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Compact rack and pinion for A7 Special
theprisioner - 12/2/19 at 02:23 PM

I am thinking of fitting a rack and pinion steering to my 1937 Austin seven Special.

It has a lot of non standard features so I am not destroying a potential concourse car.

Requirements

* Should ideally be designed for a car. There are lots of carting type racks around but not sure they are strong enough.

* The total width of the rack is paramout part of spec as there is little room for this mod.

* Ideally it should be a one sided rack as there is little room under engine and the rack needs to mount to one side.

Any Ideas welcome

watsonpj - 12/2/19 at 02:36 PM

SEICENTO is compact and one sided I think that's what they used in the Furore

Theshed - 12/2/19 at 03:02 PM

Its an fairly easy job to chop one to the right length....

jps - 12/2/19 at 04:16 PM

quote:
Originally posted by theprisioner
* The total width of the rack is paramout part of spec as there is little room for this mod.


What width are you aiming for? BMC mini racks must be fairly narrow (and would maintain a marque link!)?

nick205 - 12/2/19 at 04:44 PM

Might be a daft question, but by "one sided" do you mean the pinion should be offset to one side rather than in the centre?

theprisioner - 12/2/19 at 06:10 PM

Basically the steering has a link rod side to side retaining that may have some advantages. If I then link the rack into that with a ball joint it becomes a minimalist design. I don't have room for a double sided rack so compactness is desirable.

minitici - 12/2/19 at 06:29 PM

If it is just a worn out A7 steering box you have - why not go for a VW 1302 steering box like Paul Neil-MacLachlan fitted to his special?
(apart from the cost that is!)
If I ever get around to improving the Hamblin - that is what I will use.

MikeRJ - 12/2/19 at 11:31 PM

If is still has the original beam front axle and you mount the rack on the chassis you are inviting a bump steer problem. Mounting the rack to the beam would fix that, but then you need a steering column that can accommodate the front axle movement.

theprisioner - 12/2/19 at 11:35 PM

It has the Bowden independent suspension

theprisioner - 12/2/19 at 11:43 PM

this is interesting if expensive

https://www.unisteer.com/1928-1940- street-rods/search-by-vehicle/ford/1928-1940-street-rods/cross-steers.html

MikeRJ - 13/2/19 at 02:46 PM

quote:
Originally posted by theprisioner
It has the Bowden independent suspension


Is that the system with the twin transverse leaf springs? If so you probably already some amount of bump steer, fitting a conventional rack could actually improve this if you get the geometry correct.

If there simply isn't room, then you could modify a standard rack to make it single ended, in much the same way people cut down Sierra racks for Locosts etc. The toothed parts of the rack is relatively short compared to the total length.

There are also racks that mount the track rods in the center of the rack rather than the ends, the Mk2 Astra and 7th Generation Honda Civic spring to mind.

theprisioner - 13/2/19 at 04:28 PM

Very good response I do not want to pay $500 for a US rack