Lmackattack

I would fill the radiator with water and then put dish soap and then run/ Drive it so it gets good and hot for a few hrs then drain it. you will need to do this a few times to get the brown color out. that slime you see can be alge. I would flush it a few times like this before you re fill it with Anti freeze. they make a chemical that you can add into it as well if you dont think dish soap works good. Valve cover gaskets are super easy. pull them off and the gasket is right there. I like rubber gaskets as they dont leak as bad. the speedo cable just screws into the back of the gauge. some pliers is all you need. Same deal near the trans output shaft yoke at the adapter. If the cable is still good you should add some sort of oil or graphite into it from up by the gauge and let it soak in the cable to help prevent rust. it will also help keep the gauge from jumping if the cable is binding a little .

my question is what did the cam lobe look like if its wiped out that can be a big repair bill on a truck you bought that has not even turned a wheel yet.

Now that we know you have a RL685LST we know the truck should have had a mack trans installed from the factory and the frame is set up for mack mounts. Rob is spot on with his notes of how eastern and Western R models will have different rear mounts due to the difference in frames. The RL/RL685 trans mounts will not be the same as a Eastern R685. I suspect the current RL frame mount is going to be correct and the trans side of things is of a eastern Mack as you noted the trans is not original to the truck. the untrained eye may have not seen the difference in mounts and was easily overlooked when installed. Rob provided us with photos that you can clearly see what is what between east and west coast R model mounts.

IF you have pictures it will help us see what issue you are looking at.

Here are pics of the steel timing cover for a eastern R model not sure if that would be the same parts as a Western RL as they used aluminum front crossmembers /engine mounts

Take a pic of the passenger side of the engine. let me see the injectors and valve cover.

From what I hear its from 2 things. Extreme down speed of the gearing. they put in 2.xx rear ratios, run in direct, and drive at 60mph. it is impressive however half of it is from drivers attention to MPG. they dont idle them either. a owner operator may see these kind of MPG but the avg company worker wont. I dont see why volvo cant do the same as the engine rears and trans is all the same

what does the truck vin start with? RL685? if so that calls for a 237hp maxidyne and should have a mack maxitorque transmission. if the truck was built with a off breed trans that may be the reason the mounts are off.

Just wondering here... what was the normal running oil temp of the old E6 engines? all the R models I drove never had a oil temp gauge. The 3406E and C15 that I ran would match the water temp for the most part. I hear some say oil temp should stay at or slightly above 212 to boil any condensation out of the oil. rarely did my 3406 run higher oil temp than 210.

Dan said the same thing. I was not aware the CH cab had 2 different cab depths like the R model did. I never really followed the CH model thru the years. That is odd that they went with the short BBC cab when a deeper CH cab would offer more space for day cab. Heck if a Bench seat was offered a few more inches is always needed for the guy having to ride in the middle. and that shiftier sticking out of the dash is horrible. no reason it could not be put on the dash with push buttons like the new trucks have. I have never understood the short BBC that todays mfg strive for. Id rather have more leg room and have to move the seat a notch or 2 forward than to drive a cramped cab with the seat banging against the rear wall. The truck looks promising and has potential if volvo dont fuck it up like they did with the titan. yes late to the game (as always) but I do think it has a shot if it proves reliable.

Just saw this post. (been busy with kids!!!) Amazing work once again! love the detail you put into these trucks. are you still making model parts kits for the RS700. I recently knocked the dust off my old RS700L and started to get it ready for the road again. Its been about 6 years the last time I went to a Truck show with it.

that 3 leaf suspension was for on road use. the springs were known to brake in the off road. they also would brake the shock mounts due to excessive travel. will it work for you. im sure it will.. is it set up right for a dump truck. not really. price should be the deciding factor here in my opinion. that being said a exporter would pay about that much for it.

lots of B models were upgraded to 237 or 285. if it has 2 spin on filters thats a good clue but could also have been converted. do you have a pic of the engine? any part numbers on the turbo or injection pump that you could use to cross reference?

Thanks to everyone for the help with this. I also need to give thanks to Josh Yoos as he explained how he converted many of his trucks to Air ride cab. For those who are looking to do this conversion here is what worked for me. I unbolted the old solid mount hood rests from the fire wall and replaced with R model hood Roller brackets that bolted right up to the same location on the firewall. I then installed these parts on the Hood. they were direct bolt on after the old solid mount pads were removed. Hood Roller #55MX26 Hood Bracket #140QM213 Hood plate #140QM212

Im not very current on all of the offerings at mack (volvo) but a ratio of 2.47 is way to fast for logging. This sales man sounds like he was selling you a truck he had in stock and needed to move or was just clueless on how to spec a truck for on/off road use. And please take no offense but you should have noticed that highway spec gearing on the agreed build sheet. Im shocked the salesman had the balls to sell you on that.. the M drive has a 14.94 first gear compare that to the old 2 stick 6 speed that has a 14.10 first gear in Lo-Lo with the popular 4.17 rear gear ratio . These new salesmen seam dead set at selling fuel saving packages. they push this new Low RPM on road spec to everyone. Many of these guys dont understand the need for stability in the off road at max weight limits. the 3.25 will be better but I agree with KT that its still a fast gear for the off road but the M drive may make use of it? I know if it was manual trans it would be hard on the clutch if staring out in soft sand. the locking rear diff is a nice addition to a truck used in the off road. I thought macks auto power divider was the best until I drove a truck with the locking rear option. the truck I drive now has power divider lock and rear rear diff lock. thing can drive thru anything as long as my front axle dont sink in. it amazed me how much better a truck was with the diff lock option

Great looking older Mack... dont see to many of these...

I just had a issue where my Dash courtesy toggle (top of dash LH side) was killing my marker lights. replaced the switch all good now. this was on my 77'

got a assembly on Ebay tonight. need to source one more.. i also got set up on pai... great to see so many aftermarket parts available since Volvo is of little help these days

ill try that tonight. thank you

yep i ordered new rollers last week and fitted them yesterday hopeful it would fix the hood rest issues but I suspect i need that channel attached to the plate. previously that plate had a large rubber puck bolted to it. i removed the puck thinking the new rollers would make contact on the plate but they dont.

(driverside) I have the plate that bolts to the hood but not that channel. where can i find a current Pai catalog. i thought i need to be a distributor to access their online parts. thats what i was told years ago. thank you

i drove my RS700 for one season in Chicago with no Power steering.. no fun so I put a power steering unit off a Valueliner. best thing i did to the truck.

there was a guy in Florida making stainless steel covers. both eastern and western. i forget who it was but he was always bringing them to the mack show out in PA

my 77 RS700L vin is RS786 32474 LST. I think western RS700 series production ended in 78' when the superliner was introduced?

yep looking for the old style. thank you for those numbers