Ricky Beals Posted April 29, 2022 Share Posted April 29, 2022 I have the Mack truck in subject line. It only has a tractor brake inside cab. I purchased a 30,000 lb dozer and I was wondering if I could add trailer air brakes and tow this dozer. Would need a tag trailer rated for 40,000 lbs. Before I even waste time thinking about it was going ask some of you more knowledgeable guys if this was even a possibility. Quote Link to comment https://www.bigmacktrucks.com/topic/69632-2000-mack-rd688-trailer-brake-question/ Share on other sites More sharing options...
Onyx610 Posted April 29, 2022 Share Posted April 29, 2022 Yes you can, either yourself or Mack can do it for you. There’s a lot of info/vids out there on doing it too. Quote Link to comment https://www.bigmacktrucks.com/topic/69632-2000-mack-rd688-trailer-brake-question/#findComment-496338 Share on other sites More sharing options...
Moparmike Posted May 4, 2022 Share Posted May 4, 2022 I just did about the Samething as you I purchased a excavator but I got my gladhand kit from anything trucks haven't Installed it yet but seem to be everything I need bunch of good videos on YouTube I just need to figure out the trailer wiring now before the gladhands 1 Quote Link to comment https://www.bigmacktrucks.com/topic/69632-2000-mack-rd688-trailer-brake-question/#findComment-496687 Share on other sites More sharing options...
Ricky Beals Posted June 22, 2022 Author Share Posted June 22, 2022 I have a Kolbelco 135 what is yours. How long is your trailer on the flat part? Quote Link to comment https://www.bigmacktrucks.com/topic/69632-2000-mack-rd688-trailer-brake-question/#findComment-501007 Share on other sites More sharing options...
Joey Mack Posted June 23, 2022 Share Posted June 23, 2022 Ricky.. Do you have a red and yellow park brake buttons? if yu only have the yellow, you need a tractor protection valve for the truck. and maybe a new anti compounding valve in conjunction with the R-12 valves, in the frame.. There are a few way's to do it.. ... just curious... jojo 1 Quote Link to comment https://www.bigmacktrucks.com/topic/69632-2000-mack-rd688-trailer-brake-question/#findComment-501021 Share on other sites More sharing options...
Ricky Beals Posted January 11, 2023 Author Share Posted January 11, 2023 JoJo I guess I never saw this reply from you. Well the truck should be getting out of the shop from the inframe next week. Anything trucks sells a kit for around 500.00 that has everything in it to hook it up. I have the PP-1 dash valve Quote Link to comment https://www.bigmacktrucks.com/topic/69632-2000-mack-rd688-trailer-brake-question/#findComment-520874 Share on other sites More sharing options...
Ricky Beals Posted January 30, 2023 Author Share Posted January 30, 2023 (edited) Can someone tell me where my foot valve is located on the 2000 rd688? Or how to find it. Thanks Ricky Edited January 30, 2023 by Ricky Beals Quote Link to comment https://www.bigmacktrucks.com/topic/69632-2000-mack-rd688-trailer-brake-question/#findComment-524191 Share on other sites More sharing options...
Joey Mack Posted January 30, 2023 Share Posted January 30, 2023 It is directly under the brake pedal. It is hard to get to without pulling the floor pan. What is the issue? Jojo Quote Link to comment https://www.bigmacktrucks.com/topic/69632-2000-mack-rd688-trailer-brake-question/#findComment-524203 Share on other sites More sharing options...
Ricky Beals Posted January 30, 2023 Author Share Posted January 30, 2023 The trailer airbrake kit I’m buying from anything trucks says I have to connect to foot valve. Just doing my homework before I get started. Quote Link to comment https://www.bigmacktrucks.com/topic/69632-2000-mack-rd688-trailer-brake-question/#findComment-524207 Share on other sites More sharing options...
Joey Mack Posted January 30, 2023 Share Posted January 30, 2023 Ok.. that makes sense. Open the hood and look under the cab. You will see a dozen air lines going to the treadle valve and such. Quote Link to comment https://www.bigmacktrucks.com/topic/69632-2000-mack-rd688-trailer-brake-question/#findComment-524208 Share on other sites More sharing options...
terry Posted January 30, 2023 Share Posted January 30, 2023 Can’t you do the same thing on the air lines down on the back end of frame by rear ends, the foot valve is basically just a supply and delivery lines right? Terry 1 Quote Link to comment https://www.bigmacktrucks.com/topic/69632-2000-mack-rd688-trailer-brake-question/#findComment-524216 Share on other sites More sharing options...
Ricky Beals Posted January 30, 2023 Author Share Posted January 30, 2023 Terry that would be a question for JoJo but I’m thinking those foot valve lines tie back into the tractor protection valve which will be under the cab. Quote Link to comment https://www.bigmacktrucks.com/topic/69632-2000-mack-rd688-trailer-brake-question/#findComment-524251 Share on other sites More sharing options...
Joey Mack Posted January 31, 2023 Share Posted January 31, 2023 are you adding a red button to the dash? or is one already there? Quote Link to comment https://www.bigmacktrucks.com/topic/69632-2000-mack-rd688-trailer-brake-question/#findComment-524254 Share on other sites More sharing options...
Ricky Beals Posted January 31, 2023 Author Share Posted January 31, 2023 JoJo I will be adding a trailer park button beside my tractor brake button. It’s part of the kit I ordered. Quote Link to comment https://www.bigmacktrucks.com/topic/69632-2000-mack-rd688-trailer-brake-question/#findComment-524263 Share on other sites More sharing options...
Joey Mack Posted January 31, 2023 Share Posted January 31, 2023 ok.. I was hoping it was already plumbed and you were making it new.. I havent done enough of them to describe the procedure without the instructions or air line diagram.. I'm sorry, Ricky.. Quote Link to comment https://www.bigmacktrucks.com/topic/69632-2000-mack-rd688-trailer-brake-question/#findComment-524265 Share on other sites More sharing options...
Ricky Beals Posted February 13, 2023 Author Share Posted February 13, 2023 (edited) So we are welding a 3/4” plate on back for pintle hitch. I have the gladhands that have a spring on them that seal themselves off when not hooked up. The gladhands have a female thread coming out of the back of them. What do people use to run through the 3/4” plate that will attach to gladhand and airlines but also go thru the 3/4” Here is a photo of gladhands for illustration Edited February 13, 2023 by Ricky Beals Quote Link to comment https://www.bigmacktrucks.com/topic/69632-2000-mack-rd688-trailer-brake-question/#findComment-525304 Share on other sites More sharing options...
Joey Mack Posted February 13, 2023 Share Posted February 13, 2023 brass bulkhead connectors.. Something like this, but with the thread size and lenght you need.. jojo Quote Link to comment https://www.bigmacktrucks.com/topic/69632-2000-mack-rd688-trailer-brake-question/#findComment-525308 Share on other sites More sharing options...
Ricky Beals Posted February 14, 2023 Author Share Posted February 14, 2023 Perfect. Thanks JoJo Quote Link to comment https://www.bigmacktrucks.com/topic/69632-2000-mack-rd688-trailer-brake-question/#findComment-525313 Share on other sites More sharing options...
Joey Mack Posted February 14, 2023 Share Posted February 14, 2023 Y.W.! Quote Link to comment https://www.bigmacktrucks.com/topic/69632-2000-mack-rd688-trailer-brake-question/#findComment-525314 Share on other sites More sharing options...
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