Tight steering....

[shaunroche]

I've just replaced the track rods on a steering rack and shimmed it so that there is very little play in them...If the track rods are a too tight will this lead to impossibly stiff steering as the car is now undriveable and the steering won't return to centre?

[Triumph1300]

Yes, there is a specified figure for this, I think in the factory manual of the load required to move the rod.
If they're too tight, the rack will be very stiff once installed

[shaunroche]

A-ha....found the problem!

On the nearside end of the rack is a little plastic bung which is being pinched by my solid rack clamp thereby putting lots of pressure on the rack.

I've removed this bung and put some tape over it and now the steering is spot on!

[Richard the old one]

I am pleased to read that you are now happy with your rack and I am assuming that you did not free up the ball joints but just removed the nylon plug. It was lucky that you spotted this problem as I have not heard of any other people having had this problem. Had you fitted a new plug? When I was missing one I just taped over thee hole and did not notice any problems.

I have previously wondered about the plug that you have removed as it is described as being part number 145108 - Plug Nylon - Rack Damping. Obviously with the original rubber mounting bushes would not have applied as much pressure on the plug as with the new solid mounting arrangement.

[shaunroche]

Hi Richard, the first job I did was to free off the ball joints and reshim them so they were a bit more on the floppy side and then refitted the rack.

A quick turn of the wheel showed the steering to be as tight as ever.

As the track rods proved not to be the problem I was worried that the solid rack mounts I have been making and selling were too tight, causing the rack tube to be crushed: this was after a lot of analysis using FEA on 3d CAD so I feared I'd got it all wrong!

Off comes the rack again and the only way I could think of testing the clamp force was to tighten the clamp whilst supporting the rack and turning the pinion.
Offside was fine, no crushing was seen, but the nearside would nearly stop the rack from moving. It's then I spotted the plastic bung!

As you say, removed and taped over I can't tell it's not there, the steering does feel much more precise and I'm very satisfied that the solid rack clamps are really doing their job. If anything I might just be able to discern that the track rods could do with being a bit tighter, so I've ordered some new superflex ball joints, shims and tab washers and will change it all again next week.

[Flyfisherman]

A-ha....found the problem!
On the nearside end of the rack is a little plastic bung which is being pinched by my solid rack clamp thereby putting lots of pressure on the rack.
I've removed this bung and put some tape over it and now the steering is spot on!

Shaun

That little plastic bung is shown with the parts diagram for the steering -rack and pinion (part No. 145108)
https://www.rimmerbros.co.uk/Item--i-145108
when I removed my rack so years ago I could not see that bung and I could not buy one either so the rack just got refitted.

Paul

[Richard the old one]

Both Moss and Rimmers sell the nylon plug for about £2.50.

[Carledo]

Oddly, I fitted one of your N/S rack mounts to a cheap (Paddocks IIRC) recon rack that I put on Mahesh's car, but this has experienced no problems with stiff steering. I didn't check that the plastic button (the existence of which I knew about) was in place on the rack though! Just assumed it was, with it being a recon!

Nor have I ever had a problem with the several earlier type of solid rack mounts that I have fitted to Dolomites, Toledos, Spitfires, Heralds and GT6s etc over the years!

With it being a fairly cheap bit, would it be possible to experiment with perhaps filing it back a bit, possibly the inside face, so that tightening the rack clamp doesn't exert so much pressure? Just a thought, I know it will work without it, but even a threepenny bit of plastic doesn't pass the production accountants if there's no reason for it being there!

Steve

[xvivalve]

All 'reconditioned' racks do away with this nylon plug, replacing it with a thick band of painted over masking tape!

[Mahesh]

I've had the car up on stands over the weekend,
and would advise split/slit washers on the solid
rack mounts.

Steve had tightened them well, I was present to
see, but I'm not exactly a gentle driver and both
bolts were down to the last four threads.

Re: cheap rack, I have been lucky, once the car
was up, I checked and both wheels are registering
to less than a mm of steering movement.

I would not chance a cheap rack again ever.

[shaunroche]

Yeah, I've considered putting a void in the clamp just in case, so now I know that bungs there, I can do something about it. I was worried about crushing because I can't legislate for a variation in the rack tube.

On one hand, I would expect all the tubes to be within a certain tolerance as they would be mass produced from the same set of dies in the foundry. On the other, this is BL we're talking about!

I always suggest putting some loctite on the threads and using flats and spring washers. If I remember correctly Mahesh, you had one solid clamp and one std, meaning that the solid rack clamp would go on the opposite end to the bung as that is only on the nearside.

Of all the twenty or so clamps I've supplied, I'm the first person to have a problem, probably because this rack is a NOS one and not a recon, as Alun says, I suspect they don't bother putting the bung back in on a recon....

[Carledo]

OOPS! Think I put the one solid mount on the N/S of Mahesh's car, for oil pump clearance reasons! But my memory could be wrong!

Steve

[shaunroche]

Hmm... wouldn't recommend that way.....I don't think it's that close to the oil pump, unless the engine mountings have no stiffness left in them!

You've now got the end that hardly moves restrained and the end where the steering input goes, where there's both torsion and axial movement less restrained...that puts a moment on the nearside which could, in theory, cause a fatigue failure in the rack tube.

In reality, probably not, but I would swap them over personally... remind me, there isn't a plate under the offside clamp is there? We'll, there shouldn't be.

[xvivalve]

In reality, probably not, but I would swap them over personally... remind me, there isn't a plate under the offside clamp is there? We'll, there shouldn't be.

There is, but it is an integral part of the subframe.

[Richard the old one]

If you are not fitting one or both solid clamps you need to note that there is a need to fix the O.S clamp first and that the plate under the N.S clamp and the sub frame have slots in them so that the plate can be used to force the clamp tight against the poly mounts to stop movement. This fact is not made very clear in any of the manuals that I have looked at. I can not remember which way you have to push the plate but when you push it one way I think it is towards the rear of the car it forces the u fixing clamp sideways to hold the mount tight.