Denis in MI Posted August 25, 2016 Share Posted August 25, 2016 Hello, I'll give a little back story first to explain how I became the owner of this truck. A good friend of mine recently came to the conclusion that he was never going to get around to restoring his old Mack R685 semi tractor that he once used for his business. Not wanting the truck to go to the scrap yard or for parts he contacted me and gave me the truck. I was reluctant at first because it had sat outside since he stopped using it in 2004. Unbelieveably all it took was a few new batteries and the truck started right up and was able to drive itself up onto a trailer. From what I can figure out the truck is a R685ST. The engine gives its model as a ETZ-675. I'm trying to find some info on the truck and engine but I haven't been able to come up with much. Is there a good service manual available for this truck? Only thing I really need to figure out right now is the fluid types and capacities but I want to get a manual for future repairs and service. I hope to put this truck to work on my farm and hauling some antique farm tractors around. Having a semi tractor is going to be a big step up from pick ups and my old 2 ton grain trucks. thanks in advance for any advice and help. Quote Link to comment Share on other sites More sharing options...
Popular Post Denis in MI Posted August 25, 2016 Author Popular Post Share Posted August 25, 2016 Going to try and share a few pictures. 5 Quote Link to comment Share on other sites More sharing options...
Popular Post Denis in MI Posted August 25, 2016 Author Popular Post Share Posted August 25, 2016 3 Quote Link to comment Share on other sites More sharing options...
Freightrain Posted August 25, 2016 Share Posted August 25, 2016 Welcome to the forums. Pretty solid looking truck for a Michigan unit. Nice friend! You can send/email your VIN to the Mack museum and they will make up a package for you that will include the build sheet and even a manual among other trinkets. A donation is always a good thing after you receive your information. Might take a few weeks or so to get it. I'm guessing it has a 237/5spd in it? I'm not good with motor numbers, but looking at the air cleaner that is my guess. 1 Quote Larry 1959 B61 Liv'n Large...................... Charter member of the "MACK PACK" Link to comment Share on other sites More sharing options...
j hancock Posted August 25, 2016 Share Posted August 25, 2016 Nice find! Mack manuals can be found on ebay. The 237 HP engine in the truck is pretty much bullet proof. It will either have two or three filters on it. ESI with two filters will have a pan capacity of 28 qts. or ESI Plus will have three filters and a pan capacity of 51 qts. Motor oil designed for diesel engines with 15W40 should be used. Trans and rear ends will use 80W-90, 80W-140 or 85W-140 gear oil. Both trans and rears are checked at plugs to determine fluid levels. Drain and refills will be good considering the truck has been sitting. Quote JimIt doesn't cost anything to pay attention. Link to comment Share on other sites More sharing options...
Denis in MI Posted August 25, 2016 Author Share Posted August 25, 2016 The previous owner is a good friend of mine and like I said just wanted the truck saved. The truck was used for hauling concrete forms with a flatbed trailer and knuckle boom crane. Since my friend purchased it in the 80s the truck never saw the road in the winter. It is in remarkably good condition as far as rust and the odometer shows around 220,000 miles. The engine is a turbo charged 6 cylinder, it has a 5 speed main box and a auxiliary that has low-high-reverse. It has a Mack engine with three oil filters, does that mean it should take almost 13 gallons to change the engine oil? I'll include a picture of the engine tag maybe you guys can tell me what I have. Quote Link to comment Share on other sites More sharing options...
Brian Blaylock Posted August 25, 2016 Share Posted August 25, 2016 (edited) 237 engine with six speed transmission good set up Edited August 25, 2016 by Brian Blaylock 1 Quote Link to comment Share on other sites More sharing options...
Denis in MI Posted August 25, 2016 Author Share Posted August 25, 2016 Does anyone know for sure if this would be the correct service manual? https://www.ebay.com/itm/381721155423 thanks, Denis Quote Link to comment Share on other sites More sharing options...
j hancock Posted August 25, 2016 Share Posted August 25, 2016 Those manuals would be helpful. 235/237 HP with 3 filters would be the ESI Plus and would require 51 qts to refill. Quote JimIt doesn't cost anything to pay attention. Link to comment Share on other sites More sharing options...
Superdog Posted August 25, 2016 Share Posted August 25, 2016 in '79 it would have the big pan,54 qt. total,pan & filters Quote Link to comment Share on other sites More sharing options...
BillyT Posted August 25, 2016 Share Posted August 25, 2016 Does look solid,good engine/tranny combo! That pickup earned it's keep! 1 Quote Link to comment Share on other sites More sharing options...
Jeff M Posted August 25, 2016 Share Posted August 25, 2016 That combo also gives you five speeds in reverse. You'll find that third gear on the main works best in reverse. Quote Link to comment Share on other sites More sharing options...
thomastractorsvc Posted September 2, 2016 Share Posted September 2, 2016 Good save. Watch the publication dates as changes were made over the years to the manuals the date on that was for 1980 so that would be the best for your truck. Quote Robert"I reject your reality and substitute my own." Link to comment Share on other sites More sharing options...
68-f-model Posted September 2, 2016 Share Posted September 2, 2016 Nice looking R model. Quote Link to comment Share on other sites More sharing options...
Outbehindthebarn Posted September 2, 2016 Share Posted September 2, 2016 On August 25, 2016 at 5:43 PM, j hancock said: Those manuals would be helpful. 235/237 HP with 3 filters would be the ESI Plus and would require 51 qts to refill. What is the story on the variation on crankcase capacity? ESI and ESI plus???? never heard of that before. I have noticed the 2 filter and 3 filter differences. And what is the story behind the 235 and 237? are they the same? Quote Fun is what they fine you for!My name is Bob Buckman sir,. . . and I hate truckers. Link to comment Share on other sites More sharing options...
j hancock Posted September 2, 2016 Share Posted September 2, 2016 The ESI (Extended Service Interval) was recommended by Mack to have an oil/filter service at 16,000 miles or 3 months or 300 engine hours. Whichever happened first. The ESI Plus with three filters and larger capacity pan was 25,000 miles or 6 months or 600 engine hours. With the advent of better synthetic lubricants, change intervals have lengthened these days. Same engine. In the sales literature, the engine is listed as a 237 and in the service books, it is called a 235. Dunno beyond that. Quote JimIt doesn't cost anything to pay attention. Link to comment Share on other sites More sharing options...
sodly Posted September 3, 2016 Share Posted September 3, 2016 Not to draw this conversation off-topic but, speaking of oil change intervals.... how often do folks change oil in collector trucks that don't get driven much? Annually? Bi-annually? Just curious what others are doing. Quote Link to comment Share on other sites More sharing options...
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