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doubleclutchinweasel

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Everything posted by doubleclutchinweasel

  1. doubleclutchinweasel
    That is probably your tractor protection valve. It is supposed to close if you lose a hose on the trailer and prevent all the air in the tractor system from escaping. When you pull the red knob, this should close the valve. However, when you apply treadle or trolley valve, air will still be supplied TO the service side of that valve. But, if I remember correctly, it should not pass through (or I could be wrong about that...been a while). If plugging it does the trick, excellent. If not, you could always plug the outlet at the treadle valve which goes to that vavle...or simply cap the line. This would prevent any air from the service brakes from going to the T-P valve. Sounds like you have it in hand,
  2. doubleclutchinweasel
    Two ways that can work. 1. When you pull the yellow, the air is dumped off both circuits, & the red stays up. When you push the yellow down, both circuits are charged, releasing the brakes. 2. When you pull the yellow, air is dumped off the tractor side, & the red pops out automatically, dumping the air off the trailer circuit. To release, you have to push the yellow in and then the red. But, with the red out, there should be no air going to the trailer "emergency" or "pilot" line. However, regardless of pilot pressure, applying the treadle or trolley valves will apply pressue to the trailer "service" or "signal" line. The air from the red goes to one side of the tractor protection valve. Air from the trolley or treadle valve goes to the other side (the one with the quick-release diaphragm). Without a trailer, the red should be out, cutting off the air to the t-p valve. Since I don't pull a trailer with mine, I removed the trailer connection hoses, & plugged the connections with pipe plugs.
  3. doubleclutchinweasel
    So, basically, if you gave a 15-speed, & aren't using "1st" in high range, you are missing 6th gear...
  4. doubleclutchinweasel
    Well, with the new filter in place, & a pan full of Rotella 15W40, the beast is happy. This is hard to describe, but the oil pressure "acts" better. Oh, it still idles hot at 50 psi, & goes down the road at 75. But, on start-up, the pressure comes up "smoother" & stabilizes better. More of a feeling than anything I can explain. And, I think I know why. The filter I took out of the canister was the wrong one! It was a P550750 filter. While physically the same basic size, it does not have the correct gaskets on the ends to seal properly in the can. And, get this, it checks out as a bypass only filter, not the duplex filter it should be. Some $&@! $#&^*#$& put the wrong part in there! No wonder it's happier now! God, I hate people...
  5. doubleclutchinweasel
    What? Looks perfectly normal...doesn't it? Maybe that's an "export" truck?
  6. doubleclutchinweasel
    The plumbing on those old trucks was fairly simple. Jut map out a circuit, and you should be able to trace it out. I have diagrams, but they are all '72 & earlier.
  7. doubleclutchinweasel
    Here are a few I saw at local stone suppliers. One may be a "visitor".
  8. doubleclutchinweasel
    I thought you would only get air out of the blue (service) line if you applied service brakes (foot or trolley). When you push the parking brake release (yellow) down, and the trailer supply (red) down, you should get air to the red (emergency) line. May have to disconnect the lines to see if there is a problem with the tractor plumbing, or if there is air returning from the trailer somehow.
  9. doubleclutchinweasel
    Oh. A 700! And with big 8. Awesome. Drove one years ago (only once or twice). It had the 2-stick 6-speed. Stout truck. Always thought a 700 cockpit looked kinda cool with the shifters going out the front of the floorboards! That air leak wouldn't be coming out of the tractor protection valve at the rear of the cab, would it?
  10. doubleclutchinweasel
    Lots of slack adjusters available. Just need the spline spec & the length. There are some out there with multiple holes to give you some adjustability. Fairly easy to fix.
  11. doubleclutchinweasel
    I'm still trying to figure out an extra gear on a 15-speed. Don't know where that would be. I'm like everyone else, familiar with "nothing" & "double-nothing" on a 13-speed. But my 15-speed doesn't have any unused gears...
  12. doubleclutchinweasel
    I just noticed the V8 emblem on the hood! What is the model number? R615?
  13. doubleclutchinweasel
    Sure thing, 'Dog. That valve was the first piece I changed on mine when I got it home. It was leaking. Could turn it and make it better or worse. I got quite an education in Mack air brakes. Almost every piece of mine has been changed. Even upgraded from DD3 parking brakes to spring brakes. Look up my content. There are a couple of posts about the brake upgrade. And, there's one entitled "sometimes I wonder" that shows everything I had done up to that time. Let me know if I can help with the air brake circuitry.
  14. doubleclutchinweasel
    Here is a picture of my parking brake valve, taken as I was changing it out. If you look closely, you can see part of the ID number stamped into the side. The most common "yellow button" valves were the PP1 and PP2. The PP2 has the anti-compounding feature, which keeps you from adding brake force to the parking brake if you press the pedal when the spring brakes are applied. It does this simply by porting some air to the "release" side of the parking brake at the same time the service brake is applied. Pretty simple, and pretty clever. I am also attaching a couple of .pdf files for these 2 common valves. Maybe you can find your number listed! PP-1.pdf PP-2.pdf
  15. doubleclutchinweasel
    Looked into changing the system over to the spin-on filters of the 675. Not just the filter circuit. The oil cooler, the water pump housing, the radiator hose, thermostat housing, and other assorted small parts are all different. So, I changed oil and filter with the original setup this morning. Used a Carquest 85233 filter. Had 2 gaskets from Carquest. One was a 90114, which is just an O-ring. The other, a 90414, is best described as a slightly "elongated" O-ring. Either would probably work. I used the 90414, and positioned it in the housing so the outer rounded portion fit down into the groove in the housing, and the inner rounded portion was "up". This made the gasket look like it was "crowned" upward toward the inside, which matched up nicely with the shape on the bottom of the cap. Hard to explain! Filled the crankcase (5 gallons). Filled the filter (3 gallons). Started it up, cracked the filter vent, listened to the air escape. When oil started coming out, tightened it down. Used 2 new copper washers on the plugs (7/8" ID on the oil pan & 1" ID on the filter vent plug). Cleaned a LOT of sludge out of the filter canister. Nasty! We'll see...
  16. doubleclutchinweasel
    That's how I'm approaching mine...keep it running first, & make it pretty later. Preservation first: restoration second.
  17. doubleclutchinweasel
    There are a few different valves. If you look at the valve, there usually is a tag on it with a number. That number is a big help! My parking brake valve incorporated an anti-compounding valve. Very handy. You can download the Bendix handbook, which has lots of good stuff in it. I redid virtually my whole system. So, let me know if I can help.
  18. doubleclutchinweasel
    I have Bendix info somewhere that tells which are interchangeable. 2 different drive attachment methods, I think. Not sure which is the oddball. 550? Actually, after looking, I think I was thinking about the 500 vs 501 difference...which, as mentioned already, was related to the power steering connection. So, never mind!
  19. doubleclutchinweasel
    Like I said, it shouldn't be that complicated to do a "remote" filter setup. Here is my concept of a dual-filter, full-flow system. The flow rates and other specifications of these filters match the standard filters for a 237. But, they have a built-in relief valve to allow oil to bypass when the filters are maxed-out, instead of having the relief valve in the block. This can be mounted anywhere it is convenient, and connected via hoses. The ports in each end are 1" pipe threads, just like the fittings that screw into my canister. Two of these pictures are just external views. The other two are cutaways showing the supply and delivery porting. If you really wanted to get cute, a relief piston could be integrated into the block, allowing the bypass oil to go to a separate bypass filter. I guess I'm really surprised I can't find something equivalent to this online. Seems pretty "universal" to me...
  20. doubleclutchinweasel
    TRQ-7220 Quadruplex Shift Sequence Based on the gearbox ratios I got off another Wiki article, here are all the effective ratios for a TRQ-7220 Quadruplex. You can see where the ratios overlap, and would be skipped. You can also see why some of the LO-LO ratios would not be useful in a progressive sequence. Those could have been used, however, for "road speed control" for specific applications. I have done this with lots of the other old transmissions as well, if anybody is interested. Author doubleclutchinweasel Category Antique & Classic Mack Info Submitted 08/13/2014 11:59 AM
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  21. doubleclutchinweasel
    Based on the gearbox ratios I got off another Wiki article, here are all the effective ratios for a TRQ-7220 Quadruplex. You can see where the ratios overlap, and would be skipped. You can also see why some of the LO-LO ratios would not be useful in a progressive sequence. Those could have been used, however, for "road speed control" for specific applications. I have done this with lots of the other old transmissions as well, if anybody is interested. Mack Transmissions.xls
  22. doubleclutchinweasel
    Mine was a '72 printing...
  23. doubleclutchinweasel
    That's funny! I was just looking at those same pics in my book last night! Was just about to comment on the direction of oil flow. Great minds, huh? I found a note in my manual which indicated that, at one time, the oil flowed through the filter first, then through the cooler. But, as shown in your pictures, the "current production", as they called it, went through the cooler first, and then through the filter. So, the images I posted are correct for my particular model. And, agin, the filter is holding oil today. So, the check valves work...sometimes. You know, I remember my dad pulling the can out of an old R when I was just a young'un, and that can was not full, either. And, I know he had not drained it. I guess check valve issues were common on those cans...even back then.
  24. doubleclutchinweasel
    I grew up on a 5 + 4 Mack Quadruplex. Freightrain is correct about one thing; save the "split-shifting" with 2 hands till you get used to it! But, you don't necessarily shift the MAIN first. UPSHIFT whichever box you need to shift first, then DOWNSHIFT the other. If you try to downshift the main first, for example, you probably won't have enough RPM to do so. And, if you can, there's really no need to split-shift. I can give you a couple of different patterns to use. There is also a slight difference between an 18-speed and a 20-speed. Since the Hi-Split and 5th geear are both overdrive in the 18, there are a couple of gear combinations which are duplicates, and should be skipped. On the 20, there are no duplicates. First of all, the LO-LO on the compound is rarely used. In fact, the only time I ever used it, other than for backing, was to get moving in a steep place, and then only with one or two gears. First Sequence (18-speed box) (this will work for most conditions, and has no split shifting): LO-SPLIT 1st LO-SPLIT 2nd LO-SPLIT 3rd LO-SPLIT 4th DIRECT 4th (this is your 1:1 gear) HI-SPLIT 4th (overdrive) HI-SPLIT 5th (double overdrive) Second Sequence (18-speed box) (for heavy loads): LO-SPLIT 1st DIRECT 1st HI-SPLIT 1st LO-SPLIT 2nd DIRECT 2nd HI-SPLIT 2nd LO-SPLIT 3rd DIRECT 3rd HI-SPLIT 3rd LO-SPLIT 4th DIRECT 4th HI-SPLIT 4th HI-SPLIT 5th If you need more on the bottom end, start out in LO-LO 1st, go to LO-LO 2nd, then to LO-SPLIT 1st. On the 20-speed, just split 5th the same as 1st-4th. The heavy-duty models had the 4-speed compound on the left, and the 5-speed main on the right. Some of the lighter ones had tat reversed.
  25. doubleclutchinweasel
    Cab Mount (Upper) - 20QL250 (4 pcs) (alternate - BWP-NSI MA9R, PAI FMT-4900) Cab Mount (Lower) - 20QL1144 (4 pcs) (alternate - BWP-NSI MA9O, PAI FMT-4740) Radiator Mounts - 20QL231P9 (2 pcs) (alternate - BWP-NSI MA9AE, PAI FMT-4750 (possible slight difference in length))

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