BPM’s FZJ80 Family Cruising/Exploration Machine

[bpm]

Good to know about DH6. How tall would the spacers need to be to bridge the gap between the DH6 and the battery hold down?

A spacer about 7/8" tall and 1/2" deep could sit on the ledge of the battery to bridge the gap. Here's another image. The front lip is curved and the back is more flat.

 

[bpm]

I started working on fabrication of a rear bumper with my brother this weekend using a shop that he worked at previously and the help of a family friend who owns the shop and knows the plasma cutting table/software better than we do. We started out by designing most of the structure using large pieces of cardboard taped together and clamped to the frame/crossmember. Those measurements went into EnRoute, the software used to cut the steel plate) I decided to use 3/16” steel plate all around for the bumper shell. I’m leaving the crossmember in place so I think this will be sufficient for my needs with a little bit of reinforcement. We’re using 1/4” plate for the frame mounts and mount-to-shell supporting braces. We’re lifting the shell off of the frame/crossmember with a combination of 3/8” and 3/4” plate. This will leave about a 3/8” gap between the bumper and tailgate when dropped open. We plan to cut side steps into the left and right sides of the bumper to enable easy roof rack access.

We plan to make 2 swing arms using 2” square steel tubing and spare tire spindles from Ruffstuff Specialties. The arms will lock open with 2 pull pins attached to the spindle housing and will lock closed with one T pull pin in the passenger side spare tire arm with the help of a Destaco 341R clamp latch. The passenger side spare tire arm will hold the driver side arm closed. I plan to use UHMW plastic pads bolted to the bumper for the pull pin contact surfaces and swing arm beam load support when closed. A receiver hitch for light towing will be incorporated into the bumper but we are still working out a design for that. I think a little bit of crossmember cutting will be required in order to put it in the position I am looking for.

Hardware links:
https://www.kinequip.com/destaco-341-r-pull-action-latch-clamp.html
Indexing Plungers - Pull Pins - Round Handle - Steel Plunger - Steel Housing (CP-R) - Fixtureworks - CP-K320R
Indexing Plungers - Pull Pins - T-Handle - Steel Plunger - Steel Housing - with Lockout (CP-TLO) - Fixtureworks - CP-K320TLO
Spare Tire Spindle

 

[bpm]

 

[bpm]

Alright fellow mudders... after some financial austerity and scratching our heads on why we're hearing vibration/noise at 50mph and above after installing the slinky long travel kit I think we're getting close to working on and maybe actually using this thing for its intended purpose...

Dobinsons caster correction plates that came with my slinky kit are installed and my pinion angle is still off by 5-6 degrees. This seems illogical based on reading @ab0tj and I have done but this is where we are. Seems some reading indicates that ~4" of lift should equate to around 5 degrees or so of caster/pinion angle that needs to be corrected, and these plates are supposed to be able to correct for 5 degrees.

Some questions for anyone who may know:

Could a lack of weight in the back ( I just have the halfway built custom rear bumper and my spare in the back) cause this pinion angle difference?
Could we install caster correction bushings in the radius arms in conjunction with the plates to solve this pinion angle problem? Perhaps in conjunction with the DC front shaft I bought? (in hindsight I understand now that a DC shaft can't compensate for this much pinion angle difference.)

T-case

Front diff

Front bumper and winch have been installed too...

 

[lumbee1]

@bpm Do you have the 7-pin mod? If you do, you can pull the front drive shaft, lock the center diff, and go for a drive to see if the noise is still present.

I installed a DC front shaft a few years ago and have custom caster correction plates. The DC shaft made all my noises go away. I have approximately 3.5" of lift in the front.

The weight of the bumper/spare will have no bearing on the noise. Leave them, don't leave them, doesn't matter.

 

[coues7]

I'm getting ready to go down this same path and this has me worried. With limited up travel, based on GW Nuggets research, is a lift of that height for 35' really necessary? @GW Nugget

 

[bpm]

@bpm Do you have the 7-pin mod? If you do, you can pull the front drive shaft, lock the center diff, and go for a drive to see if the noise is still present.

I installed a DC front shaft a few years ago and have custom caster correction plates. The DC shaft made all my noises go away. I have approximately 3.5" of lift in the front.

The weight of the bumper/spare will have no bearing on the noise. Leave them, don't leave them, doesn't matter.

Thanks for the tip. I should mention the list of things we've done to troubleshoot:

Have locked the center diff and pulled front shaft out. Noise and vibes are gone in that state.

Have tried swapping T-case with a friend. Noise still present.

Have tried a DC shaft in the front. The DC shaft was a completely new custom build by Tattons Tattons Drive Lines - https://www.tattonsdrivelines.com/
He uses spicer joints I believe and they are all new. u-joints in the back have been replaced and the back shaft balanced as well.

With the DC shaft in:

The noise isn't constant. It's most prevalent when letting off the gas above 50 or when the u-joint angles change from dips or bumps in the road at the same speeds. It also occurs when medium to hard braking from 40 and below when weight shifts forward and the angles presumably get steeper.

The vibration isn't constant. It's most prevalent around 40-50 mph but then smooths out above. The vibration also happens in the medium to hard braking scenario above.

A couple of shops in town swore up and down it was the rear diff. I took it out, sent it back to Zuk to examine, and it was perfectly fine.

A few sources have suggested wheel bearings but those have all been redone (new bearings), and the noise doesn't occur when the front shaft is out.

There's probably something else I'm forgetting...

 

[bpm]

Thanks for the tip. I should mention the list of things we've done to troubleshoot:

Have locked the center diff and pulled front shaft out. Noise and vibes are gone in that state.

Have tried swapping T-case with a friend. Noise still present.

Have tried a DC shaft in the front. The DC shaft was a completely new custom build by Tattons Tattons Drive Lines - https://www.tattonsdrivelines.com/
He uses spicer joints I believe and they are all new. u-joints in the back have been replaced and the back shaft balanced as well.

With the DC shaft in:

The noise isn't constant. It's most prevalent when letting off the gas above 50 or when the u-joint angles change from dips or bumps in the road at the same speeds. It also occurs when medium to hard braking from 40 and below when weight shifts forward and the angles presumably get steeper.

The vibration isn't constant. It's most prevalent around 40-50 mph but then smooths out above. The vibration also happens in the medium to hard braking scenario above.

Rear shaft has been rebalanced and both u-joints replaced.

A couple of shops in town swore up and down it was the rear diff. I took it out, sent it back to Zuk to examine, and it was perfectly fine.

A few sources have suggested wheel bearings but those have all been redone (new bearings), and the noise doesn't occur when the front shaft is out.

There's probably something else I'm forgetting...

@digitalmarker has recorded some issues he's having with pinion angle and tried a wide variety of radius arms/caster correction parts.

Thread 1: Help me diagnose a driveline vibration - Slinky 3" lift - https://forum.ih8mud.com/threads/help-me-diagnose-a-driveline-vibration-slinky-3-lift.1211570/page-5

Thread 2: Castor/pinion angle question for de-grring - https://forum.ih8mud.com/threads/castor-pinion-angle-question-for-de-grring.1011419/page-5

I get the feeling that I'm in the same boat as him in terms of the caster being correct, but the lift height is putting the pinion angle in a place that is both not good for the stock shaft and not good for a DC shaft (my front diff flange to DC shaft angle is more than the recommended 1* difference).

My next steps are to try my stock front shaft again, maybe try the stock shaft from a buddies vehicle, double check the balance on the DC shaft.

 

[lumbee1]

@bpm I had almost the exact same situation. Heading home from a trip to the mountains, we started to get a vibe in the drivetrain. 70mph on the throttle and no vibe, as soon as I started to coast the vibe was bad. I tried to stay steady on the throttle to limit the noise and vibrations but It continued to get worse over several hundred miles. Luckily I didn't have to do any roadside maintenance and we made it home. First order of business was lock center diff and remove front shaft. All the noise and vibrations went away and I placed an order for the DC shaft soon after.

I used Carolina Driveline in South Carolina. the DC shaft was approximately $300. Caroline Driveline wanted something like $100 to ship it. I had a friend pick it up for me instead and bring it to a local event.

 

[ab0tj]

@lumbee1 unfortunately DC shaft didn't help in this case. Too much angle in the joint on the pinion end of the shaft (5 degrees), maybe.

 

[on the rocks]

@bpm you seem to be focusing on the front DC. Have you done anything with the rear? Rebuild or likely more important get the adjustable upper control arms and possibly the lower? I ran a 3.5" lift for 20 years and never had a front DC issue, still running the original OEM and never touched it. I have rebuilt the rear DC a few times and it helped with the vibrations but the biggest difference was the upper rear arms to get the DC angles back as close to spec as possible when I finally got sick of taking the rear DC in for replacement U joints.
And yes, more weight in the rear would affect mine and make it better only because it was lessening the angle when compressed from the weight.

 

[digitalmarker]

@digitalmarker has recorded some issues he's having with pinion angle and tried a wide variety of radius arms/caster correction parts.

Thread 1: Help me diagnose a driveline vibration - Slinky 3" lift - https://forum.ih8mud.com/threads/help-me-diagnose-a-driveline-vibration-slinky-3-lift.1211570/page-5

Thread 2: Castor/pinion angle question for de-grring - https://forum.ih8mud.com/threads/castor-pinion-angle-question-for-de-grring.1011419/page-5

I get the feeling that I'm in the same boat as him in terms of the caster being correct, but the lift height is putting the pinion angle in a place that is both not good for the stock shaft and not good for a DC shaft (my front diff flange to DC shaft angle is more than the recommended 1* difference).

My next steps are to try my stock front shaft again, maybe try the stock shaft from a buddies vehicle, double check the balance on the DC shaft.

So a quick update on my situation since the last post in my thread.

I was having a lot of problems ever since I installed the 3" Slinky suspension and running Delta 4" arms. Factory drive shaft sounded like it's about to explode, and the DC shaft (I tried several) were vibrating/pulsating so heavily, it was borderline un-driveable. The owner of 4xo (manufacturer of slinky springs) was not helpful with troubleshooting this, which is pretty s***ty considering the exuberant cost of their suspension kit. In retrospect, I wish I stuck with my 4" slee kit which had zero vibration and worked flawlessly, so lesson learned there.

I borrowed a set of factory arms with OME yellow poly bushings from a buddy. This reduced the caster correction so far back (likely -2*) that vibration disappeared almost entirely, but at the expense of driving feel. The truck felt very loose on the freeway and over uneven surfaces - not terrible but definitely not a long term fix. With the truck loaded up with gear and family it was downright sketchy in some parts. I also noticed small cracks starting to form in the poly bushings after only 2k miles.

I ended up scoring a set of Delta VS arms that were a "one off" production. The way Dave from DVS described them is that they have caster correction for a 2" lift, but were longer than the 2" model - so kind of like correction for a 3" lift which is in-between their 2" and 4" arms.

The arms made a huge difference - the handling improved dramatically, likely due to the combination of improved caster settings (I likely ended up at 2.5* of caster - haven't gotten it aligned yet), as well as the gain of wheelbase length - the 3" arms pushed the front wheel to the center of the wheel well. Paired with the DVS rear panhard bracket, the truck handles really well.

The downside is that the vibrations returned, although they are not nearly as bad as they were with the 4" arms - but I still feel a bit of a shake at 30-35mph, and then again at around 50mph. I noticed that the vibrations are most pronounced with engine under load, especially going up a hill. Less pronounced when cruising on side streets and easy on the throttle.

At the end of the day, the caster angles vs the vehicle height is what makes all the difference here. Unfortunately with my height (3" slinky springs) and weight (slee shortbus bumper and winch up front), I am still getting vibes - but now they are more tolerable and I am willing to live with it for now to keep the improved handling.

So, my options from here are to either deal with the minimal vibes, throw more money at the problem and try to find another suspension setup, go part time (which I really don't want to do), or see if I can add some weight in the front to lower the front end just enough to reduce/eliminate the vibes. I am going to test the last theory by strapping a couple of sand bags to the front bumper to see if lowering the front end just a bit to reduce the vibes. If that works, I see a heavier bumper (like the ARB or Ironman) in my future.

 

[bpm]

I suppose it's time to update this thread. It's been a few years and I've changed a lot since so it would be good to circle back on what's happened.

First, the noise that I was hearing and reported here.

I ended up purchasing and downgrading to the intermediate springs for the slinky kit instead of the heavy springs. I ended up using the roof top tent on the bed of my Ram more than the LC, and never really put much weight in the LC. After more rounds of troubleshooting, we pretty much settled on this issue being a side effect of a) not enough weight in the rear end and b) the new gears just needed to be worn in more. The noise is still there some during highway speeds with little load in the vehicle, but I have no issues driving down the interstate.

Now, the big changes.

The paint job was in a state of needing attention and I was interested in having raptor liner applied to the vehicle but didn't have the equipment/time to do it myself. There were some additional issues that needed to be addressed such as rusting around the windshield, removing the top rack/ribs and sealing up the roof holes. I ended up taking the vehicle to a shop in Grand Junction called The Rust Doctor. They specialize in restorations on old Land Cruisers.

 

[bpm]

 

[bpm]

Now it's almost 2025 and after all of this work, Im considering selling her. We're considering some big life changes that will result in long term international travel and it pains me (and my frens) to see it not being used for what it's built for. More on this later...

Additional things I started buying for but have not yet done:

Hurricane Fabrication tailgate storage mod
Electrical stuff for auxiliary power needs (fridge, etc) in the rear
Hood latch cable