doubleclutchinweasel

The slack adjusters have now arrived at the parts house. They should ship out on Monday, and be here by Thursday or Friday. I should have the front spring back in by then, so I can put these on next weekend, maybe.

Found a guy a couple of hours away who can make me a couple of replacement leaves fo $50 each. He's another old 40-year veteran spring maker, and was recommended by the Mack dealer there. So, I pulled the spring out this morning. Use a cut-up cross tie for blocks. Jacked up against the middle of the front crossmember. After spring was removed, put another block on the axle, and let it down until the frame rested on it. Also have a block under the front crossmember. Front pin wouldn't quite go out from the outside-in, because of a slightly tweaked bumper mount. So, I pushed it back in and went out the other way. Of course, the spring got out of kilter, and had to be weaseled into position before the pin would go in. Pictures of the hanger cap soaking, the truck blocked up, the spring cleaned up and resting comfortably in the back of the Tahoe (FUN by yourself!), and a close-up of the broken leaves. U-bolts came out with a little torque, so I didn't have to torch them. Should make it easier to duplicate them, having them in one piece!

Holy crap. This is funny!I had stumbled across St. Louis Spring earlier, and had sent them a message from work. When I checked my work email, they had already responded. His price is about 1/3 that of Stengel brothers. I'll be talking to them soon... Thanks again, Kent

Thanks, Dude.

You ain't right!I was lookin' at new springs for my old R. And, the more I learn, the less I like the prospect of diggin' two more 40-year-old springs out of the junk yard. I mean, they're the same age as my worn out and broken things. I checked with Stengel Bros. They can hook you up, but that's almost as much as I paid for the truck! Know of any other reputable spring shops (preferrable in the SouthEast...so shipping doesn't cost more than the springs)?

Ya know... Some of the old U-model sales brochures point out that the left-side spring had more leaves than the right-hand one (like 12 vs. 10). For what it's worth...

Thanks, Ron.When you mention the rear spring hangers, I assume you're talking about the entire bracket which bolts to the frame. And, I also assume you re-used your original axle. Did yours have threaded front pins or straight front pins? Kent

Yeah, them's all familiar names, alright! I've always been in the Dodge group ("team green"). Made v-belt pulleys (sheaves) and couplings for 13-1/2 years, then moved when we built the new roller bearing plant in '96. Made our own housings for years, and used Timken (tapered) and FAG (spherical) inserts. Dodge had wanted to make their own tapered bearings for about 40 years, but couldn't make it happen. I was "lucky" enough to get to make it happen. No pressure, right? If you're ever here in western NC, I'd be glad to show you around.Kent

OK. Those points all make sense. I just need to round up some decent tall jack stands.The company I work for is Dodge (no relation whatsoever to the auto maker). We make mechanical drive components (gearboxes, pullys, couplings, etc...). A few years ago, Rockwell sold us to Baldor. So, now Reliance and Baldor motors are part of the same company. Weird, considering the years of competition. Then, ABB, a Swedish outfit, bought the whole kit and kaboodle. Huge freakin' company. They paid something like a billion dollars CASH for the Baldor/Reliance/Dodge corporation. I've been lucky. Started as a machine operator. Worked on about every type of machine they had. Did maintenance. Did engineering. Modified and rebuilt machines. Designed machines. Traveled extensively (can't tell you how many times to Europe...lost count years ago). Was the engineering manager for 5 years. Hated it. Would rather do it myself. Am doing it myself now! Our plant is one of the most profitable facilities in the global organization (I take credit for that!). We do something like $140 million in business per year with only about 115 people total. Can't publically tell you the profit numbers, but they are obscene (again, I take credit for that!). But, with the headaches that come with high-profile projects, I need a release. The old Mack is just the ticket. Sure, it needs work. But, once I get the springs fixed, I can drive it. I'm working through the air system, but I try to leave it drivable most of the time. I dread the springs. It looks like it could be a royal pain in the rump! MUCH more to come... Kent

No, seriously Rob. How the heck do you block that thing up? Front crossmember, maybe? Kent

Oh, yeah. Very familiar with a Blanchard. The first night I went to work (been there 30 years this Thanksgiving), I ran a 48" blanchard grinder. Saw a guy forget to pull out the stone spacers (used when wheel segments got too short) when he put on new wheels. Touched the parts, and "poof"! New set of stones reduced to rubble. Funny as h%#l!Worked on maintaining and rebuilding CNCs, programming CNCs, buying CNCs, blah-blah-blah CNCs. Was part of the plant start-up crew when we built the plant I'm in now. Been designing tools and fixtures off and on for 25 years. For the past 8 years or so, I've been developing process and designing machines to in-source our own double-row tapered roller bearings, previously sourced from Timken. But, when it comes to figuring out exactly how to jack up the old Mack, and still manage to get jack stands under it, I'm a newbie!!! And, dang, them's gonna' be some tall jack stands, ain't they? Kent

Good news, Rob.I went out and laid down in the mudhole which used to be a yard before all this rain, and with very little fanfare, loosened and re-tightened those 4 bolts on the rear spring hanger. I grumble a lot about the build-up of grime on this old truck, but I really have to hand it to the guys who used it last. There is grease everywhere there is supposed to be grease. They apparently did maintain their trucks. Oh, there are frozen-up things here and there, but, by and large, most of the important bolts still turn. So, maybe this won't be all that bad. Of course, I still need to get a spring and new U-bolts. But, I feel better knowing the bolts aren't frozen! More to come... Kent

Thanks again,Rob.Tricks I've leared through the years which have helped keep whatever sanity I have left are: (1) lots of penetrant (I like PB Blaster), (2) a little bit of heat, and (3) always hit the head of the bolt (like trying to drive it into the hole) before you try to remove it. And, usually, I "tighten" just a fuzz before loosening. I work every day on machine tools, and sometimes getting the screws out is the worst part of fixing them. If I recall correctly, isn't that rear housing aluminum? Steel bolts really hate aluminum threads! Kent

In the lower picture, I am showing the front of the spring, viewed from inboard. I cleaned it off a little with a screwdriver, and I believe the grease fitting is in this end of the pin. The other end appears flat. I see a small hex-head cap screw on the bottom of the hanger, which appears to line up perfectly with the pin itself. Would that be the retaining screw? On the other picture, I am showing the rear of the spring from the outside. I am assuming that split-line is where to take this end loose. It looks fairly obvious. Of course, I've already learned that, on stuff this old, nothing is ever simple! Kent

Yeah, I've found a few already. Prices are much higher now. And, some need to be explained a little better (which volume, or what printing). I'll keep looking.Looking through some images of old brochures. Looks like the 3-leaf, tapered springs may be 55" lomg, as opposed to the older 54" springs. If so, it would probably take a lot more modification than I want to do. So, I may be better off to stay with the originals. More to come,,, Kent

Yes, there are no backing plates, and the brakes are open, like you said.I think I'll bring home a new size 24, and just try it. If my measurements are correct, it looks like everything should clear by about 3/16 of an inch. And, I believe this is an all-original setup, as the build sheet called for DD3 chambers, and the chambers are mounted directly to the brackets, with no adapters anywhere. Thanks, Kent

Thanks, Rob.No, I don't have that manual. But, now that I know it exists, I can snag one. The different springs to which I am referring are the factory front springs Mack started putting under the Rs in the later '70s. The first ones appeared in either '75 or '76. From the looks of them, everything appeared the same, except for the springs and the riser block on which they sit. I was hoping one of our readers might have both an older and a newer truck, and might know about the interchangeability of them. If all else fails, I may grab a pair of them, and a pair of the originals, when I make my parts run. If they work, Fine. If they don't work, fine! I know that the first ones I ever noticed were on an R600 with an FA-535 axle. But, I didn't notice what year that truck was. More to come... Kent

Still waiting on the new slack adjusters. Should be here in another week or so. Trying to identify the size of the brake chambers on here. Can't find numbers on anything. In the Bendix literature, they mention only size 24 and size 30 DD3s. It's definitely not a 30. So, if they only made those 2 sizes, it must be a 24. And, I think it is safe to assume the service brake chambers would be the same. The service chambers on the other axle MIGHT be 24s, but it's hard to tell. They are definitely 20s or 24s, based on the physical size. A new 24 (or even a new 20, for that matter) looks like it will be a pretty tight fit in there, between the clamp band and the axle housing. Has anybody put late-model chambers on one of this vintage ('70)? Did you have any clearance issues? What sizes did you end up with? If nobody has, I may end up being the Guinea Pig! Kent

Hello, Everybody! Looks like I have a couple of broken leaves in my left front spring on the '70 R600. The front axle is an FA-535. I've never pulled one of these springs out before. So, assuming everything is blocked-up safely, what's the routine? Looks like the front of the spring is attached by a pin. I would assume there is a locking bolt of some kind under all that crud which releases the pin. I can't tell much about the rear attachment, as it disappears into the rear spring box. Do you separate the halves of the hanger box to get it out? Is the rear solidly mounted, or does it slide in that box (one end has to give, right?!). I have access to more of these springs (looks like standard 12 X 0.323" leaves), but I can also get the later 3-leaf "tapered leaf" springs. How difficult is that swap, assuming all the spacer blocks and caps are there? Is that spring a direct interchange? Do different axles have different mounting pads, or is there some commonality? Anything y'all can tell me about spring removal/replacement, and about swapping-in those later ones, would be much appreciated. And, as always, pictures are great. Thanks, Everybody! Kent

No, I won't trash 'em!

Wow! I forgot to look! They were smaller than I originally thought. Seems like the heads may have only been about 3/4"-7/8". And, with the bolt out, I cold easily slide the adjuster on the shaft. That's how I got a decent measurement on the shaft; by pulling the adjuster out and measuring the shaft "behind" it.Kent

I found a mail-order outfit that can get these. So, I ordered 2 left and 2 right pieces. Should be here in a couple of weeks. As soon as it quits raining, isn't 120 degrees, and my shoulder and elbow quit killing me, I'm going to pressure wash 4 decades of crud off the steering knuckles, and see what kind of shape the kingpins, bushings, and thrust bearings are in. I plan to replace them all anyway, but it would be nice to find tha it didn't have to be done right now. I'd really like to finish all the air system first, THEN work on the front end. Oh, and I do have 1 broken leaf on the left front spring. I'll need to fix that pretty soon, too. Got my North Carolina "Weighted Antique Auto" tag today! Those guys sure know how to make money! More to come... Kent

Okay... I figured out that these are Bendix "DD3" chambers, or an equivalent. They were most commonly used on buses. Lots of folks on bus and motor home forums talk about them and how to change tham out. So, I'm not in new territory here. And, apparently, you do just remove the override circuit, and upgrade to a more modern chamber. As near as I can tell, these (and the service chambers on the other axle) are size 24 chambers. But, I am not 100% sure, as old chambers and equivalent new chambers vary in appearance and outside dimensions. If this tendonitis would ease up in my shoulder and elbow, maybe I could crawl around under there and see what the heck's going on! More to come... Kent

Looks like I can change this over to a "regular" spring brake cannister, and remove the emergency release mechanism. I am currently looking around to see what is available. These cannisters are fairly small, and there isn't much room to go up to a larger size. As near as I can tell, the rears are only size 20 or 24s. I see that bendix makes a 20/24 and a 24/24, one of which might physically fit. To counteract the relatively small cans, they use a fairly long slack adjuster (7"). So, I probably need to stay with the same cylinder area. It would help if I could find some numbers on the old parts! I'll keep looking. More to come...

I took one slack adjuster loose to see what was in there. The center bolt and washer do indeed hold a more-or-less standard adjuster in place. The cam shaft is 1-1/2" X 10 splines, which is fairly standard. The adjuster length is 7", and is offset about 5/8". The Bendix numbers I found in the book are 279946N and 279947N. These look right. Now, all I have to do is find some "in-stock" somewhere!