Freightrain

Ok.......stupid idea.........but would be cool to have. My question is how difficult would it be to switch mine over to air(from electric). Besides getting starter, some plumbing, and a large air tank. I've got about 6 yrs on the batteries and I'm sure they'll be coming due for replacement. I could sell off the electric stuff and put air on it instead. Stupid idea, right. How "undependable" would it be? I have air supply at home to keep it charged up, but on the road how bad could it be? Don't usually have long stays away from home(day or so). I suppose if I had problems I could use a tire to charge tank if it leaked down. Anyone have some parts for sale that I could start piecing it together?

Sounds like a neat truck. Would love to have an AIR starter on mine! Way cool. If you can locate the engine number on the front of accy drive(pass. side), front of motor, that will tell you alot about the engine. Does it have SPLIT intake manifold(two pcs, one for each head)? That's the hopped up version of 673. Be sure to add your serial number to the B model registry(find link on front page of forums). Serial number will be on Pass. frame rail behind front spring perch. Compare this to what is on title, as it could be mis-matched(like mine). It will be "B61Txxxxxx" in about 1/2" stamped letters.

Friend ran it on his '97 F350 Powerstroke. It really helped on the long hills, as he pulled 50' race trailer. Stan Walls put some on his 673 in his B model, though it didn't really help much. I think the right volume would have alot to do with it, and not sure what he used to regulate it(something off a pickup type hook up I think). Might not have been big enough?

Ya, depending on what kind of mounting plate you have. If you only have side rails, it won't be bad. Mine has 3/4" plate that it's mounted too. Makes it really heavy! I did notice a ride difference after putting it back on!

Well, I used my engine crane to pull it off. You can slide it around on the pavement, sorta, but not pick it up. They aren't light at all! I've since put it back on truck and converted my trailer to pin style coupler.

Here are the pics to what I've done to mine. http://groups.msn.com/bigmacktrucks/larrysmack.msnw Worked out pretty simple and much sturdier then originally. Looks pretty original after painting it black too(just missing the "ribs", but since I added 1x1 sq. tubing under floor, ribs weren't needed anyway.

How did you wire the plug? Did you install a different 5,6,7 pin out back? Sounds like you might have something crossed up(if it's 7 pin, did you wire in the contant hot?), this could be backfeeding to brakelight switch? I suppose this happens with NO trailer hooked up? Another question: is this an air/elec unit? or plain electronic unit like used in pickups? My air/elec unit has an adjustment for "power level". If you adjust it up too far, it will leave the brake lights on. I ended up disconnecting that wire, as it was there so "IF" you actuated the brakes by the unit only, it would operate the brake lights. Safety gizmo I suppose? I was not worried about it.

Pretty neat looking R!

Build the building as LARGE as you can afford now. Square footage is the main thing, as all the add-ons can come later(floor, ceilings, power, heat, etc). Make sure you get it built tall enough to fit anything you happen to get. Big trucks and 10ft doors don't match(ask me how I know this).

Unlike most other brands, Mack usually flairs their frames in the front to get the motor lower, giving a lower hood height.

Just another day at the shop Rob? LOL!! Glad to hear you got it running again....though with a loss of nerves with it. Got to love those primer pumps. I ran mine out in the street ONCE, lucky it's a neighborhood and not much traffic at midnight. Open the hood, pump a while, cranked it up. WHew! Note to self, don't let tank get below 1/4 and sit on downhill run. She will run dry!! How's the speedo stuff going?

Wow....how do they keep the tar off all that chrome? I only run my B up the highway and can't keep it that clean!!

Not sure the type of cans you have, but likely you might find that a regular 30/30 maxi will bolt up? Wish I had a good picture of what my truck had on it originally. I was able to fit maxi's without modifications.

Sounds like you have a very solid plan going there. Can't really add too much too it.

Depends on where the air leak is? On the Dash or out at motor? The dash control is a really simple little gadget too. A paper gasket and an o-ring. If the o-ring on the knob is dried, it will allow air to blow past. Pull it apart carefully and replace o-ring. It's been about 5 yrs, so can't recall the detail on it but just pay attention and you'll be fine. Mine leaked pretty bad at first and I put new o-ring in it and it's fine. Just be careful with paper gaskets.

I can't think why it would work any different? What's wrong with yours? I've heard all kinds of horror stories about air wipers and how they don't work well, or stuck in one direction. Seems they are a pretty simple device and I can see if they get sludged up, the valve won't work thus rendering them useless. Should be THREE air lines going to it. Mark them if you can't keep them organized(mine stayed put and easy to figure where they went).

No expert on 13 spds, but I'd say that's a pretty good guess. What do the air lines hook to? The PTO is usually down on the bottom side of the main box.

Ok, put my name on the list.

Seeing you have hand brake, I'd start there. Take a quick spin around the block and then check temp of parking brake drum. Real hot? Then it's hangin up. Like Trent mentioned, try rolling each tire, as that would determine if it's a wheel brake. I had a rear brake/s-cam hanging up on mine when I first got it. I had to bump the clutch to get truck to release and roll. It would be fine there after, but first trip of day it would hang up. With the constant greasing now that problem has faded away. There is a grease point on all brake shoe hinge points. If that bushing gets dry, the brake shoe will stick at where ever it's put. Another issue with mine was front brakes were unhooked(no air) and the shoes were froze tight. It took heat to get shoes off pins. After some honing and grease they work flawless now.

I think my compressor is a bit on the weak side for CFM. 6hp/60 gal, but single stage, so it's not exactly real powerful. I'm kick'n this electronic conversion around, but I'll keep options open. I need to get that old speedo pulled apart first, then work on getting electronic version. Then the machine work will be the simple part LOL! Does your old box have the same part numbers on speedo gears?

Well, I have the time to poke around, so I'll drain the grease and check it out. Thanks

Yes, there are THREE different double bearings in these(main, counter, and rear box-output shaft). I'm working on output shaft,and the countershaft would be easy with just a cap to remove. The main shaft is the problem as I can feel it when I shift into Reverse. Sometimes I get a "ratcheting" sound when backing up, meaning gears are touching and likely it's mainshaft Reverse and the countershaft 2nd gear touching. I usually just give the handle a slight tug and it goes away. I might drain the box and pull the PTO cover and see what the countershaft is moving. I know this box has always been really noisy after a long highway trip. If left in double neutral it really bangs around, so I usually leave the main in a gear to give it some tightness and keep it from "slap'n" around. It does remain quiet while under power, so it's not a major issue. Rob, I'll get the old one out and start taking it apart. I know it would end up being a tedious job getting the bezel off. Got lots of time, so guess I'll get started. Is there a certain number of tabs the ring should have? for a certain diameter of ring(if that matters)? I suppose the ring will be 3-4" in diameter. I can index the cutting pretty precise using the super spacer(horizontal rotary indexing head). I could also just X and Y the notches like a bolt pattern too. I could use a ball end mill which would give the tabs a nice radius between them.

That sounds very do-able Rob. I could go off the passenger side since the drivers side has the hole for original gear assy. Machining is no problem, I could make the gear(reluctor ring), just need to know how many teeth to put on it. I have access at work to super spacer to rotate part accurately to space teeth. Now, getting a speedo and making it fit my old case? That would take some work. Not sure how to uncrimp face to get them apart. I do have an extra old one that stopped working so I have a sample to work with. How new of speedo do I need to find to get guts for electric version?

Here's the crazy part Rob. The speedo gear is only held by compression from rear nut, no splines or the such. I suppose I could make a ring and as long as it's as thick as the original part, it could easily replace it. Then I would need to figure a way to get sending unit near it. Since the housing is off, I suppose I could machine/weld if needed. The speedo was always like 8 mph off anyway, so I was hoping to get it closer. I was thinking to mount a ring on flange or such and do the same thing. This would be better though, and since I have it apart would be an easy modification. I'd like to keep the stock speedo(for the original look), but would love to change over to electronic control so I could calibrate it. Never really looked into it, so not sure what is out there. Likely nothing cheap or easy that would work with my stock speedo.

After playing with Stans E9/500 hp V8, I can understand the smoke issue. The little video I posted shows the thick black smoke with just a quick swat of the throttle. I could imagine under a good pull!! LOL!