Community Forums

MarkofSJC · 05-02-2012, 11:35 AM

Newbie question here.

We're looking at a 2008 Country Coach Magna - our first coach. That year they went to disk brakes on all wheels including tag. The two coaches we're interested in both have about 20,000 miles.

These are heavy coaches (62,000+ lbs

) with ISX 600 HP engines (which I would assume means they didn't spend life in the slow lane

)...but they do have three stage exhaust brakes, which shifts braking from brakes to engine.

What would be a typical number of miles before most need the front pads replaced? On some of the cars we've owned, it was typical around this mileage, but I have no experience with an RV.

Related question...what's a rough cost if they just replace pads?

All responses appreciated!!!

Mark

2-Nickels · 05-02-2012, 05:21 PM

Your question is a tough one to answer, if your driving uses the Jake to slow down all the time and then uses the brakes for stopping from slow speeds the brakes could last 10's of thousands of miles. If your driving has you using the brakes most of the time because you forget to use the Jake you could go through brakes every 10,000 miles. Our coach is near 50,000 lbs and I changed the front brake pads @ 50K, now at 61K I am told there is no signs of wear, I use my two stage Jake all the time.

Pusherman · 05-02-2012, 05:25 PM

The brakes on these coaches will last upwards of 100K miles as long as there are no other problems, such as high temperature problems from sticking brakes, etc.

From a wear standpoint, the answer is a very long time, much longer than 20K mi.

I do recommend having the brakes serviced periodically, which generally does not require any parts. Just cleaning and lubrication where necessary.

deandec · 05-03-2012, 11:21 AM

Just an observation:

62000 lbs / 600 hp = 103 lbs per HP

Huge engine for a heavy coach so exceeds the recommended minimum 100:1 ratio before adding the toad.

MarkofSJC · 05-05-2012, 11:27 PM

Quote:

Originally Posted by deandec

Just an observation:

62000 lbs / 600 hp = 103 lbs per HP

Huge engine for a heavy coach so exceeds the recommended minimum 100:1 ratio before adding the toad.

(sound of something whistling over my head)

You got me deandec...I have no idea of what you mean. Is my potential a good set up or a bad one? This year was the first that went to all disk brakes with all aluminum wheels (less unsprung weight) and upgraded all tires to 315s.

Do your calculation mean this is going to be the RV equivalent of a sports car?

Mark

Papa_Jim · 05-05-2012, 11:50 PM

Quote:

Originally Posted by MarkofSJC

(sound of something whistling over my head)

You got me deandec...I have no idea of what you mean. Is my potential a good set up or a bad one? This year was the first that went to all disk brakes with all aluminum wheels (less unsprung weight) and upgraded all tires to 315s.

Do your calculation mean this is going to be the RV equivalent of a sports car?

Mark

No, I think he is inferring that the coach may actually be a little underpowered.

Based on the standard that the engine in any coach must be matched to a minimum standard of 100 HP of coach weight for every 1 engine HP.

My coach is 29000 lb, with a 350 HP engine.

29000 lb / 350 HP = 83 lb/HP

That should mean that by comparison, my coach should be the race horse.
It doesn't feel like a race horse, but it certainly has enough power.

I don't exactly know what all this has to do with your concerns about the brakes.

deandec · 05-06-2012, 10:33 AM

Sorry, I was off topic, but responded to your statement:

"(62,000+ lbs

) with ISX 600 HP engines (which I would assume means they didn't spend life in the slow lane

)"

I envy folks who are considering a unit with a big engine, but then am reminded that the big engine is needed to just move the heavy rig around.

So, you might expect to be in the slow lane at times with that combo. (I did not perceive that your comment was tongue in cheek.)

Also, I think that beautiful rig would have a three stage engine brake rather than an exhaust brake. Much better set up.

dons2346 · 05-06-2012, 11:26 AM

The GVW on that coach is 52,000 not 62,000

52,000/600 = 86.7lb/HP

Still a respectable number.

Gary RVRoamer · 05-06-2012, 02:02 PM

You really need to add the toad into the weight/hp calculation - the engine has to move the total actual weight.

The 62k lbs was probably the GCWR, though I doubt if the actual weight would go that high unless towing a large enclosed trailer.

Back to the brake question, few motorhomes with exhaust or engine brakes ever wear out the service brakes. 100k+ miles would be fairly typical according to a Freightliner rep at a rally I attended.