72 Duster Resurrection

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FABO has by far been the best forum I have been on for any project, you guys definitely know some mopar stuff!

On that note.....Duster work has continued. I am putting more parts back on the car.

One issue. As I go to torque the LCA pin nut (spec is 145 ft-lbs), the entire pin just rotates in the LCA due to the grease I used to assemble the new bushings. See pic:

20180313_195108_1.jpg


Is there any way to back the LCA pin up so I can torque the nut? For that matter, what holds the LCA on the pin? The torsion rod and strut rod?
 
Yep torsion bar and LCA hold the pin in on the back end and the LCA poly bushings rotate on the pin. Strut rod really holds the lower arm from being pushed back. Since you have polyurethane lower inserts, you will have to torque the pins into the K frame then install the lower arms. I would wrap the pins in multiple like a lot of layers of aluminum tape at the back end to prevent the pins from getting marred up, then grip em w a vise grip or pipe wrench to hold em, and torque the nuts down. Then install the lower arms.
 
That nut doesn't get torqued untill torsion bar is in, ride height set, with full weight on car
 
Hm, Im a bit confused here.

@replicaracer43 Because the pin spins freely in the LCA, why would having the torsion bar in and the car's weight on it change anything? The pin would still spin freely when I go to torque it.

Seems like I need to do @moparmat2000's method and back the pin up and torque it to the K frame first, then the LCA, torsion bar, and strut rod.....
 
Duster Captain said:
Hm, Im a bit confused here.

@replicaracer43 Because the pin spins freely in the LCA, why would having the torsion bar in and the car's weight on it change anything? The pin would still spin freely when I go to torque it.

Seems like I need to do @moparmat2000's method and back the pin up and torque it to the K frame first, then the LCA, torsion bar, and strut rod.....
Click to expand...
OH.... you have poly lower bushings....ok, well that explains it. I never use those, I only use rubber lowers, I found the poly would deform out of shape after about 50 laps on a asphalt race track, and the issue of the arm being able to slip fwd and backwards on the bushing..I only use factory type lowers anymore
 
replicaracer43 said:
OH.... you have poly lower bushings....ok, well that explains it. I never use those, I only use rubber lowers, I found the poly would deform out of shape after about 50 laps on a asphalt race track, and the issue of the arm being able to slip fwd and backwards on the bushing..I only use factory type lowers anymore
Click to expand...

Yep, these are poly bushings. I'm just looking to drive on the street, nothing on the track. The poly bushings are supposed to be be better for longevity on the street I hear.

So I'll just grab the pin from the back and torque the nut on. Seems like thats the only option.
 
Duster Captain said:
Yep, these are poly bushings. I'm just looking to drive on the street, nothing on the track. The poly bushings are supposed to be be better for longevity on the street I hear.

So I'll just grab the pin from the back and torque the nut on. Seems like thats the only option.
Click to expand...
Your plan will work, but won't stop the arm from sliding on the pin. Rubber bushings last 100k miles on the street..
 
replicaracer43 said:
Your plan will work, but won't stop the arm from sliding on the pin. Rubber bushings last 100k miles on the street..
Click to expand...

So whats the big deal about poly vs rubber? Poly is usually advertised as the "high performance" alt to rubber. I know its harder, so it deforms less. I thought it also lasted longer than rubber...
 
Duster Captain said:
So whats the big deal about poly vs rubber? Poly is usually advertised as the "high performance" alt to rubber. I know its harder, so it deforms less. I thought it also lasted longer than rubber...
Click to expand...
Yeah, it's advertising I think, it's my experience that it's inferior for a lower controll arm bushing. I like them for uppers, for sway bar links ect. Some "upgrades" really are no upgrade.
 
Making progress.

Old drag link
20180223_150738.jpg


Cleaned and painted sway bar
20180223_153158.jpg


Old vs new tie rod ends and sleeves
20180318_134723.jpg


Disk spindles with new lower ball joints attached. I got tired of cleaning and painting at this point, its just going in the car as is.
20180223_163323.jpg


New pitman arm installed
20180318_134803.jpg



New idler arm installed. I screwed this up by not putting the washers in between the stationary steel sleeve of the idler bushing and the tabs on the frame when I torqued it down. That deformed the frame tabs so I need to take it apart and smack it back in with the washers in the right spots. Not fun.
20180318_134816.jpg


New shocks installed.
20180318_123152.jpg


Spindles and drag link installed.
20180319_180242.jpg


I still need to:

-finished torquing everything
-install rotors (w/new bearings)
-install calipers
-connect, fill, and bleed brakes
-wheels/tires

Closer every day.
 
Ok, so I have the front rotor and calipers back on and have greased all my suspension.

20180403_202902.jpg


Almost ready to drive, I just need help with one final thing:

I cannot get the rear drum brakes bled for the life of me.

After I installed everything, I bled the master cylinder, then started from the farthest wheel cylinder to the closest and bled using a helper, then the hose in bottle method.

When someone holds the pedal down and I crack the bleeders on the front disk calipers, I get clean air free fluid to come out.

But I can not get any fluid to be delivered to the back drums.

The brakes are still very spongy and will work only if you pump them. And only then on the front. Rear drums do nothing because they are getting no fluid.

My entire brake system is new. I even shot compressed air down the new hard line going to the rear while both rear drum bleeders were open and I got air to blast out the bleeders. So there's no blockage (again, all lines and cylinders are brand new).

I suspect my distribution block/ proportioning valve is faulty.

I bought one of these brand new from Inline for this:

upload_2018-4-8_16-8-34.png


This is the correct part for my 72 all drum car to 74 front disk conversion, right?

I detached the line going from this block to the rear of the car and had someone press the brakes and got a weak trickle out that port.....

Any thoughts? This is the only thing stopping the car from driving now.
 
You need one for 73-76 disc / drum.

Also if the chassis line going from valve to rear axle tee is original it may be clogged. I'd disconnect it at both ends anf blow compressed air through it to make sure its not blocked.
 
I called and talked to inline tube and did some internet research. The combination valve (distribution plus prop for rear brakes) is the correct one for a 74 disk drum setup.

Every single inch of brake line is brand new(inline tube pre-bent hardlines and new hoses all around)

Both back drum cylinders are new

Both from disk calipers are new

New master cylinder

I disconnected the line going from the combo valve to the rear and blew some air threw it and got air out each open rear bleeder separately so the lines are all clear (again, they're all new).

I have also spent several hours with a mighty vac and eventually a pressure bleeder(pumps fluid down through the system from the maser cyl). Many qts of brake fluid have come out each bleeder(fronts and rears).

And still I have a spongy brake that acts like this:

First pump, pedal goes to floor
Second pump, pedal goes halfway down and stops pretty firmly

I also verified with someone holding the pedal after the second pump that the front wheels are locked but the backs are free to spin.

Also a test light on the warning switch lights up when connected to batt positive and the switch post on the combo valve.

So I think my combo valve is off center but I can not get it to re-center. I opened both front bleeders and pressed brake pedal. Brake warning light still on. I then removed the lines going from combo valve to both front wheels and pressed brake pedal (even stomped it). Warning light still on.

Im confident that I have all the air purged from my new brake system but I. just. can. not. get my combo valve to deliver fluid to the rear. Any yes, this is the second new combo valve I have tried.

I think my master cylinder has a built in residual pressure valve on the rear brake output but I dont think that should matter..

Anyone have thoughts?
 
Charrlie_S said:
Sounds like a bad master cyl.
Click to expand...

I thought that as well. I am on my third master cylinder. I bought a reman duralast, then a new duralast, and now have a new master from pirate jack: MC5621 - 1960-1974 Mopar A, B, & E Body Master Cylinder (Disc/ Drum)

Same problem on all master cylinders. I bench bleed them and block exit ports while pushing piston in to check for internal leaks also before installing. So Im pretty sure its not my master cyl.

moparmat2000 said:
Are rear drum shoes adjusted out with star adjustor wheel so they barely contact the drum.
Click to expand...

Yep, adjusted the star wheels so the shoes are just barely scraping the drums but still let them spin.

At this point I would like to have someone knowledgeable take a look and tell me that Im not going crazy here. Anyone live close to Houston and want to earn a beer?
 
I think the drum only cars had this distribution block:

upload_2018-6-20_13-11-16.png


Which is what I removed from the car before I converted the front to disk brakes.

I think the one I have is correct, but I just cant get it to deliver fluid to the rear. I suspect the internal valve that moves to block a leaking fluid circuit is stuck and I cant seem to get it to re-center..
 
May or may not be correct in the ebay ad, however both my 67 and 69 barracudas have the valve you have shown. Both were 4 wheel drum brake cars. The valve i have for my 67 for the disc conversion looks more like a GM proportioning valve i think. Its been 3 years since i have seen it up in my loft w the brake line kit.

Screenshot_20180620-133349.png
 
I think i bought a GM style disc/drum proportioning valve for my 67, but only because my 74 parts car had the same GM style valve in it. May have been cobbled in, but i doubt it the way it was plumbed and bracketed in. Chrysler was sourcing Saginaw PS pumps and GM tilt columns by then so i never gave it a second thought. When i get home this weekend i will check in the brakeline box and see which one i bought. The GM one is more common, works, and is waaay cheaper. I will also take a look because i believe i kept the original proportioning valve and mount bracket off the 74 dart on the shelf. I will snap pix for you if i still have it.

Sonnys car is going to be a disc/disc car, so i will likely source the same style GM valve set up for disc/disc, and plumb it in accordingly.
 
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I've seen those valves while doing some research but everything I've seen tells me the combo valve I have is the right one.

That is also what Inline tube said when I explained my situation to them. Also, the pre-bent brake line kit from them for a 72 duster with disk/drum located the ends of the hard lines right where my valve expected them to be.

The mystery continues. I'm trying to find someone local with some mopar knowledge to have a look.
 
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