Center drag link questions

[mxracer41]

Is there a sure way to tell if the center drag link is actually bad? My steering in my 540 has gotten gradually looser over the past year and it's pretty bad now.. :( So far I have replaced the tie rod ends, LCA bushings (powerflex), sway bar links (all in the front end), rear lower ball joints, and I believe that's it. I'm sure at my mileage (191k) the center link has got to be pretty worn. However, I know the steering box can directly affect the steering, as can the idler arm bushing, etc.

The main reason I ask is that when I get under the car and feel for play in the center link, I can't feel any movement at all. So, I am a little hesitant to replace the whole thing for $200+ if it's not the cause. Anyone have any suggestions to narrow down the cause? Could it be that the gears in the steering box are worn down and causing the loose feeling? Any input is appreciated. Thanks!

[54zero]

Look for rips in any ball joint boots , that tends to let dirt in and wear them down. Also I like to have both wheels off the ground while someone shakes the wheels for me lightly back and forth From the rims not the steering wheel .While that's going on I like to put my hand over each ballpoint and feel for play that way. It's much more noticeable then just looking.

[mxracer41]

Look for rips in any ball joint boots , that tends to let dirt in and wear them down. Also I like to have both wheels off the ground while someone shakes the wheels for me lightly back and forth From the rims not the steering wheel .While that's going on I like to put my hand over each ballpoint and feel for play that way. It's much more noticeable then just looking.

I'll give that a shot for sure, from what I can remember the rubber boots were fairly intact; definitely nothing obvious so if they are torn it is minor. I just can't justify dropping $200 for the part if it doesn't need to be replaced... I'm a broke college kid and gas is also expensive as hell so parts cost must be kept to a minimum lol. And DIY is definitely a must as well :)

[edjack]

Good test: get the front of the car up on ramps. Crawl under, and have a helper rock the steering wheel back and forth about 6 inches. Wrap your fist around the tie rod links at the pitman and idler arm connections. You will probably detect a good bit of play, and even clicking, at the pitman arm ball joint; it wears out first. They're generally gone by 80k.

You can waste your time with aftermarket ball joint pullers, but the BMW special tool is the only one that really works well, and will save you time and effort. It's worth the $100.

[kimokk]

If the center link ball joints are ok and you want to save some money just replace the idler arm or the idler arm bushing. The bushing is less than $20. See section IV of this DIY (http://www.bimmerboard.com/forums/posts/65885).

[edjack]

This is my second BMW, and I've yet to see the idler arm bushings wear out.

[kimokk]

Cool, how many miles on both? Probably more likely the two ball joints on the center link.

[mxracer41]

All good ideas, thanks everybody. As for the idler arm I tried to feel for play and that thing is rock solid, so I don't think that's the problem at all. When I replaced my tie rod ends I did notice the threaded ends on the center link that they screw into were fairly loose, boots were all still intact though. Not sure if this is ok or not, probably not I'm guessing..

How about the steering box? I know there's a manual adjustment you can do to adjust the gears or something of that sort.. but that screw to adjust it with is near impossible to get to.

[Justin517]

At 191k miles, if you can confirm it is the original I'd say just replace it and the tie rod ends and forget about it for another 150k+ miles.

Sometimes peace of mind is worth the money.

[jaym540i]

Is there a sure way to tell if the center drag link is actually bad? My steering in my 540 has gotten gradually looser over the past year and it's pretty bad now.. :( So far I have replaced the tie rod ends, LCA bushings (powerflex), sway bar links (all in the front end), rear lower ball joints, and I believe that's it. I'm sure at my mileage (191k) the center link has got to be pretty worn. However, I know the steering box can directly affect the steering, as can the idler arm bushing, etc.

The main reason I ask is that when I get under the car and feel for play in the center link, I can't feel any movement at all. So, I am a little hesitant to replace the whole thing for $200+ if it's not the cause. Anyone have any suggestions to narrow down the cause? Could it be that the gears in the steering box are worn down and causing the loose feeling? Any input is appreciated. Thanks!

Change all the front suspension and steering components such as the center link and tie rods. With the mileage that you have on your car you will be amazed with the difference. It will be like a new car in feel and handling.

[54zero]

So you replaced the outer tie rods. I'm used to working on rack an pinions , the part you say is loose is usually called the inner tie rod. Not sure if its the same thing for center links but anyhow they are ball joints so they should move freely that's fine as long as you don't feel the balljoint jumping around in the socket. Ifs it's really loose though there worn out and need to be replaced.aside from that I'm also interested in what the adjustment for the gear box does and how to adjust it. Can anyone chime in?

[mxracer41]

So you replaced the outer tie rods. I'm used to working on rack an pinions , the part you say is loose is usually called the inner tie rod. Not sure if its the same thing for center links but anyhow they are ball joints so they should move freely that's fine as long as you don't feel the balljoint jumping around in the socket. Ifs it's really loose though there worn out and need to be replaced.aside from that I'm also interested in what the adjustment for the gear box does and how to adjust it. Can anyone chime in?

Yup I only replaced the outer tie rod ends, which were absolutely shot. And yeah the 540 just uses one big inner tie rod, aka the drag link. I'm not too knowledgeable when it comes to suspension and steering stuff, but from what I understand some cars use two inner tie rods instead of one center link? And yeah the joints that connect the ends to the center link felt pretty loose, so I may just have to bite the bullet and replace it... although hopefully the newly improved steering will be worth it :)

As for the steering box adjustment, there's a nut on top of the steering box with what I believe is a 5mm allen bolt on the inside part. From my understanding you just loosen up the nut and screw in the allen bolt until it begins to feel like its getting tougher to turn, and back it out about an 1/8 of a turn. While doing this I've heard its good to have a second person at the wheel testing the steering to make sure it's not getting too stiff, etc. I've heard mixed opinions about doing this, some say it's an amazing improvement, some say it's a bad idea, etc. I was going to try it but the nut is ridiculously hard to get to so I left it alone for the time being.... however if anyone has done this and has any tips to share I'm all ears!

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Change all the front suspension and steering components such as the center link and tie rods. With the mileage that you have on your car you will be amazed with the difference. It will be like a new car in feel and handling.

For sure, I've changed LCA bushings, sway bar links, and tie rods so far and the biggest change I felt was the increase in stiffness and more precise handling that came after replacing the LCA's with the powerflex poly bushings. Of course not hearing the constant clunking of bad sway bar links was an improvement as well :)

I will probably just end up doing the center link; not sure of any other way to improve steering feel other than replacing the box. Getting rid of my giant 4 spoke steering wheel might help the feel too but the single stage airbag newer style wheels are rare and expensive :(

[philly98540]

As for the steering box adjustment, there's a nut on top of the steering box with what I believe is a 5mm allen bolt on the inside part. From my understanding you just loosen up the nut and screw in the allen bolt until it begins to feel like its getting tougher to turn, and back it out about an 1/8 of a turn. While doing this I've heard its good to have a second person at the wheel testing the steering to make sure it's not getting too stiff, etc. I've heard mixed opinions about doing this, some say it's an amazing improvement, some say it's a bad idea, etc. I was going to try it but the nut is ridiculously hard to get to so I left it alone for the time being.... however if anyone has done this and has any tips to share I'm all ears!



I adjusted my steering box. Your description of how to do it is pretty spot on. The resistance at the steering wheel is the key to getting it right. Very slight adjustments near the limit really impact the drag at the steering wheel. Takes some fiddling to get it right. I did mine when I did my timing chain guides and major overhaul work the other year (122K), so that provided the clearance to get to the nut and allen screw. I don't think Houdini could do it withot removing some stuff first. Just no room at all. After I did it, the on center steering play was reduced by about half. Still a steering box and not rack/pinion car, but a bit better/tighter feel.

At your mileage, I think you likely have some loosness at the drag link ball ends and possibly the pitman arm. Do as Edjack said and get it on ramps so the car weight is on the susp. then have someone turn the steering to while you confirm exactly where the play is. If your boots are free of rips/holes, the parts may still be good. Change just whats needed to save cash. I think you should forget about the box adjust until you need to dig in for more repairs.

[mxracer41]

Well, got it up on a lift and gave it a good shakedown. Sure enough, the inner tie rod on the drivers side is shot, easily has 1/4 to a 1/2 inch of free play. So I guess it's time to replace :(

Now for the real question: What is my best option for parts? I know TRW is the OE manufacturer, but I know that Lemfoerder is a very reputable and proven brand as well, and their part is a good bit cheaper, about $149 vs $200 for the OEM from Bavauto. Anyone have experience with the Lemfoerder that wants to contribute some feedback?

[kimokk]

I got one of these (http://www.oembimmerparts.com/product_p/32211096059e39.htm) from Max at oembimmerparts.

[mxracer41]

I don't see that one for the 540, I'm guessing their not interchangeable.

[John in VA]

While I haven't needed to replace any suspension components at 80K miles, I have used Lemforder components on my 2002, E30, & E28s with excellent results. I used Meyle HD LCAB assemblies on the E46 - doing fine after 3 years.

[ElleShooTiger]

Get the TRW steering parts. There's a reason that BMW chose them over Lemfoerder for the V8 steering parts. IIRC some people have reported that the Lemfoerder steering parts are not nearly as good quality-wise as their control arms are.

[kimokk]

I don't see that one for the 540, I'm guessing their not interchangeable.

Sorry I meant this one. (http://www.oembimmerparts.com/product_p/32211096059e39.htm)

[mxracer41]

^^^ Thank you! That's an awesome price compared to all of the others that I've seen for the TRW part. Although this says it's made by TRW/Lemforder...?

[kimokk]

^^^ Thank you! That's an awesome price compared to all of the others that I've seen for the TRW part. Although this says it's made by TRW/Lemforder...?

If you want the TRW one send Max an email that you want to order the TRW brand vice the other one. He's pretty responsive and easy to work with. Also quick shipping!

[mxracer41]

Ohhh ok I understand. Was the price listed applicable to both brands?

[kimokk]

Ohhh ok I understand. Was the price listed applicable to both brands?

Yes as far as I know. If you find any lower prices he will match those too.

[mxracer41]

Awesome, thanks a ton man. I think I'm gonna go ahead and order that. My steering is beginning to feel like the steering on the ford excursion I used to drive... :(

[Caneri]

I just replaced a the center link on my 2000 bmw 740il. when I started the vehicle to test drive, it appeared as if the vehicle was going up and down and the right wheel was definitely way off to the right. I can't even drive it to the alignment place. please help!