Board logo

Steering rack shortening??
andya - 26/10/02 at 06:41 PM

Hi All
Ive built my chassis 4 inches wider(basically 4 inches added down the middle) and made my wishbones a little longer so the front track is the same as the Sierra rear end.
I have a Sierra non power steering rack but the steering input shaft is just outside the chassis rail.
I have heard of people shortening racks and lengthening the arms.

My question is: How??

My other Question is: If I used an escort rack I guess the input shaft would probably be inside the chassis rail but could I extend the arms that much?

Cheers
Andy


interestedparty - 26/10/02 at 06:47 PM

I know MK shorten racks and provide longer track rods for their Indy, and would, I'm sure, be able to help you

John


philgregson - 28/10/02 at 01:00 PM

This problem is more than one of squeezing the rack into the chassis.

The most important thing to consider is that the point at which the steering arms themselves pivot at the rack (when traveling straight ahead) lines up with the line joining the upper and lower wishbone mounts.

If you don't you will suffer (to a greater or lesser extent depending on how far out you are) from bump steer.

However I'm not an expert on this by any means so I would suggest that it is worth asking someone else if you need clarification.

Cheers,

Phil


Dunc - 28/10/02 at 03:51 PM

I agree with you phil but there should also be an imaginary line joining up all the ball joints at the wheel end too for it to be true and I can confirm that when using the sierra uprights this is no the case.


interestedparty - 28/10/02 at 04:39 PM

I reckon the thing to do is to be aware of the bump steer issue, try to reduce it as much as possible, then stop worrying about it

John


James - 28/10/02 at 05:07 PM

Instead of having to chop and re-join a Sierra rack, can you not just extend the arms of an escort one?

Cheers,

James


John - 29/10/02 at 01:03 AM

James,

I am also intending to use a Sierra rack with a +4in chassis. I would prefer to use escort rack but I imagined it was just as difficult to get hold of one as it is to get hold of an escort donor. Or will a Mk3 rack work.

John.


wicket - 29/10/02 at 12:55 PM

I got a mk2 recon rack from our local motorfactors, £23-00 + £20-00 deposit returnable when I took a knackered rack, any old rack, back to them !


Simon - 29/10/02 at 04:17 PM

Andy,

I built my chassis four inches wider (like you - just added four inches all the way down the middle).

See

http://www.locostbuilders.co.uk/photos/cgi-bin/showpic.pl?10000022.jpg

for a pic of my rack to give you some idea how much shorter it is.

I have access to AC/DC welder, so cut and welded, as for internal, I don't have access to lathe to drill, and rethread, I cut the threaded bit (that t c a fits into) off and welded further in!!! TCA's extended too.

However, as I mentioned somewhere else on this forum, I have no faith in it. I was just to give me an idea on dimensions and to allow me to move the car around. When needed, I'll be commissioning someone such as Hawke Cars (cos they're local) to do the job properly.

ATB

Simon


Stu16v - 29/10/02 at 06:04 PM

Mk2 Escort steering racks are fairly plentiful, still being made new as demand is high. Mk3 one wont work because it is mounted at the back of the wheels on the donor so when it is fitted you turn the steering wheel left and the car goes right! (my mate actually did this...how we laughed). Extensions can be made to extend the arms, but the inner joints are unlikely to be in the ideal position to minimise bump steer, unless your chassis is the standard width at the front.

[Edited on 29/10/02 by Stu16v]