How often should rubber heater hoses be replaced?

[belfert]

I have some rubber heater hoses that run front to back in my bus for the driver's heat and defrost heat.  How often should I replace these?  They are now 15 years old. 

I had a larger heater hose coming out of the engine split last year.  It wasn't rubbing on anything at all.  It did get exposed to hot exhaust gases when my exhaust pipe was broken a few years back that may have affected it.

I would like to replace these hoses, but they are so convoluted.  I don't see how they installed the hoses unless they did them before the air tanks and everything else was in place.  I also don't quite understand why they ran three hoses either.  I need to get out the manual I guess.

[rv_safetyman]

Brian, I hate it when you ask a rubber related question   With my background, I always feel compelled to answer the question.

So, here is my answer:  DEPENDS

Our applications are easier on hose than a gas engine.  Our temperatures seldom exceed 200* while gas engines are almost always over 220* today.

Where the "depends" comes in, is what material the hose is made of.  Silicone hose lasts a long time,  Next comes good quality rubber hose (truck and bus quality such as Gates Green Stripe or Blue Stripe or other equivalent hose).  Lastly is relative cheap knit reinforced hose like you would find at Checkers or similar suppliers.  For sure you should NEVER use cheap rubber hose - just not worth it (even name brand).

You can tell if the hose is silicone (color) and maybe with it you would have another year or two.  If the whole run is hose (don't think that would be standard practice - at least not in an Eagle), I can almost guarantee it is not silicone ($$$$$$). 

Assuming it is rubber, and if you know it is 15 years old, I would replace it - no questions asked.  Just not worth risking an engine (DDEC should catch it, but you can't be 100% sure).

Take a close look, my guess is that the run is mostly metal tubing with hose connections. 

When you buy good rubber hose, bring a nice full wallet.  If you choose silicone, bring a Brinks truck

Can't answer the three hose plumbing.

Jim

[belfert]

It is certainly not silicone.  As best I can tell it is a decent quality rubber hose.  It does appear they ran hose the whole distance because I have been crawling under the bus following it.

The hose appears to be 1" which is really expensive.  I've looked at new hose previously and silicone is actually less money than Gates green/blue stripe.  It is still around $4 a foot.

[belfert]

Any other thoughts on this?  It looks like I will be crawling under my bus this evening to look at how all the hoses run.  I dread both the time and expense of replacing these hoses.

[rv_safetyman]

Brian, I would look to see if there is a way to run lengths of copper tubing for most of the run.  I don't know about Dina construction, but you say you are climbing underneath.  In another thread you mention having "C" frame rails.  Any chance you can run the runs under the floor or high in the bays". 

I ran my runs through the bays using some PVC tubing to support the hose in a couple of places.

Copper tubing would be a less costly and more robust.

Jim

[belfert]

If I need to go 1" is copper tubing really less money?  I'm more than a bit worried about copper cracking due to vibration.

The frame rails end at the drive axle.  The luggage bays are done like most buses without any frame rails in the way.  There are already three PVC pipes about 2" (metric really) running through the luggage bays.

[David Anderson]

Copper tubing would be a less costly and more robust.

Jim

Jim,
You sure about that?  Last time I priced a role of 60', 3/4" type L copper at Home Depot it was about $230, so 1" would be more than hose, probably.  Can you even get type L in 1" in a 60' role?  Type K is usually a bit cheaper, but will only be in 10' sticks.  

If you tie them up with Adel (sp?) clamps, (those used in airplanes), chaffing would be minimized.  They can be purchased from Aircraft Spruce or other online aviation warehouses.

There may be a reason we don't see copper tubing in vehicles.  It's either cost or reliability.  If it is cost then replacing with it will be the only time you do it in your bus.  If it is reliability, well we don't want to use it then.

David

[buswarrior]

Lots of copper pipe in my 1975 MC8.

Lots of copper pipe in the old highway trailer promoted to storage trailer I inherited at the recreational property, with no spring brakes, so older than the MC8.

happy coaching!
buswarrior

[belfert]

I did rip out a ton of copper pipe from my OTR A/C system so I guess copper can be work in a bus.  No leaks in the copper I am aware of.  The A/C didn't work because several condenser fans didn't work which caused the system to overpressurize and blow a plug.

As far as longevity, if I used hose I suspect I wouldn't need to replace it again.  I would guess that 10 years from now we won't be able to afford diesel fuel for these pigs although I can't predict the future.

[lostagain]

All the plumbing in my Courier 96, (1977 convertion), is copper. Never a problem with it.

JC

[rv_safetyman]

As has been said, I am pretty sure quite a bit of the tubing in my Eagle was copper.

I have not purchased copper tubing lately.  I just went to McMaster Carr and it looks like the 1 inch tubing is over $10 per foot!!   Brian said he is looking at hose that is $4 per foot (does not surprise me for proper quality hose). So, I guess hose makes more sense.

I am not sure that you need 1 inch, but it would not hurt.  I used 3/4 inch hose for the plumbing to the AquaHot and then 3/4 from the AquaHot to the Red Dot heat exchanger (also AC) in the front.  Plumbing the AquaHot into the system lets it be the "relay" pump (sorry, can't think of the word) and also can supply additional heat to the front heater via the diesel boiler.  We found that the engine heat is not enough in really cold weather.

The only reason I brought up copper is because I figured it was cheaper for long runs  (could have used the word "assumed"   .  Nothing wrong with hose as long as it is of a quality equal to Gates Green/Blue stripe.  For my hose I used Aeroquip FC332.  Way overkill, but I had good access to it at a pretty good discount.

Jim

[David Anderson]

There may be a reason we don't see copper tubing in vehicles.  It's either cost or reliability.  If it is cost then replacing with it will be the only time you do it in your bus.  If it is reliability, well we don't want to use it then.

David
[/quote]

You guys answered the question.  It is the cost.

David

[buswarrior]

Back then, copper was what worked for the lowest material/labour price.

then the plastic tubing improved to where that is what is used today for airline, and rubber lines for other stuff.

You can track the improvements in materials by putting a line-up of coaches together and seeing what has changed.

Many of us are quite old enough to still not completely believe that plastic can be trusted in these applications, especially if the sun shines on it....

happy coaching!
buswarrior

[belfert]

The reason for 1" line is that is what is used today in my bus.  Some of the reason for the 1" may be because my bus had both a heater core in the A/C system and actual wall radiators down the sides.  The return or supply for the wall radiators was up front.

I would be happy to downsize the hoses if I could.  I only have the two defroster units and the driver's heater core remaining.  If I knew the BTU ratings on the defrosters and heater core I have an engineer friend who could figure out the supply sizes.

This project is really pushing my budget.  Hose has to be bought 50 or 100 feet at a time.  That cost alone would be $400 to $500.

[belfert]

I found a place that sells Dayco gold label hose in 1" for $2.57 a foot.  That should fit within my budget.