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Triumph TR6 - Stiff Steering Rack
|I've had this car only a few months and just recently found the time to investigate why the steering seems so bloody stiff. The previous owner restored the car from the ground up (lucky me) and I first suspected that he'd somehow tightened the steering column up by incorrectly fitting new bushes. Systematically disconnecting everything from the top U-Joint down has revealed that my suspicions were incorrect. I now have the tie rods unscrewed from their ends (eliminating the trunnions from the equation) and the steering column disconnected from the rack and it's clear that the stiffness is purely in the rack itself.|
Of the cars I've messed with in the past, I've never had to get inside a steering rack, so this end of things is all new to me, so I need some advice. Is it possible that the rack has been incorrectly adjusted (I presume that's what the shims I see in the exploded diagrams are for)? When I push and pull the rack, it doesn't feel as though the resistance is from any kind of gunge, it feels more mechanical. It's as if I have to force the rack past the pinion.
Any help will be much appreciated. I'd like to get the car out and safely running in time for a mountain run the weekend after next.
Thanks in advance,
|Have you removed the bolt from the rack and inserted a Zerk to lube it?|
I've always felt my car has that "HEAVY" feeling in the steering and have noticed it in others I have driven. I guess it's just something that makes it a TR6...does your steering feel any different when the front end is off the ground ?..it should obviously be lighter.
As Rick mentioned try lube.. in the rack I recall the book saying no more than 5 squirts of grease.
Remember..it's a hairy chested man's car !
hope that helps
|The steering is still pretty heavy even with the wheels off the ground (and a healthy thatch of hair on the chest!). I really feel that it's dangerous, as you not only have to apply a significant amount of force to turn it into a corner, but also to straighten it up out of the corner.|
I did apply grease to the rack and it seemed to make no difference - hence the reason I suspect that it was maybe badly adjusted.
Anyone familiar with playing around with the various shims? There are a couple below the big bolt with the grease fitting - what do those control? According to the diagrams I've looked at, there are also some further down along the pinion shaft too. What are those for?
Did you reconnect the column shaft to the rack to be sure it is still stiff (with the tie rod ends still disconnected)?
The reason I ask is that I had the same problem with a TR6 that I had many years ago. It was dangerous, as you say, because I had to muscle the car into the turn and then muscle it back out. Turned out to be a nearly siezed king pin...or is it called trunion.
I know you checked that but maybe it only stiffens when loaded with the vehicle weight.
Let us know what you find
|HP Henry Patterson|
That's what I'll try next, as soon as I get the rack back on the car. I removed it last night and disassembled the plunger and pinion assemblies.
My inexperienced eye detects no appreciable wear on either the rack or the pinion - but I'm not sure what the normal wear pattern is.
What I did notice, however, is that if I loosen by a few turns the large nut that holds the plunger assembly in, it all becomes much smoother and freer in operation. I also noticed that the spring is a much heavier duty one than the one in the drawings in the workshop manual - but this could be down to artistic license, I guess. Has anyone looked at the spring in their rack?
Another interesting difference from the manual is a washer below the spring - effectively lengthening the spring by 1/16" or so. I'm wondering if a PO replaced the spring and added the washer because he couldn't find one long enough...
personally I suspect that your problem does lie in the steering rack plunger area.
When I begun restoring my car last year I had experimented with the entire steering and suspension components to relieve any slopiness.
Besides the obvious, you have to have the correct amount of shims above the plunger in the rack so as not to exert too much downforce and at the same time not too many shims as this will give you a very light and unpredictable steering.
So, get your manual out and do the following:
a) determine what the length of the plunger spring should be.
b) get the proper shims as some previous owners simply used washers(not correct)
c) adjust either remove or add shims to your preference.
d) fill rack with heavyweight oil, I believe 90 wt is what may be recommended.
You should be spot on after this exercise.
Interesting to find out after all is done.
|Dino - 90wt oil? I thought this rack took grease and not oil.|
You know, I'm beginning to suspect that the spring is the culprit here. The rack becomes tight way before the shims even come into play - and it's all due to the force of the spring. Somebody correct me if I'm wrong, but the spring isn't there to adjust the clearance in any way - that's a function of the length of the damper plus the shims - it's just there to take up any slack. As I mentioned before, my spring is very heavy duty. I can't compress it between my finger and thumb. I think what's happening is that it's pushing the plunger hard against the rack way before the shims even come into the equation.
The workshop manual I have doesn't help much in describing the adjustment procedure. I did, however, find something in an MG BBS posting that indicated the spring should be removed, the cap screwed all the way in and then back out until it just frees up - at which point you can measure the gap that needs to be filled with shims. Is that the same procedure to be used for our racks?
|Phil, I also have an MGB and I had done the same thing. |
If memory serves me right, there is a "convex" type of metal piece that rests on the rack(below the spring) which in turn is being pushed down by the spring/washers/cap assembly.
I had removed all and at that point it was easy to fill the rack and yes I had used a heavy oil as it has to travel throughout the rack...now this was for my MGB and for the life of me I cant rememnber on the TR, but it makes sense, think about how far would grease travel in the rack anyway?
Let us know, Dino
|I'm confused..page 30 of the Bentley book tells you to remove the plug of the "steering unit" and grease 5 strokes, but page 356 calls it the "steering rack damper" with no mention of oil or grease at refit...are they both the same part ?|
|Phil, check the archives for talk on steering rack grease vs oil. As I remember there is quite abit on it.|
Apparently the rack was designed with oil in mind and some were produced with oil installed but somewhere
in production maybe as far back as the TR4s they started installing grease. I have done both and I didn't see or feel any difference in lubrication or in the ease of steering. I changed back to grease though
because I found the oil dripping out the ends of the boots. But maybe I put too much in, regardless some guys swear by grease others by oil, they both work.
But that is not your problem, it sounds like either
you have the wrong spring or not enough shims.
You're right about the spring it is there just to take up slack and if it bottoming out it's not donig its job. Try installing some extra temporary shim to see if that solves the problem. As I remember the spring in my rack is very much the way you discribed, very sturdy.
|Update - in case you're interested.|
Turns out that the stiffness in the steering was the result of a combination of factors:
The washer that was added to the spring was probably put there in an attempt to take up some wear in the rack at some time. Removing one shim (the RIGHT way to do it!) and the washer put the end play within spec and smoothed out the action of the rack.
The second thing that I discovered (after bolting the rack back on and then attaching the column) is that the u-joints in the steering column were sometimes being forced beyond their designed limits - resulting in binding. The rack has solid mountings and any play that would normally be there with rubber is obviously missing. I solved this one by unbolting the rack and then attaching the u-joints. Turning the steering wheel a few times forced the rack slightly over to the left of centre, and when bolted down in that position, the binding is gone from the u-joints.
All in all a satisfying outcome!
Thanks for all the help and suggestions, guys.
|Phil ('66 Sprite)|
This thread was discussed between 22/03/2005 and 02/04/2005
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