Avoiding Bump Steer

[TR Man]

That will be the rally boys buying them up for all the MK2 escorts in classic rallying.

Stuart.

 

Stuart,

 

I have sent an email to 'Quaife' enquiring about a heavy duty Mark 2 Escort rack. Have you ever heard of them?

 

Regards,

 

Martin

[stuart]

Stuart,

 

I have sent an email to 'Quaife' enquiring about a heavy duty Mark 2 Escort rack. Have you ever heard of them?

 

Regards,

 

Martin

 

Yes they do good gearbox and diffs. You could try this place as well.Kelly Bray Steering co

Stuart.

[TR Man]

Yes they do good gearbox and diffs. You could try this place as well.Kelly Bray Steering co

Stuart.

 

 

Will do. Thanks for your help, Stuart.

 

Regards,

 

Martin

[mike ellis]

Thanks Mike. I live in Ireland so probably could not make it to view your TR. However can you tell me the width of your rack and does the wheel turn 2 or 2.5 revs?

 

Regards,

 

Martin

 

 

Martin,

 

I am away for a few days but when I get back and if I can get into my garage through the snow I will take measurements for you.

 

Mike

[LGFromage]

Martin

 

This is a good topic!

 

FYI the TR4 and TR4A workshop manual contains general arrangement drawings on the zero and 3 degree castor suspensions together with some component dimensions. Having studied these, the Moss catalogue, and previous comments I would like to offer the following observations (hopefully useful).

 

With a TR4 sized steering wheel (16in diameter) 4A-6 steering arms p/n 307211/2 would be my favourite. They satisfy the appropriate bump steer charistics and, being 1.5in longer than the earlier type, give the steering a lighter feel. The only reservation is that a check on full lock each side should be made to ensure that the suspension stops are met before the rack runs out. In fact I suggest that this check is made no matter which steering arms are used.

 

If using a TR3A sized steering wheel (larger than TR4) then the early type (P/N 129836/7) of 3 degree castor steering arms could well be better. They would need to be swapped L to R and R to L just as Stuart indicated in his earlier post. The manusl contained no info on the later type (P/N 134541/2) but I like to think Triumph had adopted the above swap and and used different part numbers - but that is just a guess.

 

You should note that if the only available steering arms are those for the zero degree castor suspension then the ends should be bent down by 0.25in.

 

Finally it would be nice to hear what kind of arrangement you are planning for the horn and indicators.

 

Good Luck,

 

Tim

[john.r.davies]

Martin

You should note that if the only available steering arms are those for the zero degree castor suspension then the ends should be bent down by 0.25in.

Tim

 

 

Good advice above, AFAIK, but may I quote Staniforth again?

Steering arms "can be bent if generously heated and allowed the slowest cool you can manage"

They can crack if treated any other way!

 

JOhn

[TR Man]

Martin,

 

I am away for a few days but when I get back and if I can get into my garage through the snow I will take measurements for you.

 

Mike

 

 

Thanks Mike. I would be interested to know how near the right hand inner tie rod joint is to the pinion box (if that's the correct term) when the wheels look straight ahead.

 

Don't rush I have pleny of time to wait for a thaw!

 

Regards,

 

Martin

[TR Man]

Martin

 

This is a good topic!

 

FYI the TR4 and TR4A workshop manual contains general arrangement drawings on the zero and 3 degree castor suspensions together with some component dimensions. Having studied these, the Moss catalogue, and previous comments I would like to offer the following observations (hopefully useful).

 

With a TR4 sized steering wheel (16in diameter) 4A-6 steering arms p/n 307211/2 would be my favourite. They satisfy the appropriate bump steer charistics and, being 1.5in longer than the earlier type, give the steering a lighter feel. The only reservation is that a check on full lock each side should be made to ensure that the suspension stops are met before the rack runs out. In fact I suggest that this check is made no matter which steering arms are used.

 

If using a TR3A sized steering wheel (larger than TR4) then the early type (P/N 129836/7) of 3 degree castor steering arms could well be better. They would need to be swapped L to R and R to L just as Stuart indicated in his earlier post. The manusl contained no info on the later type (P/N 134541/2) but I like to think Triumph had adopted the above swap and and used different part numbers - but that is just a guess.

 

You should note that if the only available steering arms are those for the zero degree castor suspension then the ends should be bent down by 0.25in.

 

Finally it would be nice to hear what kind of arrangement you are planning for the horn and indicators.

 

Good Luck,

 

Tim

 

Thanks Tim, this is good information. I looked up Moss' site and see that the number you quote (307211/2) is a TR4A part and on their diagram appears to be much more swooped downwards than the 3A equivalent. It seems to be 'N/A' currently though. I will be fitting a smaller steering wheel than normal as we are also fitting EPS. I hoped to be able to fit a horn in the centre of the steering wheel but am not quite sure how this will work as yet. I am happy to have a switch with a long stalk (right and left) to work the indicators and fitted to the outside (right) of the dash board within finger reach of the steering wheel. It would have a light and a loud 'clicker' to warn that it is in use.

 

To get back to the rack and pinion. Having had a look at the image would you fit a narrower rack as well as use the 4A steering arms?

 

Regards,

 

Martin

[LGFromage]

Thanks Tim, this is good information. I looked up Moss' site and see that the number you quote (307211/2) is a TR4A part and on their diagram appears to be much more swooped downwards than the 3A equivalent. It seems to be 'N/A' currently though. I will be fitting a smaller steering wheel than normal as we are also fitting EPS. I hoped to be able to fit a horn in the centre of the steering wheel but am not quite sure how this will work as yet. I am happy to have a switch with a long stalk (right and left) to work the indicators and fitted to the outside (right) of the dash board within finger reach of the steering wheel. It would have a light and a loud 'clicker' to warn that it is in use.

 

To get back to the rack and pinion. Having had a look at the image would you fit a narrower rack as well as use the 4A steering arms?

 

Regards,

 

Martin

 

 

Martin,

 

I suggest that it would be appropriate to emulate the TR4 R&P installation. The workshop manual gives the dimensions betweeen the track rod ball joints (the ones inside the concertina gaiters) as 26.78in for the TR4. The 3A chassis is 4in narrower than the 4 so the equivalent R&P dimension for your car is 22.78in but something reasonably close should do.

 

The thing that concerns me is that on full lock the pinion may run out of rack and get damaged if the suspensiom steering stop is not reached first. (When checking first make sure that the rack is correctly centred). For a RHD car this is likely to happen on a left hand turn. The solution is revised steering stops (reduced turning circle)or shorter steering arms.

 

Since you plan on using EPS with a smaller steering wheel than normal TR4 3 degree castor steering arms should suit. A check on running out of rack would still be advisable.

 

Moss seem to indicate there may be a problem with availability but the other usual suspects are worth trying. If stuck it might be worth contacting TD Fitchett (01952 619585) for second hand ones.

 

Tim

[TR Man]

Martin,

 

I suggest that it would be appropriate to emulate the TR4 R&P installation. The workshop manual gives the dimensions betweeen the track rod ball joints (the ones inside the concertina gaiters) as 26.78in for the TR4. The 3A chassis is 4in narrower than the 4 so the equivalent R&P dimension for your car is 22.78in but something reasonably close should do.

 

The thing that concerns me is that on full lock the pinion may run out of rack and get damaged if the suspensiom steering stop is not reached first. (When checking first make sure that the rack is correctly centred). For a RHD car this is likely to happen on a left hand turn. The solution is revised steering stops (reduced turning circle)or shorter steering arms.

 

Since you plan on using EPS with a smaller steering wheel than normal TR4 3 degree castor steering arms should suit. A check on running out of rack would still be advisable.

 

Moss seem to indicate there may be a problem with availability but the other usual suspects are worth trying. If stuck it might be worth contacting TD Fitchett (01952 619585) for second hand ones.

 

Tim

 

 

Thanks,Tim.

 

I tried the steering, full lock to full lock, and everything seems to work well with no obvious problems.

 

The width of the rack is about 24 inches (i.e. through the gaiters 'joint to joint' by feel).

 

I have the original arms (3A) fitted but it is easy to change over to the TR4 ones as you suggest and will shop around and see if I can get a pair from TD Fitchett. Thanks for that tip.

 

Thank you again for your help.

 

Regards,

 

Martin

[mike ellis]

I have at last managed to crawl under the car and take some approximate measurements of the Escort rack. The track rod length is about 7.5 inches between ball joint centres (approx, by feeling in the gaiters) and the distance between inner ball joints is about 22.5 inches. This equates closely to the dimensions of the original steering and for this reason I have left the steering arms as they are. The pinion is about 4 inches from the rh joint. In order to achieve this from a standard Escort rack the track rods need shortening by about 8cm and rethreading to 1/2" unf to take the Mini track rod ends which fit into the original steering arms.

 

The steering wheel turns just over 3 times lock to lock which compares with 2.5 for the original. A TR7 rack would turn 3.9 times. IMHO some of the lightness advantage of r&p steering conversions comes from the reduced gearing rather than the r&p itself. I don't know what the corresponding figures are for TR4 and Mini rack.

 

For the sake of completeness, I use an intermediate shaft from the Moss conversion and a TR7 top coupling.

 

Mike

[TR Man]

I have at last managed to crawl under the car and take some approximate measurements of the Escort rack. The track rod length is about 7.5 inches between ball joint centres (approx, by feeling in the gaiters) and the distance between inner ball joints is about 22.5 inches. This equates closely to the dimensions of the original steering and for this reason I have left the steering arms as they are. The pinion is about 4 inches from the rh joint. In order to achieve this from a standard Escort rack the track rods need shortening by about 8cm and rethreading to 1/2" unf to take the Mini track rod ends which fit into the original steering arms.

 

The steering wheel turns just over 3 times lock to lock which compares with 2.5 for the original. A TR7 rack would turn 3.9 times. IMHO some of the lightness advantage of r&p steering conversions comes from the reduced gearing rather than the r&p itself. I don't know what the corresponding figures are for TR4 and Mini rack.

 

For the sake of completeness, I use an intermediate shaft from the Moss conversion and a TR7 top coupling.

 

Mike

 

Thanks for taking the trouble to do all of that, Mike.

This info is very helpful.

 

Regards,

 

Martin