W202 (98) - C250TD Estate - Drag Link/Tie Rod Assembly/Track Rod Ends

[artz]

Symptoms:

1. Advice Item on MOT says O/S inner Drag link end ball joint has slight play.
2. O/S front tyre worn through to material but only on the inside (3"-4") so not actually visible unless regularly checked.
3. Slight knocking from front wheels when going over rough roads, pot holes etc.

Had this car in the family for a while and the slight intermittent knocking noise has developed slowly over perhaps a year or two.
MOT and abnormal tyre wear gets me checking out MBClub threads which I find a bit confusing as does Drag Link, Track/Tie Rod Ends what the hell are they?
After finding some good threads here and here I decided it must be the Track Rod End/Ball Joint, however I read the MOT Advice Item again (and checked with tester) which clearly says 'inner Drag link end ball joint' so my problem is not as simple as a replacement Track/Tie Rod End and after reading a few other posts around the net, replacing just these alone doesn't seem to work too often!

After a bit more research I found this photo and diagram below which I found useful when trying to work out this seemingly common problem.

You can see the outer and inner ball joints and in between them another joint which I hope someone can name (thrust arm linkage perhaps?). Number 4 is the steering damper by the way, which looks worth/necessary to replace at the same time.
So after many hours of research I believe (please tell me otherwise) that only the outer track/tie rod ends can be bought separately/cheaply and presumably why everyone makes the mistake of fitting them first.
My guess is that these tie rod ends probably need replacing (in isolation) after a big thump or kerbing rather than after a slow degeneration from constant wear and tear of 100,000-ish miles.
So in conclusion, rather than 'jump in' I'm going to wait until the knocking or abnormal tyre wear are a real problem and then change the whole Drag Link - Tie/Track Rod Assembly which as far as a novice like me is concerned is going to be both difficult to do and expensive with the tracking then/also having to be done by a pro.
I have found a steering rack/drag link/tie rod assembly here (Ebay) for £78.50 delivered but obviously check if its the correct part for your own car.
Lastly I would really appreciate help/posts/comments here and in particular how do you do the job itself - is it as difficult as I think its going to be?
A good step by step guide would be very cool here but when I do get around to doing this job I will definitely film my efforts/f**k up's and post it here.


Thanks in advance and I hope this helps others with the same problem... and budget!


Teach-Me-Auto...A nice video of doing this job on a Dodge Ram, different to a Merc but it certainly gives a good overview.

 

[artz]

UPDATE

I fitted new discs, pads and sensors today (failure on MOT) and had a good look/pry at all the ball joints including the joint which the MOT Advice Item referred to below and what maybe called the 'thrust arm ball joint'.

This part is almost definitely not available other than as part of the drag link - tie/track rod assembly.
After really giving it a good going over there is minimal to very slight play in this joint & all the other ball joints seem reasonably sound too???????????
The only real movement (up - down, left - right) I can find is on the wheel bearing so on changing the tyre I got another indy to check who confirms my suspicions.
My MOT has an advice item attached so that next year its the first thing checked and what do you know "you need a complete tie/track rod assembly and tracking 'definitely' this year sir" - you mug! I'm clearly not going there again, however cos its computerized now, I assume that all/any MOT garage will pick that up straight away?
I hope I'm being overly cynical here but I very much doubt it?
So I hope this helps/warns others and any advice regarding tightening up the bearing would be very much appreciated, I think the procedure is also in the Haynes manual which should be arriving in tomorrow's post!

P.S. I confronted the MOT'r on retest today and he couldn't of been nicer, no retest fees, a new sidelight bulb for nothing and he pumped up all my tyres - and of course no problems for next year... if I come back - hmmmm????

Luck & Light!

 

[LawrenceMB]

Hiya, re adjusting the wheel bearings do make sure you don't overtighten them (they could heat up & seize on a long run - ie: siezed front wheel at 70mph!!!). The correct procedure would be to remove, clean & repack with grease the bearings if they we're still servicable, but if you know they've been regreased, or at look regreased this century (newish looking grease in them & no signs of overheating - in which case you'd replace them), and there'd no 'grumbling' noise from them (see below) then you can simply adjust them like thus:
- Alloy wheels: front wheel off / Steel wheel can be left on throughout proceedure sometimes but probaly easier to just take off also?
- remove the small steel half-domed wheel bearing cap by using a hammer & cold chisel under the cap edge gently around it's circumference
- Remove the split pin/retaining pin in the castlelated nut
- GENTLY tighten the castlelated - just until it bites - this may mean it's only tightened a quarter of a turn or less? maybe more, depending on condition of it. Spin the wheel hub/brake disc assembly backwards & forwards a couple of times (careful not to get fingers trapped between brake disc & calipers).
- Loosen castlelated nut again until it's NOT EVEN finger-tight.
- Now, very gently, tighten the castlelated nut again until it just, & only just, BEGINS to tighten, now back the nut off again slightly until a catlelations on the nut lines up so you can pass the split pin back in - do not tighten nut to enable fitting of the split pin, only backwards (anti-clockwise).
- Temporarily fit the split pin - just drop it in at this stage - no need to secure yet
- Refit the road wheel temporarily
- spin the road wheel with one hand & have the steering turned so you reach in & rest a couple of fingers of the other hand on any coil of the road spring. If you can feel any 'rumbling' (you won't hear it unless it's real bad) through the road spring then the wheel bearing has had it & needs replacing.
- If no rumble felt through the road spring, stop the wheel from spinning, straighten the steering up & with one hand at the top of the wheel & one hand at the bottom of the wheel, push & pull the wheel to make sure you can feel some 'play'. If there's no play then you've overtighened the wheel bearing which can be dangerous & you need to pull out the split pin again & loosen off the castlelated nut at the wheel bearing one more 'castlelation' back & then wheel back on & check for play again. It shouldn't be excessive play - but there should be some play - this allows for the bearing to expand when it gets hot without seizing.
- When you're happy there is play - but not excessive (as long as you can feel even the smallest amount of play then that's enough), then remove wheel again, secure the split pin properly (should really replace the pin but if it looks strong then ok to reuse).
- then make sure the the metal bearing cap you 1st removed is about half full with HIGH TEMPERATURE wheel bearing grease & refit cap tapping on gently using a small hammer & blunt cold chisel working around the circumference a bit at a time (will have to go around at least twice) until the cap is fully home. Do not hit the centre of thge cap with a hammer because if it dents it will rub on the spitpin & castlelated nut when the wheel is turning.
- Refit the wheel, one last check you've still got a little play in the bearing, then turn steering slightly to the right & off the jack.
- Tighten up the wheel nuts themselves when the wheel is back on the ground & you're ready to go.

NB: If you ever hear a grumbling from any of the wheels when driving, & that noise disappears/changes with slight movements of the steering wheel, then it's probably a shot front wheel bearing, which at the least you need to confirm by the finger-on-the-coilspring test above, but ideally removal, washing (not in water - in mineral solvent) & visual inspection of the bearing. If you're unsure get a professional to take a look. Don't take a chance with suspect wheel bearings - you can imagine what'll happen if a front wheel suddenly locks at high speed. But don't be scared off adjusting them as outlined above if they don't rumble on the road or through the road springs as above. Just make sure there's at least minimal play in them, so they're not overtightened
Cheers