doubleclutchinweasel

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

Kent,

There are always a set of those manuals on ebay. It depends on the vintage whether it is two, or three books in total. These are the manual the dealers used and they are very good at explanations for repairs and give many helpful tips. My set was for my 16th b'day, (many years ago) and I still reference them often. I've seen them go from less than $10.00 per book, to over $50.00 per book. The last pages of the manual(s) give the revision dates so it would be best to get a manual that supports your project year.

Rob

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

Type 24/24 chambers should fit if you do not have backing plates for the brakes and they are open. Otherwise you will need to either install type 20, or go salvage yard searching for a later set of chamber mounting brackets to move the chambers inboard and longer "S" cams to tie everything together. You could also make a spacer to offset the chamber mount closer to the centerline of the truck and install longer "S" cams to make up the difference. You have offset slack adjusters now due to someone probably retrofitting the chambers currently mounted.

Rob

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

A lot of front spring pins on a Mack screw into the front hanger. The rear mounting if in a box, drop the rear cap and the assembly will need pried out but it is one piece rubber. This rubber allows for the spring to lengthen and shorten when in use.

You will probably have a tough time putting parabolic springs under the front as they were not offered and are expensive to have custom made. It can be done however.

Do you not have a TS-442 service manual? This book set by itself will answer near any question you would have on the older R model trucks. They are on ebay often.

Rob

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

If you plan to remove the DD3's keep in mind that, if working, they still have good value, even as cores, so don't dumpster them.... latest rebuilt exchange prices are around $450 to $600 depending if your core was rebuildable. Rebuild kits are available, I get mine from Motor Coach Industries (MCI) but there are others.

However, when you look at "maxi's" going for $45 there is an incentive to convert... providing you have the physical room!!!!!

If you review the link in my last post you will see they are not complicated to overhaul, just fiddley..

however, for ease of maintenance and parts availability modify it to a standard spring brake air system, parts are off the shelf.

BC Mack

No, I won't trash 'em!

Kent

What size did the bolts end up being???

Ron

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!

The air compressor is internally lubricated from the back of the auxiliary drive shaft in the engine and

drains back thru the flange where it is mounted to the block.

The coolant lines are the two #6 aeroquip lines that you show in your photos one running in the back to the block

the other running to the bottom of the water pump.

The smaller #4 aeroquip line coming from the pad on the front of the compressor goes to the air governor which

controls the cut in and cut out of the compressor.

Ron

That all makes perfect sense. Thanks, Ron.

Kent

More questions!

I was looking at the Tu-Flo 600 on my '70 R600 (ENDT-673C), and trying to figure out the plumbing.

The air intake is from the pressure side of the turbo, and the outlet is obvious. But, I'm not too sure about the oil and water lines.

I had read in another thread that the oil supply is actually fed into the crankshaft through a tube on the back of the drive shaft. But, I've also read that these compressors can be fed externally. And, I am not sure where the oil return is. I would assume it would have to be at the bottom of the crankcase, gravity feeding back to the engine. But, I'm not sure.

I am not even certain that there is cooling water running to the unit! If not, where are the best places to tie into the engine cooling system to provide supply and return water? Maybe tee into the fittings which supply water to the cab heater box? I don't see any plugged-off lines anywhere that look like anyone has removed any plumbing. Or, are 2 of the lines in the pics, below, water lines?

I have located 3 external lines on the compressor, but am not sure what does what. I am attaching pictures, below.

The left picture clearly shows the inlet and outlet. It also shows 2 smaller lines plumbed-in. The right picture is of the back-side (against the block), and shows a third line plumbed-in. Could 2 of these (the 2 on opposite sides of the body) be coolant lines?

Please help!

Right here, perhaps?

Here's what they looked like...

I'm thinking this whole rear mess needs to be upgraded!

The small reserve air tank in these pictures, I assume, is an isolated air supply specifically to release the parking brakes to allow you to move the truck off the railroad tracks before the train comes!

some of them had a drain plug right in the bottom metal radiator hose. this is the metal part of the hose that attaches between the engine and radiator with two short pieces on either end.

Hadn't looked there. Will check it out.

Thanks,

Kent

Might have to post some pictures for us to see...never seen three brake lines to a brake chamber! Plus, you cannot "override" the spring brakes with no air!

Where does the "third line" go in, the service chamber (front) or the emergency chamber (rear).

This is a new one on me...

I'll get you some pics soon. It's weird! The service and parking brake hoses go into what appears to be the "wrong" end of the chamber. And. the 3rd hose goes into the top of it. Makes no sense.

I'll get pics...

Another of many projects...

I'm looking at the spring brakes on the rear of my '70 R600. They are an old-type spring brake, with no provision for a "caging" tool.

They are also a bit rough, and are on my list of goodies to replace...very soon.

But, the old air system uses 3 lines to the brake chamber; 1 for service brakes, 1 to release the spring brakes, and (apparently) 1 to override the spring brake in the event of main system air loss (via dash-mounted valve).

None of the current brake chambers I can find have 3 ports, instead having only 2. I am assuming these new chambers either did away with the emergency override, or the valving/relays are set up to deliver this emergency override through the normal spring-release port.

Anybody been there/done that?

I see that Bendix has some different service relay valves, and at least one of them has some type of provision to modulate the spring brakes through the foot valve in the event of main system air loss (R14, I believe it was). But, they don't go into great detail about it. I have emailed them, and asked for clarification, but I'm not going to hold my breath waiting on a response.

Thanks,

kent

Well there should be a drain plug on the bottom. Who knows what a previous owner did?

Since you are changing hoses anyway, get the new bottom hose in your hands to check that it is correct.

If it correct, then just take a razor knife and slit it and start it draining. Can control the flow better than just pulling it off straight.

Jim

Yeah, that was my plan "B"! I was hoping to find a drain in the bottom.

You said "plug", not drain cock. So, am I looking for something fairly flush in the bottom of the tank(s)? Possibly with a recess for a square or hex key to remove it?

Thanks,

Kent

Silly question!

How do I drain the radiator on my "new" 1970 R611? LOL!!

I looked on the bottom of the radiator, but did not see a drain cock or drain plug.

I need to replace all the hoses, and would prefer not to get drowned.

Also, is there a plug somewhere near the top of the engine to help purge the air out of the system when re-filling?

Thanks,

Kent

Well, I finally did it!

Went to Knoxville today, and brought it home.

Put belts on it, checked everything out 1 more time, threw in a few gallons of fuel, and drove it 3 hours home...through the worst thunderstorm I've ever seen.

Not a single malfunction, I'm happy to report.

Of course, now I have 3-4 years worth of very intense work to do!

Going to do some electrical repair first (don't have marker lights). Then, a compressor. Then, new air system. Then a clutch. Then, cosmetic stuff. But...it drives!

Yea!!!

Kent

Wow, I got it from both sides today. Feels like I got both barrels of rock salt out of a sawed off and looks like this deal's gonna go south before it even got started good.

I spoke to the grandson and wanted a face to face after work to make my offer. I hate talking on the telephone but he couldn't meet with me and just wanted me to make him an offer. I took my best shot and didn't even try to haggle. Gave him my top offer. He didn't seem too excited, which didn't surprise me since he really didn't seem too motivated to sell the truck in the first place. He mentioned something about the truck having a lot of sentimental value and he'd have to talk to his grandfather about it. Well we all know what that means.

The second blow came when I talked to the old man about it. He tells me it'll be a $5,000 truck after we fix it up and starts talking about patching the fender, putting tires and batteries on it, and whatever else it takes to get it road worthy. I tried to tell him I already had an out of state buyer lined up who wanted to restore it himself but I'm thinking now he's wanting to keep this one too like the last three I bought for us to fix up and resell.

When I told him I already had an out of state buyer lined up he asked me how I planned to get it to him. I told him I wasn't at that stage yet since I haven't even bought the truck yet so he starts figuring how much it would cost for one of his drivers to drive it to Marion, NC then fly back here to Alabama. I mean God love him he's one of a kind, mind always working on a plan.

Anyway, how was your day? Let's just hope the grandson agrees to sell and I'll get back to you when he does. The rest of it we'll worry about later if and when I get the truck.

Does anybody else have deals go like this?

Oh, I've had dozens of these deals fall through already!

I'm still not sure what I'm going to do tomorrow. I think the old girl would drive home fine. I mean, I've already driven it around their area long enough to have been half-way home! I'm just getting old and more easily scared, I guess! Just have these aweful feelings something's going to blow up over in the I40 river gorge!

I know the truck runs good, and everything works fine. But, it always will when you're within walking distance of the shop. Problems only show up when you're in "dark territory".

Know what I mean?

Old fashion ajusters look so.

The only fixing nut is at the end of the shaft.

But this one is of 1945.

Vlad

Actually, what I saw doesn' look anything like that. I'll check when I get home this evening; I MAY have a picture that shows one of the adjusters. I took several in that area, so MAYBE I got lucky and caught a glimpse of one!

Thanks,

More to come...

Kent

It is a bolt and when you remove it and the washer behind it the slack adj should slide off,to replace the bushings you will have to take the s cam out and to do that you have to remove the drums,I would leave the bushings till you replace the brake shoes..

Sounds like what it looks like. The other post, above, mentioned a fairly small bolt on a Mack-specific adjuster. But, as I said there, this hex is HUGE. It is almost as large as the shaft itself. Any way I can identify what we have here by looking? The adjuster collar/bolt looks exactly like the others I've seen, except for the lack of a snap-ring.