Converting to truck tractor - air line question

Am in process of converting an International 4300 to a truck trailer. Frame has been shortened and fifth wheel put on by a professional shop. Went to 4 shops and nobody wants to mess with the air lines, so I am trying to make sense out of it myself.

I have another international 8600 tractor, and going to use it for reference. My questions:

1. I picked up a connections, trailer protection valve, tractor protection valve, and a foot brake valve off a donor International. I see the hose going from the foot brake valve to the trailer protection valve is larger on the 8600 than the same hose on the 4300, assuming this is the service brake line. The foot brake valve is different on the 4300 and the 8600, not sure because smaller truck, or because it was not provisioned for a trailer. Should I swap this valve, or not?

2. Are there any proportioning valves I am missing, or this is about it?

3. I am mechanically very capable , but looking for the information to do this right.

Thank you

 

The air valves have different cracking pressure, the length, diameter of hoses, type of fittings ie straight. 45 or 90 degree all play a role in how long it takes to brake. Then you have different valves, full function abs, relay, tractor protection, control valve for trailer/tractor brakes, one way check directional to keep air for spilling or blow back, quick release, leveling valves for air ride, 2 air tanks, compressor, air dryer, gladhands, abs sensor, abs ring hubs, air bags for air ride, transmission for high and low range, and splitting gears is air controlled. Air gauges, govenor, low pressure sensor, service brake valve, low warning indicator, pancake chambers, spring brakes chambers, or disc brakes, slack adjusters, scam and scam bushings, brake shoes, brake drums, diff locks.

Pneumatic brake systems require spiders, brake chamber/disc caliper, scam bushing mounts that are welded to the axle. Typically if you dont have an air system all ready and you want to do the change, it's you would buy the axle, around $800-$1000 each. It will come with everything but hubs, drums, and wheels for basic non driven. For a truck you get that and the pumpkin/differential, etc but the cost is a lot more.

I'm sure there are a few things I didn't mention. To upgrade a system to full air system is expensive, and labor costly. Lastly, tractors and trailers are manufactured with engineers behind it. An example, a straight fitting is not a choke point where adding 90 degree elbow is the equivalent of adding 8 feet of air line. The size of airlines ie 1/4, 3/8 and 1/2 all have different flow rates.

Your better off buying a used truck. Best place is an auction. You can pick then up cheap and mod it to your use. Changing a truck that is non pnuematic to pnuematic system is impractical. It can be done, however I suggest talking with a company for a procedure/plan/blue prin . They will ask for truck info if they agree but it would cost you $1000 or more most likely.

That is why shops will say no. It's a big safety risk and liability on their part.

 

I would not touch it. Not for that.

Better to shop for a truck that fits what you want ready to go at a moment's notice with no need to descend into the 7 circles of trying to build something that is not meant to be.

 

Now, if the truck in a all ready built for pnuematic system. It can be done, but the cost will still run more. I've seen tractors extended and shortened based off of needs. Conversion from that to straight truck for septic pumping to dump trucks, or sleeper turned into a day cab for local use.

In my honest opinion, I would consult a company like meritor or bendix. They can do a write up for you. As for diagram, they are out there. It shows what and where.

 

The truck Does have air brakes, just trying to provision it for a trailer hookup.

Looking at the diagram, I already have an MV3 and TP3 valves. No hand brake valve needed for my purpose. I have a foot brake valve from an 8600 but dont think it will bolt on. It has a larger hose on guessing the service line. Is this because its a bigger truck, or because it supplies trailer as well?

I will take your advice and consult them. I didnt think they would talk to someone about a question like this, but I will give it a shot. Thank you for the diagrams.

 

cant tell you the line size, but if the tractor already has an air system and you have your 3 air tanks (wet tank, primary ( brakes) and secondary tank( everything else) you should in theory be able to hook up the secondary tank to the tractor pigtail. unless ive misunderstood what you were doing.

 

Well, I went ahead and did this.

Step 1, found a guy parting out an international prostar tractor
Step 2, picked up a bendix tp3 trailer protection valve, bendix e8p foot valve, and brackets for rear lines
Step 3, ordered 3/8 1/2 and 5/8 nylon DOT hose
Step 4, replaced original e8p with this one, same unit but two delivery ports on top were 1/2 instead of 3/8, both these went to trailer protection valve
Step 5, installed a spare rebuilt MV3 dash valve and routed the trailer line to the trailerr valve
Step 6, plugged one of the ports on trailer valve because no trailer hand brake
Step 7, hook up lines to back of tractor, test

It works!

The e8p foot valve has a leak in it, so I just ordered a new one. Old one was leaking too, so all good.

One thinf I noticed, the trailer service line on this truck is 5/8, bit on my daycab 8600 its only 1/2. Not sure why, but doesnt really matter.

Next I have to add the electrical, but thats not a big deal.

Thanka to all for the help.

 

Thanks for coming back with the update. Never underestimate the power of " I can do this"

What was the cost of shortening the frame and adding the 5th wheel. I have a 05 387 Pete that was stretched to a box truck when I bought it, thinking of taking it back to a tractor. Thanks

 

I paid 2400 to have a -very- reputable shop do this. I am in Los Angeles. That included a holland fifth wheel, driveshaft shortening, rear axle alignment, etc. Done right.

 

Thanks for the reply. Just curious, what year International and what engine?