mechohaulic

do you have an air dryer that hasn't had the filter changed restricting air flow ??? being a '70 doesn't mean someone hasn't "modified" things through the yrs . has this issue been there or just become noticeable ??

when you say " all 4 segments drop the same" , does this unit have dual air system ( red and green needle on gauge);i don't remember when that started. when dump body was installed, were the air tanks moved or replaced? the main wet tank has a check valve connecting other half of tank;; when gauges are at 130 if you open each drain on the tanks individually ; does each drain have full pressure of air coming out ? have seen the one way check limit air to other tank half. tank not having an external check has one internal , pain in a-- to change, AFTER draining tank remove fitting on end of tank flashlight can see the internal check, long extention and grease on the socket will remove the check. have also seen an improper discharge line from compressor become restricted from wrong line too close to high heat compressor air. also as you stated ;;yes older units weren't made to build air like todays iron ;; NOT counting fire apparatus ; they had a rapid build up system.

what are you running for a signal light switch? old square original box or has it been updated ?

how many wires running to the back tail lights ?? rear turn signals on tractors didn't come to be till later yrs. were they working= now don't ?? brake switch is air operated .. front signals working ?? B61 tractor or straight truck.if it's tractor, are brake lights working in light plug ?

So when the Mack museum calls and makes You an amazing offer ; will you be able to say -yes or no. with out a doubt all Your effort has paid off and You have built an above museum quaility show piece.

depending on how the term "longest serving " title is meant, i know the R -model fire truck i delivered while working at waterbury mack in CT to winchester center back in '71 is still there may only be for parades or major emergencies . CT has (had) a ruling a fire apparatus can only remain front line equipt for 20 yrs. many times after the 20 yrs a unit is sold/ donated to another dept.

you didn't circle the difference of the one dot vs two dot in the trees under the big red circle of the trees and the air intake difference circled in red.

sounds like my marriage==first look -not bad; start pokin , moving "stuff "around ;; then the issues start add😁ing up 🤣, once again couldn't help myself LOL

once again it's proven never too old to learn. after 50 + yrs of wrench pushing, wasn't aware the first digit in the B series indicated weight rating.. sure makes sense . B 81 == 80 k weight with diesel. thanks for info..

I had an extensive set of left -hand drill bits just for that reason. lucked out many times when the left hand drill bit screwed the broken bolt out.

when men were men LOL. didn't need 600 hp or auto trans . didn't haul as many loads either ;; hey can't have everything

welding on the flange would ultimately crack the flange. many of the u-bolt set ups had flat stock welded to the 5th wheel and ran along top of frame having other end welded to rear of frame rail location of less stress . another thought, when days of u-bolt mounting took place, trucks weren't (on a regular basis) carrying 100 K payloads. still find myself totally amazed looking at old pictures of loadbeds hauling huge construction equipment using chain drive tractors. air brakes ???😄 no. had friend tell me of him loading old cable excavator on flat bed ; when he started up rear of trailer the tractor lifted off the ground and away the whole unit went, tractor was the only source of brakes (hand brake)..LOL

back in the day; 5th wheels were mounted with only long u-bolts ; way too much movement. most all wheels mounted later were bolted to their own plates which were bolted to angle iron bolted through the frame rails not the frame flange . as stated earlier, with out the main frame plate on the 5th wheel too much flex would be on the chassis. of the 50-60 + 5th wheels i mounted while at Mack none were direct mount to the frame. all were either welded to angle iron bolted to the frame (sliders) or bolted to the iron that was bolted to frame (fixed).

sure hope this forum receives follow up on this truck not only fixing the run situation but a few facts (engine, trans etc ) and updated pictures . R 700 is a nice ride to have .

just a thought if the truck is sitting in the field (high grass) i would take a clean 5 gallon can of fuel = hook in to the supply line ; possibly remove primary (red) fuel filter to check for contaminated (water etc ).proper way replace filter with new clean fuel not that bad drain it and fill it and reinstall ;;; only to get the truck in a more suitable location for repairs. only going by the picture shown.then follow ALL the ideas above.

today's law enforcement vehicles are titled " robo cop cars. I can remember the ford galaxies. I was a caretaker for a few homes in town even then they were broken into, so i used what was called a house phone (sorry youngsters ). point is watching the fords pull in the driveways. beside the car when the door opened out steps this Trooper at least 6ft tall or more( there were height restriction then) and proceeded to put on this tall hat making him look 7 ft tall. remember when the large single blue strobe lights were installed! that was technology back then

the fitting on the side for air filter service indicator is a special fitting..should not be a clear open hole. purposely has restricted hole. filter if good or replaced can run with out the filter indicator. should be 1/8th pipe thread. a pipe plug won't be an issue till an indicator (plastic cyl with resettable plunger) is found. they are installed so owner doesn't have to keep disassembling the filter housing. plus the indicator aren't the most accurate;;

don't feel bad at 71 years old I HAVE A LOT OF THINGS WORN also. sorry couldn't help myself ;;;;LOL. a number of fire dept members should have same air filter set up.I would try for a new filter element. before a wash ; do everything possible to fine a part # . at least have a number for cross-over. remember it says can be washed ;; that meant when it was a few yrs old ;; don't think it would mean 50 yrs old when the paper is dried out and water may destroy it. just sayin.

the plug on the side may have been where they had the plastic service indicator.

where is the outside air intake . with an either capsule container(cylinder with spring cap) on lower section i wouldn't think it has oil bath,, custom made for fire truck application hopefully as you disassemble it you keep the forum posted. custom built by body installer? is that an air or electrical wire going to top corner?

WHERE IS there this week-end ??? truck show CT area. going for cordo shot right knee friday; i hopefully can walk around 25 p[us trucks 😁😂

there is no way i would have seen the bird(small dot) missing. LOL . it's still fun .

we are all playing with trucks ; they are just a little bit bigger ;; so we're still kids.😄

another positive of days gone by ; everything had it's own sound be it the great muscle cars, the music , and the big rigs. a Detroit 318 duel 3 1/2 pipes sounded way better then todays 8 in pipe dumps. noise is noise ; that's todays "music" and 8 in pipe trucks just noise. the sound of DD, cat, cummins ,Mack and music back then will never be duplicated by today's world.

old style budd wheels with inner and outer nuts always got never-seize; daytons only got lube from WD-40. a lubed thread tightens more when lubed.