Geoff Weeks

The early trailer system HAD NO PARKING BRAKE, they had an emergency/break a way, brake that only held for so long, long enough to chalk the tires to prevent it moving. SOP was to position the trailer, flip the TP control to emergency and chalk the trailer before disconnecting. It is why today, the TP control valve says right on it "Not for parking"! Early TP controls didn't "pop out" when air pressure was lost, often they were simple "flip" valve like are used today for air suspension dump. The TP (TP-1 or TP-2) had the cut-off function built into the actual T-P back behind the cab. With that set-up, if the valve was left in the "normal" position, the trailer would charge and the brakes release with no input from the driver when the pressure built up high enough. It was one of the major changes brought in by -121 brakes, the controls had to pop out to "safe" condition on the loss of air pressure, and remain out until the driver push them back in. edit: Before someone else points it out, I shouldn't have written "chalk" but "chock". A mind is a terrible thing to loose!

Somewhere I read that Heavy Haulers with out maxi's had to have eough chalks carried to hold the rig. We always had dunnage to block the wheels. From what I could find researching on line, the rules I knew are still in effect, Pole trailers and heavy haul under a listed deck height were exempt from the spring brake rule, so Goldhoffer (sp?) platform trailers, and trunnion axle trailers are exempt.

Yeah, I don't know the exact height, but it is why trucks can pull Loveland and Aspen passes and not loose much power. If you don't take the tunnel (or are prohibited) Loveland is just under 12,000 ft (11,900 something)

I can recommend this book, Very dated by now, but an easy read and he covers lots of the theory in a way I could understand. 40 some odd years ago, I was working on Turboing a slant 6, got the math done and was building a manifold when life lead me in another direction. Had selected a turbo after learning how to read a turbo "map" from this book. Turbochargers - Hugh MacInnes, Betty MacInnes - Google Books

No, "backpressure" is never needed or good, there is always some, but if the turbo is well matched and free-floating (no wastegate) it will speed up at altitude and try an make up the lost air, but that shouldn't cause a problem. Eventually it will reach a point where it can't make up the additional air and the diesel has to be de-rated, often about 7000 to 10,000 ft.

I was pulling Bozeman grade after dark, fully loaded, when it sounded like I blew a tire, then the air kept coming, and I was looking at the air gauges trying to figure out what tank let go, then I saw the pyro! Ok I wasn't the quickest on the draw, but I had blown the crossover hose. Backed out as much as I could and made the top in the breakdown lane, coasted down the Livingston side and into the Yellowstone Truckstop. Next morning I bought a length of turbo hose and fitted it. Truck did fine back to Iowa and the next trip, but the trip after, it either cracked or holed a piston. I never opened it up afterword, and sold it, but always wondered what let go. Judging by the blow-by and the fact it came on all at once while pulling at speed, I think the piston cracked in 1/2 and punched a section out of the bowl. Got the load "re-powered" and drove the truck 250 miles home, took about 8 gallons of oil to make it! As to the bracket for the mirror, no I don't, I think Mr Chapin was making them, but don't know if he still is or how to contact him, try here: /www.chapindesignih.com

Way too high, expect cracked pistons and head/valve problems. Smoke limit is around 1300 and aluminum melts a little over 1100. I saw 1500 a few times with turbo problems, and saw the results and they weren't good. 1450 is "rolling coal" and all the damage that brings.

Only problem on straight pipes (other than noise) is if they are really short, and that really only applies to throttled engines. If a throttled engine is working hard climbing a hill then goes from wide open to fully closed, the vacuum can draw cool air back over the red hot exh valve. None of that applies to a diesel. As much as I despise straight pipes, I know of no damage it will do, other than to annoy everyone.

I think Trump would be a very hard client to protect. His nature is to do what he wants and not listen to those around him. He famously wanted the metal detectors and "gates" remove for his rally on the ellipse on Jan 6th. Saying "they are my people, they are not here to hurt me, let them in" or something close to that. Compliancy, can ruin the best plan, and it looks like security got complacent.

Yeah, that would still be legal the way I read it, as long as it isn't towing a trailer. So I guess it depends on your plans for the truck?

Well, the fact that he doesn't have an arrest record (public records that are searchable), calls into question the other claims as well. We all know highs school kids never make stuff up or exaggerate!

To get back to the OP problem, I was doing some reading on the exceptions to the spring brake requirements. 393.41 sub parts B and C seam to indicate that spring brakes would not be required if the tractor NEVER towed a trailer, as it pre dates the requirement. The spring brake requirements were only retro-active for "combinations". Which I guess explains why you can see single vehicles (straight trucks) with driveshaft brakes later than when spring brakes were common on tractors. Also mentions the "heavy haul" exception. It does seam to indicate that if you did put smaller cans on to gain spring brakes you would be against the law as now the brakes are not as effective as when the truck was built. Whether that would bring you grief or not, I don't know?

Not the info I am hearing, no arrests, no police contact in the past, no affiliation with any groups and registered as a republican. Where does your info come from? Sounds like a a bunch of made up stuff to stir up people already looking to blame others.

Wrong! Are legal but cost about 10x what a diaphragm chamber does. They are smaller in diameter for the same "size" and will fit where clamp chambers will not. You see them more on heavy off road equipment than on on-road trucks. Also can be had with spring brakes built in. When spring brakes are in the chamber the spring is in the 1/2 closest to the push rod, and a tube surrounds the push rod and butts up to a large (thick) washer on the push rod, applying the brakes. I almost lost a finger to one of these when searching for an air leak on a bus when the brakes tripped and caught my finger between the tube and washer. The one that got me, was a rotochamber on a Austrian bus (Graff-Stief sp?) , but worked like the Maxi, unless I am mistaken and it was a Maxi? I don't think so, it happened over 40 years ago so my memory could be off. A -30 rotochamber is smaller in diameter than a -30 clamp chamber. Re-reading your post, I think you are confusing old Maxi-brake with roto chambers. Roto chambers don't use O rings, they use a rubber cone kinda like an air bag with out the top and bottom plate. Maxi-brakes had a piston (as did other types of piston spring brake chambers) Maxi's were the ones that couldn't be "caged" in the field like most modern brakes can. easy to mix them as they look somewhat similar. Roto chambers claim to fame is they have an almost constant force over the whole travel. Top to bottom, Maxi, rotor chamber, rotor chamber diaphrgm.

Oh, that is different, yeah trailers before -121 didn't have parking brakes, only emergency (break a way) brakes. Most vans and flatbeds got spring brakes around 1975 but specialized and heavy haul were exempt and may still be. I thought you were talking about tractors using air for parking. Never heard of or saw that. I've towed many trailers without spring brakes. RGN's multi piece heavy haul stuff etc didn't have any parking brakes. I think they may now need them, but in the 90's they didn't. The newest heavy haul stuff I pulled had an extra air tank and manual valve to release the brakes so they could be "assembled" into hauling configuration from being stacked on the main deck for transport to-from the load/unload points. Std procedure was to back close to the trailer, air it up then pull the red line and back under.

Never saw a parking brake like you describe using air to apply, as its weak point is obvious. Early air braked vehicles (every one I've seen) had drum or disk driveshaft brakes for parking/E brake or had the weird system B models sometimes used with the remote "cans". I did see one hydraulic "hydrovac" system modified with a toggle to open the "back" chamber to atmosphere to apply the service brakes as an additional brake for winching. I'm sure it wasn't factory and was done at a shop, the lines were too small and the length of them would slow the boost application. Tru-Stop disk driveshaft brakes were the only one of it's kind that could meet the required stopping distance, but lacked the self applying component of spring brakes. They could be single or dual caliper depending on what was needed. My Dart had the dual caliper originally but was long gone by the time I got it, brackets and cross bars were still on the truck. It is early 50's. The requirement for self application on loss of air pressure is what killed "hand brakes" on trucks. They did continue on some buses, however.

It may be total BS, but I remember hearing years ago, the GM Astro and Mack windshields were the same. That said, and competent glass shop should know for sure. When working on the British buses, we had to adapt the window opening to a glass we could get. It wasn't as hard as it sounds, but does somewhat depend on the curve on the outer edge of the windshield being a match to the body. IHC's cabaovers all had the same windshield from the 80's through the end of the cabovers in the US and still used that cab elsewhere in the world. If all else fails I'd see if I could adapt one of them, as they weren't hard to get a few years ago.

I'd be interested in the documented history of them. My K's just had a single hinge mounted round mirror. Never heard how the evolution to the modern "west coast" mirror came about.

Unfortunately it seams this is just the latest, not the 1st.

Butler County DA confirms one bystander dead, and possible 2nd. All according to ABC news. Possible assassination attempt at Trump rally; shooter dead, DA says (msn.com)

All over the news, but haven't seen any reports of any deaths? Any link to the reports of injuries?

I would caution that straps and/or chains are not a substitute for a cage, neither are designed to absorb a blast, straps will be cut like hot butter and chains can become shrapnel. The are plenty of videos on the net of a tire coming apart in a tire cage, it is a single use item, they are there to absorb the energy release. BTW tube type and tubeless contain about the same stored energy. so MRSMACK doesn't have to find a picture and to set other hair on fire:

The site history is gone, but the site is alive and well here: Home - Forums (justoldtrucks.com) All the older stuff has been lost, which is unfortunate. A lot of info was lost.

My point was while there is nothing wrong with tubeless, and the availability of tires in stock for them far exceeds tube type, there is no NEED to change. If I had tires that were serviceable I would use them, rather than throwing them out and spending money on tires AND rims.

Lock ring wheels/rims are NOT dangerous, if you know how to work with them. Not having them on the front, but having them elsewhere doesn't make much sense. The amount of energy stored in a truck tire, be it tubeless or tube type is considerable and needs to be treated with respect. I have thousand and thousands of miles on lockring wheels and never had a "dangerous moment'. I have had blow outs on the steer at 70 MPH with both tubeless and tube type, of the two, type type was easier to handle, the truck didn't want to pull or wander like the tire flip/flopped in gutter of a tubeless did. Of the countless lock ring wheels I have serviced over my years, I NEVER EVER had on blow apart. It isn't luck, it is knowing how to work with them. Fine, if you want to spend money on new rims and tires, but if your tires are sound you don't "HAVE TO". The Firestone RH-5 deg wheel was a bad design, and the only one I will not have, they have made people think that all multi piece rims are like handling a live grenade, which simply isn't the case. When properly handled and assembled, the bead of the tire expands over the lock-ring and forces it into the lock groove, once that happens you could cut the lock ring into sections and it still wouldn't come apart. Far too many assemble, clip on an air chuck and walk/run a way, and if it doesn't explode assume they did it correctly.