Brake lines from hell!

[Mack Turner]

Was it standard for these coaches to change from Hardline to rubber to Hardline to rubber from front to the back multiple times or has my brake lines been cobbled together? Coach is at a shop to replace the rubber brake lines which I thought were just going to be at the calipers, now they tell me my brake line running from front to back jumps back and forth between rubber and steel, is this normal and should I worry about replacing those rubber lines? The ones on the front at the caliper were dry rotted.

[Mike Shumack]

That is not typical.
Usually all the lines will be the nylon material (plastic) except where some movement of the line is expected (like the short section from the frame to the wheel ends).

[Mack Turner]

The lines going from the caliper to the line running along the frame are standard hydraulic hose lines like you'd see on any kind of large truck, maybe I'm using her incorrect nomenclature calling them rubber? The shop working on them says it looks like they used the same hydraulic line in places to get from front to back over different stuff and in places the line completely disappears from sight and they can't see how it's run. This is on an 01 Patriot 33.

[Mike Shumack]

I see. I thought you had air brakes.
I'm not sure how the factory ran the brake lines on your setup. I would expect them to use the longest continuous lines available but it wouldn't be surprised if they had a couple of sections of shorter brake line on the chassis section.

[Mack Turner]

This year model was air over hydraulic with the front and back using the same master but the resivor is split front/back.

[Mike Shumack]

If the issue is that there is a "mixture of brake line types" and if your already working on the brake system for some other reason, I would change to all the rubber running along the frame to steel line (except the flexible rubber sections needed at the wheel ends, of course).

The problem with the rubber brake lines is that they degrade internally. When the hose fails internally it can trap pressure in the caliper when the brakes are released, causing that brake to drag and that will cause faster wearing of the lining and could cause the brake to overheat. The other problem with the rubber hose is that it can get soft and then when you apply the brakes, the hose swells or balloons and that reduces the pressure getting to that brake. And that can cause uneven braking or brake pull (where the Coach wants to steer itself in one direction when brakes are applied) -  that's if the bad hose is on a front caliper.

[Mack Turner]

The current lines running from front to back are steel with hydraulic hose at certain points to get over obstructions, this started because the driver's side hydraulic hose from the caliper to the frame rotted in half so I decided to replace anything I could that was of the flexible hydraulic hose line and in doing so the shop discovered that certain points along the frame use hydraulic hose to get past or over obstructions and I did not know if this was standard or if someone did this aftermarket?

[Mike Shumack]

I understand. I don't know the answer regarding how the Coach was originally built.
As your Coach is almost 30 years old, I would recommend that you replace all the rubber brake hoses - if your not 100% sure of its condition.
Stainless steel line everywhere is my preference, but if you need to, use flexible brake hose is some places, I wouldn't worry about it as long as it is all replaced.
Good luck.

[Dave Atherton]

Gentlemen, let me be very clear unless we fully understand the braking system starting at master cylinder to the wheels, I would have a experienced service shop preform the repairs. Throwing out
Few thoughts, first what pressure is produced from the master applying brakes, second rubber hose
able to handle Dot 3 brake fluid with out breaking down the rubber hose. Fitting and hoses must be DOT
Reg approved. Many mistakes, In retrofitting brake lines to each axle must be equal measure from
Supply line from master Cylinder to tee at center axle to wheels. If that is not correct you will have unequal braking force because different amount brake fluid will applied more braking force to one
wheel. Understanding the braking force put on Rotors or brake drums. Last dealing with the braking
system if your not trained and not fully understanding  DOT Reg’s you are putting a very big monkey
on your back and need someone qualified to sign off your work meets required Reg’s .
Dave Atherton Retired Cat Mechanic

[Mack Turner]

The shop working on the coach is R-S truck and diesel, supposed to have all certified heave diesel mechanics. They replaced the lines from the frame to the front wheels. Their opinion was I shouldn't mess with the ones along the frame and they didn't think the ones at the back wheels needed to be replaced. My son's an auto mechanic and he didn't have the equipment to pull the wheels off or get to the lines but I think we're still going to use a brake vacuum system just to pull all new fluid to all the wheels.

[Eric Maclean]

Mack
The Magnum coach's were set up at the factory with two master cylinders below the driver's station from there the lines run from the masters with a pair of flex lines ( Raybestos # BH381081)(40 1/2") which run from the masters over through a whole in the left frame rails where they connect to steel brake lines one runs the full length of the frame to above the rear axle where it connects to another flex line (Raybestos#381082)(39") which runs down to the rear subframe where it is connected to a tee fitting where steel lines run across the sub H frame to the rear axle and again connect to flex lines (Raybestos # BH383373)(42") which terminate at each of the rear calipers.
The front brakes come from the masters with a flex line as stated above at the inside of the frame rails the flex line connects to a steel line which runs over to the cross member in front of the fuel tank where it connects to a tee fitting from there two steel lines run inside the frame rails on each side beside the fuel tank then come out through the frame rails where they connect to flex lines
(Raybestos#BH383373 )( 42") which go to the front calipers.

Mack in total there are 7 flex lines.
The flex lines numbers I've given are what I used on my own coach these lines are common flex lines used on International medium duty trucks 3800 or 4800 series.
The rest of the parts to fit the Magnum chassis are as follow.
Calipers (same for all four ).....................Centric #14179001
Calipers hardware kit ( one per axle)......Centric #11779003
Brake Pads .,.,...........................................Centric #10602360
Front Rotors...,..,.......................................Centric #12079023
Front axle seals ......................................Stemco #383-0136
Front wheel bearing ( inner). ..................Bower  #HM212049X
Front wheel bearing ( outter)..................Just.    #3782

Hope some of this helps
Eric

[Mack Turner]

Thank you very much for your help Eric I will take a look at what I have this sounds correct from what I can tell.