BJ73 steering question (1 Viewer)

[Aussie BJ73]

Hi all, first time posting in the forum, visited a few times online but figured I’d register today, some very nice and interesting vehicles on here . Hopefully I’ve picked the right spot to ask my question

I’ve got a 1985 model BJ73 FRP top, has around 377xxx KM on the dash, 3B diesel which has been Turboed, 5 speed with Fairey over drive etc. I’ve had it for around 4 years now and it’s done about 15000km in that time. When I got it the original suspension was pretty tired and worn so I had it replaced with EFS suspension, Albeit with 2” lift and the appropriate wedges in the front end to suit. At the same time, BF Goodrich 33” tires fitted, Which may of been a mistake . It used to have much narrower Yokohamas on it which I sold to a friend so the BFs were cheaper to fit to it then find the same narrower ones with a deal I was given.

My question is regarding driving at speed, 100km an hour in this instance. I’ve had a wheel alignment done, which seems to of made no real difference. Tie rod ends were replaced 2000km ago, steering dampener around 5000km ago, shackle bushes and pins are tight, king pins appear tight if I jack the vehicle up and rock the tires. The steering pump has been rebuilt and steering box appears tight but not to tight so it doesn’t bind up. U bolts holding everything are tight. All four tires are close to new, rims also new. No damage present to them. When I’m poking along on the road, it’ll wander slightly at around 80km an hour, then at 100 but it doesn’t need correcting much. However, as soon as I hit a bump as such, it’ll want to take me over the other side of the road, steer everywhere and is terribly difficult to correct. I never drove it when it had narrower tires and older suspension fitted, as I didn’t have a learner licence yet. I’ve read that the lift may of thrown it out, and with wedges it should have corrected it. The wedges did help marginally when they were fitted, but it’s still bugging me. My father quotes it felt as a normal car would and didn’t feel it had any issues before I had the suspension and big tires fitted. I’m really annoyed by this because it’s a fun vehicle to have and at lower speeds it doesn’t cause any issues. I’m beginning to think it could be the bigger tires, I’ve heard BF’s love to follow ruts and bumps in the road. I’ve seen quite a few 75 series around here with the same tires on, never heard of any issues. But there’s a fair chunk of them that still have the narrow tires they came from the factory with, so maybe it is that. It may be something simple, but I can’t pick it, any inputs are muchly appreciated

 

[bj70bc]

There is a nut on the top of your steering box, if you loosen the outer nut then turn the center (iirc) you will tighten the box play up, they say dont overtighten it, very little adjustment at a time. Id look it up and read more before you try it. I did it
bigger castor shims maybe, i made '6deg copy' shims out of old tacoma leafs for my arb lift+shackles
seemed to do the trick

 

[Aussie BJ73]

There is a nut on the top of your steering box, if you loosen the outer nut then turn the center (iirc) you will tighten the box play up, they say dont overtighten it, very little adjustment at a time. Id look it up and read more before you try it. I did it
bigger castor shims maybe, i made '6deg copy' shims out of old tacoma leafs for my arb lift+shackles
seemed to do the trick

I did forget to mention about that but bj70bc, I’m assuming your talking about the one on top in the middle, loosen the nut then tighten the thread with a flat bladed screw driver? It’s always been near the end of its adjustment in the down position since I’ve had it

I’ll look into the shims though, that does sound like a good idea

 

[bj70bc]

I had to get rid of the 33 12.5 bfgs that came on mine, just way too wide

Steering arm studs torqued?

 

[Aussie BJ73]

I had to get rid of the 33 12.5 bfgs that came on mine, just way too wide

Steering arm studs torqued?

I’m thinking of going back to the narrow tires it would have come with from factory just to see, I may have access to a set just to try.

Believe so, Ill check that later to make sure

 

[Sundowner]

What's your toe-in measurement?

 

[Rigster]

Hi all, first time posting in the forum, visited a few times online but figured I’d register today, some very nice and interesting vehicles on here . Hopefully I’ve picked the right spot to ask my question

I’ve got a 1985 model BJ73 FRP top, has around 377xxx KM on the dash, 3B diesel which has been Turboed, 5 speed with Fairey over drive etc. I’ve had it for around 4 years now and it’s done about 15000km in that time. When I got it the original suspension was pretty tired and worn so I had it replaced with EFS suspension, Albeit with 2” lift and the appropriate wedges in the front end to suit. At the same time, BF Goodrich 33” tires fitted, Which may of been a mistake . It used to have much narrower Yokohamas on it which I sold to a friend so the BFs were cheaper to fit to it then find the same narrower ones with a deal I was given.

My question is regarding driving at speed, 100km an hour in this instance. I’ve had a wheel alignment done, which seems to of made no real difference. Tie rod ends were replaced 2000km ago, steering dampener around 5000km ago, shackle bushes and pins are tight, king pins appear tight if I jack the vehicle up and rock the tires. The steering pump has been rebuilt and steering box appears tight but not to tight so it doesn’t bind up. U bolts holding everything are tight. All four tires are close to new, rims also new. No damage present to them. When I’m poking along on the road, it’ll wander slightly at around 80km an hour, then at 100 but it doesn’t need correcting much. However, as soon as I hit a bump as such, it’ll want to take me over the other side of the road, steer everywhere and is terribly difficult to correct. I never drove it when it had narrower tires and older suspension fitted, as I didn’t have a learner licence yet. I’ve read that the lift may of thrown it out, and with wedges it should have corrected it. The wedges did help marginally when they were fitted, but it’s still bugging me. My father quotes it felt as a normal car would and didn’t feel it had any issues before I had the suspension and big tires fitted. I’m really annoyed by this because it’s a fun vehicle to have and at lower speeds it doesn’t cause any issues. I’m beginning to think it could be the bigger tires, I’ve heard BF’s love to follow ruts and bumps in the road. I’ve seen quite a few 75 series around here with the same tires on, never heard of any issues. But there’s a fair chunk of them that still have the narrow tires they came from the factory with, so maybe it is that. It may be something simple, but I can’t pick it, any inputs are muchly appreciated

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Hey Aussie,

Welcome to the forum - your family that will help you get the rig you love to a point where you love AND trust it.

What your are describing is definitely NOT normal, so don't give up on your love.

I am running 35"×12.5" tires on my 76 and they have the smoothest ride. Will they like to ride up the ruts? Yes, but not terribly so... just enough that it makes you pay attention.

I used to drive professionally, so I have a bit of experience with all sorts of scenarios. Could you please describe to me what is happening to the steering wheel, which I assume you have firmly gripped with at least one hand while your cruiser is lurching all over the road after hitting a bump?

You also mention that your steering box adjustment screw is at the end of its adjustment. How much play is in the steering?

If: tie rods/ball joints are tight, linkages are tight, etc, and there is no play in your front bearings (preload is correct) then you may need a steering box rebuild? Also check your steering arm for play and/or damage.

Also, is the steering dampner (shock that sits sideways on the front) any good?

Good luck!

 

[Felde]

Hi
Interesting configuration: 3B with Fairy Overdrive. Never heard that. You need to tell more, but that's for another time.
I also have a BJ73 3B. OME lift and 31 BFGs. The steering is generally not very thight on our rigs.
Can't tell what the 33s do, but I second @Sundowner: Check toe-in and caster.
Do you have the adjustable steering rod ends? Those usually need to be adjusted after some time. I found the factory preload to be too low.
Play in our steering may also result from the joint in the steering column. It is hard to reach, gets seldom greased and thus wears and develops some play. Be very careful with adjusting the steering box. That screw actually doesn't really reduce or fix any play (which would be in the bushes & bearings), but increases the force of the balls to the worm drive. It is an old box and the worm drive will have pitting. More load = even more wear. And those are NLA.
Other suspects are the steering knuckle bearings and pins and the pitman arm and ball joints.
You say the issue occurs when hitting a bump at higher speed? Our leafsprung rigs don't like bumps: Instead of moving up, like coils do, it throws the axle backwards. And if the bump is not hit equally on both sides, it twists the axle horizontal, which for sure affects the steering:
Check your shackles (angle ok?) and your bushings.
Good Luck Ralf

 

[Sundowner]

I also have a BJ73 3B. OME lift and 31 BFGs. The steering is generally not very thight on our rigs.

Didn't know that; mine is pretty tight. It's not like a 911, for sure... but given the configuration in the front end, I've been happy with how little play there is.

Can't tell what the 33s do...

The size shouldn't be a huge factor; tread patterns and pressures and everything else, however, should definitely have an impact.

You say the issue occurs when hitting a bump at higher speed? Our leafsprung rigs don't like bumps: Instead of moving up, like coils do, it throws the axle backwards. And if the bump is not hit equally on both sides, it twists the axle horizontal, which for sure affects the steering:

If it's a coil-sprung solid axle, the same behavior will occur: control/radius arms will allow an arcing movement in one plane (front to rear) and the track/panhard bar will create an arc in the other (side to side). Both arcs can and will induce bump steer, as will actual bumps...but from my read of the original post, the steering is somewhat touchy in and of itself: anytime I see that, I start thinking about a toe that's set badly, and is causing something else to start moving unpredictably as well. A quick check with a tape measure can find a really bad case of it, but I prefer measuring from the brake rotor surfaces with two straightedges clamped thereabouts.

 

[Aussie BJ73]

@Sundowner @Felde Thankyou guys for you suggestions , I have improved it by adjusting the toe in a fraction more, loosened the clamps off, rotated the shaft a bit, then tightened back up until it was steering nicely. Now if I hit a bump, it won’t go everywhere. The steering wheel however still moves a bit, I haven’t checked the dampener as of yet, it is relatively new but it could be busted. Is there a bigger dampener you can get for these BJ’s ?

@Sundowner the steering play is minimal, I’ve actually backed that off yesterday. I’ve got a Max Ellery service manual for it and it quotes anything under 40mm of play is acceptable, mines about 20mm so I’m happy there. I have considered rebuilding the steering box, not because of this up until now but because the power steering seems hopeless , but this is more insensitive one day to check it out.

@Felde I’ll post somewhere else about the overdrive, it’s mounted on a H55F transmission, the engine handles it well and is good for hills cause you have half a gear. Shackle pins and bushes should all be tight, they’ve done 15000km work since they were fitted, they’re greased when the drive shafts are done

One other thing I’ve been thinking now Sundowner mentions it is the Toe in measurement, would anyone have a rough idea what it would be, with this vehicle fitted with BFG 33” tires?

Thanks again all, this forum is really helpful

 

[Sundowner]

One other thing I’ve been thinking now Sundowner mentions it is the Toe in measurement, would anyone have a rough idea what it would be, with this vehicle fitted with BFG 33” tires?

Warning: response contains opinions.

Direct Answer: Nope, no clue. I'm sure there's a factory spec, but that number is out the window as soon as you change anything that locates the tire contact patch in relation to the vehicle.

Better Answer: Toe is weird...like, seriously weird...and that's because it's subjective despite having some objective ranges that it needs to fall within. It's really the last thing that you need to adjust, after you've adjusted/fixed/replaced everything else; most of the other stuff in the front end has almost no variability in what it can or needs to do, but caster and toe really alter the feel of things and they're heavily impacted by other factors. I've often adjusted toe in or out after a tire change; sometimes, I've done it after a rotation because the slight differences in tread patterns caused a different feel in the front end. So, it's really a process of figuring out what makes the rig do what you want it to do. I really do need to look up the factory spec, but for this wheelbase and track width, I'd probably start 33's at 1/8" or 3mm in, and see how it felt at highway speed...and I'd probably back it off from there, depending on how heavy the steering felt. Right now, I think mine is set at about 2mm in - I'm running a 33x10.50, for reference - and it's okay...but my front end isn't your front end. Same goes for my roads and driving habits and travel speeds and preferences. So, yeah, I'd probably just play around with it and see what happens; you're likely to find a sweet spot somewhere, in my experience.

Also: bigger damper = bigger damping...and bigger damping = bigger potential bandage. Just be careful to not mask a problem; check the existing one to see how it feels.

 

[Felde]

Great it worked out for you.
Safe driving!
Have a nice one, guys Cheers Ralf

 

[bj70bc]

1/4 inch toe-in is common on a 4x4, measuring an 1/8 on that stuff is kind of within the margin of error/ play.
Thats what mine went to and definitely helped

 

[Sundowner]

Couple of thoughts, here; no disrespect intended.

1/4 inch toe-in is common on a 4x4...

True, but it depends on (among other things) the tire size: 1/4" in on a 37", absolutely...but I probably wouldn't want that much with a set of 31's.

...measuring an 1/8 on that stuff is kind of within the margin of error/ play.

I have to respectfully disagree, here. If you're measuring to a set of matched points on the tread blocks, then yes: 1/8" may be within the margin of error, depending on tire wear. If you measure from the brake rotor with a leveled and aligned pair of straightedges, then 1/8" is a reasonably coarse measurement that need not be settled-for. I change my toe settings in 1/32" increments using that measurement method, and there's a noticable difference on clean pavement.

Example: I used to run 3/32" on a 35" MTR on another rig, with a 93" wheelbase. If the toe setting drifted to 1/8" the return-to-center started feeling heavy, and if it went the other way to 1/16" the steering was all over the place and followed pavement grooves/ruts like it was on rails. And yes, that's exactly what I deserved for now swapping out my rock tires when on pavement, but it's a very good example of the point, regardless.

In all cases, I do not consider 1/8" to be within the margin of play in the steering; if there's an 1/8" of play in my linkage - either individually or collectively - then I have repairs to make. I'm not sure if that's what you meant by that word, but I wanted to clarify how I was reading it, regardless.

Again: no disrespect intended, just a difference of opinion.

 

[bj70bc]

If you're measuring to a set of matched points on the tread blocks, then yes: 1/8" may be within the margin of error, depending on tire wear.

this is what i mean, but ya

 

[Sundowner]

this is what i mean, but ya

I used to do it that way and I just got too many mixed results; sometimes I was dead-on, sometimes the steering felt incredibly twitchy, and sometimes it felt overly heavy...so I started using the rotor method.

My concern is this: a single set of tires can come from several different moulds, all of which may be similar but not exactly the same. My current set of 33's has this exact anomaly; the tread depth was 2/32" different on the fifth tire (shallower), and it was the one tire out of five that was from a different run, and almost certainly from a different mould...and there are subtle but definite differences in the tread. So: I use two inexpensive 36" aluminum levels, each of which is marked with tire diameters on 1/2" increments, and I just clamp those to the brake rotors with the front axle at ride height. No more guessing.

I keep intending to make an adapter for the level bodies that will let me bolt them to the lug studs or something of that sort, but I never get around to doing it. Same goes for a ruler that I can install at the front and read the toe at a glance from underneath; that would make life very simple, and my front end alignment very accurate.

Anyway, that's a derail; apologies. Carry on.

 

[bj70bc]

^^yes, a much better way

 

[Broski]

I’m using this setup, bolts to the lug nut’s and is good for tire up to 40”
I can say with certainty that 3/16 is not enough for the 39s I’m running

 

[Broski]

1/4 inch toe-in is common on a 4x4, measuring an 1/8 on that stuff is kind of within the margin of error/ play.
Thats what mine went to and definitely helped

So just to be clear, 1/4” overall each side.

 

[bj70bc]

1/4 overall,
measured on 34" straight edges (front and back measure points), each centred on each side's hub face (theres a tool)
worked well for me to stop wander
bigger tires = slightly more toe in needed ( from what ive heard )