.

With a connector added on each side, I can make it fit the connector at the front of the slave brake cylinder at the airpack and the 3-way connector on the frame splitting the brake line to front and back. Not ideal, but for the moment with only slow local driving on our own yard it will hopefully work.

 

[fasttruck]

Remember with an air system the first several feet on he discharge side of the pump must be metal or metallic so it does not melt from the hot air being discharged from the pump. A plastic line up to the pump will fail.

 

[Robo McDuff]

Thanks for the heads-up. I will use modern plastic air hoses only the last part of the way to the glad-hands.

The hydraulic hose I will use as replacement for the brake line between the end of the slave cylinder in front of the airpack to the split-connector on the frame, about 20 inch away, mostly upward. So heat should not be a big problem, certainly because this truck is mnot going to be used on normal road, only forest roads to carry concrete and stone debris to fill a ditch.

 

[NY Tom]

This stuff is good and made in England. Not sure if you can get that in Czech Republic though. Cunifer tubing. It is sold in English and Metric diameters.

Brake, Fuel and Hydraulic Line | FedHill

Cunifer the fast, easy and rustproof replacement for steel brake lines. Hard to find brake line nuts, flare nuts, brake line fittings, fuel line and brake line flaring tools.

www.cunifer.com

Here is a USA distributor website if it helps.

http://www.fedhillusa.com/

Tom

 

[Robo McDuff]

Thanks. My problem is that this section of brake line has a 10 mm tube. I can get 8 and 12 here, but not brake-line quality 10 mm. I don't want to use the much smaller 8 mm, and the 12 mm I cannot fit in the connectors.

 

[NY Tom]

Federal Hill Trading Company

Cunifer the fast and easy replacement for steel brake lines. Hard to find brake line nuts. Fuel line and brake line flaring tools.

store.fedhillusa.com

 

[NY Tom]

I tried to link to the 10mm section of that website. The size you need is available just not sure how easy it will be to get it to you.

 

[Robo McDuff]

Thanks a lot for the link. Problem is that this does not count as document, so quick transport is crazy expensive, slow mail still $$ enough. Let's see how the hydraulic line holds up for now.

 

[NY Tom]

I see reason why it should not work fine. Good luck with it.