Former Boston FD , B85F-1211 project, Mack Brothers....

[T-Mack1]

On 4/3/2025 at 8:17 PM, Geoff Weeks said:

Post your solution to the selenium unit when you get to that point.

Will do.

  I have been talking with my buddy who is most likely a genius that never went to college.  Machinist, Top 50 GM mechanic at one time, and Electronic GURU.  I had him look at all the options including using the more modern Leece Neville rectifiers (one Pos one Neg. ).    His opinion, since the selenium rectifier has significant resistance forward, one of those 3-phase rectifier modules would be a big improvement.     He said get one that is rate higher than the alternator output.  120A at a minimum, for our 100A ALT.  Also said get the lowest voltage one you can get.  So, after he looked at the spec's of one I found, we got a 800v 160A bridge rectifier module.  I just have to build a heat sink for it.  Again,  working with him on size for it.    He said that we should see slightly higher charging AMP's and at a slightly lower RPM.

EDIT: the bolts on the module are M6-100 which is nearly equivalent to the 1/4-28 bolts used on the Selenium rectifier.

[mowerman]

Excellent thanks for sharing. Nice going bud…. Bob

[Jack Mack]

Been awhile since  Mack brothers posted, Tom is exploring Ireland with his wife and enjoying retirement, me I still have a bit to go yet and resent him everyday he forgets that others have jobs.

Original fuel tank has been repaired and lined  , all painted , frame and brackets painted , I assume the retired guy will get it in by end of this week.
Me? I have been working on taking off hydraulic system and  stabilizers  added by Boston FD, everything including tank  leaked, truck undersides covered in thick oil, but engine and transmission are very clean and mostly oil free other then PTO pump which will be coming off. Federal siren ,Tom  went over works and  ready to mount , have correct Mack truck spotlights  on windshield frame, sourced correct Mack Unity windshield alternating red lights , engine is getting detailed bit by bit . Still looking to check out a  sister truck with original fenders yet to start working on restoring rear end to original and looking for wheels  and tires as we  want to move away from 11x20 split rims and go radials. All in all Tom and I are having great time and  enjoy working on the truck!….Jack

[mowerman]

holy cow you been busy,,,,got more done in a few months than most of us have in many years,,,,,mine is also caked up underneath like yours ,,,started pulling steering box couple weeks ago then hear come more chores and then extreme heat here lol....so box is still in there,,,,great progress bud,,,hopefully your bolt pattern is the same on your wheels...1100.22.5s are everywhere rims and tires,,,just take your pick and go for the best deal,,best of luck,,,,and yes i would love to be touring ireland,,,bob

[mowerman]

your lucky to be in your area,,,,tons of parts compaired to reno lol.bob

[mowerman]

was just wondering whats wrong with your front fenders,they look perfect,,,you mentioned running down some other  ones on a parts truck??????

[Jack Mack]

Was right about the retired  guy getting the tank  in, it was 90 degrees in Pa., I come home beat from work to see legs sticking out under truck. Tom got the tank in, looks great , I felt bad so got him some  ice water and poured in 15 gallons of Ethanol  free gas , no leaks! Still not making it to Macungie show which is so far away , uh about 20 minutes! ….Jack

[T-Mack1]

On 6/3/2025 at 6:39 PM, mowerman said:

was just wondering whats wrong with your front fenders,they look perfect,,,you mentioned running down some other  ones on a parts truck??????

We think out fenders and hood were replaced.  In the Boston pictures, the R/S fender had a bell.  Well we don't have any holes there.  So, the question is were they correct.  But, you are right and they are in really good shape and we are keeping them.  The fender inserts I had to redo because they weren't original and were yellow.

[T-Mack1]

My next project is going to be redoing the air brake hoses and converting to spring brakes. We only have service brakes on the rear.  When we bought the truck last Nov/Dec,  the air lines to the tiller trailer were just cut off.  I had to disconnect and plug them so we could charge the air tanks and see if the brakes worked, which they did.   Since then, we found leaks in the fuel tank so took it off and sent it out.  Well, my thought was, with the tank off,  why not clean up the j-brackets holding it and the frame rail.  Well, in the process of getting the forward bracket off, I cracked the flex hose supplying the brake treadle valve.   Now we have a air leak that I can hear, even with the engine running.  Side story, when I was in Mack Trucks quality group doing audits on how the trucks were built,  the young auditors would walk up to me and say, "Hey Tom, you have an air leak".  They would walk over and eventually find it.  Well, I would have to get my ears right next to it to hear it, where they heard it from yards away (note, our building was very quiet).  So,  if I can hear the leak with the engine running, it's a good leak.   

I want to replace the compressor discharge hose (101 line to you hard core Mack mechanics),  that flex pipe to the treadle and all the rubber brakes hoses to the wheel chambers.    Also want to check the check-valves on the air tanks, and the compressor unloader (called the compressor governor now a days) and clean or rebuild if needed.    I already started compiling parts.  Need to measure hoses and order them.   I'm thinking of using the Plastic brake lines to run the park/emer brake chamber lines (I have experience with them, I got while working at the Macungie plant).  It's easier to work with and the copper prices are rather high right now.

One thing I was wondering,  is that treadle supply flex line suppose to be flex or would it have been copper in 1957 ??  All the other line coming out of the treadle are copper.  

[mowerman]

lol that’s a good question and thanks for all your updates…. My DM just about needs all lines changed and yes plastic tubing is the way to go… let’s keep up the good work bob

[mowerman]

And come to think of it   … your front fenders do look a little different not sure why and I’ve never hear of aftermarket B fenders … Bob