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Sierra steering column parts
DH2 - 5/6/13 at 07:49 AM

I've wandered down the Sierra upper steering column route on my rebuild. Now I'm looking at how to mount it, I don't quite understand how it is all supposed to work. Does anyone have any idea or photo of how it is all mounted in the Sierra?

The lower collapsible/slider mech is fairly self explanatory, but the upper 'collar' part I've not quite got... What is the purpose of the spring? The two bearings in the collar are loose without the star washer bits, but they don't fit right into the bearings? If it is rigidly mounted by the 'ears' on the collar, what is the purpose of the (apparently) collapsible section?




DH2

adithorp - 5/6/13 at 08:30 AM

The spring pressure at the bottom end and the plastic ring (indicator canceller) act to press the "star washer bits" into the bearing and takes out the play. Don't discard the plastic ring even if you're not using the indicator stalks or you'll have a load of play in the column (plenty have made that mistake).

The collapsable section in the shaft (bottom triangular bit slides in/out) allows the column to collapse if the rack is pushed backwards (in a front end collition). The corrugated section in the housing and the sliding section in the shaft, allows the steering wheel to collapse should the driver hit it (if they're dumb enough not to wear a belt/harness or the whole scuttle is pushed backinto the driver)

DH2 - 5/6/13 at 09:52 AM

quote:
Originally posted by adithorp
The spring pressure at the bottom end and the plastic ring (indicator canceller) act to press the "star washer bits" into the bearing and takes out the play. Don't discard the plastic ring even if you're not using the indicator stalks or you'll have a load of play in the column (plenty have made that mistake).


OK, that's what I was guessing - so the steering wheel/boss applies some load to the whole lot against the spring. In fact, that 'preload' must go all the way to the rack? That should make it fun using a QR wheel without a boss.

quote:
Originally posted by adithorp
The collapsable section in the shaft (bottom triangular bit slides in/out) allows the column to collapse if the rack is pushed backwards (in a front end collition).


Indeed. So where abouts on the triangular shaft does the plastic bush/bearing normally sit? Must be a fair way up to allow the UJ attached to the end of it to move up towards it in the event of it collapsing? Whereas I'm looking at the lower bearing housing being close to the UJ, which would mean not alot of collapsibility anyway.

quote:
Originally posted by adithorp
The corrugated section in the housing and the sliding section in the shaft, allows the steering wheel to collapse should the driver hit it (if they're dumb enough not to wear a belt/harness or the whole scuttle is pushed backinto the driver)


Hmmm, I reckon you've impaled yourself on the shaft before that collapses!

I'm wondering if this column is just making me work for not alot of gain - what other options are out there that people use?

Thanks for your reply.

DH2

[Edited on 5/6/13 by DH2]

adithorp - 5/6/13 at 10:36 AM

It does rely on the wheel pushing down on the plastic bush. Don't know how they get around that with a QR wheel.

I'd say the bottom bush/bearing sits about a couple of inches above the extention clamp. If your extention shaftand U/J's are offset then the bottom end doesn't have to be collapsable anyway.

The design of the wheel and centre pad prevent the shaft impaling you. It was crash tested by Ford afterall. It has to be ridgid enough in normal usage remember. 80kg of driver however hitting it at 30mph will collapse it.

The point of using the Seirra column and wheel is that it's from a "type approved" car so passes IVA requirements. Use one of your own design or an aftermarket wheel/pad and it comes down to the testers opinion of whether it meets the requirements.

DH2 - 5/6/13 at 11:09 AM

I am rebuilding, so no IVA required, but still would prefer not be impaled should something unfortunate happen!

Thanks for sharing your knowledge.

DH2