Steering Rack Bushes - Nuts and Bolts

[airheadboxer]

I’ve just replaced the steering rack bushes on my van and thought I’d share some observations about the nuts & bolts.
 
On my van, as well as dabs of yellow paint on some of the heads, the 4 bolts were marked as high tensile grade 10.9 items (i.e. a higher tensile rating than 8.8 grade) and the locknuts were the domed or tapered type (non-nylon/Nylock insert type) and presumably grade 10 items as well.
 
LOCK NUTS
I can't comment on the use of the Nylock type in either grade 8 or 10 in this application. All I can say is that the domed type I took off seemed to offer way, way more resistance to being undone once loosened than any Nylock nut I’ve undone in the past. Just a personal thing.
 
If you want to stick to the 10.9 domed or tapered self locking nuts then not all the VW after-market suppliers seemed to offer them and even then you may have to search for the nut as a sundry or general item rather than against the model/steering menus.
 
Here’s  a few examples I did find of grade 10 lock nuts (maybe worth checking the style of locknut on your van beforehand as it may have changed slightly in 1988?) 
P&P and minimum order values can be a problem in some cases though:
 
Brickworks  show the same domed style as I took off and are rated10.9. Cheap as chips:-
https://www.brickwerks.co.uk/t3-parts/s ... flake.html
 
Heritage – shown as “Genuine VW”. These are a non-domed shouldered type, look to be stamped with a “10” to indicate grade 10, are shown in a steering rack diagram as specifically for this application, are  titled as a “ Steering Rack Clamp Nut M8”and the “Fits Vehicles” table shows “ Product Vehicle Years: T25/T3 1988 – 1992” but again check that for yourself:-
https://www.heritagepartscentre.com/uk/ ... ut-m8.html
 
Or eBay – these domed ones may be the cheapest option if you include P&P and only want 4 nuts (£2.01 inc P&P for a set of 4) – description stated 10.9 grade at the time:-
https://www.ebay.co.uk/itm/371139486328 ... SwnDZUDxGT
 
Heritage again - although this link shows the same domed style as mine, it doesn’t state 10.9. In its favour though is that the Fitting Info does show “steering rack to chassis (T25) Nut” but do check this yourself in case this changes :-
https://www.heritagepartscentre.com/uk/ ... ut-m8.html
 
BOLTS / BOLT SET
The bolts on my van are 60mm long, and this is what I found for anyone who might need them.
 
GRADE 10.9 -. At the time I couldn’t find any of the usual VW suppliers I use offering the 10.9 grade bolts.
Nor could I find any UK based eBay seller offering just the correct length 10.9 bolt on its own at the time.

If you want to stay faithful to the 10.9 grade, and you’re happy to buy a complete nut and bolt set (including an un-needed washer), then this eBay seller was the best I came across as they’ve taken the time to show the nut and bolt dimensions in detail (pure drawing office porn!) and were showing 100% on their feedback.
The bolt head is slightly different (it’s flanged, but that’s not a problem is it?) but the unthreaded/threaded lengths are the same as mine (38mm unthreaded / 22mm threaded = 60mm overall) and the lock nut is the same as mine. 
£8.95 inc P&P for a set of 4 nuts/bolts/washers which looked pretty reasonable to me:-
 
https://www.ebay.co.uk/itm/184525426550 ... SwVH1fppA5
 
 GRADE 8.8 - If you are happy with Grade 8.8 bolts then this is probably the best I’ve found as it identified them as a “Steering Rack Mounting Bolt”
 
https://www.brickwerks.co.uk/t3-parts/s ... flake.html
 
STAINLESS STEEL - I found a VW aftermarket supplier offering a 65mm long stainless steel bolt in their steering section for this application – it linked to the fixing bolt on a diagram of the steering box components so it is clearly intended for this purpose. The thought of using a stainless bolt in this situation doesn’t do anything for me without knowing a bit more about it (e.g. grade). I’ve always been under the impression it was too “brittle” (don’t know why, maybe depends on the grade??), but that said, stainless is used in yacht rigging which can also be under huge stress.
And in any case it can polish up nicely if bling is your thing.
Check out item 4 on the drawing in this link:
 
https://www.customandcommercial.com/vw- ... ing_parts/
 
E D I T - added this re torque values:

TORQUE VALUES:
 The Haynes manual shows 25Nm for the steering rack bolts.

The reason I mention this is that I was surprised at how easy it was to get to the 25Nm torque value doing the nuts up compared to how much effort I had to put into getting them to release even though the thread under the nuts was in perfect condition, they weren’t rusted in and I’d used lashings of Plusgas over a couple of days just in case. Prior to bolting up I had wiped the threads of the bolt with an oily rag, but don’t consider that any more than a “normal protective oil film” (see reference t that in the link below).

The link below is to the Norbar Torque Tools site guide shows the recommended maximum torque values for various bolts including Metric course threads (last table).

https://www.norbar.com/Portals/0/downlo ... eGuide.pdf

You’ll see that for 10.9 grade bolts the recommended maximum torque is 35.3Nm so the 25Nm as quoted in Haynes is well within that, but it does make me wonder if the factory used a torque setting closer to the 35.3Nm value on 10.9 bolts and hence the amount of effort I had to use to undo the original bolts. Just a thought.

BUT if you are using 8.8 grade bolts the maximum recommended torque value shown in the table is 25.5Nm – so no room for adding a bit to the 25Nm value for “safety’s sake”.

End of E D I T

CALCULATION OF THREAD LENGTHS - As a matter of interest I found this – taken from here:
https://www.andrewsfasteners.uk/standar ... ers-bolts/

“Typical, unless specified in a product standard, dimensions for thread lengths (b) is calculated as follow:
Where l is length of the bolt and b is the threaded part of the bolt (E D I T: and d is the diameter of the bolt):
    for l <= 125 mm: b = 2d + 6mm
    for I >125 mm but <= 200 mm: b = 2d + 12mm
    for l > 200mm: b = 2d + 25mm
For bolt, where lengths l <= 0.5d the bolt should be fully threaded.”

Example for an M8 diameter bolt and a length of 60mm, the thread length is:
 2d + 6 = 22mm thread length,
So the plain portion will be 60 - 22 = 38mm
 
OR, if you prefer it in table form for Imperial and Metric bolts:
https://www.asmc.net/bolt-screw-thread-lengths/
 
I’m not an engineering expert and this is just my experience which may be of use to anyone making their decisions. Your choice, your responsibility.

I hope this helps and brings some of the info dotted about into one posting.

[slowcoach]

Excellent post

[TONYT25T25]

Did you take the rack off, or replace in situ, heard this can be done, also what bushes did you use as replacements, Poly ??

[R0B]

Thanks for taking the time to post this up.

[airheadboxer]

slowcoach & ROB - thanks for the feedback 

TONYT25T25 - I used the in-situ remove-the-bolts-and-lower/drop-the-rack method, but I took the old bushes out slightly differently and I will try to add that as a seperate post tomorrow.  The rack wasn't keen to move away from the mounting so it could be lowered over the mounting lip just below it, but it did go in the end. If I had to do it again I'd raise the front on stands for a bit more room and the option of turning the wheels side to side for a bit more wriggle on the rack. Maybe I should have done that anyway

Yep, went the polybush route. 2 reasons - money left over from the COVID lockdown (wife couldn't go out and spend it) and ease of insertion. I can't be sure if using the original type bushes would have had the same affect/effect (can never remember which way round this should be) but now, when I turn the wheel (non power assisted), its not like winding up a spring before something happens, its much more direct. You don't realise what you are putting up with until it changes. That said, in todays high winds there was still some wander, not as much though.
Hope that helps.

[TONYT25T25]

Thanks for previous information regarding bolts and this feedback.  Always looking for an easier way to solve an issue.  My steering rack bushes were picked up as having slight play a few MOT s back as an advisory but not since, so have not got around to changing them yet.  Seen a few You Tube and other explanations on how to change them and would probably go the poly way if I did.  I know what you mean about side winds there was a certain part of the M27 I would drive along and dread it, constantly fighting to keep in a straight line, but did not realise this may have been attributed to steering rack bushes.

[airheadboxer]

I forgot to add something about torque values.  I've added this to the original post above.

The Haynes manual shows 25Nm for the steering rack bolts.

The reason I mention this is that I was surprised at how easy it was to get to the 25Nm torque doing the nuts up compared to how much effort I had to put into getting them to release even though the thread under the nuts was in perfect condition, they weren’t rusted in and I’d used lashings of Plusgas over a couple of days just in case. Prior to bolting up I had wiped the threads of the bolt with an oily rag, but don’t consider that any more than a “normal protective oil film” (see reference to that in the link below).

The link below is to the Norbar Torque Tools site guide shows the recommended maximum torque values for various bolts including Metric course threads (last table).

https://www.norbar.com/Portals/0/downlo ... eGuide.pdf

You’ll see that for 10.9 grade bolts the recommended maximum torque is 35.3Nm so the 25Nm as quoted in Haynes is well within that, but it does make me wonder if the factory used a torque setting closer to the 35.3Nm value on 10.9 bolts and hence the amount of effort I had to use to undo the original bolts. Just a thought.

BUT if you are using 8.8 grade bolts the maximum recommended torque value shown in the table is 25.5Nm – so no room for adding a bit to the 25Nm value for “safety’s sake”.

So there you go, probably another bit of useless information.

[tobydog]

Prior to bolting up I had wiped the threads of the bolt with an oily rag, but don’t consider that any more than a “normal protective oil film” (see reference to that in the link below).

It's probably the oil/plusgas that you applied that made it easier to torque them up

I bought my first Norbar torque wrench in 1975 after snapping an FS1E M6 cylinder head stud (10Nm from memory) heartbreaking at the time   Still have it and use it

In a previous working life in toolmaking, torque wrenches were never used, it was all down to feel. The company that I worked for however only used top quality fasteners, once you get over M8/10 you have to be a major numbskull to over tighten/break them

Always torque wheel nuts up...