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TR4a Inner Rack Bushes


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Good morning all

I've noticed some lateral movement in the steering rack assembly, which is more pronounced at the pinion end. When the pinion is moved, the toothed rack will actually move fore and aft in the tube, suggesting there is some wear in a bushing. I have obtained a bush for the left ( nearside) of the car but have not seen one for the pinion side.

I have not yet stripped the rack, so wondered if it does have a bushing and is it available to order or is this movement controlled by the cup that sits over the rack, which may also be worn? I am trying to service/ retain original equip where possible, so an exchange unit would be a last option.

Thanks in advance

Kevin

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Hi Kevin

There are shims on the adjusting plunger and the pinion to take up play between rack and pinion end (read workshop manual to see how to do this). The bush is in the tube on the opposite end to the pinion. There are also adjusting shims for the inner ball joints. You have to take the rack off the car to do it properly. It is a bit fiddly to do but follow the manual and all should be well. Don't make it too tight. While the rack is out you should take the opportunity to replace the rubber gaiters and steering rack mounts if they are old and worn out.

The job probably looks more daunting than it actually is.

Keith

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1 hour ago, keith1948 said:

Hi Kevin

There are shims on the adjusting plunger and the pinion to take up play between rack and pinion end (read workshop manual to see how to do this). The bush is in the tube on the opposite end to the pinion. There are also adjusting shims for the inner ball joints. You have to take the rack off the car to do it properly. It is a bit fiddly to do but follow the manual and all should be well. Don't make it too tight. While the rack is out you should take the opportunity to replace the rubber gaiters and steering rack mounts if they are old and worn out.

The job probably looks more daunting than it actually is.

Keith

Hi Keith

Now got the rack out..looking closely at the pinion splines I'd say the pinion needs replacing anyway, as the splines are quite worn, and since I'm fitting new ( used but good) lower couplings I think I'll replace the pinion and then re-adjust to take out the play. Looking at the pinion splines with a magnifying glass they are actually badly pitted and rusted which you cannot really see with the naked eye.

I suppose they should be regularly greased really as on the lower end they are subject to wet weather/water ingress into the coupling. 

I'll fit the new bushing and new mounting rubbers, but the gaiters are still good (must be real rubber!) ..

Kevin

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Hi Kevin,

I looked for some photos I alreday made.

It is very sad to say I tryed a lot to keep it and finally kicked out the original because it is a very poor construction.

As Keith pointed out: on the driver side there is a think like a "coin" to press the rack from behind against the pinion to get the play out there.

This grinds on the rack, in the middle position more, to the left and right more and more less, like a flat funnel.

29471913_01TR4Arackandpinion.JPG.506c1b389ea10aabb31f9f8e8853e9bb.JPG 1521866908_02TR4Acointopressrackagainstpinion.JPG.4c8a73fa0259df4e20e1115388f9515b.JPG 91722912_03TR4Aspringtopresscoinagainstpinion.JPG.bd742a37aacf9e525837376eff62ade3.JPG95492781_04TR4Apinionwornbycoin.JPG.a67e1764be3ef4b148f9e4cc6e3ead61.JPG

If you adjust the play (with this damage) like told in the workshop manual you cannot steer the car anymore,

you have to give it more play - too much on my old steering rack. I don't know how the new construction is made in this point, I did not open it - but it is new.

On the passenger side there is a bush, also like Keith pointed out. I made my own one because the bush I bought had to much play on the pinion.

703360307_05TR4Asteeringbushselfmade.JPG.487620f766e69751cfe0990ffb7d4eb2.JPG

Problem is you have to stick the rack through the bush when you put all together,

and the biggest diameter is the thread rolled (?) on the end of the rack!!! So you always have play to the rack!!!

This may be german engineering - but it is the truth.

1442093361_06TR4Atheradonsteeringrackandsteeringbush.JPG.d0887da026d74975aef306d657abbdfd.JPG 

On my new steering rack there is a reduction of the diameter in both ends of the rack to a thread with smaller diameter.

So there is absolute no pay on the steering rack anymore. So far so good with the new steering rack.

 

But the new rack is a construction 100% in the tradition of our TRs, a very poor construction. You cannot angle the track rods as far down as the originals!

So the wheels pull and bend on the steering rack every time you lift up the car, you better dismount them and never forget this.

1308253174_07TR4Aangleonoldsteeringrack.JPG.7390db71836a945d2a98786e72718ea7.JPG 936338897_08TR4Aangleonnewsteeringrack.JPG.ae49159d5dd458ac96b5ac9105477337.JPG 1593829832_09TR4Awheelspullonsteeringrack.JPG.19ed834efd743bea3f03e5b7ea67e34d.JPG

But what will you expect from a steering rack that costs only pocket money.....

By the way, this also can happen when you use aluminum brackets instead of the original rubber one or same size made of PU.

Don't now if this anyone already pointed out....

Ciao Marco

   

Edited by Z320
rolled (?) thread
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26 minutes ago, Z320 said:

Hi Kevin,

I looked for some photos I alreday made.

It is very sad to say I tryed a lot to keep it and finally kicked out the original because it is a very poor construction.

As Keith pointed out: on the driver side there is a think like a "coin" to press the rack from behind against the pinion to get the play out there.

This grinds on the rack, in the middle position more, to the left and right more and more less, like a flat funnel.

29471913_01TR4Arackandpinion.JPG.506c1b389ea10aabb31f9f8e8853e9bb.JPG 1521866908_02TR4Acointopressrackagainstpinion.JPG.4c8a73fa0259df4e20e1115388f9515b.JPG 91722912_03TR4Aspringtopresscoinagainstpinion.JPG.bd742a37aacf9e525837376eff62ade3.JPG95492781_04TR4Apinionwornbycoin.JPG.a67e1764be3ef4b148f9e4cc6e3ead61.JPG

If you adjust the play (with this damage) like told in the workshop manual you cannot steer the car anymore,

you have to give it more play - too much on my old steering rack. I don't know how the new construction is made in this point, I did not open it - but it is new.

On the passenger side there is a bush, also like Keith pointed out. I made my own one because the bush I bought had to much play on the pinion.

703360307_05TR4Asteeringbushselfmade.JPG.487620f766e69751cfe0990ffb7d4eb2.JPG

Problem is you have to stick the rack through the bush when you put all together,

and the biggest diameter is the thread rolled on the end of the rack!!! So you always have play to the rack!!!

This may be german engineering - but it is the truth.

1442093361_06TR4Atheradonsteeringrackandsteeringbush.JPG.d0887da026d74975aef306d657abbdfd.JPG 

On my new steering rack there is a reduction of the diameter in both ends of the rack to a thread with smaller diameter.

So there is absolute no pay on the steering rack anymore. So far so good with the new steering rack.

 

But the new rack is a construction 100% in the tradition of our TRs, a very poor construction. You cannot angle the track rods as far down as the originals!

So the wheels pull and bend on the steering rack every time you lift up the car, you better dismount them and never forget this.

1308253174_07TR4Aangleonoldsteeringrack.JPG.7390db71836a945d2a98786e72718ea7.JPG 936338897_08TR4Aangleonnewsteeringrack.JPG.ae49159d5dd458ac96b5ac9105477337.JPG 1593829832_09TR4Awheelspullonsteeringrack.JPG.19ed834efd743bea3f03e5b7ea67e34d.JPG

But what will you expect from a steering rack that costs only pocket money.....

By the way, this also can happen when you use aluminum brackets instead of the original rubber one or same size made of PU.

Don't now if this anyone already pointed out....

Ciao Marco

   

Hi Ciao

I'm hoping to replace the pinion and the cupped spacer. There will probably be a small difference in radius between a worn rack and a new  cup washer, but I'm hoping for a compromise when it goes back together between a little play and sudden tightness when I adjust it up. I'll also install the new bushing to the left side as like a big end bearing it is down to the phospher bronze so hopefully it'll be an improvement .

Your issue with the rack ends not dropping enough is precisely why I'm trying to avoid a replacement. Have you looked into why they don't drop enough? If the domed nut is longer or a different shape internally that could cause it, or the ring groove machined on the inner end of the track rod. This could effect your suspension travel in rebound so could be a problem when the suspension is actually working through corners etc.

I assume this is why Standard Triumph had to machine the rack with larger threaded rack ends and nuts in order to get the correct degree of radial movement in the track rods?

Regards

Kevin

 

Edited by boxofbits
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29 minutes ago, boxofbits said:

If the domed nut is longer or a different shape internally that could cause it, or the ring groove machined on the inner end of the track rod. This could effect your suspension travel in rebound so could be a problem when the suspension is actually working through corners etc.

Regards

Kevin

That might be te reason, I did not open it and cannot modify it this way.

My idea is to make longer shock absorber backets, one of other projects, material is already in my workshop.

I do it this way because I drive shorter coils springs at the front and because of this have less suspension way there.

Cheers, Marco  

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11 minutes ago, Z320 said:

That might be te reason, I did not open it and cannot modify it this way.

My idea is to make longer shock absorber backets, one of other projects, material is already in my workshop.

I do it this way because I drive shorter coils springs at the front and because of this have less suspension way there.

Cheers, Marco  

Okay, I'm using standard height springs as the TR has a fairly low roll centre I would think in factory trim. Btw, I've just looked at the new rack bushing and it is not coated with tin/lead like many other bearings , but it does look quite worn all the same. Would've edited my previous post but after initial edit the option disappears, at least on an iPad!

Kevin

Edited by boxofbits
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Bush removed and well worn as suspected. If anyone is looking for a new TR4a rack pinion gear most are showing N/A and on long term back order. However, managed to order one from SC Parts from stock. Price is higher but Hobsons Choice really !

Preferring to repair my original rack as Marco found with his new rack, where the track rods don’t drop as far as the original and could possibly compromise suspension movement in bends and corners is another example of repro quality...

Kevin

Edited by boxofbits
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