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Dinnu

Member Since: 24 Dec 2019
Location: Lija
Posts: 3383

2012 Defender 90 Puma 2.2 CSW Santorini Black

Adwest 4 bolt steering box overhaul

I have opened up the 4 bolt steering box (Adwest) from my 1988 90 that I am slowly restoring.

I had exchanged it for a 6 bolt (gemmer) that I had spare quite a while back, because the original 4 bolt had sprung a leak from the sector shaft.

I thought that all I need to do is fit a kit and be done.... The good news is that the sector shaft is in perfect condition, no wear on the sealing area.

But I found a bit of wear on the sector shaft bushes. Mine are with bronze bushing not with needle bearings. I made a rough measurement of the wear and it is about 0.4mm of play in the sector shaft (I did not feel any wear before removing the seals).

So my question is : are these bushes available? Part numbers? If no, has anyone successfully made and replaced these bushes?

My other option is to mix an match parts from another box. I have another box, it is with needle bearings, but the sector shaft is bent, the follower wheel (the one that meshes on the worm) is dented, and I think there is a flat spot on the worm as well - so unsure if there is damage to the casing as well.

Other option keep the 6 bolt, as that had nothing wrong with it, but that box gets so much bad reviews!! 1988 90 Hard Top, 19J Diesel Turbo, Shire Blue - Restoration ongoing
2012 90 CSW, 2.2TDCI, Santorini Black

3rd Jul 2021 4:59pm

Dinnu

Member Since: 24 Dec 2019
Location: Lija
Posts: 3383

Googling and more googling, found needle bearing STC1055. Description is "Steering Box Needle Roller Bearing".
Wonder if this is for an Adwest, and if I can retrofit my box from bronze bushings to needle bearings. Do not know if the later boxes had case hardened sector shafts to handle the needle bearings. 1988 90 Hard Top, 19J Diesel Turbo, Shire Blue - Restoration ongoing
2012 90 CSW, 2.2TDCI, Santorini Black

3rd Jul 2021 5:41pm

Oldowner

Member Since: 26 Dec 2018
Location: South west
Posts: 615

2007 Defender 90 Puma 2.4 HT Aintree Green

The Adwest 4 bolt box uses 1x B2012 bearing in the top cover, and 1x B2016 and 1x B2020 on the lower section. Koyo are OEM for these (it was Torrington, but I think Koyo purchased Torrington)

I have rebuilt a number of 4 bolt boxes. The worms are often pitted either on the centre of the worm or on the bearing seats on each end - these are often overlooked as people only concentrate on the sector shaft seal wear.

3rd Jul 2021 6:41pm

Moneypit

Member Since: 27 Feb 2018
Location: North Yorkshire
Posts: 271

Just got a recon exchange 4 bolt unit yesterday, £195 inc delivery. Thought at that price it wasn't worth my time to mess around rebuilding it myself

Click image to enlarge

3rd Jul 2021 8:43pm

Oldowner

Member Since: 26 Dec 2018
Location: South west
Posts: 615

I wouldn’t mind stripping a new recon box and see what is changed-

Bearings are £30, sector shaft grind and rechrome seal lands £45, Corteco full seal kit £20, replacement worm £75, doesn’t leave much profit margin if done properly.

3rd Jul 2021 9:06pm

htb2

Member Since: 02 Nov 2018
Location: Carmarthenshire
Posts: 524

Is that not a contradiction? "a new recon box", we know what you mean.

3rd Jul 2021 9:36pm

Dinnu

Member Since: 24 Dec 2019
Location: Lija
Posts: 3383

Thank you oldowner. I will cross check the dimensions of those bearings, and see if they fit my box.
At the top, I have a bronze bush as well. I have not checked that for wear.
The worm seems to be in good condition. I have not taken that yet out, but its rotation feels smooth.
Yes, I’d rather rebuild mine, than getting an exchange unit, if that is possible. 1988 90 Hard Top, 19J Diesel Turbo, Shire Blue - Restoration ongoing
2012 90 CSW, 2.2TDCI, Santorini Black

3rd Jul 2021 10:38pm

Dinnu

Member Since: 24 Dec 2019
Location: Lija
Posts: 3383

I went on SimplyBearings website:

B2016 Imperial Drawn Cup Open End Type Full Complement Needle Roller Bearing 1-1/4x1-1/2x1 inch
B2020 Imperial Drawn Cup Open End Type Full Complement Needle Roller Bearing 1-1/4x1-1/2x1-1/4 inch
B2012 Imperial Drawn Cup Open End Type Full Complement Needle Roller Bearing 1-1/4x1-1/2x3/4 inch

They also have bronze bushing... which are also interesting me, as the original box was after all with bronze bushing. As said, I do not know if my sector shaft is hard enough for the roller bearings. After 30 years of use, the sector shaft is in perfect condition, and the wear is on the bronze bushings.

AI2024-16 Oil Filled Bronze Plain Bush 1-1/4x1-1/2x1 inch
AI2024-20 Oil Filled Bronze Plain Bush 1-1/4x1-1/2x1-1/4 inch
AI2024-12 Oil Filled Bronze Plain Bush 1-1/4x1-1/2x3/4 inch 1988 90 Hard Top, 19J Diesel Turbo, Shire Blue - Restoration ongoing
2012 90 CSW, 2.2TDCI, Santorini Black

4th Jul 2021 6:56am

Dinnu

Member Since: 24 Dec 2019
Location: Lija
Posts: 3383

Just an update.
I made a mandrel so as to be able to push the lower bushes out of the casing. These are the Permaglide type bushes.

Unfortunately my vernier calipers are not able to reach inside the bore to measure what the OD of the bushes should be, but I suspect that the OD should be 1-13/32 - at least that is the only dimension I could find with an ID of 1-1/4.

Click image to enlarge 1988 90 Hard Top, 19J Diesel Turbo, Shire Blue - Restoration ongoing
2012 90 CSW, 2.2TDCI, Santorini Black

6th Jul 2021 6:22am

blackwolf

Member Since: 03 Nov 2009
Location: South West England
Posts: 17280

2007 Defender 110 Puma 2.4 DCPU Stornoway Grey

An illustrated thread on your steering box overhaul would be very welcome!

6th Jul 2021 8:49am

Dinnu

Member Since: 24 Dec 2019
Location: Lija
Posts: 3383

Sure Blackwolf, will try to do that. Anything in particular that would like to see documented?
I think the only difference between my box and the later ones are the bushes instead of the needle rollers.
For reference, date code and serial number of the box is 8-A-1646 1988 90 Hard Top, 19J Diesel Turbo, Shire Blue - Restoration ongoing
2012 90 CSW, 2.2TDCI, Santorini Black

6th Jul 2021 9:54am

blackwolf

Member Since: 03 Nov 2009
Location: South West England
Posts: 17280

Nothing special, but I feel that it is an interesting project and a steering box overhaul is something I don't remember seeing covered by a thread on here before. I am sure I'm not the only person who'd be interested, if it's not too much trouble.

6th Jul 2021 10:40am

Bluest

Member Since: 23 Apr 2016
Location: Lancashire
Posts: 4183

2007 Defender 110 Puma 2.4 XS CSW Java Black

I would be interested too, mine is currently leaking. 2007 110 TDCi Station Wagon XS

6th Jul 2021 11:00am

hank

Member Since: 12 Sep 2016
Location: South Wales
Posts: 2286

Me too. After researching rebuilds I saw some reports of poor quality rebuilds offered by exchange companies so I went for a 'good used' box sourced online which when fitted turned out to be a not so good used box. So would be interested to rebuild my own! > 110 XS Double Cab

6th Jul 2021 11:27am

Dinnu

Member Since: 24 Dec 2019
Location: Lija
Posts: 3383

If it is just leaking, then this is what I found:

1. To replace the bottom seal, it is better to remove the sector shaft, install the bottom seals, and then re install the sector shaft - care not to damage the seals with the splines, even through there is very good guiding by the 2 lower bearings to center the sector shaft while installing. The splines are smaller than the sector shaft, but it could me that the seal gets scratched by the splines. A bit of tape on the splines would prevent this.
Also it is far easier to remove the bottom seals after removing the sector shaft.
And it is also easier to inspect the sealing surface on the sector shaft this way.

2. To replace the input shaft seals, I read and saw You tube videos about drilling 2 small holes in the seal and using a self tapper to extract. I think this is too risky. If the drill bit 'walks' and damage either the worm shaft or the housing, then you are in for more expensive bills. To remove the input shaft seal, I used compressed air in one of the ports. This pushed it out very easily - cover the box with a plastic bag unless you want red walls. Also to keep the original seals orientation, I put a self gripper tool on the input shaft to keep the seals on the shaft. Of course you have to do this before dismantling anything otherwise the air would take the easy way out.

3. The sector shaft can only be removed and installed when the steering angle is at a specific angle. It should be practically all the way steered to the right. What I noted is that the flat spot on the input shaft where the bolt for the UJ pass through should be facing upwards (important to know this when re installing the sector shaft). If nothing else has been disturbed, when installing the sector shaft, it should go in almost exactly the same angle you pulled it out. While installing, you should look at the gear engagement with the actuator rack. Just use a flash light and can see from the top. Wiggle a bit the sector shaft until the teeth mesh and the sector shaft can drop till the follower wheel touch the worm.

Additional Note to remove the sector shaft, after full right turn, just undo the top 4 bolts, then release the center locking nut and then gently tap at the bottom of the sector shaft to push the top cover out. For installation you will need to separate the sector shaft from the top cover. This is done by winding (clockwise direction) the adjuster nut.

4. For adjusting the backlash between sector shaft follower wheel and worm wheel, only adjust when the steering is dead straight position. You will always get backlash when away from dead center. If you try to adjust away from dead center, then it will be too tight at center.

But I will add a better instruction when I re assemble mine. But make sure that you have a bit of spare ATF fluid so you can top up yours until I can re put mine together and document it.

1988 90 Hard Top, 19J Diesel Turbo, Shire Blue - Restoration ongoing
2012 90 CSW, 2.2TDCI, Santorini Black

6th Jul 2021 12:30pm

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