Rear shock top pin sheared... - PeachParts Mercedes-Benz Forum

Shern · #1 03-10-2018, 11:33 PM

Ugh. Was doing rear shocks today and the pin above the lock nuts sheared off. On both sides! If they were this tight, I'm not sure if I should continue, lest I face the same issue on the bottom nuts too and find myself with an undriveable car.

Has anyone faced this issue? What did you do?

Diseasel300 · #2 03-11-2018, 12:43 AM

This happened on my SDL. Spray the nut with penetrating oil and let it sit for a while, then lock onto the shaft below with a vice grip (VERY TIGHT) and give the wrench several sharp, firm raps with something like a pair of dykes. The shock will break the bond and let you back the nut off.

Shern · #3 03-11-2018, 01:01 AM

Quote:

Originally Posted by Diseasel300

This happened on my SDL. Spray the nut with penetrating oil and let it sit for a while, then lock onto the shaft below with a vice grip (VERY TIGHT) and give the wrench several sharp, firm raps with something like a pair of dykes. The shock will break the bond and let you back the nut off.

When you say the shaft below, where exactly do you mean? I was able to grip the shaft from the tire well after slicing off the dust guard when I was changing the front shocks, but there doesn’t seem to be anywhere to grab on the rear except for the top remaining part of the pin... if I grab that I’m SOL when the nut gets to that point.

Diseasel300 · #4 03-11-2018, 01:10 AM

On the 126, there's a very small gap below the shock mount that's just wide enough to get a pair of vice grips in there. Not sure if the 123 is the same or not. If not, you'll have to gain access to the shaft somewhere, risk boogering up the threads on the shaft, or use a nut splitter or a grinder to cut the nut off.

Shern · #5 03-11-2018, 01:24 AM

Unfortunately on the W123, the tire well obstructs just about everything...
My fear is that if the pins sheared I might have even worse luck down below on those two nuts. Read a couple threads about those shearing off as well.

Shern · #6 03-11-2018, 01:30 AM

Also, thanks for the tip re: nutsplitter. Had no idea that was even a tool... in theory, could i use a nut splitter the whole way through? Top and bottom? I don’t need to recycle the hardware and cracking the nuts off seems a hell of a lot easier than soaking in oil and messing with vice grips

tangofox007 · #7 03-11-2018, 08:35 AM

Quote:

Originally Posted by Shern

Also, thanks for the tip re: nutsplitter. Had no idea that was even a tool... in theory, could i use a nut splitter the whole way through?

A rotary tool (ie: Dremel) might be more useful in the future than a nut splitter. For starters, I would cut a screwdriver slot in the top of broken rod.

vonsmog · #8 03-11-2018, 08:59 AM

that happened to one of my w123's, so I just used the air impact to take the nuts off. It spins fast enough to just take them off in a flash.

Shern · #9 03-11-2018, 12:45 PM

Quote:

Originally Posted by tangofox007

A rotary tool (ie: Dremel) might be more useful in the future than a nut splitter. For starters, I would cut a screwdriver slot in the top of broken rod.

Fair point, but lacking clearance.

Shern · #10 03-11-2018, 12:47 PM

Quote:

Originally Posted by vonsmog

that happened to one of my w123's, so I just used the air impact to take the nuts off. It spins fast enough to just take them off in a flash.

I might be able to borrow one, thank you

leathermang · #11 03-11-2018, 02:04 PM

For close work.... heat is very helpful.... if you use good safety measures.... you can isolate very hot flame IF you use oxy-Acet and your smallest tip.... the one often used for jewelry working..
but you have to worry about everything near your flame...
there are a couple of ways.... one is asbestos gasket material and the other fiberglass cloth ..
Heat as much as you can... spray with water... repeat... then check for loosening..
Look at your local welding store .... for the fiberglass protective cloth.. or Harbor Freight..
plus
https://www.google.com/search?source=hp&ei=L26lWpbjH4LejgTkuL-YDw&q=asbestos+gasket+sheet&oq=asbestos+gasket+sheet&gs_l=psy-ab.3..0l3j0i22i30k1l7.1337.13363.0.15471.25.23.1.0.0.0.542.2267.2-4j1j1j1.8.0....0...1c.1.64.psy-ab..16.9.2701.6..46j35i39k1j0i67k1j0i131k1j0i20i263k1j0i46k1.426.khzsl5Tz1mM

Shern · #12 03-11-2018, 10:08 PM

Success!

In the end, it was a $12 nut splitter from Autozone. Not the most elegant solution but hey...
Bottom bolts came off easy. What a difference in ride quality! HD Bilstein all the way.
Thanks for the tips all.

Diseasel300 · #13 03-11-2018, 11:25 PM

Glad the nut splitter worked! The HD's really do improve the ride, firm but forgiving.

Shern · #14 03-12-2018, 01:39 AM

Quote:

Originally Posted by Diseasel300

Glad the nut splitter worked! The HD's really do improve the ride, firm but forgiving.

Absolutely. I’d even go so far as to say fun, especially on corners now.

Diseasel300 · #15 03-12-2018, 09:50 AM

You haven't experienced "fun" until you've driven an R107 SL with the original 120K 1983 shocks installed. I'm positive that there's a ridge running down the center of the driver's seat from clenching.....