Hyd to Air brake Conversion?

[rollintall62]

Hey Fellas,

I have a 1953 Mack L Model Types 85 pumper. I have had this truck for about 8 yrs now along with others. I am currently about midway thru a restoration and I am working on the hyd brake system. My question to everyone here is, has anyone ever had the idea of, know anything about, or ever wanted to place an older body on a more modern chassis in order to gain the more modern benefits, which in this case would be an air brake system. I know that they have made trucks in this year range that were air brake equipped even with a gas motor but as we know the trucks for parts in that configuration are not always that easy to come by. So I was kicking around the idea of placing my L model onto maybe a C model chassis........ OR Locating a l model that I may be able to salvage the complete brake system off of. I would assume that the axles were the same and the air brakes or hydraulic brakes would be the same. So thoughts folks would be appreciated. Thanks all

[KECorbin22]

I been playing with that idea also, I think it would be simpler to transplant body unto a late model chassis with air brakes and hub piloted wheels, to convert a fluid to air would depend if your rears have bolt on brake backing plates, and if you can find the correct change over, no problem, next problem would be supplying air and storage, plus your brake pedal would have to be changed, also running all air lines for park and service, the biggest hurdle would be your front steer axle, no brakes or change out your complete front axle. Be interested in what others say about this.

[609albert]

this is an interesting idea, I have a 54 L 85 ,we completely restored the brake system,hydrovac ,master ,wheel cyls all new lines etc,and put a power steering unit in., is nice ,but you always think if you could put the body on another mack frame with air,

disel and faster and better than 5mpg.

[Maddog13407]

the front axle isn't an issue nor is the rear. most any B,R,A or L Mack axles would bolt into a firetruck. the treadle valve hurdle isn't that hard, just cut the hole and bolt it in the floor. any old air tank will do as long as it has enough capacity and with modern nylon lines, lines are easily ran. only major hurdle is a compressor. either have to upgrade the engine or add a belt driven compressor which isn't that hard either. my cousin and I are actually doin this conversion with a regular B20 truck. but of course we have a few parts trucks for doner parts.i have a 56 B475 firetruck that came from the Navy with a Hemi and actually have been thinkin about the brake system as its hydraulic and had Dodge axles. kinda dreading finding wheel cylinders and a hydrovac as this one wouldn't be as easily changed over to air

[rollintall62]

BMT- I just picked up four new front wheel cyl for my L Model from Napa of all places. They are perfect matches from what I had and if it would help you I can get ya the Napa part numbers off of the boxes. I had a local shop reline the the orig shoes and a guy I know had NOS inner wheel seals. I thought that at some point I had seen an engine driven air compressor that Mack had equipped the truck with that was bolted to the side of the block and it was on a 707 Gas........Lemme know if I can help on the brake numbers......

[Maddog13407]

White Wc22's had belt driven compressors and Mack put belt driven compressors on the 413 Chrysler they put in R410's as well so its possible

[Joe Ditchkus]

Belt driven compressors were very common on a lot of trucks up to the 1970'S. The gaspots from that era were belt driven IH,Gmand Dodge. The small V-8 Cats 1160,3208 were belt driven.It should not be hard to find a bracket or belt driven compressor.Joe D.

[SMFire History]

Our 52 L125 is equipped with air brakes. If you'd like any pics let me know. We're going through everything now and replacing what needs it. So far rear cans and some hoselines.

[1958 F.W.D.]

BMT- I just picked up four new front wheel cyl for my L Model from Napa of all places. They are perfect matches from what I had and if it would help you I can get ya the Napa part numbers off of the boxes.

Why does everyone think that finding parts is such a hassle these days- with the infinite number of resources available through the internet- especially when you find places like this or facebook with the numerous groups on there....Parts can, have and will continue to be found!!!

Another thing that you have to remember is that many parts are not exclusively Mack, such as the hydraulic wheel cylinders- the ones that Mack used from that time period were either of the big three- Ford, GM, or Mopar. My 1958 FWD uses a GMC master cylinder, and the clutch slave cylinder is a Ford master cylinder. In any case, brand new ones are still available to this day from Bendix and Wagner through NAPA and other distributors.

[609albert]

rollintall62 what are the NAPA #'s for the wheel cyl. and are the fronts and rears the same #, thanks in advance

[Raymond]

Good Day I Have replaced all on my 1953 Model A 475 pumper with new master cyl. front and rear cyl all Wagner Lockheed from NAPA .Take all cyl. with you when placing order and ver importaion write down where each came from ,for each cyj. porting is such to allow you to bleed the air from system ..I never replaced the HryVac Booster and brakes work fine ..The master cyl was 100 and each wheel cyl. 50 lpus tax. and new steel lines and fittings Good Luck

[j_martell]

Belt driven compressors were very common on a lot of trucks up to the 1970'S. The gaspots from that era were belt driven IH,Gmand Dodge. The small V-8 Cats 1160,3208 were belt driven.It should not be hard to find a bracket or belt driven compressor.Joe D.

a high school buddies dad is a local electrical contractor, and had an old ford cherry picker. It was (is?) a gas job with a belt driven compressor for the brakes and pto.