Help improving my steering (manual box) please!

[db]

Being a wobbly old A108 I'm not expecting it to be any better than a Land Rover, but I'd like it to be as good as I can get it.
I think there's wear in the kingpins- do I replace, re-bush, shim? Are parts available?
I want to adjust my steering box but the instructions just confuse me. Can someone pit it in simple language please? The fluid level was low so I've topped it to the fill plug with EP90.

[Pete]

You need to work out where any slop is present, otherwise you run the risk of changing every part as a precaution - which is no bad thing if you have the finances.

[db]

All the ball joints etc are fine mate, it's only those two components. I've never experienced kingpin steering before so I'm not sure what's required.

[Pete]

They are not great, mate,

You can replace the bushes, ream them out to size, replace the pins if worn; and once you are Lubed up you are ready for action.

[db]

At least I can make some improvement! thanks

[pinoccio]

db if you attempt to adjust the grub screw on the steering box. and you do it with the wheels in the straight ahead position. be carefull as you will incure a tight left and right turning at the steering wheel. the grub screw is only there to take up the slightest of wear in the worm gear on the shaft within the steering box. and as this wear is most likely only on the shaft in the wheels straight ahead position. it mostly causes to much friction when it is adjusted. hence after adjustment if you are not carefull. a tight left and right feeling on the steering wheel . and as pete says. if you need new kingpins and bushes. you will also need a reamer to ream the new bushes after you have installed them. regards reggie

[db]

That's pretty much exactly what I've done!
How do I correctly adjust it? I've sort of turned it in and out and tried to leave it at the point it feels loosest.

This kingpin business, is it diy-able with a bit of engineering skill and common sense? It sounds suspiciously like a job for an expert...

[Dave999]

depends on age of box

you have either a side steer worm and sector box like a worm and peg set up from a vintage car

or

a side steer saginaw ballnut box

the former uses a worm screw with a thread that gets fatter at each end
like this
https://www.ebay.com/p/NOS-Mopar-1974-1 ... 1250865697

or saginaw style uses a ballnut and screw like this

https://www.summitracing.com/int/parts/ ... /overview/


however for your truck the thread of the screw goes the other way. the one in the picture is a 20:1 car set up

would need to know year and possibly have parts book to ID what you have.

both set ups need the sector shaft wedged into the teeth on the ballnut or worm to a specific extent.

the former type wears out in many ways that can't be repaired but by having fewer moving parts is more robust
the latter follows car boxes but uses the CAB Over set up in respect to the thread of the worm screw.

You can get 16:1 ratio for your truck if its the saginaw type but its a lot of internet and ebay searching.

Truck Ballnut in 16:1 ratio Note orientation of Thread

ballnut truck d100d2006065.jpg (23.98 KiB) Viewed 1929 times

Adjust the proper way
you set preload on the bearings that the worm screw turns in with the box off the car by adjusting how far the top of the box is screwed in
you twist the input splines using a torque wrench to identify correct pre load on the bearings

then you do up that grub screw to get a rise in turning force of X across the centre position of the box

as such its pointless doing all of that work unless you are rebuilding the box

lift front wheels
nip up the adjuster screw to make it stiff in the middle of the wheel travel (not loosest, stiff)
so you can feel that stiffness at the edge of the steering wheel
then knock it back a smidge so you can't feel it at the edge of the wheel but you can if you try to turn the wheel by its centre boss.

top up the box with red waterproof grease Mobil NLGI 2 i think

best mix is 50:50 that stuff and gear oil.

what year is your truck?

Car Ballnuts to illustrate thread direction and thread size

ball.jpg (100.63 KiB) Viewed 1929 times

[db]

It's a 1970 Dave. There's a pic at the start of the thread if that helps i.d. it?

I need to drain it then and fill up with your mixture instead, then re-adjust.
Thanks

[Blue]

Kingpins, jack the van up on the axle one side at a time, tyre needs to be about an inch off the ground. Large crowbar under the tyre, get some one to force the tyre up and down while you look to see how much lift you have in the kingpin, more than about 20 thou. needs looking at. To check for rock in the bushes the crowbar needs to be wedged into the wheel to rock it in and out while you look at the stub axle to see if it's rocking, any rock is too much.
I assume a kingpin kit is available, and it is something you can do. reaming the bushes to size is the tricky bit, tight but not too tight. I've changed shedloads over the years and I can tell you from experience that unless they've been regularly greased they'll be shot.

[db]

Thanks Blue, Nothing has been lubricated for YEARS!
I've not checked for vertical movement but there's definitely side play.
I'll ask around, someone must sell bits.

[Dave999]

A100 steering sin't easy to find documnted on the net

if its your box that is the problem

undoing the lock nut
undoing the 4 cover plate nuts and winding that cover off the adjuster screw should let you see what type of box it is

if it is a ballnut and screw box the ballnut looks like its made of brass. its isn't of course that would be silly but its passivated with a yellow green surface treatment

king pins.

whack a load of grease through them and they will be fine for a day or two

[db]

Dave I've followed your adjustment guide and while the steering seems ok-ish, the clunking that started after my first attempt (before I started this thread) has now got to the point where I'm fairly confident I've buggered the box.
I think it's time to find out if I can remove and dismantle a steering box. Wish me luck...

[db]

According to the book mine is the worm & sector type.
Also according to the book, I have remove the box and the whole damn column as one assembly and split it on the bench

[Dave999]

OK so you will probably need a new worm.
or the wheel like tooth thingy on your sector is loose

My steering box trials and tribulations indciated that there are loads of parts with loads of part numbers
but in many cases they are all the same and buying by eye from Ebay photos works out alright in the long run.
i only wnt off half cocked on a sector for a C body or truck thibnking it was a standard one.

i.e there will be bits that can do the job somewhere.

i had great luck with www.mmpar.com

they have so much obsolete stuff they don't know what to do with it

I phoned them, said what i wanted and they eventually found me NOS part from a late model. which was identical to my 1960s part numbered 1970s produced Australian bit

it wasn't cheap but it allowed me to build my box back to brand new. the only old stuff in it is the case and the adjuster screw.

however now i have built a box like mine i can spot all the bargains on ebay mis labled etc.

having it in bits clean and laid out in front of you just really helps

i came across so many of the worms when i was looking for ballnut parts but the job was made some much easier by having parts books to cross refernce between years and production countries

the worm box works with a sector shaft that has a rotating wheel for the teeth
whereas a ballnut and screw box works with a fixed tooth sector early had 5 tooth late had 3.

the case will either have drawn cup full compliment rollers for the sector or brass like bushes. a bushed box needs machining to fit rollers.

the hardest bit to get is the thrust bearings for the worm or ballnut/screw... pleanty with no cup availble but if you want a new beraing and cup it gets awkward.

Dave