Strange front shock sticking
 

Hey fellas,

My car has been doing this ever since I bought it but a more recent incident confirmed there is something not right. Often times when I have to stop quicker than normal (not even slamming the brakes on) the front end will clunk and stick. When I accelerate the front end will make a pop sound and rise to the normal height. Yesterday I was coming down a hill to a stop sign and turning right. I got the usual thunk but when I accelerated, it didn't pop back up until a while later. The front driver's side felt like it was riding on only the spring (very bouncy). After the car shifted into O/D I heard a thunk from that side and the suspension returned to normal.

I know I need to install a guide rod mount kit on that side because I can rattle the guide rod with my bare hands. The passenger side guide rod is tight and doesn't move. The shocks on the car are aftermarket from Midas or something and they seem to be leaking or have already leaked. My question to y'all is: Would my issue be a sticking shock or would a guide rod cause the suspension to act like that?

Thanks.

I'm guessing this is on your '83 SD then?

If your front suspension sometimes goes into chicano mode and does not return to the normal ride height I would stop driving it until you can work out why. That sounds really dangerous to me.

Chicano mode -- I love it. That is funny!

It got stuck that one time. Usually it just pops, clunks and thunks. I'm thinking it is the shock because it is not an OEM spec unit and it looks to have been leaking or already leaked out out. I guess I'll have to throw in a set of Bilstien touring shocks when I get the $$ together to do the guide rod mount.

I don't think a sticking shock is going to be strong enough to do that - I could be wrong but I suspect something a bit more serious than that. I hope not. But whilst you are down there looking at the shock check the rest of the suspension very carefully.

Maybe I should take some pictures and post them because I am not a suspension genius. I replaced all the tie rods and steering dampener and that solved my wobbling problem over 40MPH on rough terrain but that is all I have done. The clunking issue has always been there, I just haven't had the time or funds to address it. I'll take pictures of everything I can down there and post them up.

Last time I checked for play in the front wheels was before I replaced the tie rods and I had 3-9 play and very little to no 12-6 play.

Oh, yeah, the car did sit for a few years and was rarely driven in that time.

If you are at all unsure you'll find that you'll get a good response to pictures here - we all love pictures!

Here are the pictures I took earlier tonight.

Index of /images/83mercedes-benz300sd/suspension

I hope you don't mind me adding direct links to some of the pictures you took - it looks like you're using your own server or something like that?

If that isn't OK let me know and I'll edit out the links.

On the whole it doesn't look totally terrible to me - I can't see anything hanging off or snapped off!

However there's evidence of worn out bushings and possibly split ball joint boots? I do think the shock is toast too unless the oil muck is coming from somewhere else. Please bear in mind that whilst they say the camera never lies it is sometimes difficult to diagnose things this way.

Anyway here are the pictures of the bits that concern me.

Can anyone who actually owns a W126 let us know?

http://www.eatoncomp.com/images/83me...n/IMG_1140.JPG

http://www.eatoncomp.com/images/83me...n/IMG_1148.JPG

http://www.eatoncomp.com/images/83me...n/IMG_1151.JPG

http://www.eatoncomp.com/images/83me...n/IMG_1153.JPG

http://www.eatoncomp.com/images/83me...n/IMG_1154.JPG

I've got so questions about these pictures
 

1) Have you checked to see how loose the bolt is on the end of the anti-roll bar?

It looks loose in this picture - the rubber bushing doesn't look like it is compressed

http://www.eatoncomp.com/images/83me...n/IMG_1157.JPG

2) What made the mark in the muck on the shock?

http://www.eatoncomp.com/images/83me...n/IMG_1155.JPG

3) How often do you check your tyre pressures?

It looks like you're running under-inflated...

You might also say that the camber is a bit out the inside of the tyre is wearing a bit more than the outside

http://www.eatoncomp.com/images/83me...n/IMG_1150.JPG

You can re-post the pictures all you want; they are hosted on my personal web server. I didn't post them directly in because some forums get upset if large pictures are linked into a thread.

I'll answer your questions in order.

The ball joint boots on both sides of the car are broken. Given the involved process of replacing them, I will have to wait. I might even need to take it to a shop to have them done.

I have not checked the roll bar bolts but I will when I get home.

I made the mark on the shock for perspective. It is caked in dirt and grease. I had an oil drain tube leak and the PS pump seeped a little from the front shaft but not badly when I bought the car.

I noticed the tire wear as well. The guy put air in them before I brought the car home but probably not enough. I'll fill them to 30PSI; I think that's what they take.

I had an alignment done about 6 weeks ago after I installed the new tie rods but once I replace a few more things, I'll take it back and have them check it again. I might as well use that 6 month alignment warranty.

The thing with busted ball joint boots is that they usually go hand in hand with worn (as in broken) ball joints. In my mind I can imagine a sticking stubborn ball joint causing the chicano effect more than a shock...

...but this is pure guess work.

More investigative work is needed I feel.

In IMG-1147 it looks like the shock is bent. Bent shocks can cause the problems you discribe. Anyone else see this?

Paul

I definitely see what you are referring to. I kinda figured it was something to do with the shocks. I guess a set of Bilstein Tourings are in my future.

Do I need a spring compressor or can I jack up on the control arm/have a fat chick sit on the fender? I guess I should do a search, huh? Let's see, "fat chick on fender."

Oh, I also inflated the tires to 50PSI. The max PSI listed on the tires is 51PSI.

That's the maximum pressure of the tyre not the pressure it is meant to be inflated to - you'll be bouncing around the road like you are on a po-go stick...

So then I should go off the door sticker instead? They were already pretty close to the door sticker rating. Maybe just a few to 5 PSI low at most.

I can feel less rolling resistance when driving but not too much ride difference. Maybe that's because I need new shocks. Or I could complete the Chicano mode and get some raaymz and rig up some hydraulics to make it bounce!

If you keep those tyres blown up balloon style (or should it be styleeeee?) you won't need the hydraulics!

Always always follow the door sticker advice. I once hired a car in the US and the tyres were incorrectly inflated to something silly like 50 PSI - Before I got to the US (this was for the first time) I had heard a lot of talk about American cars handling dreadfully what with live back axles only good in a straight line etc => but wow that hire car (a Ford something or other) was terrible. It would hardly go round corners until I reduced the tyre pressures to the value specified in the hand book.

Oh yeah I forgot to say - over inflating tyres is dangerous. At high road speeds the tyres can heat up - if you are already at the maximium pressure and the air in the tyre starts to expand (due to heat)...


...pop!

I'll deflate them back to spec before I go on my lunch break.

I'm looking at getting the following parts for my car:

Guide Rod Mount Kit FEBI $ 0.00 $ 79.99 $ 79.99

Guide Rod Repair Kit KARLYN $ 0.00 $ 11.46 $ 11.46

Bearing Bracket Bushing - Front
forward Position (front) Of Suspension Bearing Bracket 126 333 12 43 Or 126 333 13 43. FEBI $ 0.00 $ 23.63 $ 23.63

Bearing Bracket Bushing - Rear
rear Position (rear) Of Suspension Bearing Bracket 126 333 12 43 Or 126 333 13 43. FEBI $ 0.00 $ 24.65 $ 24.65

Shock Absorber B4 Touring Series
comfort BILSTEIN $ 0.00 $ 57.80 $ 115.60

Air Cleaner Mount
for Heat Shield See 617 094 02 20. FIRST EQUIPMENT QUALITY $ 0.00 $ 2.92 $ 8.76

Air Cleaner Bracket
see Also 617 988 01 11 Rubber Buffer Mount And 617 094 02 20 For Buffer Mount Heat Shields. MTC $ 0.00 $ 36.76 $ 36.76

I'm thinking the guide rod repair kit is the part that connects the opposite end from the bearing bracket. Since I have to take that end apart, I might as well install new stuff in there. I am referring to IMG_1143 , 1144 , and 1148 from my previous link to the pictures. I also notice that the new shocks don't come with dust boots. I'm assuming that is something that will need to be installed even though my current shocks do not have them.

If I can't find a good air cleaner bracket in the junk yard tomorrow, I'll place the order for a new one. Mine is beyond shot.

I ordered the parts. They should be here in a few days. I'm also working on rebuilding my A/C again so I will be quite busy this weekend.

Also, can anyone tell me if I need to find a spring compressor to change out the shocks or is there some way to do the job without needing to compress the spring? What size 12 point socket do I need for the bolts at the bottom of the shock? It looks like 12mm.

You don`t need a Spring Compressor to change the Shocks.

The lower shock bolts take a 10mm 12 pt socket or box wrench, if you can get it in there. lower one`s are a pain, but doable.

The top Shock nuts are a 17mm.

A while back when PNP was having a %50 sale, I bought a set of steering knuckles off a 90 W126. were low milage and price was right. Idea was when I need to change the lower Ball Joints, have them put into these, get them painted up and purdy. :) then when time to do the front end re-build, less down time.

Charlie

You don't need a spring compressor, but make sure that you support the lower control arm with a jack!!

I got the shocks in the mail today. I'll start installing them tonight.

Is it possible to change the shocks without jacking the car up at all or just a little?

Do I need to get dust boots for these shocks or is it acceptable to run them without? The 300D I saw in the junk yard didn't have dust boots on the shocks.

It depends how strong you are! If you can compress the shock then the top pin will come out of the chassis...

Might make it a bit easier to get to the bottom bolt with the wheel removed.

I forgot to mention to use a jack under the Control Arm. put a little pressure on it to hold it when removing the top nuts, other wise it will drop down.

Same with the rears, a jack under the Trailing Arm will hold it from quickly dropping when you are at the last one or two threads from removing the nut.


Charlie

I found this thread. It answers a lot of questions.

http://www.peachparts.com/shopforum/diesel-discussion/121825-300-sd-front-shock-change-question.html

I know what you mean about the shock popping down! Last weekend I attempted to remove a shock from an 82 300D because I wanted to be a cheap @$$ and not buy new shocks. I unbolted the top nuts and on the last nut, it went BANG sending the bolt flying off into the yard. This car was on rim stands and the spring didn't fly out and kill me, so I don't think I have that to worry about.

Any one know about the dust boots? I don't want to find out about this after the fact.

I was out looking under the 126 and 123`s. the fronts have the dust boots and that rubber foam bumper stop up inside the dust cover.

I can`t see looking from under the rear, because the top of the shock is way up inside the spring. But from what I remember, the rears don`t have the dust covers. they are protected up inside the spring from road debris.


Note:

I just looked in Fast Lane. and the picture of the SD shocks front and rear show no dust boot.

The same year 123 300D (84) show dust boots on the front, none for the rears.

I have noticed some 126`s in the yards, not having dust boots on the front, and thought some one installed rears on the front. then realised the lower bolts are way different. 17mm in the rear and 10mm 12 pt on the front.

I did see a 126 yesterday (90 or 91) in one of the PNP`s I was in, that had dust boots on the front. they were grey shocks as I remember.
I was going to pull them, but the wheels were turned and the steering locked. things looked new.


Charlie

I installed the shocks this morning. I didn't even have to jack the car up. I put the washer and the rubber spacer on the rod end of the shock, fit the rod through the shock tower hole and pushed the bottom of the shock up until it cleared the lower control arm. I did have to fiddle with them a little to get bolt holes to line up. I do feel the need to complain about the shock rod mount design. These shocks only had a slit for a flat-head screw driver to counter torque the bolt while tightening down on the shock tower. Needless to say, torquing that much on a flat head doesn't go well. I wound up busting my finger on it and bleeding all over the passenger side engine bay. A nice torx or hex indentation would have helped a lot.

Now on to the bearing bracket and guide rod. I still get clunking in the front end when braking or going over bumps even though I solved the "Chicano mode" issue.

Wow - great stuff - I'm glad to hear that whole chicano thing isn't going down any more...