Front end rebuild - PeachParts Mercedes-Benz Forum

lrg · #1 11-11-2002, 01:28 PM

The left side front end on my 123 started to make a slight clunk when braking yesterday. I put it on the lift and found play in the lower pivit (not sure if it's called a ball joint or a trunion). The bearings and tie rods seem solid. I'm off to get an indy mercedes shop to look at it. While I do most everything myself on this car I don't have the tools and press to do this myself. Any estimates as to what this should cost? Anything else that I should be replacing while I'm at this? The car has 150,000 miles and other than the front bearings and steering shock I believe it is all original and steering is still decently tight (although not like new). Thanks for the feedback.

gsxr · #2 11-11-2002, 03:26 PM

I'd look reeeeaaaal close at the lower control arm bushings. If they show signs of decay, now would be a convenient time to replace them. The parts are cheap, the labor isn't - requires spring removal to take off the lower control arm. The lower ball joint is another PITA job - wouldn't surprise me if it were $200-300 each at an independent MB shop (parts & labor). Most everything else - all steering links, upper control arm + ball joint, etc are pretty easy DIY jobs that can be done at any time.

My 123 needs *everything* up front - all rubber stuff, ball joints, and steering links. The rubber is just shot, and some of the other joints (although still tight) have torn boots so they are on a limited life span. Cost to replace EVERYTHING (uppers, lowers, all steering stuff except idler arm) is ~$300 in parts... plus a spring compressor rental or something. I'm thinking of taking the knuckle off and having a shop press the ball joints for me, if I can't make the AutoZone free rental tool work (others have with some mods.) Should be a fun 10-20 hour job this winter... yippee!

=:-O

Regards,

#3 11-11-2002, 04:35 PM

The track rods will cause this. If the sound seems like it's coming from just below your left foot, you need to check them carefully.

Good luck,

lrg · #4 11-11-2002, 04:50 PM

Thank you both for the feedback. Larry, I can actually see the lower pivot joint move back and forth a tiny bit when I wiggle the rotor hard. Also, I sprayed some grease in the joint and the noise went away. The rubber seal has been gone for a while there so I think the dirt and water finally got to it. That's definitely my problem and obviously I'll need to do both sides. I'm trying to get the most bang for my buck here and not end up spending $1,000+ if I can avoid it. I think gsxr's direction to do the PITA stuff first makes sense then I can do the rest myself later. We use this car daily so I can't really afford to have it laid up while I run around renting tools and getting parts pressed in. Thanks again and I'll let you know what happens.

engatwork · #5 11-11-2002, 06:21 PM

Sounds like the lower ball joints to me. I consider it a pretty easy diyer type of job. You don't need to compress the springs to do the ball joints. You can rent the special tool needed to press the joint back into place.

Go ahead and replace the upper ball joints by installing new upper control arms. Don't forget the alignment after the work is done.

RunningTooHot · #6 11-11-2002, 11:49 PM

I am doing the front end on my car right now. Parts are cheap for these cars. If you are planning to keep the car until it turns into a lump of iron oxide, or some other horrible fate renders it dead, I would replace *everything* that you can. It is a big job, but it is even more of a PITA to have to take it apart again should you need to replace something else in the near future. Personally, I like the idea of not ever having to think about anything in the front end for another 200,000+ miles.

Getting the lower ball joints out is a matter of brute force, but very straightforward (especially after soaking overnight with PB Blaster). But don’t even think about trying to get them back in by yourself without renting the proper tool! If you are thinking about having someone press them in for you, be very careful in whom you select.

adamb · #7 11-12-2002, 06:45 AM

Someone commented on needing to compress the spring when replacing the lower control arm bushings, but I found that this job can be done in about 20 minutes a side.
I simply get the car up on axle stands, remove the wheel, position a jack with a chunk of wood under the inner control arm pivot, safety a tie-down to the outer control arm, remove the inner control arm bolt, slowly lower the inner control arm with the jack, insert only 1/4 inch of at leats a 2 foot pry bar into the inner bushing and pry it out, do same for other end (will be in 2 pieces), then orient the new bushings properly and press in with a c-clamp, then get car aligned.
The first side took me 1.5 hrs, then the second side took only 20 minutes with the right tools all set up and ready to go.
I haven't done ball joints on a Benz yet, but My right side Ball joint is beginning to show sitgns of wear, so I'll tackle those soon.
Have fun,
Adam Bush

savagetom · #8 11-12-2002, 06:09 PM

I read wiht interest your comments about doing the lower control arm bushings without a sprig compressor. I have a question. What do you mean by "safety a tie-down to the outer control arm"? Those springs are very powerful and I don't want to kill myself.

Thanks.

gsxr · #9 11-12-2002, 06:37 PM

My thoughts exactly. If you attempt Adam's method, be EXTREMELY careful, and have your life insurance policy paid up .

Use chains or something as retaining devices and make sure your hydraulic jack(s) are firmly seated.

I still recommend using the proper MB spring compressor, it can be rented from Performance Products...

Regards,

adamb · #10 11-12-2002, 06:43 PM

In order to lower the inner portion of the lower control arm when you remove the bolt, the jack will catch the spring tension and then you will let the jack down very slowly. The safety tie down can be anything that prevents the control arm from swinging out away from the car. I didn't use anything on the first side, then after reassembly I realized that the other side would go faster if I pre-positioned the tie down on a solid part of the frame to the ball joint area before removing the inner bolt.
Also, before removing the bolt, put a little upward tension on the inner tie rod mount with the jack. When the control arm is then lowered, the spring tension is very little, and it doesn't seem to stress the other joints/ components enough to do any harm.

Side note: I see that you're from West Virginia - I just got back from Cool Ridge this past weekend. My wife is from there so we went to see her parents. I will be going there again for Thanksgiving, so if you are close you can swing by and I can show you, but it's really not that tough, especially after you do the first side.
Have fun, Adam Bush

#11 11-13-2002, 11:24 AM

I have to chime in on the compresser thing. I did all this suspension work over the past summer. I managed to compress the front springs with a universal type tool but the whole time I was very uncomfortable with the possibiltiy of injury. That spring is so powerful and you are working in a very small space.

The best thing to do is get all the necessary parts and rent the right tool. It is special to mercedes and can be obtained from Performance Products. With that tool, you can easily compress the spring and just remove it while you work on the suspension. Very much more relaxing.

Also, to do the rear suspension parts you will have to compress those springs as well and only the special mercedes tool will fit so try to kill both birds at once. Don't wast time and energy trying to find a local tool that will somehow work....I did that already. Be warned that it is a hard job in the rear (getting at the bushings that connect the trailing arms to the body of the car). No room. If you have a lift, life will be much better.

Nic
'85 300CD