Trek 4700 headset overhaul

[Gixxerman]

I have noticed over the last few months that the headset on my Trek 4700 has kept coming loose.
I kept adjusting it to take up the slack, only for it to work lose again.
Then last week I noticed orange water coming out the lower headstock bearings.
So there has obviously been some water ingress.
I took off the forks and checked the bearings. The upper ones seem fine, but the lower ones are very rough. I have done my best to clean them with (spit!) WD40. But they are still very noisy.
I tried to remove the bearings from the frame to get a better look, but they are proving very difficult to remove without the required tool. I have tried a few bodges and some very light persuasion but they will not budge. I am reticent to use any great force for fear of damaging the headstock.

So what are my best options?
Re-pack them with grease and hope for the best?
Replace the bearings?
Replace the whole headset? I have seen one on Wiggle for £22.50 (http://www.wiggle.co.uk/token-tk737acb-heavy-duty-threadless-mtb-headset/)

I expect that I would have to get the LBS to remove the old headset. I could fit the new one myself as I have a suitable puller. But if the LBS is removing the old one, they might as well fit the new one whilst they are at it.

 

[RecordAceFromNew]

By the time you get brown water I suspect bearings are rusted and are now junk. You could check the races if they are still perfectly smooth if so you might be able to just replace the bearings. It is curious that the headset "kept coming loose" - was the headset properly preloaded by the bolt on the stem cap before the stem bolts were tightened?

If you are thinking about diy the first thing is to ensure you get the right replacement. I think current Trek 4700 have semi-integrated headsets for which the one in your Wiggle link won't do. But I am sure older 4700 were traditional. This should help you identify what you have. Perfectly decent headsets can be bought for under £20.

Removing worn headsets is relatively easy and requires no special tool for steel/alloy steerers/frames, installation is a little trickier and though not essential easier with a headset press (cheap imitations are available on ebay).

 

[Gixxerman]

Looking at that pdf mine defo has traditional bearings. Can they be disassembled in situ without having to remove the bearing cups from the frame? I can move the seal a bit with a screwdriver but it just can't seem to pries it out.
Yes the bearing were properly adjusted and the pinch bolts tightened. I think that the ball bearings just kept wearing do to poor lube, resulting in excess play.

 

[RecordAceFromNew]

Looking at that pdf mine defo has traditional bearings. Can they be disassembled in situ without having to remove the bearing cups from the frame? I can move the seal a bit with a screwdriver but it just can't seem to pries it out.
Yes the bearing were properly adjusted and the pinch bolts tightened. I think that the ball bearings just kept wearing do to poor lube, resulting in excess play.

Certainly. Once you have loosen the cap/stem bolts and taken the stem/bars/spacers off the steerer, the fork/steerer/crown race should slide down the headset/frame (with no more than gentle persuasion, there might be a slightly sprung O ring) leaving you with a handful of headset bits falling off all around you disappearing into every crevice you have never noticed before, with only the top cup of the bottom part and bottom cup of the top part of the headset remaining on the frame. Don't do it on clean carpets!!

 

[Gixxerman]

Managed to get my balls out eventually .
Struggled to remove the locking ring. Trying to pries it out using a screwdriver failed. Eventually I used a pair of needle nosed pliers. That is the end of the good news.
The bad news is that (as expected) my balls are very rough and pitted as are the cups. So new headset it is.
I was toying with making my own cup removal tool from a bit of old pipe and replacing the headset myself.
But I think that I will just let the LBS replace the cups and bearings if the cost is not too high. I expect to pay about £30 all in. If it is much more expensive than that, then it will be back to DIY.

 

[Gixxerman]

OK I have decided to go down the DIY route.
I made a bearing extractor from a length of 22mm copper pipe, by splitting about 30mm of the end into 4 tangs.
I fitted a large bolt and some washers to the other end to give me something to hit with the hammer.
The tool worked like a charm and the cups are now out.
However, I now have an issue in what headset to buy. The main cause of confusion is the stack height.
I would like to get a headset with the stack height as near as I can to the one that I am replacing, as that will mean I can get away with the same spacers I have now.
So how do I measure that stack height if the old headset (bearing in mind that it is now off the bike and it pieces).
Do I reassemble the headset of the bench and measure the height of the whole headset?
Reassemble meaning lower crown race + bearings + lower cup with upper crown race + bearings + upper cup place on top of each other. Do I need to include the cap nut in the height figure?

 

[lulubel]

Wouldn't it be easier to just buy a few random-sized spacers? Then you can buy any headset, and you'll know you have the spacers to work with it.

 

[BimblingBee]

Stack height is the bit that sticks out for the frame. You could measure this and compare with the specs of those that you are considering buying. Although they are all generally fairly similar. It would only be a big problem if you ride with the stem slammed down to the top of the headset, otherwise you could adjust with spacers.

Chainreaction have some good deals on a the moment on headsets (with stack heights shown in specs!)

Pretty easy job on your Trek.

http://www.chainreactioncycles.com/Models.aspx?ModelID=24980 good value?

 

[Gixxerman]

Right I have set that I think will do the job.
However, when I came to fit it, I discovered something that I need a bit of clafication on.
The headset came with a lower crown race. My old headset lower crown race came off without any effort (it was quite loose). I thought the lower crown race normally needed quite some effort to remove?
But looking at the forks, it appears that there is something that looks a bit like a crown race still on the forks. But it could just be they way the forks are made.
It can be seen in the pictures.

 

[BimblingBee]

Yep, that bit on the fork can come off. On the opposite side of the fork (in the picture) there may be a little notch to get a flat bladed screwdriver in. Tap it with a hammer and it will come off fairly easily.

If you look closely there may be a very slight taper towards the bottom of steerer tube...

 

[accountantpete]

The bit on the fork is the original crown race and was made for sealed bearings (which you have in your new headset).

They have simply popped another crown race over the top - one that took caged bearings. It will never have seated correctly - hence your problems.

I agree - try and prise it off.

 

[Gixxerman]

Nope, no notch. I tried to see how tight it was by trying to move it with a pipe wrench. But it will not move. It really does look like it is part of the fork assembly to be honest.
I really can't see that it is the lower crown race as the lower crown race is already off. Unless for some bizzare reason it had 2 lower crown races on it (from and earlier bodged headset change maybe?). But that is unlikely of the headset is a bontrager one which would suggest that it is the original factory fit.

 

[BimblingBee]

It's supposed to be tight. You won't (and shouldnt) get it off by hand or twist it with mole grips etc. Screwdriver and hammer and spray are your friend! Don't be shy!!

 

[simon.r]

It does look as if the fork still has a crown race fitted.

They can be a ba***rd to remove, but will suddenly 'go'. A thin screwdriver tapped in under the race will generally start it moving (where the white scratch is on the right hand side of your photo). You may need to 'tap' fairly hard!

 

[Gixxerman]

Took it to the LBS. He refitted the "second" lower crown race to how it was and it actually spun freely on the suspected other lower crown race, He said that it was very strange that the lower crown race should not be lose like that. After some inspection he said that it was a lower crown race and should be removed. He carefully tapped a stanley knife blade below the crown race. After a few rounds of this, he had a big enough gap to get a screwdriver in and off it came. So it would seem that for some reason, someone had fitted a new headset in the past and put a lower crown race on without taking the old one off. The third picture shows how they would have sat on the bike. No wonder I had the problem with water ingress in the lower bearing. Thanks guys. I will now fit the new headset. Hopefully, this is the last of my troubles with the repair.