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MG MGB GT V8 Factory Originals Technical - Factory V8 Steering?
|A bit of background first! I've owned my V8 for nine years now and for the last four used it as an everyday car. The steering effort has always been slightly stronger than a GT (or conversion possibly?) but this was always a feature of the factory cars.|
Three weeks ago I took her to visit in-laws.
Return trip 500Mls, during which she ran like a Swiss Watch. On the way we hit a huge pothole on the offside front. I stopped and checked the wheel but luckily the steel outer rim and the tyre didn't seem to have sustained any damage.
We carried on for another 100 miles with no apparent damage and had a nice weekend. (During which I covered another 35 miles or so).
On the way back the car seemed to be favouring the front offside brake (pulling right at high braking speed) and the steering felt whooly.
On returning home I had it checked with a tyre fitting outfit who have a laser checker.
I gave operator the 'book' - toe-in 1.6 to 2.4MM and his reply was "Yeah - but it should be OK at about 1"!!
After this the steering was certainly easier but there was no castor return - by which I mean that I could turn - say - into a tight roudabout and the car would just keep going around when I let go of the wheel (scary!)- of course this made it very uncomfortable to drive (to say the least).
I took it to the guy (Dave) who has always looked after it and explained to him the problem, as I have here.
His immediate diagnosis was tight kingpins (it is lubricated every 3000mls).
So - Dave had it in and disconnected the track rod ends, applied heat to the kingpins, forced new grease through; getting rid of old grease - fitted two new track rod balljoints (which I had), checked the rack (fitted new gaiters) and set the steering up properly.
Result - Nil
The castor return comes back OK, to a point, but the car in the straight ahead will jump left or right if a small bump is hit (particularly at low speeds) and needs continual correction. It seems to only steer by effort rather than thought, as it used to be (does that make sense?) the steering is just dead and very hard work.
Any ideas???? Sorry to go on a bit.
|J M SWIRE|
|Is there any stiffness in the steering with the front raised off the ground? That would be my first check, a finger tip should be enough to send it from lock to lock, but don't bang up against the end-stops.|
'Normal' resistance when turning but no castor return indicates a lack of castor rather than stiff steering, you should check and compare the castor and camber angles of both kingpins. If the wheel goes into a big enough hole then the tendency will be to push it backwards a bit, possibly bending the A-arms, which will reduce the castor angle.
Toe-in errors shouldn't cause the effects you are describing, and your operator reckoned one inch would be OK!!!? I think not! Did the castor return vanish after the laser checking or was it like that immediately after hitting the pot-hole?
Jumping left or right with a small bump sounds like bump-steer which can happen when the steering geometry is changed, like the track rods being other than horizontal, which can happen with lowered suspension. How to the heights compare side-to-side from the cente of the hub to the bottom of the chrome strip, front and rear?
Pulling to one side with significant applications of front brake can be caused by a non-damping damper on the side it pulls to, as well as a sticking caliper on the side it is pulling from. Is it pulling *to* the side that hit the bump?
I know what you mean by stering by thought rather than pulling on the wheel, that is what my CB roadster is like. My V8 is noticeably heavier but it is an RB with a 1" smaller wheel. The V8 is only about 29 lbs heavier than the equivalent 4-cylinder GT, and whilst that would be quite a weight to carry about in one's arms it is barely 1% more in terms of total vehicle weight and as such I wouldn't have expected to feel it in the steering. There is about 87lb/3% between CB and RB V8, about double that between a CB roadster and an RB V8.
|Thanks Paul - |
1. I'll check for stiffness the way you describe tomorrow. As Dave disconnected the track rods to find which side was stiffest I assume he did that. He certainly said that both were very stiff but didn't qualify it with which was the worst side.
2. I was worrying about something being bent by the hole but none of these symptoms seemed to appear until quite a few miles later. Although the pothole was certainly a big jolt it may have nothing to do with the trouble.
3. Sorry - I did put 1" didn't I? Meant 1mm of course. Even that though is not 1.6 to 2.4 is it? Again though it has been disconnected and re-done since then.
4. Will check the heights too. Apart from a Spax tele conversion and PH stiffer anti-roll bar it is standard (i.e. not lowered)
5. It is pulling *to* the side that hit the bump. Have spare dampers so could change them.
It felt better in the rain today which suggests to me it was getting a bit of extra lube from the moisture but nevertheless it is not 'right'..
Will do those jobs tomorrow - weather permitting.
|J M SWIRE|
|Martin, make sure that there is no strain on the steering column. If the rack has turned in any way the extra strain on the pinion will give much the symptoms you describe. I tried putting shims (washers) ender the rack to take the column away from the manifolds and it felt much as you describe. There must be no strain on the steering universal.|
|Thanks Ian - |
I think I'm definately mking headway.
Tried your trick of pushing from lock to lock with a fingertip Paul - you've got to be joking! Can only just push it with my foot and it needs a good hand on each side of the wheel and a good shove to do it by hand. While it was jacked-up there definately seemed to be resistance in the actual steering column (I could hear it rubbing). I took off the steering wheel and sprayed a liberal amount of Duck oil down the shaft and also further down where it goes thru the bulkhead. Also sprayed around the UJ (although that probably won't make any difference). Just to make doubly sure I also re-greased the kingpins and it definately eased up a lot. Still no go with the fingertip though! Can't think there is actually anything wrong with the rack set-up as you mentioned Ian - it's just a standard BL factory car.
You have me worried about the ride heights though Paul. Not easy to measure but here goes, as near as I can tell.
Nearside - front 38 cm: rear 39.5
Offside - front 38.6 : rear 38.6
Not exactly symetrical!! tyre pressures are same side to side.
The rear is particularly puzzling because the springs are virtually new o/e and I fitted new shocks at the same time.
I wouldn't know how to adjust that anyway.
Having said that she's certainly better today - castor return is quite strong now and steering effort maybe as good as it has ever been. It still has that disconcerting feeling that it wants to plough on in the straight ahead position though with input needed to keep it straight. It's hard to explain really but doesn't feel quite right.
|J M SWIRE|
|somthing you could try . the bottom wishbone assembly can wear and a good whack can cause it to move because the 2 wishbones are only bolted to the spring pan.if this has happened and the wheel has moved back you will lose an amount of caster on that side.get a piece of string and have a friend hold it on the rear wheel so it passes through the centre, pull it tight and hold it to the front of the front wheel.align the front wheel so it touches the string on the front and rear of the front wheel.this is how you get an exact measurement for wheelbase ,if you measure the wheelbase (hub centre to hub centre)then repeat the other side it may show up your problem.if its realy bad you can measure with fingers between the tyre and the rear of the wheel arch ,good luck|
|Have you tried the steering uj behind the exhaust manifold? my factory V8 suffered very stiff steering a few years back, turned out to be a partially siezed uj...a very cheap fix it is too.|
|Thanks for all this input - very useful it is too!|
Thanks for that Mark - I'll bear it in mind.
I'm a believer in trying the simple things first and then moving on to the more technical so I was pleased to hear about the UJ John.
Considering the improvement today with a bit of oil you may have a good point there. I didn't know it could make such a difference I must say!
Although I am only the third owner and have had the car for 9 years (I also have complete logs and bills for every mile) she has now done nearly 250,000 miles, is cherished, but not pampered, and that steering UJ is probably the original (in fact I don't think I have reference to it in my records). I'll get a new one tomorrow - it can't do any harm!
Cheers and thanks - the saga will continue no doubt! Martin
|J M SWIRE|
Check the rack mountings. Cracked mountings or failed welds between brackets and crossmember are becoming more common. It would only take a tiny amount of lateral movement to cause the column to foul on something.And John's UJ tip is a good one. These eventually fry due to proximity to the manifold and can get very stiff. Try some WD40 applied externally as a test. I would disconnect the track rods and test each wheel and the rack independently. I'm impressed that your mechanic Dave used heat on the kingpins. Most people struggle and then give up!
|Martin, You have a lot to be going on with now but just to add a bit more: I would be looking for the rubbing which you mention. The steering colomn comes off easily (though getting it back on is a bit more problematic due to the U/J bolts). This would enable you to isolate the stiffness to the column, U/J or rack.|
|The track-rod ends *are* (or should be) stiff if you try to move them by hand off the car, but when on car the effect is minimal.|
Stiff steering with the wheels raised is very bad news. Removing the UJ will allow you to determine whether it is in the column or the rack/swivel axles, or indeed the UJ itself. Disconnecting the track-rod ends from the steering arms will allow you to determine whether it is in the rack or the swivel axles. The steering column should not need lubricating. If the steering suddenly got stiff after the pothole then something is definitely damaged.
This thread was discussed between 14/03/2004 and 18/03/2004
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