Rob Posted April 1, 2011 Share Posted April 1, 2011 Got a few questions:My 74 RL700 is needing replumbed in the brake system. The truck is loaded with Strat-O-Flex lines that are hard and brittle. I've decided to completely replumb with plastic and brass. I'm wondering if the brake lines from the bulkhead fittings on the steer axle should be plastic, or rubber air brake hose? One of my trucks has plastic lines in this application, and a couple others have rubber line. On this truck which has wedge brakes, the quick release valve for the spring brake chambers is on the frame rail as is the relay valve for the service brakes. I know plastic air brake line is durable enough to take the constant flexing of the application but I'don't know if it's legal or not. Anybody aware of DOT rules concerning this?Thanks,Rob Quote Plodding along with no job nor practical application for my existence, but still trying to fix what's broke. Link to comment https://www.bigmacktrucks.com/topic/18547-air-brake-plumbing/ Share on other sites More sharing options...
MidniteMechanic Posted April 1, 2011 Share Posted April 1, 2011 As far as I know plastic is not legal. Rubber is the only way to go on any flexible connection. Plus plastic will kink on the steer axle. Plastic will break with extended flexing. Quote Link to comment https://www.bigmacktrucks.com/topic/18547-air-brake-plumbing/#findComment-75262 Share on other sites More sharing options...
ducky698 Posted June 2, 2011 Share Posted June 2, 2011 As far as I know plastic is not legal. Rubber is the only way to go on any flexible connection. Plus plastic will kink on the steer axle. Plastic will break with extended flexing.Hi, Australia has very tuff laws on this sot of thing, safety first. plastic was legal years ago for memory, then they stopped it some time later due to the hose been easy to kink, in saying that there still is a few trucks out there that have plastic. flexi rubber hose would be the way to go on every thing from chassis to axles, where a moving part meets a non moving part the rubber is the one.Grant Quote Link to comment https://www.bigmacktrucks.com/topic/18547-air-brake-plumbing/#findComment-78870 Share on other sites More sharing options...
gearbox Posted June 15, 2011 Share Posted June 15, 2011 Some plastic or nylon has a braid in to resist kinking meets our standard in Australia but the cheaper non braid does not meet the tube is marked with a J no. from memory can't remember the no. and AS standard for our hose but rubber DOT hose needs to be used between chassis and axle where there is constant flexing and movement in suspension and steering Gearbox Quote Link to comment https://www.bigmacktrucks.com/topic/18547-air-brake-plumbing/#findComment-79728 Share on other sites More sharing options...
Freightrain Posted July 24, 2011 Share Posted July 24, 2011 I used plastic on the rear axle of my truck when it was still spring(don't move much). I can see air ride being more of a problem, and I used rubber on it now. Heard it was illegal. Quote Larry 1959 B61 Liv'n Large...................... Charter member of the "MACK PACK" Link to comment https://www.bigmacktrucks.com/topic/18547-air-brake-plumbing/#findComment-82333 Share on other sites More sharing options...
ThaddeusW Posted July 24, 2011 Share Posted July 24, 2011 Rob,I have never seen plastic on the drive axles. Not even on my B which had about half of its lines updated to plastic, rubber to all the axles. Quote -Thad What America needs is less bull and more Bulldog! Link to comment https://www.bigmacktrucks.com/topic/18547-air-brake-plumbing/#findComment-82349 Share on other sites More sharing options...
Lmackattack Posted July 24, 2011 Share Posted July 24, 2011 Plastic on the frame to and from valves etc...rubber or some sort of flexible hose that will Händel movement from a frame located valve/fittings to an axel..that's what I have always done.. Quote Link to comment https://www.bigmacktrucks.com/topic/18547-air-brake-plumbing/#findComment-82350 Share on other sites More sharing options...
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