I have an oil pressure gauge on my 1971 VW with 1835cc engine, which also has a tach. I figure 10psi oil pressure for each 1000 rpm, so 30psi at 3000 rpm.

 

@AB Earl, I do not believe this truck had the infamous "fork-lift" damage, thankfully. Looking at the Driveshaft it looks good for its age and spins on a smooth plane from the quick check I did. I will do a more intensive test tonight.

I have the new tank in. It was $135 from partsgeek.com and looked pretty good. I forgot to snap pics. Will upload some tonight. It came painted so I just threw it in. Was going to rubberize coat it but decided ... nah. May still blast the bottom side with a rubberized coating. Its still very accessible.
In my excitement to get it in, I mounted it, connected all the lines and refilled it with all that new gas I pumped from the old tank, only to realize, this tank did not have a drain plug. In hindsight, I have drilled and tapped the new tank for a drain plug. theoretically I could always hotwire the pump to run with the key on and pull a line to drain the tank if I need to or just hand pump/syphon it, but a drain plug is handy...
That's a problem for another day.

As for the vibration, I pulled out the old dial indicator. I set it up to each wheel and gave them a spin (truck is still up on jackstands.)
Every wheel, measured at the outermost edge of the wheel itself run a max variation of .5mm or less. Three of the four wheels run .4mm variation or less. So that is 1/2 of 1 mm variation through the entire rotation. and that is measured off powder coated wheels that have a rough texture, not smooth. So I am going to call that "within tolerance."

So I believe the frame is straight and my wheels all "track" straight on their respective hubs, front to back.

So that leaves the terrible alighnment I'm sure I have (front end has new ball joints and few tierod ends etc...), the fact that the suspension is not level (Front/left is lower than the right etc.), and I could still have issues within the axle etc.... not sure. Again the vibration wasn't like, bone shattering or anything but definitely noticeable... For all I know, a tire could be out of balance too. I mounted and balanced them 3 years ago.... who knows! They could have developed flat spots, but I think I would feel that immediately, not just a certain speeds.

Plenty left for me to troubleshoot at home.

Tonight I will learn how to level the suspension to get that straight (front end) and see where that gets me.

Thanks everyone!

 

@Cussboy,

Yes, I also have a set of gauges for my 69 Type3... Oil pressure, Cyl. temp, and volts. I may upgrade to this VDO style gauge because it uses an electric pressure sensor instead of that "destined to fail" plastic pressure line. Those are more expensive though, so its lower on my list. I am going to take my temp gauge ( the aftermarket one) out of the install. My stock sensor reads fine and there is not a good provision for me to install the sensor for it. I'd have to drill and weld in a bung for it or find a thermostat housing that fits the Mazda with one already in... not worth the hassle. Stock works fine.
I will rework my dash install to just have the Oil pressure and Volts gauge.

As for my PSI, when I was running it the other day it read 40 psi on start up, that was cold at around 1100 rpm (1st start rpm) so I am not going to worry about it. I think my pressures are good. I am sure it will diminish as the oil warms and like you said, it increases accordingly with RPM when running at temp. No idiot light on the dash so lets not worry .... lol (famous last words)

 

Josh, if you adjust the torsion bars, you need to take the weight off of the suspension (unloaded) during adjustment, then set the truck back on the ground to see the results. From what I am reading in your posts, the truck is still on jackstands, but just make sure the stands are under the frame, and not the front axle.

 

AB, you are 100% correct. I assumed as much anyway but also read up on the front suspension removal/installation/adjustment in the shop manual. Seeing as how I am not removing the torsion bar, I am just going to try and raise the left/front about 1/2". I can't remember how far off the right/front and left/front were from each other. I will drop the rear back on the ground and only lift the front, that way I can make an adjustment, drop it down to check and then lift again easily to confirm.
1st time doing truck torsion bars so this should be fun. I've messed with my old Volkswagen's bars to lower it so this should be familiar.
Once I get it level, its off to the alignment shop.

 

Welp, I think the bolt is stripped. Right in the middle.

So I was loosening the Anchor bolt to try to get both sides to be at the same "angle." Driver torsion bar mount was at 17* at the start, passenger was at 25*. So I figured i'd take some preload out on the drivers side and I should be good (I think Im using the correct terminology.)
Welp, got them both even enough (see pics of angle finder) and dropped it back down on the tires.
Driver side as @ 32" from ground to fender, passenger was at 33 1/2"! so it did not get better.
Fine, I put it back up on jackstands and started adding in my preload on the driver then. I figured it was at 17*, Ill got to 15 or 16* and I'll check. got to 22* and it stops decreasing, even gets worse...
I peer in the hole of the bracket (very hard to see in there) and it looks like its stripped in the middle of that bolt.

(Many swear words were said)

So it looks like this is just a really long bolt. I might see if I can take it out and just go get a nut and washer or a replacement bolt at the local hardware store. I assume it has to be a grade 12 or 10 at least because of the load its under.

Im debating if I should try to remove the bolt as it will obviously get worse if I do so. The "key" might be stripped already as well and get worse if I do so, which might ruin my ability to just put a nut on top of the bolt to use the good/exposed threads....

See pics.

Drivers anchor after 1st adjustment

Passenger anchor - static, not adjustment

Top of drivers/anchor bolt. looks clean enough to remove (or just put a nut and washer on)

 

So I found a nut and a better tap. Im going to clean up the treads, but here is my question.
If Im looking at my suspension correctly, the "tighter" I make that bolt (more exposed threads) the more preload should be on the torsion bar correct? I.e.: giving me a higher ride height, correct?

Im guessing these torsion bars are worn out, big time. They do have 280k miles on them.

Ive found some upgrades/replacement/lift torsion bars from the Aussies, but it'll cost me $500 and I would think at least a 4-6 weeks to ship.

Thoughts on my situation? I have considered pulling the bolt all the way out to inspect the assembly, but I run the risk of it not going back together. I found a few bolts online but they may not have enough of the bolt threaded. OG bolts on ebay are ridiculously priced so thats out. I have not been able to find a new set online.

Maybe I need to pull the torsion bar on the drivers side and re-index it to accommodate the stripped bolt?

Anyone have any experience with this?

 

I have not tried to reindex the torsion bar bolts Josh......I would think that you could do that though, in order to get lined up on a good portion of threads.......but I think that I would try to find a fully threaded replacement bolt, or a good original bolt first.
A previous owner (or mechanic) must have tried to raise the front suspension while the weight of the truck was on the suspension.

 

So lots of cussing and swearing.
1/2" ratchet slipped on full pull right into my face....huge bruise. Not what I planned but we bleed for our fun right?

So, I went with the "new nut" on top of the existing torsion bar bolt. I cleaned up the threads real nice... 12mm x 1.5 pitch if anyone needs to know, then slipped a new grade 10.9 nut on top of the bolt with a washer to act as a reinforcement for the "threaded key."

Tightened the sucker down a bunch more turns but stopped when it started to suggest to me that I had gone far enough. Truck was still lop-sided, but not by much, so I figured, if I can't raise the drivers side up, I'll just lower the passenger down.

Cleaned up the threads on the passenger side bolt and turned it down about 2 1/2*. The torsion arm was at 27.7* and I turned it up (loosened) until it got to about 30.1*... All while the vehicle was on jack-stands mind you....
Dropped the truck back down and now Im roughly 32 1/4" from ground to fender seam on both sides... about as level as its going to get.

Rear is 33 3/4" passenger, 33 5/8" driver
Front is now 32 1/4" square... Manual says 10mm (.39") from left to right variation, so I'd say thats fine.

At this point, I think I'm good to take it to get Aligned. Frame looks good, I didn't see any play or variation in the driveshaft, so I think that vibration is either the alignment, or just worn out internals (tranny, diff, who knows) and who cares at that point. It wasn't violent, only noticeable... lets be real here... it has 280k miles on original everything... poor thing is worn out.

I have longer term plans for a new rear differential I can put a locker in so probably a used, Ford Explorer or Toyota axle, with new lift leafs in the rear. I'm also eyeing some cool lift and beefier torsion bars from Australia when I start going on my Off-Road adventures... overland stuff. No serious rock crawling here.

Lets see how the alignment does.

Cheers!

 

OUCH!!

Well, hopefully it will all be worth it soon Josh! My 4x4 truck is a little lopsided in the rear also......I haven't tried to fix it, or adjust it in any way yet. Let us know how the alignment goes!