Rob

Hi Rod, theoretically a 44,000# rated rear suspension will effectively carry it's rated load when centered directly perpendicular to the centerline of the trunion that supports the suspension. The fifth wheel placement has to do with steer axle loading and how much of the load one wants onto the truck suspension, and on the trailer suspension. A slider fifth wheel tries to balance this for best comfort, driving ease, and legality, (sometimes). Real truck drivers, (I am not) will give you much more clarification but this is my understanding. Rob

Looks like SWW562 Walking Beam to me. Rob

I'm wanting to change the oils in my transmissions, and axles. Is there one type that will work for all so I can buy a single barrel? I've got tri-plexs, quadruplexes, and a TRDXL-1071. Also have a Brown-Lipe auxillary. All the rears are Mack. Thanks, Rob

It may or may not be right, but it does work for me: I use an air cutoff wheel grinder with a 1/8th thickness wheel to eliminate the rust area(s). The surrounding metal to the repair must be sound. Make a patch that is slightly larger than the area that is cut out, and spot, or tack weld into place. After this is solid, stitch weld in 1" steps to make the panel as one. Grind flat, use "Metal to Metal" on, and over the patch area, knock this down with either 24, or 36 grit paper, then use "Z-Grip" over the top for a second and third, (if needed) coat. Finish sand with 180, prime with a good quality primer/surfacer, let dry and sand smooth with 320-500 grit sandpaper. I prefer wet paper with a splash of dishsoap in the water. I don't do this type of work very often anymore, but here are a few photos to maybe help. I was alone in the shop last Thursday so couldn't snap pictures when either cutting, or welding, but pretty easy to see the results. Be sure and rustproof the underside or the repair will not last long. I use "Rust-free" rustproof/undercoating products. The stuff dries to a wax like film that is not going away easily and does a great job of sealing these area(s). Rob

I think I have that same filter housing on my R-795. It is about 4 inches smaller in diameter than the larger Donaldson units. Mine has been replaced and is not original to the truck. I can't say with absolute certainty but if the filter housing is original to the chassis it should be fine. Larger is not always better. Physically larger will hold more dirt before replacement. Making the assumption that it takes more fuel, and air to make horsepower, the filter housing, (if original to the truck with a 350 horse engine) should be sized properly for the design criteria in which it operates. The filter restriction gauge that is on the side of the unit is an indicator that is calibrated to show a red band, (it should be currently yellow, white, or clear) when the element requires replacement. A "Bourdon Tube" gauge calibrated in inches of water column is much more sensitive to vacume changes and will give the subsequent meter deflection you mention. Filter medias from manufacturers rate filter restrictions and ratings at different levels. It is best to consult the websites for the elements to have accurate representation of when to change. I prefer an in dash gauge for filter restriction. The type you have that mounts into the side of the filter enclosure simply "trips" and shows the red bar when it's set point is reached. A gauge that you can see in, or under the dashboard is instantaneous and "live" when you accelerate. Hopefully this information is of use to you. Plenty of answers to be had from this group, just ask. Rob

I have two uncles that drove for McLean in the good ole days too. Bill, and Bob Denton. Both are originally from south central Illinois. Bill has passed on, Bob is still kicking and owns a feed store in Effingham, IL. I never got to ask Bill about the trucks they ran, but Bob preferred the "L", and "B" model Macks. Rob

If I interpret your question correctly, you are asking for a plastic auto body filler to slap into rust holes; There is not a product on the market that will provide an adequate service life in this application. I use Evercoat brand "Z-Grip" filler. For direct to metal groundcoat application, I use Evercoat "Metal to Metal" brand filler. There may be better products out there but with more than 20 years of use without a single failure of the products, I see no reason to change. I'll help you any way I can, just ask. Rob

Boy did this turn out to be an ordeal. Upon attempt at reinstalling the exhaust onto the truck, the cast iron elbow that mounts to a boss on the exhaust manifold, and couples to the turbocharger via a casting with piston rings decides to part company falling about a foot and finding my hand between it and the frame of the truck! "OUCH" is what I said first; This of course was followed by a few other obsceneties forthwit. The mounting boss on the manifold had been broken and shabbily repaired by others. It's been over twenty years since I attempted to weld cast iron, so I though I'd better enlist some additional knowlege before destroying an almost non existent part. Asking a competent welder for the type and brand of electrode to use, how much pre, and post heat needed, and how to properly cool the repaired part, I was ready. After deep "V" grooving the boss and manifold area for at leat 75% penetration, clamping for alignment, I pre heated and tack welded with .55 nickel/iron rod. I then "stress relieved the part, unclamped and repositioned so all my welding would not be out of position, but rather flat. I burned in a root pass that had very good edge wetting all around the part in one inch steps with stress relieving and cleaning each time. I then did the same again with side beads. To finish up I did a wide weave to tie all together. I believe that the electrode melted together in the center of the "V" groove that I ground into the parts. After some finish grinding, it was time to let it cool to put it back together. I installed the manifold onto the engine, mounted the turbo and associated lines, (oil feed, drain, air), bolted up the cast elbow that smashed my hand, and low and behold the damned exhaust was not going to fit! The prior repaired mounting boss was not welded back to the manifold square, and the exhaust compensated for the misalignment! Well after a brief time out for some more "rapid fire obscenities", I got to work. Chopping off the "Marmon" clamp flange on the pipe, and ultimately shortening the pipe by 16 inches, I installed a piece of stainless flex pipe. This allowed me to have the proper bend(s) to clear the frame and flywheel housing with about half an inch on each side of the pipe. I had to then refab the pipe running under the truck and around the fuel tank to make it fit to the muffler. All did ultimately line up well. I do need to make a couple of exhaust hangers to get the weight off of the turbocharger elbow. I suppose this is what made it break in the first place as there are no remnants of hangers under the truck. The byproduct of all this is that now I don't smell any exhaust in the cab and I guess that is a good thing! Never did get to pull that trailer again as it is on it's way to the west coast for shipment to Australia. Rob

Yeah, Ain't nothin like the heat, smell, and ground pounding, that surrounds a coal fired steam engine! Glad you had a good day of it. Rob

I found this funny as I am a federal civil service employee myself..... Rob A guy goes to the IRS to apply for a job.... The interviewer asks him, 'Have you been in the service?' 'Yes,' he says. 'I was in the armed forces for three years.' The interviewer says, 'That will give you extra points toward employment' and then asks, 'Are you disabled in any way?' The guy says, 'Yes, 100%. A mortar round exploded near me and blew my testicles off.' The interviewer tells the guy, 'OK, I can hire you right now the hours are from 8:00 a.m. Till 5:00 P.M. You can start tomorrow. Come in at 10:00 a.m.' The guy is puzzled and says, 'If the hours are from 8:00 a.m. Till 5:00 p.m., the why do you want me to come in at 10:00 a.m.?' 'This is a government job', the interviewer says. 'For the first two hours we stand around scratching our balls. No point in you coming in for that.'

Speed: If you have seen Larrys' video on the "two stick shifting" sequence, it is the same. Starting off from a standstill: I start off in 1st or 2nd in the main transmission, and the auxillary in Low, or underdrive; Accelerate, shift the auxillary to direct, accelerate, shift the auxillary to overdrive, accelerate, shift the main to the next higher gear and as I grab the auxillary trans shifter and pull it through neutral, I jab the accelerator pedal on and off to bring the engine rpms up and downshift the auxillary back to underdrive and proceed until in 5th gear on the main, and overdrive in the auxillary transmission. The only variance to this is from 4th gear in the main, and overdrive in the auxillary. I shift straight from 4th overdrive to 5th overdrive as the gear ratios are so close there is no reason to split the gears. The above refers to my A-40 gas dump truck. The diesel B models are very similar in operation. The shifting rpm's are different of course due to nature of the designs but are exact in operation. Downshifting is a reversal of the above. It really is quite simple once you get the hang of it. If you get to repairing your shift linkage, (it should be very tight with no slop) remove it all. Don't try to piecemeal a repair; It will drive you nuts. Pull the top off of the auxillary and check for clearance on the shift fork also and build up with brass is necessary. If you don't mind shipping the shoes I use a guy that will reline them and do you a real fine job. Real "old school" type individual that enjoys helping others. Rob

Charlie, I would have to dispute your claim about auxillary transmissions and their usage. Auxillary transmissions are installed to bring the gear spacing closer together in the main transmission. In all of my old trucks, the auxillary transmissions are all shifted near three times for every upshift of the main transmission. Otherwise to shift as your post suggests, the engine is never within the proper torque band for pulling a load. I can't imagine how my gas powered A-40 dump truck would haul 9.5 tons of sand if I didn't shift the auxillary transmission and relied solely on the main. I would proceed much slower than I'm able to now. Believe me, I use nearly every gear available when loaded heavy. I shift the 6231 "Brownie" like a duplex when empty as the shift points are too wide to not split them. This is very close in operation to my diesel powered trucks also. Rob

Went in today with a "Bitch Pitchin" attitude and the place donated/gave me the correct fittings for the hose I purchased, plus did some research as to why I was charged excessive for the hose, and promptly issued me a 30% credit! Seems the young man that rang me up charged me retail over the counter pricing. I have an account with them but always pay as I go so there was no research performed. I did get the coolant line installed, and the truck nearly completely back together when I finally found a pesky little air leak that has perplexed me for what seems like eons; a cracked brass fitting on the discharge side of the compressor. It is a compression type fitting and has really been wrenched upon. The brass is cracked through the threads. I will get the exhaust reinstalled tomorrow and once again pull the same trailer to another parking space on the same property. Rob

Hi Glenn, today I got a replacement hose for the compressor unloader that is firewall mounted, and an incorrect #6 hose for the coolant line. I will try to get the correct line tomorrow I'm wanting to reuse my fittings if possible. $5.20 per ft. for the #6 line is outrageous! Rob

Yes and thanks Paul. Unfortunately, the tractor is in very bad shape as the double frame outer rail is split badly from rust, and the cab is barely on the frame. There are very little of the floorpan left. But by god, the doors still swing and shut securely; It does run what I would consider perfect though. This is the truck that I call "Yellow Mutt". I am still amazed at how well it pulled that trailer! Rob

If I am following correctly: You do not want the wedges to "bottom out" onto the webs. It they do, there is not sufficient clamping force against the seat of the rim to avoid spinning of the rim on the hub. This could lead to the rim and tires departing the vehicle at an inopportune time and really hurt somebody. There should be a slight space inbetween the wedge clamp, and the seat on the spider when the lug nuts are sufficiently tightened. There are different stud lengths, different spacer widths etc. to accomplish what you need done. My best advice would be to take the truck and tires to a reputable tire dealer/installer and let them do the job for you. They have the experience, and the hundred dollars or so spent to ensure a safe install is money well spent. I don't handle tires much anymore as I've found that finding the right combination is best left to someone knowing more than I. Good luck, Rob

Thanks Glenn, I removed the hose and am going to get it replaced today with a like assy. Better safe than sorry. Rob

Are your spacer rings the same size keeping the tires apart? If the tires are rubbing, the spacer needs to be wider. I've never seen different rim offsets in Dayton style wheels but that doesn't mean they don't exist. I've never had problems switching sets of tires from one truck with Daytons, to another. It could be that someone mounted larger tires on a narrower rim also. Might be a good idea to check rim widths of both sets. Rob

I got a call from a friend needing a loaded container trailer moved. It is packed full of a new sawmill apparatus and weighs just about 25 tons. I've never pulled anything with my 64 B-61, so that is what I drove from the shop to the plant. After latching up the trailer, I flipped the valve in the cab, gave the trolley valve a pull downward, and with the truck in gear, eased on the clutch to check for positive latching of the fifth wheel jaws. This went well and upon raising the trolley valve to the normal position, I could not move the trailer. This was due to the small air receivers on the tractor, and a single large reservoir on the trailer that was completely empty. After the air built up, the trailer moved just fine. I decided to put a little heat in the exhaust so down the road I went. Was really surprised how well the 711 engine pulled the load. It was heavy enough that you could tell it was back there, but the truck was not taxed. The transmission shifted well, but is extremely noisy in auxillary trans overdrive, (quadraplex). I drove on back roads about seven miles and took the tailer back to park it out of the way. After dropping the trailer and bobtailing back to my shop, I noticed another coolant leak, (just fixed one last week). This time the leak was from the rear of the engine, and turned out to be the Aeroquip line from the bottom of the water pump feeding the air compressor. Does this line need to be replaceD with the same, or can something else be used? The dealer that used to build up my hoses ceased operations at the end of last year and the remaining business that sells the stuff is SKY HIGH in price, so I'd like to not use them. Thanks, Rob

I would pull the starter and try to rotate the engine assy. again. I've seen the spring for the "Dyer" drive used on these trucks broken and not letting the starter pinion retract. It then binds. Rob

A guy calls the other day offering to sell me a steel nose R686 for salvage price. The engine is blown, (EM6-300), air shift six speed that was rebuilt less than six months ago. The sheet metal is worth working with. I was surprised the cab was as useable as it was. It did look like I could split the hood, and fenders and add a few inches to them without much effort to install onto my R795. The truck has always been a roll off and was replaced with a new Freightliner using the existing hoist apparatus. I think a long, steel hood truck would be unique. I really don't need another truck, but never had one like this, so it is in the thought process. Rob

Man, that looks just like my favorite color: 1970 Mopar "Lime Twist". One of the "high impact" colors of the 70's. Looks Great!! Rob

Was there a long hood 700 series version of the steel nose trucks produced? I've never seen one myself. I've seen a DM800 series, but it had an offset cab. Thanks, Rob