Wobbly bike after servicing

[Cyclewala]

Well, I’m truly stumped.

A few days ago I cleaned & regreased the fork and headset on my ‘98 Marin and it now wobbles. It’s like the steering is not talking to the headset and front wheel. A bit like riding a buckled front wheel.

I’ve taken the fork and headset apart three times and reinstalled. Does the same with each test ride. The headset torque is just right. The front wheel runs true. All the bolts are done tight.

Bearing in mind I’ve done this sort of servicing many times before and it’s always gone back together fine. What could it possibly be? Any ideas.

Pic of the bike in case it helps.

The suspension in the fork comprises a steel spring at the end of a series of rubber spacers.

[peetee]

Something is not right with the headset. Your photos look like they show a discrepancy between the angles of the head tube and fork - they should be the same. I reckon you have made a mistake with the headset reassembly or corrosion on the steerer is preventing the upper stack components from seating correctly. Pay attention to the bearings (they may be flipped) or the conical, centring split-ring which may not have closed down correctly.
Looking again though, is that a spacer washer above the fork crown? It should be above the head tube and bearings with the other spacers and stem. If the lower bearing is currently above this it cannot sit on the conical fork race and that is what centres the fork in the frame.

[Jupestar]

Hard to tell from the photos, but it's looks off line.

What is the black part below the head tube? Looks like a spacer which could be between the crown race and the bearings. Or is it below the crown race and part of the fork?

[Cyclewala]

Hard to tell from the photos, but it's looks off line.

What is the black part below the head tube? Looks like a spacer which could be between the crown race and the bearings. Or is it below the crown race and part of the fork?

That is the lower headset cup. The lower bearing sits in that.

There is a rubber seal underneath the bottom bearing (against the fork) which seals against water/dirt.

[Cyclewala]

Something is not right with the headset. Your photos look like they show a discrepancy between the angles of the head tube and fork - they should be the same. I reckon you have made a mistake with the headset reassembly or corrosion on the steerer is preventing the upper stack components from seating correctly. Pay attention to the bearings (they may be flipped) or the conical, centring split-ring which may not have closed down correctly.
Looking again though, is that a spacer washer above the fork crown? It should be above the head tube and bearings with the other spacers and stem. If the lower bearing is currently above this it cannot sit on the conical fork race and that is what centres the fork in the frame.

The black section is the lower bearing cup. There is a rubber seal beneath the bearings and the top of the fork. There are no spacers at thdd Ed bottom of the head tube.

[Cyclewala]

I’ve updated with some better pics.

[peetee]

Push the bike forward with both hands in the bars and grab the front brake. Look down through the stem, head tube and forks as you do this.
If you feel a clunk or play and the fork crown moves in relation to the head tube the headset is your problem.
If it’s moving between fork leg and crown it’s the suspension stack.
I would also check one of those inner legs or the steerer haven’t cracked, probably at the clamp end.

[pwa]

Firstly, the handlebar stem has been off, so has it acquired a crack near the bolt holes when you put it back on?

And is the wheel properly and squarely in the forks?

[rjb]

As it's been apart several times have you lost some balls from the headset bearings or if caged bearings put them back correctly?
Is it loose balled, caged balls, or sealed bearings. ?

[Cyclewala]

As it's been apart several times have you lost some balls from the headset bearings or if caged bearings put them back correctly?
Is it loose balled, caged balls, or sealed bearings. ?

Caged balls. All intact. Going to the garage again and inspect for cracks. I thought I might have installed the bottom bearing upside down but it made no difference when I tried it the other way.

[531colin]

You put a set of balls in a cage either way up and it didn’t make any difference!!!!
That’s completely mad. … one way up you don’t have a proper bearing running on the balls, because the cage fouls on the cup.
Which brings me to ask in what way does the bike “wobble” …?
Do you mean you can’t steer it precisely? ( because the headset bearing doesn’t work ?

[peetee]

Could it be that before you serviced the headset it was gummed up and binding and what you are feeling now as instability is actually a free-moving headset that seems too lively?

[richardfm]

You put a set of balls in a cage either way up and it didn’t make any difference!!!!

It's which way up the cage is, not which way the balls are in the cage, that matters.

[slowster]

The fact that the headset feels the same when the orientation of the caged balls is flipped would be consistent with insufficient pre-load of the bearings. That is usually caused by:

- The expander bung in a steerer not being tightened sufficiently to anchor it, with the result that it is pulled upwards when attempting to pre-load the bearings, and ends up pressing against the underside of the top cap. However, your fork will have a steel or aluminium steerer, with presumably a star nut instead of a bung, and movement of the star nut is unlikely (but not impossible), or

- The top cap bottoming out on the top of the steerer tube before the bearings can be pre-loaded. That can be caused by a missing headset spacer, a missing headset part, substituting a shorter spacer, ftting a lower stack height stem, or changing the top cap for one with a deeper shoulder on its underside.

[PT1029]

Can the OP tell us he has checked the headset for correct adjustment - forks free turning (as much as all those cables allow) in frame with front wheel off the ground, AND rocking the bike on the ground back and forth with just the front brake on, there is no play/wobble back and forth movement in the heaset. As mentioned upthread, need to distinguish between fork leg/suspension wobble and headset wobble (if unsure, put a finger across one end of the headset to try to detect movement there). Also check for wobble between the fork colunm and the fork crown - unlikely, but not unheard of.

Is there a gap between the top HS race and the lowest silver spacer? It might be the top of the HS has a smaller diameter than the silver spacer and in might be ok.
Before sevicing, was the headset stiff and/or pitted? If so, new grease and bearings might mean it is now free turning and you are not used to that.
Check the top cap is 1 - 2mm above the top of the fork column and the star washer is depressed below the top of the fork column. That way you can rule out the top cap bottoming out on the top of the fork column before it has eliminated loose play in the bearing adjustment.
The fact that you say you tried a bearing cage the other way up and it made no difference, well that makes no sense at all to me. I would measure the ball size and go and buy some loose balls to replace the caged balls (being loose, you will need more balls than are in the caged set).