76 D700 Heavy Hauler Project

[70chall440]

My plan is to flush this system several times (now that all of the bleeders work). For whatever reason is seems that the front had more water/rust in it. I am not real interested in disassembling the rear brakes. My current intent is to reassemble the front brakes, bleed the crap out of the system and see what I get. I ordered a new booster but I don't want to install it if I don't have to.

[70chall440]

Today's update: got the bearings packed, wheel seals installed (4" wide and cost $53 each..). Went to install the drums, but the outer wheel bearings wouldn't fit, so I had to remove the drums, clean off the spindles and figure out what was going on there. The drivers side had a small burr on it but the pass side seemed fine. I polished them up and removed the burr and got the bearings to fit. I then reassembled the whole deal and went about bleeding the system. Got that done and put the very heavy and large front wheels on. At that point I had to test it out; well at first it seemed good but then it went back to essentially what it was doing before, although a little different. When reversing when I hit the brake you can feel the front (I think it is the left front) grab and hold, when I put it into drive it releases and moves until I hit the brakes and then it is the same deal. It seems like brakes are releasing but slowly (but a lot faster than before). In my mind it seems like if I played with it, it might sort itself out, but then again I still suspect the check valve in the booster is hanging up. Since I ordered a new booster, I guess I will swap out the old one or perhaps I will just remove the old one and take apart and see how much gunk is in it, clean it out and reassemble it. Problem there is that there isn't any rebuild kits for it so if I tear it apart I will most likely have to install the new one anyway.

[70chall440]

I am trying to figure out what the lug nut torque should be on this truck. The FSM (which covers up to 1975) shows a 3/4" stud torque being 200 ft lbs, however everything else I can find of a 3/4" stud says 450-500 ft lbs. I know they were exceptionally tight when I removed the fronts but that might be due to some overzealous truck stop guy.

[laramie]

I wonder if the 75 had a different thread pitch than the 76.  Technically, that is all I can think of that would change the torque setting.  If the 75 had a finer pitch, it would need less torque. 

[70chall440]

The FSM says 3/4x10, however I think mine are finer than that (more like 3/4x16) but I am not positive. The lug nuts are large (1.25") and have a fairly shallow dome on them. I read somewhere to put antisieze on the studs, then read on a truck forum to never put antisieze on big truck wheel studs (too late in my case, guess I will just have to keep an eye on them). if mine are 450-500 ftlbs, I am not real sure how I will obtain that, probably will have to use my new torque converter.

[70chall440]

Sorry it has been awhile since I posted anything on this. I haven't had a lot of time to work on it lately due to work, however I got some things done yesterday and today and believe I got it sorted out. As I went through on here previously, I have replaced the 4 front wheel cylinders which did yield some positive results but there were still issues with the front brakes locking up. I then focused on the brake booster system. I ordered 1 new one which turned out to be the wrong type ($200 gone); I decided to disassemble and clean the booster which services the front brakes. I removed the booster and took it apart; it was pretty grungy with rust/dirt/brake fluid but nothing super bad. There is a valve in the front of the cylinder which seems like a residual pressure valve or something close; it has a rubber base, spring and cap all held in by a small wire snap ring. I disassembled it, cleaned and when I went to reassemble it the snap ring decided it was time to depart and shot off into the unknown. After an hour of looking I went to Napa and bought some normal snap rings (2 trips to get it right); but as they say persistence pays off and I got it all back together. When I had removed it, the feed line was leaking from the MC which I expected and caught with a pan. After I got the booster back together I reinstalled it. I then went to add some new brake fluid and bleed the booster; it was then I noticed that the booster I was working on was actually for the rear brakes...  so out came the "other" booster and got to practice my brake booster rebuilding skills. Got that one back together and reinstalled. I then bled them both and it was time for a test. Started the truck up (that 360 runs really well), put the truck into reverse, the truck moved and I hit the brakes, they grabbed as always (very grabby); release the pedal and VIOLA it moved. They did grab/lock once, but I moved forward and they released. I then took it down the road to see; that's when I found out that the very large hood was not latched.... I was going slow so I stopped and closed it. Continued down the road without issue, then turned around and came back w/o issue. Actually the brakes seemed to get better as I went. I still need to tighten the lug nuts and reinstall the gas tank support (bar that runs between the 2 tanks). So, for the most part I think I am past this (finally).

[laramie]

Sweet!  That will be a cool truck.  i'd like to find one, but I really want a cabover.

[70chall440]

Thanks. That's what started my desire for a large truck, however I couldn't find one locally and I was really looking for something cheap and/or easy to get into because I wasn't exactly sure what I wanted. I fell into this one with a trade on a yard sale Harley sportser. I still am not sure what I am going to do with it, its one of those things that either I leave it and probably sell it or pour money into it to make it what I was thinking. The one major issue I have is the wheel base; it is pretty short for a car hauler. If I go this direction I am going to have to add 4' to the rear, which means there will be about 6' behind the rear axle. For most cars that shouldn't be a problem but I would feel better if the rear axle was further back about 2 - 3'.

[The Cuda Guy]

This a cool project!  Please keep us posted on your progress.

Don

[70chall440]

I will, however I don't think I will be doing much on it soon. I need to get back on my Cuda, I have procrastinated for far too long.

[laramie]

If it won't work as a car hauler due to the height/wheelbase there are two options that come to mind.

One, would be a ramp truck, but the geometry might be tough as tall as that beast is.  I am thinking like Sox & Martin or Snake & Mongoose style ramp trucks.

Two, would be to find a 70s dodge dually bed and make it a big pickup. 

[70chall440]

I have given this a lot of thought since I acquired it; my first thought was to make a tilt bed, then was thinking of lowering it or at least just the bed, now I am stuck between the two or just leave it alone (not in my character). If I am going to make a car hauler out of it, it has to come down or the bed has to tilt. Just cannot decide which direction to go. I am kind of waiting for something to pop up like some hydraulics. If I lengthen the bed 4' and make it tilt, it will work.

[70chall440]

Well it is official I am stupid... So I was pulling the D700 out of the shop yesterday and bigger than crap the brakes were dragging like before, but it seemed to be kind of working and I needed it out so I basically pushed through it and in about 10 minutes it began to work as it should and I got it to where it needed to be and parked it. As I sat there thinking about it the proverbial clue like flashed on; I remembered that many big truck require the air pressure to build up in order for the brakes to work properly. Most big trucks have a buzzer that sounds until the pressure is achieved signaling the driver that it is ok to begin driving; this truck had a buzzer that wasn't hooked up but seemed to be wired to the trans temp. I "thought" this was someone's idea of a high temp warning when in fact I know believe it was originally hooked up to the air pressure sensor. Oh well, the brakes needed some attention anyway (yes that is me justifying my efforts...)

[crash340]

Ding Ding
glad you found it!!

[70chall440]

Maybe, a truck guy is telling me that is shouldn't take 10 min (it might not be that long); something else to look at but I am over it for now.