Steering racks...

[sandman]

Does anyone know if there's a difference between Mk1 and Mk2+ racks (other than the ratio and pinion arrangement)

Why should one not fit Mk1 steering arms to a Mk2 car?

[mk1rally]

This is how I understand it.

The mk1 arm is of a differnt angle than the later ones. The Mk1 rack doesn't have as much travel (left to right, less turns) than the later one's.

If you fit a later rack to earlier arms, the ratio is such that there is a differnce in angle between the left and right wheel, obviously worse at full lock and this causes the car to be out of geometry whilst turning. This obviously affects the handling/road holding (apparently its like having loads of understeer at the front)

If you fit a matched set (mk1 rack and arms or later set and arms) this is not a problem. The later rack and arms give a smaller turning circle.

So idealy, a MK2 or later rack is the one you want for a early car and I believe all the arms after this point were the same angle. With this you get the better turning circle.

[1071 S]

That's pretty much it. Mk I rack with Mk I steering arms and VV. Easily done - especially in the UK where there are stacks of each...
MkII arms are easily recognised by the little "ears" (which Mk I arms don't have cast into the end where the track rods bolt......

Matched sets can be fitted to any car.

Cheers, Ian

Unmatched sets work as well - but maybe only for insensitive drivers posting.php?mode=reply&f=3&t=2788&sid=9 ... 46e659f316#

[Vegard]

Does anyone know if there's a difference between Mk1 and Mk2+ racks (other than the ratio and pinion arrangement)

Why should one not fit Mk1 steering arms to a Mk2 car?

I think you're both mistaken.
The ratio of the rack should be of no consequence. The only difference that could affect this cocked up Ackerman angle is the width of the rack between the inner joints. This is the ONLY thing that could possibly affect this.

Following your logics, a quickrack would cock it all up. It doesn't.

[andy1071]

The position of the outer ball joints -the track rod ends- will also affect the Ackermann.

I believe that the track rod arms are shorter on Mk2 racks to suit the bent steering arms. So as everyone says, they should all be changed together as a set.

[mk1rally]

Not sure where the quick rack comment comes into it, surely it has the same travel, but just takes less turns of the wheel to cover it?

TBH, never really found a use for a quick rack on my mini but that is going off the subject.

[sandman]

I have measured the total length of both mk1, mk2 and a quick rack.... all are more or less the same.

The angle of the Mk2 are less that that of the Mk1's (meaning the are straighter than the Mk1's.. in both planes)

What I want to do is fit Mk2 arms to a my Mk1-rack equipped racecar - to see if the change in Ackerman angle will help with the handling...
Is this at all possible or are there some unforseen problems I fail to see?

I assume the [initial] change in steering arms was to help with the smaller turn circle... (preventing the inner wheel from turning in too much)... or was there other reasons?

[andy1071]

The David Vizard trick (How to modify your Mini) was to weld nuts to the track rod ends when you fit Mk2 steering arms with Mk1 rack, so there is not a lot of difference in length/position.

The ERA Minis used a different steering arm that changed the height of the track rod end, which tends to have a greater effect on the handling. If memory serves (HA! ) it's about 10mm, but can't remember whether it's up or down. I'm sure someone can confirm this?

[sandman]

I have measured the distance between the outed edge of the inned tube on my rack and on two MK2 racks... they are both 63cm.. (My rack is installed inthe car so measuring is trick... so might not be 101% accurate.)

This means they either the inner width is the same on both types or I actuallu got a Mk2 rack installed in my car...

Does anyone have a Mk1 rack at hand and can confirm the distance between the outer edges of the inner joints (i.e side to side) ?

Cheers,

[Sean1380]

I had them mixed up on my 1978 1100 DL (SA model) they came std with a Mk1 rack, and when i put the S disks on i never even thought about the steering arms, and ended up running out of adjustment when i tried to get the wheel alighment right, ended up getting longer sprite type rod ends.

More detials and pics of the difference here.................

http://www.atfreeforum.com/kznmini/view ... um=kznmini

[sandman]

Had a look into the Vizard book yesterday and he wrote that you should not mix'em up.. He mentions that when the Mk2 was introduced the number of teeth in the rack was changed, as well as increasing the toothed area on the rack itself - effectively increasing the range of motion

The part regarding welding nuts to the rod ends was mention in releation to lowered cars....

I'll leave my Mk1-arms on for now.. until I can find the time to do a back-to-back test.

[Sean1380]

This is why a Mk1 rack runs out of adjustment when fitted with Mk2 arms...........

[max-o-matic]

Can anyone confirm that the thicker "cooper S" type arms need to go with a mk2 steering rack? or are there different types of thick cooper s arms as well?
thanks,
Max

[1071 S]

I was once told to avoid the S type arms - if you hit something you want the arm to bend rather than something harder to get at/replace....

The geometry is the same..

Cheers, Ian

[max-o-matic]

aren't they cast though? I thought they'd break before they'd bend... in any case, this is for a road car, not sure I could find a big enough pot-hole to make that kind of damage...
the reason I ask is because I have a mk1 but planning on upgrading my brake system with a proper cooper s set which comes with those thinker arms.. should I change my steering rack or can I keep the one I have?

[Tim]

I broke an S arm on my old Moke once, it was easy enough to do, but the rest of the car was scrap too.

Tim