Rear Shock Question

[diesel don]

After searching the threads, I have one final question on rear shock replacement (123 diesel).

After lifting the rear tires off the ground, do I then place a block under each tire so that they are suspended downward but still supported?

I'm good with the other stuff about rear seat removal and beginning with the top bolts, etc.

Thanks

Don

[R Leo]

A sedan, right? If so, yes, you need to support the wheels since the shock also functions as a travel limiter for the suspension.

Shock replacement is probably best performed with the wheels on ramps.

[diesel don]

R Leo:

Yep, its a sedan. Are you saying that with the wheels on a ramp, that I'd still jack up the differential so that the travel is lengthened so that the shock is therefore lengthened. I'm trying to conceptualize it in my brain and my brain isn't all that big. Please use small words

And by the way, you are one of the WVO superheros

dp

[t walgamuth]

after unfastening the top, compress the shock, then it will come out.

[R Leo]

Originally Posted by diesel don

R Leo:

Yep, its a sedan. Are you saying that with the wheels on a ramp, that I'd still jack up the differential so that the travel is lengthened so that the shock is therefore lengthened. I'm trying to conceptualize it in my brain and my brain isn't all that big. Please use small words

With the back of the car on ramps, you shouldn't need raise the car with a jack. The vehicle only needs to be high enough to allow the shock sufficient clearance to be removed (dropped straight down) out of the spring without hitting the ground first.

Also, you do know that you need to remove the back of the rear seat to access the top nut on the shocks, don't you?

Originally Posted by diesel don

And by the way, you are one of the WVO superheros

Thanx for the kudos but, I honestly think Dana Linscott is the real hero of the grassroots WVO activity.

[Brian Carlton]

Originally Posted by R Leo

A sedan, right? If so, yes, you need to support the wheels since the shock also functions as a travel limiter for the suspension.

Shock replacement is probably best performed with the wheels on ramps.

Randy, I've got to pull the rear springs this weekend on the SDL.

Is there a danger in removing the shock and then raising the back of the vehicle up using the diff?

Without the shock in place, the trailing arms will continue downward until?????

Can the spring go ballistic without the shock as a stop?? I would think that the trailing arm must have some additional stop, other than the shock???

The wheels must, obviously, be unloaded to remove the spring. You can't unload the wheels without something stopping the trailing arm. You can't have the shock stop the trailing arm because it must be removed to pull the spring.

[R Leo]

CAUTION!!
The shocks function as deflection stops for the trailing arms. Only remove the shocks when the vehicle is sitting on its wheels!!!

Originally Posted by Brian Carlton

Is there a danger in removing the shock and then raising the back of the vehicle up using the diff?

No.

Without the shock in place, the trailing arms will continue downward until?????

W/O the shock in place, the trailing arm swings downward until it contacts the subframe. The shocks limiting function prevents the suspension from traveling too far and allowing too much camber in the rear wheels which could permit the wheel to get stuffed up underneath the car in a slide situation.

Can the spring go ballistic without the shock as a stop??

No. The spring is still significantly compressed at full suspension extension and also sits deep in the tower and trailing arm spring perches. I also believe that the trailing arms must be fully extended in order to have enough room to remove the compressed spring from the perches.

I strongly suggest reading procedure 32.5-230/1 in the W123 FSM before embarking on this project. If you don't have the FSM, go here.

[Brian Carlton]

Thanks.

I understand that the shock can't be loaded in it's fully extended position when it is removed, and, additionally, the rear spring can't be fully loaded when it is removed.

There is no danger to letting the trailing arm extend until it hits the subframe, after the shock is removed.

Is there any issue caused by excessive angular deflection of the axles when the trailing arm is in full downward deflection, prior to spring removal??

[R Leo]

Originally Posted by Brian Carlton

Is there any issue caused by excessive angular deflection of the axles when the trailing arm is in full downward deflection, prior to spring removal??

I guessing not since that's how the FSM says to take out the spring.

[Brian Carlton]

Originally Posted by R Leo

I guessing not since that's how the FSM says to take out the spring.

Thanks.

[diesel don]

Any of you guys have problems with the bolts sheering off with impact driver (the lower shock bolts)?

3 out of 4 sheered off on my parts car. When I do it on the real car I obvioulsy don't want that to happen. Looks like I'll begin with PB Blast and heat.

Don

[Brian Carlton]

Originally Posted by diesel don

Any of you guys have problems with the bolts sheering off with impact driver (the lower shock bolts)?

3 out of 4 sheered off on my parts car. When I do it on the real car I obvioulsy don't want that to happen. Looks like I'll begin with PB Blast and heat.

Don

Well, if you wouldn't drive those vehicles through the salt baths you wouldn't have that problem.

I'm going down to do the SDL now. Hope it doesn't make a liar out of me.

[guage]

I'd like to replace the rear shocks on my 85 300D this weekend.
Do I need special sockets to remove the bolts?

[Brian Carlton]

Originally Posted by guage

I'd like to replace the rear shocks on my 85 300D this weekend.
Do I need special sockets to remove the bolts?

Just finished pulling them out of the SDL. Takes a standard 17 mm socket on the two lower cap screws.

See Don, that's the benefit of a Florida vehicle. Screws were a tad rusty, but came right out.

As Randy mentioned, you need to remove the nuts at the top of the shock prior to lifting the back end of the vehicle.

BTW, when you do this, the rear brake lines are stretched to the max and are not at all happy. I'd advise to disconnect the lines, although I realize all the trouble that is going to create.

Another solution is to simply back it up onto ramps. The wheels remain loaded and therefore, the trailing arms won't drop and stretch the brake lines and you have sufficient room to work underneath the trailing arm. However, you won't be able to remove the wheels in this setup and the access with the wheels on the vehicle is not all that great. It forces you to crawl underneath and work.

I will say that the factory Bilstein shocks appear to be in fine shape with hardly a bit of weeping of oil. The rods remain under gas pressure. I'll be putting the old one's back in.

[t walgamuth]

in rust belt areas it is good to avoid an impact wrench on those lower bolts. soak them with penetrating oil and work them loose carefully by hand.

sometimes the bilsteins will not leak but ride quality is gone as the area of the shaft where the wear is most will be undersize a little and allow internal leakage (this is my imagined cause) the result is a shock that does not allow the car to bounce excessively when bounced by hand and no leaking but a lousy bouncy ride. if i find the ride bouncy and no leaks i change them.

my $.02