5ton Converter Dolly

[Floridianson]

On all brake pots, parking and service, air moves in both directions though the ports. No vent on the brake pots. .

You sure about that the pots have to dump the air fast so when you let off the brake peddle there is no lag time.

 

[Castle Bravo]

You sure about that the pots have to dump the air fast so when you let off the brake peddle there is no lag time.

All the air brake setups I've been around DO function that way - The service line connects to a close proximity quick release valve so that it can exhaust the service brake pressure faster than having it head all the way to the service relay valve or brake treadle or whatever. This is done through the same line that the service air is applied.

The 939 brake chambers are weird in that they have a port connected to the OTHER side of the service diaphragm. These are the vent lines I'm talking about.

 

[Floridianson]

Plumb it like a regular air brake trailer.

Have to agree there as he is building a trailer in the most part not a truck.

 

[RobertoGatos]

You sure about that the pots have to dump the air fast so when you let off the brake peddle there is no lag time.

Positive. Brake pots vent the compressed air used to apply the brakes at the relay valve. The front brakes vent a different way but still never at the pots. Your truck might actually be venting the rear brake pots all the way up at the air filter under the drivers step.

Cut the inversion valve out of the system, and have most of the dolly plumbed. Fingers crossed, will find out how it works tomorrow.

 

[Floridianson]

You said no vents on the brake pot is what I posted about and there is as you said on the relay. All I meant is they vent somehow and fast. Yes wedge don't carry as much air but the have to vent.

 

[RobertoGatos]

Got the brakes test installed and working yesterday. Just need to finish plumbing everything for real and phase 1 is complete.

 

[Floridianson]

Thought we wanted to run the paint side up and rubber side down. Glad you are getting it figured.

 

[RobertoGatos]

Thought we wanted to run the paint side up and rubber side down. Glad you are getting it figured.

Hah, funny you mention that. I was just wondering if anyone makes a double ended king pin so I could lock the tractor fifth wheel to the dolly fifth wheel upside down on the back of the truck when bobtailing.

 

[MyothersanM1]

Maybe a little late, but I thought I'd post this Bendix diagram. It includes a converter dolly plumbing diagram. Sorry about the resolution. I couldn't find a clearer file.



You might want to consider adding a tractor protection valve (TP3) and trailer supply valve (PP7) on your truck for further peace of mind.
View attachment TP3 Tractor Protection Valve.pdfView attachment PP7 Trailer Supply Valve.pdf

Here's the complete air brake rebuild project I did to my truck. I have attached the link to the thread for your reading pleasure. You'll find the the aforementioned mod on page 7. http://www.steelsoldiers.com/showthread.php?140055-M809-series-(M818)-Air-Brake-Retrofit

 

[MyothersanM1]

Look what I found...a better file!

 

[USAFSS-ColdWarrior]

Hah, funny you mention that. I was just wondering if anyone makes a double ended king pin so I could lock the tractor fifth wheel to the dolly fifth wheel upside down on the back of the truck when bobtailing.

I don't know if anyone already has these in production. But it shouldn't be too difficult to get a machine shop with a lathe to turn a couple of grooves in a piece of round-stock of the correct diameter. I would suggest that after machining your "interlocking king-pin" be heat treated and sufficiently hardened as a "due diligence" safety factor.

 

[RobertoGatos]

I don't know if anyone already has these in production. But it shouldn't be too difficult to get a machine shop with a lathe to turn a couple of grooves in a piece of round-stock of the correct diameter. I would suggest that after machining your "interlocking king-pin" be heat treated and sufficiently hardened as a "due diligence" safety factor.

Going to try and have a shop whip one up tomorrow. Bobtailing out to Utah on Sat. and would prefer to have the weight on the truck.

Got the dolly operational and took it for a drive. Everything worked well, and the to do list is shortening.

 

[RobertoGatos]

 

[red]

what part of utah are you headed to?

 

[RobertoGatos]

what part of utah are you headed to?

Salt Lake

 

[red]

If you want to meet up let me know, I'm not far from there

 

[RobertoGatos]

If you want to meet up let me know, I'm not far from there

Thanks, Hopefully it'll be a quick trip, but might wind up with extra time depending on arrival / GP staff availability. Would be cool to see the area. Trip actually just got postponed until next week though, the staff a Hill AFB got moved somewhere else.

 

[RobertoGatos]