Lotus Elan

Steering Rack rebuild - spacers

PostPost by: SENC » Sun Dec 15, 2019 3:08 pm

Had an old rack I've been meaning to disassemble either for parts or for rebuild. Was in better than expected shape so have cleaned up and painted the bits. Ultimately will replace the tie rods as one is buggered from someone's application of a mole wrench, but otherwise no signs of damage or even much wear. Based on the spacers, the rack is from an earlier Elan and I have an S4. Are spacers available, or is it simplest to have some machined?

img_20191215_095907.jpg and
disassembled steering rack


For the moment, it will go get greased up and reassembled to be stored until needed.
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PostPost by: Greg Foster » Mon Mar 23, 2020 7:17 pm

Over the weekend I took my elan out for a spin along some nice back roads twisting and dipping. It felt fabulous!
I was feeling a bit overconfident and broke the rear free of the road on a right turn. In overcorrecting I slipped off of the road with the right front tire while turning hard to the left. No harm to the car but I dropped into a hole , not deep but enough to cause a jolt. When back up on the road I found the steering wheel was tracking with centering at 2-0'clock and the car was steering squirley. After a visual inspection showing nothing broken or loose that I saw I limped home not running over 50 MPH as above that there was a shimmey and the car would steer left under accelleration and right during deceleration.
Back at the shop I immediately jacked up the car and did a thorough inspection. Nothing visually bent and I haven't checked centers and points yet. I did remove the rack and dissasemble to make sure there was no damage. There was more left/ right play at the steering wheel, maybe 3/16" heavy at the outer edge.
I removed grease and started looking and measuring.
See next.
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DSCF1099.JPG and
'67 s3 SS
'72 +2 S130
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PostPost by: Greg Foster » Mon Mar 23, 2020 7:23 pm

So I started taking measurement to see if I could compare them with anyone elses.

A) Pinion
B) Large spacer installed above helical gear
C) Small spacer installed below helical gear
D) Non-worm end of rack tube with bronze bearing surface
E) Rack shaft where it slides in bearing D

Bearing surface looks good

Wear on gears, but not that great…or am I wrong?

There were some burrs both left and right of the hole on the part of the rack shaft which is pressed upon by the tensioner pad. I rubbed them out and the tensioner pad now slides nicely without being stopped. In the center I did notice some scratches …….
So my question is the pinion shafts which bear in the rack body… is this too much slop? Can someone measure their parts and note the measurement differences to compare to what I have shown?
Looking at the gear mesh areas of the pinion…too much wear? Can new pinions be purchased?
Greg
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So I started taking measurement to see if I could compare them with anyone elses.pdf
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PostPost by: pharriso » Wed Mar 25, 2020 1:15 pm

SENC wrote:Had an old rack I've been meaning to disassemble either for parts or for rebuild. Was in better than expected shape so have cleaned up and painted the bits. Ultimately will replace the tie rods as one is buggered from someone's application of a mole wrench, but otherwise no signs of damage or even much wear. Based on the spacers, the rack is from an earlier Elan and I have an S4. Are spacers available, or is it simplest to have some machined?

IMG_20191215_095907.jpg


For the moment, it will go get greased up and reassembled to be stored until needed.


I was in a similar position to you, the only place I found that sold spacers from stock was Lotus Marques https://lotusmarques.com/parts/catalogue/lotus/44-elan-parts/456-elan-steering-rack-parts

The spacer geometry is so simple any machine shop or hobbyist with a lath could make them for you.
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PostPost by: pharriso » Wed Mar 25, 2020 1:36 pm

Greg Foster wrote:Over the weekend I took my elan out for a spin along some nice back roads twisting and dipping. It felt fabulous!
I was feeling a bit overconfident and broke the rear free of the road on a right turn. In overcorrecting I slipped off of the road with the right front tire while turning hard to the left. No harm to the car but I dropped into a hole , not deep but enough to cause a jolt. When back up on the road I found the steering wheel was tracking with centering at 2-0'clock and the car was steering squirley. After a visual inspection showing nothing broken or loose that I saw I limped home not running over 50 MPH as above that there was a shimmey and the car would steer left under accelleration and right during deceleration.
Back at the shop I immediately jacked up the car and did a thorough inspection. Nothing visually bent and I haven't checked centers and points yet. I did remove the rack and dissasemble to make sure there was no damage. There was more left/ right play at the steering wheel, maybe 3/16" heavy at the outer edge.
I removed grease and started looking and measuring.
See next.


Greg, To get more response maybe you should have started your own thread.

I'll address your bad steering geometry in this post. You have obviously bent something, highly unlikely that anything is bent inside the Steering Rack itself.

If the Track Rods are not bent then it's likely the Wishbones are bent; They are designed to be sacrificial before the chassis is damaged.

Take the wishbones off, both top wishbones should be the same & both bottom wishbones should be the same, overlay them, is one or more damaged?
Last edited by pharriso on Wed Mar 25, 2020 1:50 pm, edited 1 time in total.
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PostPost by: pharriso » Wed Mar 25, 2020 1:48 pm

Greg Foster wrote:So I started taking measurement to see if I could compare them with anyone elses.

A) Pinion
B) Large spacer installed above helical gear
C) Small spacer installed below helical gear
D) Non-worm end of rack tube with bronze bearing surface
E) Rack shaft where it slides in bearing D

Bearing surface looks good

Wear on gears, but not that great…or am I wrong?

There were some burrs both left and right of the hole on the part of the rack shaft which is pressed upon by the tensioner pad. I rubbed them out and the tensioner pad now slides nicely without being stopped. In the center I did notice some scratches …….
So my question is the pinion shafts which bear in the rack body… is this too much slop? Can someone measure their parts and note the measurement differences to compare to what I have shown?
Looking at the gear mesh areas of the pinion…too much wear? Can new pinions be purchased?
Greg

Greg, I don't see any issues here.

C is a thrust bearing, hardened material so the pinion does not wear into the soft rack casting.

The pinion "tension" is adjusted by shims under the large Nut that the steering shaft is earthed with, less shims = more pressure. The workshop manual documents how to adjust, but from memory, you assemble with no shims & wind the nut in until the pinion is tight (but not too tight!), then measure gap between bottom of nut & face, then add shims of that thickness.I found my shims still to be of the correct thickness.
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PostPost by: Greg Foster » Wed Mar 25, 2020 9:33 pm

Phil,
Thanks for the response. I have been rooting around the internet and found Quaife sells Tony Thompson his rack rebuild parts (or rebuilds them for him) so they may have something...but seems like England is shut down..... I have a feeling you are correct regarding the a arms....and hope its not the tower. Since I am into it this far I will pull them and check. As far as the rack. There were a couple of burrs on the friction side (opposite of the cogged side) that I removed. Slight catches were noticeable when turning the wheel. I think it must have had at least one other heavy bump. Now everything slides smoothly after de-nibbing and polishing. All in all the rack seems in good shape but I wanted to compare wear with another rack and be assured there was no serious damage. When I re-assemble I will check the free-play after adjusting the pressure on the rack rod. Also, there are 2 more racks that I will be disassembling and measuring to compare wear and review the pinions... might as well while I have the time and experience. One other thing which may have happened is the splined knuckle may have slipped. I installed a new one and may not have tightened it enough. Changing to new and different items plus the space to install make for interesting dynamics.
Greg
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