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  #1  
Old April 21st 2003, 16:00
Stuart Stuart is offline
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rack and pinion

Is there a method to limit the steering of a rack and pinion on a 1303 super 1979 vert?? After bolting the suspension of a 1986 Porsche 944T the tyres are rubbing the inner body on full steering lock.
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Old April 23rd 2003, 15:16
Superman
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Unfortunately the answer is no.
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Old April 23rd 2003, 16:26
Stuart Stuart is offline
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Lightbulb

Is there a solution for this problem??? any help welcome!!!!
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Old April 24th 2003, 04:49
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Chris Percival Chris Percival is offline
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Nothing is imposable. You will just have to weld up some stops, maybe near the nuckles at each end of the rack?
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Old April 24th 2003, 04:50
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Maybe you could utilise an idler from a steering box car?
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Old April 24th 2003, 08:27
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Hi

Is it only on one side, if it is try centrering the rack. If its on both sides you could maybe fit a bolt on the end cap of the rack and have the rack touch it on lock.

Steve C
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Old April 24th 2003, 14:53
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Lightbulb Not intended as a how to do it but how I did it...

Here's a suggestion, maybe not quite superman's idea of GL.com but here's two ways:

No measurements to be taken as gospel, take your own.

I pressed two 6mm*35mm dowels 9mm deep into the rack itself. An interference fit is essential, a 'hammer in' fit is too tight, (unnecessary stress). Match a reamer to the diameter of the dowel. Loctite may be a good idea. Silver solder being my choice (heat necessary being insufficient to have an effect on the steel and about 80.000psi, much stronger than the rack. The grease is likely to ignite. ) A quality branded chrome vanadium screwdriver has just the material properties required for the dowels, a far better choice than mild steel.

The depth and surface finish of the holes is critical, to support the side-loading exerted by the stop during a shock-loading of the wheel, when driving on or near full lock. And not too deep to keep the area in check, as stress is load over area. The new effective area of the rack at the hole centre gives rise to a tensile strength well within tolerance. A good surface finish is essential to keep any stress concentration factor to a minimun. This requires an extreme level of caution and precision, as the hole can only be drilled ONCE.

My tyres are 215/40ZR17 on 7.5et52mm and the clearance is the required 'MOT inspectors fingers' and about 10mm when accounting for any possible flexing. Steering limit is now 2.5 turns lock to lock with '87 944T steering arms/stubs, so track rods need extending ~35mm. The turning circle is equal side to side and similar to that of a Merc Sprinter for example. I recall ~22 and 28mm being my measurements.

It is crude to say the least but it was all performed by myself, an Accredited Mechanical Engineer.

I've since devised a fully adjustable stop set-up on a knacered rack, I now only have to transfer the design to my '79 '03, which means taking the car off the road which is my only ride, and I got to roll.

This (unfortunatley) requires removal of the pinion and cutting and welding the tube as the plug is seriously pressed in.

I drilled out, reamed and tapped the plug (opposite end to the pinion) to M10, both axially for the stop screw, and through the hole where the M8 mount settling bolt was. This bolt it then replaced with 2 short M10 bolts, one from each side. The stop screw is locked with a nut.

On the other end, the cap is drilled to 10.5mm and a M10 nut is welded to a 3mm thick disc welded to the end of the rack. The stop screws are currently 150mm long stainless to be cut down accordingly when the modified rack is fitted and set.

The stops act on 2p coins bonded to new rubber snubbers. The dowels will be ground down and left in place.

Matt
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Old March 29th 2004, 08:00
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Hi

I have also given this some more thought.

Bolt a sturdy piece of steel to the rack using the 2 teirod mounting holes, you would need longer bolts of course, fit some lock stops to the peice of steel that would contact the inner guard on full lock.

I also own a 73 1303, its an ex curcuit race car, it uses a simlar idea to make the inner pivot point for the tie rods adjustable up&down to set the bump steer up properly.

Steve C
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Old March 29th 2004, 18:14
Stuart Stuart is offline
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Talking

While converting my 1979 1303 convertible to a 944 Turbo suspension and brake setup I discovered that the rack and pinion steering box that was on my car couldn’t be adjusted like the older steering box on the 1302/1303 pre 1974’s. While searching the internet and asking at several forums there was only one person(Mattkab) who gave me an answer to limit the steering so I went for my own investigation and found out a way that involves no welding or what so ever. You don’t even have to dismantle the steering box from the car. For my application the only thing I needed was a metal spacer and a adjustable tie rod.
Overview.

This is my solution
Step 1.
Dismantle the bracket on the passenger side of the rack and pinion. It’s bolted to the body with 2 bolts and 1 bolt that runs diagonal threw the steering rack.
Step 2.
Next go to the rack and pinion. When you look at the housing you see an lock ring that is in a recess in the body. Remove this ring.
Step 3.
The next thing to do when the ring is removed is to remove the metal plug. Just pry it out whit 2 suitable screwdrivers. When you look in the housing of the rack and pinion you will see a rubber
Damper. Know get some metal spaces that fit nicely in the metal housing. For my application I needed 2,5 cm in thickness.
To find out what thickness you need is very simple. Turn the steering wheel al to the left side. The internal part of the rack and pinion rests now against the left side of the rack. Adjust the tie rod so that the wheel/rims will not rub at all.
Turn the steering wheel to the position that the left tire is parallel to the body. Adjust the tie rod on the passenger side to the point that the tire on the passenger side is parallel to the tire on the driver side.
Turn your steering wheel all to the right. Do this carefully because you removed earlier the stop on the right side. Now determine at what point the wheel starts to rub. When you have found this point turn the wheel just al little back so there is a safe distance between the tire and the body. Now got to the steering rack. Put your finger in the rack and push the rubber damper al the way in till it rests against the inner part of the rack. Put in the spacer and putt in the plug you removed earlier. Turn the steering wheel and look if the tire rub. Whit adding/removing of spacers you can limit the steering. For me it works perfect. The only disadvantage is that the turning circle is wide but he when you want to drive 205/40/17 on the front this is for me no problem.
Greetings....... :agree:
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Old March 30th 2004, 08:15
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Hi

Stuart, that sounds like a good idea, the only thing that worries me is does the rack have a high spot in the middle position like steering boxes have? If they do this could cause the steering to be sloppy in one direction just off straight ahead position. Lack of lock is no problem, full lock and drop it will usually do it

Steve C
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Old March 31st 2004, 05:09
Stuart Stuart is offline
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I've just checked if there is a tight spot in the rack and I can say there isn't. The only modification I further will do is to mount a schock absorber to the steering rack because I've heard al lott of good things about this item. :agree:
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Old March 31st 2004, 14:54
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Stuart, are your inner rod ends dead centre at straight ahead? Do you have unequal length track rods?

I'd love to see pics of the set up on Steve C's '73

I'm soon to employ a ZF to reduce my turning circle

Matt
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  #13  
Old May 29th 2011, 18:45
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Steve C Steve C is offline
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This needs to be a sticky?

Hi

Sorry to drag up an old post.

I used the below method to limit the travel on the rack in my 1303, I used some 1/2 inch urethane sheet and cut the spacers outs with a hole saw.

I found that the clip on the end of the rack was much easier to remove if I knocked the metal plug in a whisker.

I'm using 18x8 40 ET wheels and I needed 2x1/2 inch spacers

Steve

Quote:
Originally Posted by Stuart View Post
While converting my 1979 1303 convertible to a 944 Turbo suspension and brake setup I discovered that the rack and pinion steering box that was on my car couldn’t be adjusted like the older steering box on the 1302/1303 pre 1974’s. While searching the internet and asking at several forums there was only one person(Mattkab) who gave me an answer to limit the steering so I went for my own investigation and found out a way that involves no welding or what so ever. You don’t even have to dismantle the steering box from the car. For my application the only thing I needed was a metal spacer and a adjustable tie rod.
Overview.

This is my solution
Step 1.
Dismantle the bracket on the passenger side of the rack and pinion. It’s bolted to the body with 2 bolts and 1 bolt that runs diagonal threw the steering rack.
Step 2.
Next go to the rack and pinion. When you look at the housing you see an lock ring that is in a recess in the body. Remove this ring.
Step 3.
The next thing to do when the ring is removed is to remove the metal plug. Just pry it out whit 2 suitable screwdrivers. When you look in the housing of the rack and pinion you will see a rubber
Damper. Know get some metal spaces that fit nicely in the metal housing. For my application I needed 2,5 cm in thickness.
To find out what thickness you need is very simple. Turn the steering wheel al to the left side. The internal part of the rack and pinion rests now against the left side of the rack. Adjust the tie rod so that the wheel/rims will not rub at all.
Turn the steering wheel to the position that the left tire is parallel to the body. Adjust the tie rod on the passenger side to the point that the tire on the passenger side is parallel to the tire on the driver side.
Turn your steering wheel all to the right. Do this carefully because you removed earlier the stop on the right side. Now determine at what point the wheel starts to rub. When you have found this point turn the wheel just al little back so there is a safe distance between the tire and the body. Now got to the steering rack. Put your finger in the rack and push the rubber damper al the way in till it rests against the inner part of the rack. Put in the spacer and putt in the plug you removed earlier. Turn the steering wheel and look if the tire rub. Whit adding/removing of spacers you can limit the steering. For me it works perfect. The only disadvantage is that the turning circle is wide but he when you want to drive 205/40/17 on the front this is for me no problem.
Greetings....... :agree:
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