need route for air line in MC8

[ChuckMC8]

Still working on my air throttle install and I need to run the air line from the spare tire are to the engine compartment. I'll be using 3/8" plastic line thats made for such......I dont have the factory a/c, so I have the two copper lines that were previously used for the a/c accessable in the engine compartment. Where do they wind up in the front of the bus?  thanks

[Stan]

The A/C lines end up in the central heat compartment in front of the first bay.

The easiest routing for the plastic line is to pull out the original flexible steel tube that is used for the present throttle system.

If it is like a MC-7, the tube runs inside something resembling loom that will guide the plastic tube all the way to the engine compartment.

[rayshound]

Chuck;  You might consider removing the covers up in the ceiling in the center trough inside the three bays this will allow you to feed the airline through the sheets with holes. If the bays are full of tanks etc it may be to much of a job.  Ray

[Earl-8-Ky]

Take the cealing down in the compartment in front of the first compartment. You can acess the freon lines there. I did this and used the freon lines to pull wires to the engine compartment.  The compartment I am talking about has the heater core and the A.C. evapatartor in it.

[NJT5047]

So far this sounds like a ton of trouble....FWIW, if an 8 has the same tunnels as a 9, there is a small tunnel right behind the drivers seat that exits next to the AC junction box.  On the street side rear bay wall, there's another tunnel, about 3" X 3" that runs from the rear bay to the area next to the rear junction box.    The rear tunnel was used for an air starter hose on some models.  Don't know if all MCIs have the small tunnels.   My MC9 does.  I used the front for generator control wiring.   
Drop the air throttle position air line thru the floor beneath the accel, come back up right under the drivers seat, then thru the front tunnel. thru the two bay walls, and thru the rear tunnel.  Be easy enough...if you have the small tunnels.
Another idea would be use the drivers AC evap low pressure line to get into the AC compartment.  This has been covered. 
Yet even another idea may be to go down the interior  of the coach...if you have a "run" to get from front to back....or some combination of routes.
This is far fetched, but attach a peice of wadding to a mono fishing line and get out the big air compressor and see where the fishing line pops out.  Hey...sometime these whacked out ideas work.  Sometimes... Some of the lines will exit in the condensor compartment.   Maybe a little air pressure would help ID the lines and there exit points.   If you have a sandblaster, with a big hose...major pressure could push a fishing line to the other end of the bus.  Very likely from the condensor compartment. 
Are the stubbs where the refridg lines were cut still accessible in the condensor boxc? 
Best, JR

[busnut104]

I run lines from the eng. comp to the spare tire comp and also to the comp where the big blower motor are for heating, I went underneath there is I believe 4 or 5 I will call them tubes running the lenght of the bus, I think they are for support, but they are hollow and you can fish a hose or wirre through and seal the ends with spray foam, I run my aux A/C lines through these. You will have to cut a hole in each end, and use a wire snake. Where I wanted to come up in the blower comp. I cut a hole in the floor and through the top of the tube. The tubes Iam speaking of are on the bottom of the bus.

[ChuckMC8]

Does the throttle rod in the spare tire compartment run all the way to the engine compartment in one 40'(or so) peice?
Can I tie the new air line to the throttle rod and pullout the throttle rod at the rear of the coach, thereby pulling in the air line as the throttle rod goes out?

[Stan]

I suggested that in the first resonse to your question. The throttle rod is actually a piece of high tensile steel tubing and is quite flexible. It needs to come out the front of the bus and there is no problem bending it down to come out the spare tire door. Of course you have to remove the bell crank and jam nut ot the engine compartment end.

There is no reason why you can't pull in a plastic air line from the engine end if you have some way to anchor it to  the rod and not exceed the diameter of the tube.

[ChuckMC8]

i am trying Stan's suggestion- I removed the clevis and jam nut in the engine compartment and threaded the plastic air line onto the end of the throttle rod. So far so good. I unhooked the rod in the spare tire compartment and started pulling it out the front.I was able to pull it about 6' and it has come to a dead stop. I cant imagine what would be holding it...I removed the tunnel cover in the middle bay and the rod just passes through a couple grommets as it goes through the bays....
What could be happening to keep it from coming out? Its not the plastic line that I attached to the end. It will easily pop off if it got in a bind.   Help!

Has anyone here removed the throttle rod?

[Stan]

Yes, I pulled mine out of a MC-7. If you are out six feet, you must be just pass the front of the bus. In order to go out the spare tire door you have to bend the tube down quite a bit. It is probably just binding at the buulkhead .  It is a continuous length of tube so there is nothing to prevent it coming out.

Having said that, I guess there is no way to know that some body hasn't welded a joint in it after a major accident but highly unlikely. You need to pull harder.

[NJT5047]

It may be full of crud...push it back to the front and wrap a rag around the tube and force a large dollop of PB Blaster into the tube.    Is it possible that since the tube must be bent down to gain access,  the solid section (threaded part) of the inner core is binding up where the tube is bent at the bulkhead?  Can you push up on the tube just in front of the bulkhead while your helper pulls the inner wire from the rear?  If you cannot access the tube (this assumes that it has been pulled down) in the front of the bulkhead, could it be pushed back upward in the spare tire area to straighten the tube?
Have you tried pulling the inner wire past the binding point without the DOT tubing attached?  May indicate a size problem with the air line diameter.
If the tubing and core moved 6' into the sheath, sounds like it oughta go.   
Would think that DOT tubing could be pushed thru the tube without the inner core wire if the DOT tubing was straightened before pushing it thru.   Some of the slick stuff used for pulling wire thru conduit may help.  Make a litte "bullet" guide to fit into the ID of the  tubing so that it doesn't hang on crap that may be in the tube. 
Hope the weather ain't getting you!  Summer's over now.   Been sooo nice working on the bus in warm temps.

JR

[ChuckMC8]

I hooked a chain in the clevis on the throttle rod and pulling out the front with my Toyota Pickup.....the rod stopped the truck and caused the truck to spin the rear tires (on gravel)
I guess I could get the backhoe........

[Stan]

NJT5047: This is not a cable assembly but a steel tube with a section of solid rod welded into each end. The steel tube is the mechanical connection between the throttle pedal and the governor.

However, your sggestion of dirt may be correct. On my MC-7 the tube ran inside a tube that looked like fabric loom. When I pulled the tube out it was pokished from the movement inside the loom. Chuck's bus souinds  like the tube is just in grommets, blocks or bushings and it would have a large buildup of dirt between the support points.  At one or more supports this may have piled up to jam the tube.

[JackConrad]

I can think of a couple possibilities. A build up of rust on the outside of the steel tube that is hanging up. The cloth loom is tearing and wadding up. It is catching on the grommets in the bulkheads that are welded in betreen the longitudinal framing members on either side of the tunnel, or it is hanging up in the spray foam that is applied in the tunnel in the area around the fuel tank to isolate the AC/heat air return.  Not sur about how to resolve the problem. Maybe pull it towards the back, then back forward to try to work loose whatever is hanging up.  Jack

[ChuckMC8]

OK- Here's the deal-( On this paticular bus) The throttle rod is 2 peices.  The connection is the forward bay. It is a connector nut that joins the two peices. The nut is appx 1-1/2" long. What happened is when I pulled the rod forward, the connector nut started wadding up the fabric sleeve that the rod slides in. It made it to th eend of the bay and thats where she spun the Toyota tires.
  So, I cut the rod there and in a few minutes, I'll see what I can do from this point.
 Whilst I was working in the bay, my wife pulls and yells to me that shes leaving for work, so I lean out and hit my head on the open bay door. All MCI owners have done this at one time or another.
 So, I have a goose egg on the back of my head.
My wife tried not to laugh.........wah!
Thanks for the help, I'll post what becomes the resolution. (note to self) watch out for the bay door