Steering rack preload. UDATED WITH PRELOAD PROCEDURE

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shaunw
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Steering rack preload. UDATED WITH PRELOAD PROCEDURE

Post by shaunw »

Steering rack preload. Anyone know how to go a out checking this? I know the principle ( big nut which adjusts spring loaded tension on the rack) but how do you adjust it and what tools do you need?

Shaun
Last edited by shaunw on Sun Jul 26, 2020 08:13, edited 1 time in total.

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Re: Steering rack preload.

Post by bash »

That will be these bits then. The big welded nut and bolt is the 'special tool' that I made
Image
Image

I will have to find my notes on how I adjusted the preload but once you have got the cupped socket out of the rack it could be adjusted in situ. I'll get back to you. I did reseal the whole rack with the kit fron SJ's but the pinion seals were a right pain to do without another special tool.

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Re: Steering rack preload.

Post by Pete Boole »

I made a similar tool - not sure where it is now. If I can find it you can borrow it Shaun - it's 28mm A/F. The threaded cup is supposed to be sealed in place with thread sealant at reassembly. The rack adjustment is covered quite well in the Service Notes - do you have a copy Shaun?

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Re: Steering rack preload.

Post by shaunw »

bash wrote:
Tue Jul 21, 2020 11:02
That will be these bits then. The big welded nut and bolt is the 'special tool' that I made
Image
Image

I will have to find my notes on how I adjusted the preload but once you have got the cupped socket out of the rack it could be adjusted in situ. I'll get back to you. I did reseal the whole rack with the kit fron SJ's but the pinion seals were a right pain to do without another special tool.

Bash
Cheers Bash. That's really helpful. Great if it can be done in situ cause as you know, removal is a pain in the a*se! The reason I'm looking at this is that I think my reconditioned rack may have been slightly over tightened. I was speaking to someone the other week when we had a little meet up who had the same problem and he was saying that Lotusbits kept slacking the preload until it loosened up. I'm assuming the tolerances are pretty fine.

Shaun

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Re: Steering rack preload.

Post by shaunw »

Pete Boole wrote:
Tue Jul 21, 2020 15:18
I made a similar tool - not sure where it is now. If I can find it you can borrow it Shaun - it's 28mm A/F. The threaded cup is supposed to be sealed in place with thread sealant at reassembly. The rack adjustment is covered quite well in the Service Notes - do you have a copy Shaun?

Pete
That would be grand Pete. I've got the parts manual but not sure about the service notes. I think I've got certain pages but not the whole thing.I'll have a look. Being a typical Male I tend not to read instructions but in this case I think I'll need to 😁

Shaun

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Re: Steering rack preload.

Post by Pete Boole »

You will have to remove the rack to do this properly. You need to be able to measure the turning torque on the pinion and that's going to be difficult with the rack in situ. You also need to measure the turning torque throughout to full travel of the rack bar ideally, or at least at it's stiffest point.

I thought this might be your problem all along! :wink:

Let me know if you need some of the Service Notes - it's at the back of section HA.

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Re: Steering rack preload.

Post by shaunw »

Pete Boole wrote:
Wed Jul 22, 2020 12:57
You will have to remove the rack to do this properly. You need to be able to measure the turning torque on the pinion and that's going to be difficult with the rack in situ. You also need to measure the turning torque throughout to full travel of the rack bar ideally, or at least at it's stiffest point.

I thought this might be your problem all along! :wink:

Let me know if you need some of the Service Notes - it's at the back of section HA.

Pete
Cheers Pete. I'm not entirely sure it is the problem to be honest as this is the second reconditioned rack I've had and they feel identical but because I haven't been able to solve the problem by replacing parts I've decided to go through each part new or old and test it. As you know, all hoses are new, hubs are free, steering UJs are free ( at least the hubs and UJs are free with the wheels raised) and pump is reconditioned. Suspecting the pump may not have been producing full pressure despite being reconditioned I recently had it tested and as it happens it wasn't but only by a small margin. It is now definitely outputting full pressure but this has made virtually no difference to the steering. My other suspicion is that both reconditioned racks may have had the preload set too high in order to remove play. I still have both racks so my idea is to test the removed rack as that will be much easier. If it is tight chances are the second rack is too. If it's not then the problem must be elsewhere but goodness knows what it could be! The weirdest thing is that even with the original rack the steering in my car was notably heavier than other Excels I've driven. Not stiff, just heavier. I've already checked once about two years ago but I'm going to have another look at the upper UJ too ( lower one is new).

Shaun

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Re: Steering rack preload.

Post by Pete Boole »

What caster angle are you running at the front? Have you checked it?

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Re: Steering rack preload.

Post by shaunw »

Just checked the readout results from when the tracking was done after the new rack was installed. Left and right wheels both well within specified range for caster and cross caster bang in the middle of specified range. Toe is bang on too.

Shaun

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Re: Steering rack preload.

Post by Sirclip »

shaunw wrote:
Wed Jul 22, 2020 17:43
Pete Boole wrote:
Wed Jul 22, 2020 12:57
You will have to remove the rack to do this properly. You need to be able to measure the turning torque on the pinion and that's going to be difficult with the rack in situ. You also need to measure the turning torque throughout to full travel of the rack bar ideally, or at least at it's stiffest point.

I thought this might be your problem all along! :wink:

Let me know if you need some of the Service Notes - it's at the back of section HA.

Pete
Cheers Pete. I'm not entirely sure it is the problem to be honest as this is the second reconditioned rack I've had and they feel identical but because I haven't been able to solve the problem by replacing parts I've decided to go through each part new or old and test it. As you know, all hoses are new, hubs are free, steering UJs are free ( at least the hubs and UJs are free with the wheels raised) and pump is reconditioned. Suspecting the pump may not have been producing full pressure despite being reconditioned I recently had it tested and as it happens it wasn't but only by a small margin. It is now definitely outputting full pressure but this has made virtually no difference to the steering. My other suspicion is that both reconditioned racks may have had the preload set too high in order to remove play. I still have both racks so my idea is to test the removed rack as that will be much easier. If it is tight chances are the second rack is too. If it's not then the problem must be elsewhere but goodness knows what it could be! The weirdest thing is that even with the original rack the steering in my car was notably heavier than other Excels I've driven. Not stiff, just heavier. I've already checked once about two years ago but I'm going to have another look at the upper UJ too ( lower one is new).

Shaun
Hi Shaun,
I had a lot of probs with my reconditioned rack too. Problem was excessive preload which 'robbed' the steering of any feedback and it too felt heavy/lifeless on the road.

Lotusbits were top-notch though - I took the car to them and they contacted the reconditioning guy, who them told them how to 'empirically' adjust the preload. Took them a couple of attempts (adjusting the large nut, with the rack in situ) but I was very pleased with the end result. I wonder if that's the issue that you're having too.

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Re: Steering rack preload.

Post by bash »

Empirically adjusted !!! I will have to remember that one.
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Re: Steering rack preload.

Post by shaunw »

bash wrote:
Thu Jul 23, 2020 09:14
Empirically adjusted !!! I will have to remember that one.
Bash
I had to look that up :oops:

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Re: Steering rack preload. UDATED WITH PRELOAD PROCEDURE

Post by shaunw »

Pete /Bash
I found the preload procedure online on a Ford Sierra Cosworth forum. Can I just check that this is same as the procedure in the Lotus service notes:

1. Centralise steering rack and assemble yoke and spring into pinion

2. Coat thread of yoke with Loctite 542 , tighten plug to 3.4 - 4 nm
using 28mm hexagonal bar.

3. Rotate lock to lock and re-centralise recheck plug and tighten if necessary

4. Check pinion torque is not less than 1.35 nm ( 12lbs) using special tool 15-041

5. Back off yoke plug 22-27 degrees

6. Check pinion torque does not exceed 1.7nm (15lbs) torque

7. If it does back off yoke additional 5 degrees.

All seems straightforward but what did you guys use in place of the special tool for setting the turning torque?

Regards
Shaun

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Re: Steering rack preload. UDATED WITH PRELOAD PROCEDURE

Post by Pete Boole »

That's pretty much what the service notes say Shaun. Don't forget (I still work in imperial units most of the time!) that the imperial units you have quoted are lbf.inch, not lbf.foot. Do you have a torque wrench that goes low enough? When I rebuilt my Elite rack recently I used some Mole grips carefully clamped onto the pinion shaft to measure turning torque. You have to take into account the length of the grips and you have to position them horizontally to remove the effect of gravity on the grips. I used a digital balance to then pull carefully on the grips. Once you have overcome the stiction you can get pretty good results.

Pete

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Re: Steering rack preload. UDATED WITH PRELOAD PROCEDURE

Post by bash »

Pretty similar proceedure to Pete, although there was a degree of empirical too !
Bash
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