Joining the Club my 1977 FJ 40

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Ultrarunner

Ultrarunner

Joined
Jul 30, 2024
Threads
1
Messages
19
Location
Flag, AZ
Howdy all,
This has been a long time coming for me, I have been infatuated with FJ40 for quite some time and recently had a this one fall in to my lap. A friend of mine happened to buy it impulsively and decided it wasn't for him and I am at a good spot to dedicate some time and love to it. I am not ignorant to what it costs and takes to restore vehicles as my father is obsessed with 67-72 chevy trucks and I have been involved in multiple projects over the years. I also ran a powder coating business with my dad where we did lots of restoration projects and have a understanding of metals and corrosion. I am not looking to restore this rig and I am very happy with how it currently looks. I am going to focus on getting it in the best mechanical shape as possible with the goal of turning it into my daily driver. ( I have about a mile and a half to work). This weekends plan is to give it a tune up get and see if I can get a feel for how it is running overall. The previous owner desmog it and since then it has been running rough, so I am thinking I might try and put that back to stock. I will update as I begin to see what some of these issues are.

The biggie that I am hoping to get some help with is the SOA. I think it is not properly done and would like to take it back to AOS eventually. I am wondering if it is safe to drive or if this should be at the top of my priority list. Here are some picture I took hopefully they will work if not I will have it in the garage tomorrow with some better light. There is a severe shake that happens at about 20mph but quits as you speed up the rig handles well enough. Thanks for the community support and can't wait to share my journey and to get to know more passionate aficionados.

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The front death wobble is likely due to poor caster angle, but could be exacerbated by worn out suspension & steering components, so all that needs a good once over. I'd start by getting rid of those revolver shackles in the front, those are designed to give extra axle droop for off-roading, and I don't think you need/want that with your stated intended use. Decent looking 40. Welcome to MUD.

Share some more photos of the front axle & steering setup. Does it have high steer arms? Looks like factory steering box, center link, and drag link are all in place. There are a lot of moving parts in the factory steering design, so if there is wear in some or all of the parts, these old trucks can be a handful or downright dangerous.
 
EWheeler said:
The front death wobble is likely due to poor caster angle, but could be exacerbated by worn out suspension & steering components, so all that needs a good once over. I'd start by getting rid of those revolver shackles in the front, those are designed to give extra axle droop for off-roading, and I don't think you need/want that with your stated intended use. Decent looking 40. Welcome to MUD.

Share some more photos of the front axle & steering setup. Does it have high steer arms? Looks like factory steering box, center link, and drag link are all in place. There are a lot of moving parts in the factory steering design, so if there is wear in some or all of the parts, these old trucks can be a handful or downright dangerous.
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Thanks for this, I will post more pics tomorrow. I would not describe it as a death wobble the vibration feels more in the rear end and there is not any feedback in the steering. It is a pretty severe vibration but it goes away as soon as it speeds up.
 
If the rear diff has been angled up at the front your universals will be causing a vibration - diff and transfer output flanges should be parallel. What happens is your pinion will be speeding up then slowing down every revolution
 
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Ultrarunner said:
Thanks for this, I will post more pics tomorrow. I would not describe it as a death wobble the vibration feels more in the rear end and there is not any feedback in the steering. It is a pretty severe vibration but it goes away as soon as it speeds up.
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Copy, i mis-interpreted your explanation.

You can start out by simply inspecting the rear drive shaft. U-joints tight, and bolts to t-case and diff tight? From you photos, the rear drive shaft is in phase, so that isn't an issue. See page from factory service manual here that shows proper driveshaft phasing:

Spike Strip

Post in thread 'Driveshaft Phase.'

Best I can do:
shaft.webp

If every thing feels tight, you could start by disconnecting the rear drive shaft, put the t-case in 4wd and lock the front hubs and see if your vibration is gone. This assumes that the vibration being described is in a scenario were t-case is in 2wd and front hubs are unlocked as that is how most folks drive these trucks around normally.
 
That pinion in the rear appears to be rotated so far that it’s pointing at the TC flange, being its a single cardan shaft there is no way for it to operate smoothly. The angle of the shaft is likely too severe to likely work even with a u-joint replacement, it may be a good candidate for a DC shaft. You can hop on Tom Woods and watch some of their YouTube vids to learn more about DS angles. But if you are going to reverse the SOA then I wouldn’t mess with it until that’s done. You may want to look for an unmolested front axle housing rather than reversing the cut and turn, depends on your skills.

Game plan your build intentions so you don’t start tossing $ at issues as it sits currently and be realistic with your budget and time. It will probably be easier to finish off the SOA and get it running right, than turning it back into a princess. Welcome and have fun with it!
 
Double Cardin U joint assembly. As mentioned, Tom Woods website c has good tutorials on driveshaft angles and
U joints.
 
I guess to document my process of getting this Rig up to Snuff:
-I finished the Smog Delete that the previous owner started and replaced remaining vacuum line.
- I discovered that the previous owner installed the incorrect Rotor and it nearly cut every contact point in the cap off ( Never seen anything like it)
- I removed all silicone from roof in the rain gutter and plan to reseal with "3M Urethane Seam Sealer, 08368, White Color, High Solids" unless there is something better?

Next Steps
- Decide on distributor options ( FJ 60 HEI, PerTronix or keep the points which napa quoted at $50 :oops:)
- Rebuild Carb
-Repair rust and reinforce seatbelt attachment points under fold down seats.
-Wire repair
 
The DC drive shaft works wonders....with this shortened & balanced FJ60 OEM unit in my '77 FJ40:
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I can cruise all day like this with no vibrations:
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Tom Woods will do you good!

For the electrical wiring, if your rear harness is hacked up, I may can help.
 
GA Architect said:
The DC drive shaft works wonders....with this shortened & balanced FJ60 OEM unit in my '77 FJ40:
View attachment 4062383

I can cruise all day like this with no vibrations:
View attachment 4062385

Tom Woods will do you good!

For the electrical wiring, if your rear harness is hacked up, I may can help.
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Thanks I will post as I go I haven't started to look too closely yet.
 
It's not just the pinion angle. It's the relation between the pinion angle and the transfer case output angle. For a single U joint on each end you want the pinion and tcase to be as close to parallel to each other, then you can figure what the driveshaft angle would be. My setup is off a couple of degrees from each other and run fine. Keep in mind if you using the single U joints, once installed you need to put the suspension in full droop to see if the U joint yokes don't interfere with each other. On a SOA suspension you will probably need a double cardin joint. You want the pinion to be pointing at the transfer case output like in @GA Architect 's pic in post #13. This is more expensive but easier to set up.

In your pic of the rear axle the pinion looks too high in relation to the Tcase. Is it pointing at the tcase output? The front looks like it needs a Cut and turn. Or return everything to stock spring under axle(SUA) on both axles. What's your skill set? Can you weld and fabricate? Your going to learn about steering geometry or pay someone when its all said and done. Folks around here will likely offer guidance.
 
pb4ugo said:
It's not just the pinion angle. It's the relation between the pinion angle and the transfer case output angle. For a single U joint on each end you want the pinion and tcase to be as close to parallel to each other, then you can figure what the driveshaft angle would be. My setup is off a couple of degrees from each other and run fine. Keep in mind if you using the single U joints, once installed you need to put the suspension in full droop to see if the U joint yokes don't interfere with each other. On a SOA suspension you will probably need a double cardin joint. You want the pinion to be pointing at the transfer case output like in @GA Architect 's pic in post #13. This is more expensive but easier to set up.

In your pic of the rear axle the pinion looks too high in relation to the Tcase. Is it pointing at the tcase output? The front looks like it needs a Cut and turn. Or return everything to stock spring under axle(SUA) on both axles. What's your skill set? Can you weld and fabricate? Your going to learn about steering geometry or pay someone when its all said and done. Folks around here will likely offer guidance.
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Thank you for the great information and I am taking in all the great advice. Fabrication is a strength and I am surrounded by professionals so feel confident here. the front end is going to be down the road when I decide to go back to SUA after saving and locating needed parts. My question about the shims would be if I was running a single double cardan in order to correct the diff angle because it seems like the angle is a bit steep. Tom Woods video suggested that this doesn't matter if the angle is improved at the tcase.
 
I have been pretty focused on tinkering and forget to take pictures, which I will do this weekend to update the journey but wanted to share that I got to drive it this weekend and got on some dirt. I got a driveline from Tom woods and it is night and day and I appreciate all the recommendations. I attempted a rebuild of the original carburetor which was a bit of a mess and has required me to source many broken and missing parts. I did pick up a City Racer Carb so I will have a spare and could get it on the road. I also added Pertronix electronic ignition and it starts instantly. I also had to repair the rear wheel wells so I could safely install seatbelts. The next steps are trying to tune the carb, I will try some jetting changes because I am at 7000ft for some performance and gas mileage (currently anything helps.) The rear output seal is leaking so I am going to order the Valley Hybrid Kit. Thanks for everyone's help this community is fantastic.

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Ultrarunner said:
I have been pretty focused on tinkering and forget to take pictures, which I will do this weekend to update the journey but wanted to share that I got to drive it this weekend and got on some dirt. I got a driveline from Tom woods and it is night and day and I appreciate all the recommendations. I attempted a rebuild of the original carburetor which was a bit of a mess and has required me to source many broken and missing parts. I did pick up a City Racer Carb so I will have a spare and could get it on the road. I also added Pertronix electronic ignition and it starts instantly. I also had to repair the rear wheel wells so I could safely install seatbelts. The next steps are trying to tune the carb, I will try some jetting changes because I am at 7000ft for some performance and gas mileage (currently anything helps.) The rear output seal is leaking so I am going to order the Valley Hybrid Kit. Thanks for everyone's help this community is fantastic.

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Sweet looking rig! I've got a Freeborn Red '77 as well, and I'm looking to put a lift on mine. What size tires and lift ya got?
 
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