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#1
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Tooling up for rear shocks
I'm going to tackle rear shock repalcement on my 99 ML 320. I have been pouring over the various excellent threads and think I am ready.
I'm considering buying an impact wrench. Sounds like (especially from Ron in SC) that an impact wrench can make this job a lot easier. Lowes has a 220 ft lb model for just $29.00. Do you think this will be adequate, or will I be wasting my money? If 220 ft lbs isn't enough, how many do I need? I don't do that much wrenching (I'm more of a homewrecker), but it would also come in handy to drive lag bolts in ledgers in my deck business. Also, I have a 13 mm combo wrench and a cheap ratcheting box wrench set. The box wrench is not offset. Do I need an offset 13 mm? Would the flex head gear wrench be worth the extra investment over the fixed angle offset? I don't have a torque wrench. Was hoping not to have to buy one. Can I get by without it? And how do you torque those top three 13 mm nuts in that restricted space anyway? Perhaps I can borrow or rent one if you guys think it is mandatory. TIA for all your great information. John in SC AKA sunedog |
#2
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I just did my rear shocks today on my 2000 ML430... it was not too bad, but not too easy either... I found out one of my spring was broken when I was in the process of replacing the rear shocks last week..., so I had to order new springs... I replaced them with H & R springs ($200 shipped) and Bilsteins shocks ($500 Fronts and Rears).
Pry off the cap covering the 3 nuts with a flathead. The top 3 nuts were kinda hard to take off, you just have to get your wrench and your hand in there and slowly take them off... You will need an 18mm socket for the bottom nut of the rear shocks... Also, you will need a 21mm socket and 21mm wrench to take off the 2 bolts and nuts on the lower control arm! Basically, you just need 3 sizes, 13mm, 18mm, 21mm, well, and 17mm for the lug nut and the nut on top of the rear shocks that hold the spring down. This is what I found to be the best way... take off the 3 nuts on top, then take off the 2 bolts on the lower control arm, then take of the 18mm nut on the bottom of the shock, then lift the shock, push down on the control arm, and wiggle the rear shock out of there. Aligning the holes on the lower control arm took a little bit of time too... I have the rear on jackstand, and use my jack to jack up the suspension to align the holes, you just gotta play with it for a while... As for the $22 impact... probably not so good... spend the money and get one at least $150... The control arm bolt is 135NM... the $22 impact probably won't do it... well, depends on your air supply too... Oh, and you do need an offset 13mm ratchet wrench, the flat wrench won't work... I didn't torque the 3 nuts... kinda hand tighten them really well... my impression was they were too tight because they were really easy to break loose at first... Hope this helps! Any question, let me know!!! |
#3
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Sho1,
I am getting ready to do the same on my 2000 ML430. Didn't you need to disconnect the sway bar link to lower the control arm all the way? Did you remove the spare tire and carrier? Remove the inner wheel linings? For the top bolts, did you remove from the wheel side or the spare tire side? The only tool I need to get is that offset 13mm ratcheting wrench. Any suggestions on the amount of offset needed, a picture of the tool would be nice. Also, I do not plan on using an impact wrench, do you think the bottom shock mount will be a problem without? Thanks. |
#4
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You don't need to disconnect the rear sway bar link... you just have to pull the rear shock up and push the lower control arm down(after you took off the 2 bolts of the lower control arm) and wiggle the shock out... it's really easy...
The bottom shock nut is only 85Nm... which is I believe about 70ft/lb... If you have a 1/2 inch 18mm socket, you should be ok... you don't really need an impact wrench to do the job, you will need to use a 1/2 inch 21mm socket probably with a breaker bar or if you have a 1/2 inch torque wrench, you would be ok. With a 3/8 breaker bar or torque wrench, it would be kinda hard to break loose the 2 lower control arm bolt which is at 135Nm... ~100ft/lb I believe... No specific degree offset for the 13mm wrench... as long as the tool is not flat... I bought mine at Harbor Freights Tools... and the wrench look like a "z"... Make sure you take the bushing and the washer off of the original shock... it could be rusty... I used a 2 jaw puller to pull the washer and the metal tube insert off the original shock. To assemble the new shock, you would have a wash, a bushing, the shock mounting bracket, then another bushing, and then another washer, and then the nut to hold the spring down... you'll know when you take apart the strut... Without an impact, it would just take you longer to take out the 2 lower control arm bolt, these are ~4 inches long bolts... you would have to turn forever to get them off... I didn't remove anything except the spare tire... keep the spare tire rack lowered, then you can access the 3 top nut from the spare tire side... but you gotta reach in there to get to the 3 nuts... you will kinda be hanging in the middle in a pretty uncomfortable position, but unless you have a lift to get the car up high, you just got to twist and reach in... The whole process takes about 4 hours or so if you haven't done it before... Good luck... any more question, definitely let me know... coz I know how tough it can be Last edited by sho1; 02-04-2006 at 12:51 AM. |
#5
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Did mine yesterday too. Must have been National Replace Your Shocks Day.
Anyway, I bought the el-cheapo impact wrench. It is the 250 ft lb model from Harbor Freight for the sum of $17.00. I hate to buy cheap tools, but I couldn't pass this up. Got a set of 8 or 10 impact sockets for $14.99. They have a lifetime warranty, so how can I go wrong there? The impact wrench did a fine job on the lugs and the 21 mm bolts for the swing arm. I did remove both wheels and both inner fenders (they're easy to get out). I took the spare out as well, but honestly don't think that helped me. I did all three top nuts on each side from the wheel well. I didn't have that much room under the truck because I was using some jack stands that only go up to 16". The best wrench (IMHO) for the top three nuts is a 13 mm FLEX HEAD Gear wrench. I might have been able to do it with a fixed offset, but the flex gave me way more options on where to turn it. Got mine at Lowes for about $11. To be honest, these nuts were not as tough to get off and back on as I had anticipated. You're basically working blind with both hands jammed up in a small space behind the frame rail. I just sat on a 5 gallon sheet rock bucket with my head in the wheel well and took my time. Speaking of jackstands and working under a car, please take every reasonable precaution to make it safe. At someone's suggestion on this forum, I now lay my wheels under the truck when I will be working under it. If the truck falls, they will limit how much I get squished (just a little, I hope). I did loosen the swing arm by removing the jam nut and washer head nut on the top of the links. That allowed the lower control arms to pivot down giving plenty of room to R&R the shocks. I think that made it easier to line up the holes to replace the 21 mm bolts in the lower control arms. I didn't have any trouble with that part. I didn't want to mess with R&Ring the coil springs, so I took them to a local mechanic. He struggled with them a bit because the big coils were too big for the hooks on his wall mounted super spring compressor, but he figured them out. I slipped him a $10 for his trouble, and then the owner charged me $70 for the work. I thought that was a tad high considering I was in and out in 40 minutes, but I couldn't complain because I showed up an hour before closing time on a Friday and they took care of me. And I picked up a torque wrench at Auto Zone this morning and will go back and torque my nuts. They have a great tool loaner program. Pay $90 up front, keep the tool as long as you want, and return it for a full refund. Thanks again for everyone's help. This was an advanced project for me, but I felt like I had everyone on this list helping me out. Last edited by sunedog; 02-04-2006 at 12:56 PM. |
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