Impreza steering rack mod

[SteveSPG]

WinstonWolf said:

I'm just wondering if it's possible to stick with the original "TVR" UJ and shaft if the pinion was splined in a machine shop. As I've not got a rack I don't know the OD of the output shaft.

thats what i tried with the pinion, and i think it was too small. you could try the uj used at the steering column end which is bigger.....and may well have enough meat left on the pinion.....but i never tried


.

[Chuffmeister]

My Scooby rack arrived today (with bushes and Scooby TRE's). Ford Ka UJ ordered yesterday.

In total the rack is about 118.5cm from end to end without the TRE's attached.
The length of the pinion is 7.5cm/ diameter 18mm
TRE screw thread is 4.85cm
length of the shaft from boot to end of shaft about 21cm

How does this compare with yours Peter?

Edited by Chuffmeister on Friday 1st May 15:41

[WinstonWolf]

Need to measure the OD of the spline on the TVR rack, I've just tried in situ and I reckon it's circa 20mm making my idea a non-starter.

[Chuffmeister]

After reading the above and speaking to Phazed, I may just take the pinion and Ka UJ down to my fabricator and pay them to hex-off the pinion and properly fit the UJ to it. How long is the TVR pinion?

The other thing I need to tackle is the copper pipe. Is this a difficult job?

[phazed]

Garage time in the morning, will check then.

[Pupp]

The pinion spline size on PAS cars is 3/4 and the intermediate shaft spline dia is 9/16 according to my recent research to overcome the lack of availability of the oem 115mm top joints on facelift transition cars (see separate thread). Keep this one updated please, especially with part nos.

[phazed]

Chuffmeister said:

My Scooby rack arrived today (with bushes and Scooby TRE's). Ford Ka UJ ordered yesterday.

In total the rack is about 118.5cm from end to end without the TRE's attached.
The length of the pinion is 7.5cm/ diameter 18mm
TRE screw thread is 4.85cm
length of the shaft from boot to end of shaft about 21cm

How does this compare with yours Peter?

Edited by Chuffmeister on Friday 1st May 15:41

Pinion shaft length 82mm
17.2mm dia
Rack bar length, 600mm, (same as TVR one)

Use your TVR track rods and ends.

[phazed]

Found this, like Ka.

http://www.carbuildersolutions.com/uk/steering-uni...

[Rowge]

sorry guys been busy on other things, I found the UJ from car builders was better, see page 6, with regard to the pinion, I cut mine using an angle grinder you must cut slowly leaving the pin intact you will also notice the intact small diameter, the second photo shows the removed original Scooby spline and the diameter that fits over this small diameter, I used the small remaining diameter to mount a 17mm AF nut using a g clamp to hold the nut in place, this then allowed me to file the 17mm hezagon on the pinion using the nut as a guide.


Hope this helps/makes sense, will try to put the parts list together this week
Cheers Steve

[Rowge]

A better photo showing the internal diameter from the removed end of pinion

[Chuffmeister]

Cheers Steve. Phazed has done an interesting alternative, which looks pretty sgood and uses the hexagon end of the the Ka UJ on the pinion end. I guess once this is fitted, it is a case of fitting the rack and measuing the length between the Ka UJ and the TVR UJ in the wheel arch to determine the length of the double ended splined shaft you need?

Where did you get your spacers from for the rack mounts?

Cheers
Chuffy

[Rowge]

Spacers from eBay, tried 25mm then 20, which started to bend the 5 mm plate, finally used 22mm made up of 20mm plus a thick washer, I filed the 17mm hezagon onto the Scooby pinion, until the KA UJ was a snug fit, imo the car builder solutions UJ was better due to the 8 mm clamp bolt locking the 9/16 splined shaft on the other end of UJ, also push the HEx on the UJ as far as possible on to the rack pinion hezagon before you file the slot that the 8mm clamp bolt locates into, bit hard to describe, hope this makes sense

[phillpot]

Chuffmeister said:

Where did you get your spacers from for the rack mounts?

Looks like this guy will make any size you want, in a choice of metals.

[phazed]

Bit of work yesterday.

Scooby rack showing pinion end.



Pinion shaft removed.



Removed section that needs to be rebolted 180 degrees out.



Splined end of shaft cut off and remainder ground and draw filed to a hexagon.



Ford Ka UJ drilled and second pinch bolt fitted and clamped onto modified pinion shaft.



More work later this week.

[Sardonicus]

Thats a secure solution Peter

[Rowge]

Looking good, couple of things, make sure you replace the round shim that positions the pinion to the rack, mine was 4 shims of 0.025" so 0.010" in total or 0.25mm in new money, also during the fitting you may have to move the KA UJ towards the rack to increase the clearance to chassis, I used a titanium nut and bolt as the head size was smaller, I see you have added another locking bolt, this may make things worse with regard to clearance, or may be better as you have mounted yours further from the rack than mine. Anyway check for clearance before making the 9/16 shaft between KA UJ and column UJ, couple more pics of mine

[phazed]

Will check,...........any info is good info

[Rowge]

Better photo of UJ fitted and clearance nut to chassis upright

[phazed]

I remember with my old car the clearance was mega marginal at the chassis.

[Chuffmeister]

Worth a half-width or thinner nut? That looks very close. I guess you could have the nut migged onto the bolt for security? My concern would be if that rack shifts inadvertently, it would cause the chassis to foul the steering potentially jamming it in any given direction.

Either that, or is it with having two shafts instead of bolts (or removing the bolt head/ protruding bolt) on each side of the pinion UJ, then having them welded into the UJ. A little inconvenient when you want to remove it, but they could always be drilled out if necessary. It would increase clearance too?

Bad idea?

Edited by Chuffmeister on Monday 4th May 21:43