HOW-TO: Rear Lower Control Arm & Wheel Carrier Joint Bushing Replacement

[gerryvz]

ADMIN EDIT: Part numbers for the wheel carrier support joint / bushing are discussed in a different thread, click here for details.

I finally decided to install my RDMTek modified rear lower control arms, and perform several other tasks at the same time.

These tasks included:

• Replacing the stock spring pads with "one-bump" spring pads
• Replacing the rear wheel carrier joint bushings
• Replacing the two rubber bushings at the top of the rear struts
• Replacing a lost wheel-housing body panel
• Adjust the parking brakes
• Thoroughly cleaning out the wheel well area of accumulated burned rubber
• Thoroughly cleaning the lower cladding area of accumulated dirt and debris
• Inspecting other chassis rubber and other suspension items for possible future maintenance

The job is not all that hard, physically, but is tedious and takes quite a number of hours. Given the fact that I was also doing so much other work, it took much longer.

I decided to use a spring compressor, for safety purposes, for this job. Some people say that one is not needed, but I choose to do things carefully and "by the book" when it comes to safety.

Among the tools that will be needed:

• 1/4, 3/8 and 1/2 drive ratchets, short extensions and sockets ranging from 10mm to 22mm (10, 13, 17, 19 and 22mm are specifically the ones used)
• Crescent wrench - mid sized
• WD-40, PB Blaster, Liquid Wrench or other penetrant
• 1 can brake cleaner
• 5mm Allen key or Allen socket (preferred)
• 3-4 shop rags
• anti-seize paste
• Blue Loctite
• Syl-Glyde or other lubricant
• needle-nose pliers, bent-nose preferred
• Hammer
• Sledge hammer
• low- and high-range torque wrenches
• various/assorted flat-blade screwdrivers
• eye protection

First of all, while the car is down on the ground ... loosen the lug bolts on both rear wheels.
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And then, you need to remove the inner trunk linings on the sides. Don't let ANYONE tell you that 1994 and 1995 E500s weren't made at/by Porsche. Here's proof, once again, on my 1994 car on the inside of the trunk lining.....along with another surprise in my trunk that I'd forgotten about: a rebuilt amp from when the car was a few years old.
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Next up, you need to remove the two bolts and the rubber that mount the top of the hydraulic strut to the body of the car. This is inside the car, with a second rubber bushing on the wheel well side of the car; you'll remove this second bushing when you remove the lower control arm later on. In any case, when re-installing these two bolts, the first (lower) one is torqued down to 15-18 Nm, and is then counter-held with a wrench while the secondmost (top) bolt is installed, and torqued to 30 Nm. But that's for re-assembly at the end of the process. Just thought I'd mention it here.

Here are a few photos of the removal of the upper strut mount/bushings, inside the trunk.
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You can see how compressed these upper rubber bushings get, with time and use, as compared to a stock bushing.
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Next up, pull the wheel off after raising that side of the car (you can also raise the entire back end). This is what you'll see upon wheel removal.
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Everything looked pretty good at first glance with the brake and rotor. You'll want to soak the two large bolts that hold the brake caliper on the wheel carrier for a few minutes, and then loosen them. Mine were fairly easy to remove, but on other cars I own, they have not been quite so easy. Notice that the bolts have blue Loctite; this will be important to remember to put on for re-installation.
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Hang the brake caliper so that no strain is put on the brake line. I like to use old clothes hangers, while others I know use bungee cords. Anything works fine as long as you are taking pressure off of the brake line.
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It's important to take a break every once in a while. Since this was bright and early on a Saturday morning, a nice large cup of Peet's Major Dickason's Blend coffee was most definitely in order. The cup is a relic of my 8.5 year stint working for Intel, the world's largest manufacturer of microprocessors.
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After a bit of refreshment and removal of the brake caliper, it's time to remove the brake rotor. First step is to remove the 5mm allen bolt that holds the rotor to the wheel carrier. Again, notice the blue Loctite.

Removing the rotor itself can be very difficult to do, so I've learned a good technique over the years that has served me quite well. I take a large sledge hammer (think John Henry driving railroad spikes, and you get the idea) and with MODERATE force, I give the face of the brake rotor (where the back-side of the wheel mounts to it) about 10-12 blows in a circular pattern in between the lug bolt holes, generally making about 2-3 circular rotations around the rotor. 80% of the time it will come loose after these blows, though sometimes it does require more. In this case, it took a bit more effort, but the driver's side only took about 7-8 blows to come loose.
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After removing the rotor, take some brake cleaner on a rag, and wipe down the area as good as you can, cleaning up old brake dust and residue. On reassembly, you're going to put a thin coat of anti-seize paste on this surface to help assist removal the next time you have to remove the rotor. Trust me, you'll thank yourself later for taking the small step of applying anti-seize when you re-install the rotor.
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Next up, it's time to remove the lower control arm. First of all, remove the two 10mm bolts that hold the plastic cover to the underside of the LCA. Put the bolts and the cover aside; you'll be re-attaching them to the new LCAs once you install them. Then, remove the cover itself carefully; don't snap anything. This plastic is exposed to the elements so it can be quite brittle !!
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The next thing you want to do is to compress the spring, so that it's not a factor. I know that some folks say that compressing the spring is not necessary, but I like to render this potentially deadly missile as inert as possible, so I used my Klann spring compressor and compressed it just enough so that it no longer placed any tension on the LCA. After compressing the spring, place your floor jack under the LCA, near or directly under the inboard pivot bolt.

After that, it's time to remove the inboard pivot bolt for the LCA itself. Note that the bushing is a replaceable item, but the RDMTek LCAs (and all factory LCAs) come with these new bushings pre-installed into the LCA, which is a nice touch. The bolt is a 19mm bolt and it can be hard to break loose; torque spec for re-assembly of this bolt is 60 Nm so it's going to be on there pretty good and difficult to break loose. Plus, it's under the car quite a ways so a bit of a stretch to reach. Best to use a 1/2" socket with a breaker bar, and a 22mm wrench to counter-hold the head of the bolt while you remove the nut with the socket.

After the pivot bolt is removed, you can CAREFULLY and SLOWLY lower the LCA, while still maintaining a bit of tension under it with the floor jack. Lower the LCA enough so that you can remove the spring from its carrier. The top of the hydraulic strut should also come out of the hole that goes up into the trunk, exposing the top of the strut and the second bushing that sits just beneath the trunk. See the photos below for some shots of how this bushing gets compressed over time. This is the bushing that really takes the brunt of the wear, so it's the one that is really a good idea to replace. Unfortunately it's bit more work than the one inside the trunk, but it's a good idea to replace both bushings at the same time.
IMG_2408.JPG IMG_2409.JPG IMG_2410.JPG IMG_2412.JPG IMG_2413.JPG IMG_2414.JPG


From there, you can remove the bolt that holds the bottom of the strut to the LCA (a 17mm bolt/nut) and the 13mm bolt/nut that hold the bottom of the sway bar mount to the LCA. These are both simple and straightforward to remove (and install, when the time comes).

Then, it's time to remove the bolt that goes through the wheel carrier bushing. This is a 22mm nut and bolt combo, and requires bending of the brake dust shield for best access, even on later model cars. It CAN be removed without bending the shield, but it's HIGHLY advisable just to bend the shield and then bend it back when done. It will take a bit of adjusting and tweaking to get the shield just right so that it doesn't rub on the rotor, when you do re-install the rotor, so be aware of that.

Here are a few views of my removal of the wheel carrier joint bushing. You can see that it was in EXCELLENT condition after 117,000 miles. I'd be willing to bet that if your car has more than 80K on it, and it hasn't been changed, that it looks something like this too. The interesting thing was that the bushing was extremely floppy and allows for a TON of play. Eek !!! I used a very light coating of Syl-Glyde on the bushing surface and on the rubber to lubricate the installation a bit, and so that the rubber of the bushing didn't get pinched by the installation tool.
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Here I am using the special Baum tool to press OUT the old bushing from the wheel carrier.
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And a few views of the bushing itself.
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Using the Baum tool to press the new bushing into the wheel carrier.
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And now I turn to the spring. One of my tasks was to remove the stock pad and replace it with a 1-bump pad I had in my stash.
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Then it's time to begin buttoning everything up. Installation is pretty much the reverse of removal.

Re-installing the new RDMTek LCA, with the new 22mm nut and bolt provided with the LCA. MB recommends you replace the nut anyway, so I was grateful for the new hardware.
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Re-installing the lower sway bar mount on the LCA, and also the hydraulic strut bottom mount.
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Replacing the spring back into the spring carrier. It's highly important that you put the end of the spring back into its little "slot" in the LCA spring area. It is supposed to fit in one place.
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And, some additional tasks ... such as using a scraper to lightly scrape off years worth of accumulated tire detritus from numerous burn-outs....some of the rubber was more than 1/4" thick !!
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And after I cleaned all of the accumulated dirt and rocks out of the lower cladding under the rear door, and behind the rear wheel, I installed a new plastic panel to replace one that had been missing for many years. I had this panel in my stash but never installed it, for some reason. Well, now seemed the perfect time to do that...
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[JordiC]

Well done and thank you very much Gerry. Use of the word "detritus" in an automotive DIY was brilliant.

[gerryvz]

By the way folks, these rear wheel carrier joint bushings are an item that if your car has more than 100K miles on it, and you don't know definitively that they HAVE been replaced, are 95% guaranteed to be in dire need of replacement. These bushings are difficult to see because they are behind the wheel carrier/brake dust plate, so they are rather out of sight/out of mind.

You know how I'm always harping on the fact that EVERYONE'S E500E is carrying at least $5,000 in "deferred maintenance" no matter what they think or no matter how well it is maintained? Well, just replacing these two bushings is about $500 in parts and labor to have a shop or dealer do, so just these two little $30 items alone is 10% of my $5K total.... These bushings are an item that can be purchased safely on the aftermarket (Lemforder brand via AutohauZ, or for not much more you can get the dealer part).

Seriously though, the old bushings, once removed, had a TON of back-and-forth play in them and seeing as this is the major link/pivot point for the bottom of the wheel carrier, having lots of slop in that area can't be a good thing. So, this is something that all owners should pay attention to. You can do a visual inspection from underneath the car (even with the wheel on) with a strong flashlight, and you can see the condition of the bushings. If the rubber external portion is cracked, it's just a matter of time until plenty of dirt works its way in there and the grease dries up. Do not neglect this item and be sure to proactively check it !!!

Replacement of these bushings is a considerably less involved job than shown in this thread, simply because I was also replacing the LCAs with the RDMTek modified units; replacing the spring pads with 1-bumpers, and replacing the strut top rubber mounting bushings at the same time (killing four birds with one stone, so to speak).

I'd say this would be a 3-4 hour job at MOST for the first-timer, taking one's time and being careful (and having the correct tool). I don't know how the design of the aftermarket tools is, but it appears to me that the Baum tool that I bought is significantly better than the cheaper aftermarket tools for several reasons: chief among them being that the Baum has a thrust bearing located where the thrust bolt is tightened down, which significantly eases the pressure and effort required to operate the press. IMHO it is worth the extra $20-30 to get the Baum tool. It also appears to be much more nicely made and of more precision than the aftermarket stuff....

Cheers,
Gerry

[gsxr]

FYI... no need to disconnect the rear shock from the frame to R&R the LCA (or to R&R the outer support joint). Just disconnect it at the LCA and leave the top mounting attached, unless you are replacing the rubber bushings as suggested.

Also: You had a QUARTER INCH of rubber? Oh my. *wrings hands* I'm not sure how much is on my wife's car... I'll have to go measure and post a photo. Stay tooned.

[gerryvz]

So ... did you take a photo of rubber accumulation from burnouts?

What's the skinny?

[gsxr]

So ... did you take a photo of rubber accumulation from burnouts? What's the skinny?

Yes. Many photos. Teaser attached. Full pics & details coming soon...

[samiam44]

Gerry,


What's the pn for the inner rubber piece you added. Looks like I am missing both sets.

[gerryvz]

It just keeps debris out of the area behind the cladding and wheel well. It's VERY common for these pieces to fall off by themselves and get lost. I got my replacement many years ago and never installed it until now, so I don't know how expensive they are, but I don't think they are horribly expensive. It probably wouldn't be a bad idea to add a bead of Gorilla Glue to the mounting channel and use that to hold it into position.

Cheers,
Gerry

[gerryvz]

Doing a little clean-up and addendi as it's been some weeks since I've really spent much time under my car and here on the board...

One thing I didn't mention with this how-to on the LCA replacement, is that there are two plastic parts that will need to basically be replaced when you install the new LCAs. You can either install the plastic parts BEFORE you put the LCA on the car, or you can install it after everything is done. The function of these plastic parts (one per LCA) is to hold the brake pad wear indicator cable along the LCA so that it doesn't get inside or in the way of the spring. Keeps it at a safe distance and provides a channel/clamp to keep it correctly routed.

These plastic pieces are attached to the LCA itself by way of two holes that are drilled into the LCA. Two large pins on the piastic pieces fit into the two holes, and then a smaller interior plastic pin is driven downward with a hammer or mallet into the larger diameter pin, effectively expanding its diameter and forcing it to "grab" onto the hole drilled into the LCA. This type of a pin arrangement is sort of a one-time deal, so that it is pretty much destroyed when trying to remove the plastic piece from the LCA. Ask me how I know, I found out the hard way.

Given that I was getting ready to head to the MBCA StarFest in Alabama, I opted to just route the pad wear sensor cables near the spring and hope for the best. That said, I ordered new plastic pieces from parts.com and they arrived while I was gone in Alabama. Finally just installed them onto the LCAs today. Basically all you have to do is remove each rear wheel and then use a small ball-peen hammer or mallet to pound the inner pin downward to expand the outer pin into the LCA hole. Total of about 15 minutes of work (though it felt like 2 hours in today's 93F Houston heat). Then you just insert/route the brake pad sensor cable through the grooves in the plastic piece.

You can see the plastic piece in the attached photo. I have also circled the inner/outer pin assembly that has to be pounded down to expand it.

The part number for each plastic piece is: 129 546 23 43

Current cost via parts.com (May 2013) was: $5.52 each (two are required); MSRP is $7.75

Hope this helps. It's a small but important detail for anyone doing an LCA replacement on the rear of their E500E (and probably R129 too).

Cheers,
Gerry

[gsxr]

Yes. Many photos. Teaser attached. Full pics & details coming soon...

Full pics & details posted at the link below:

http://www.500eboard.com/forums/show...ll=1#post45234

[nocfn]

I may need to buy this install tool, I don't have it.

[gerryvz]

SG-Motorsports may be able to help you out with a deal on said tool....

[gsxr]

The OE/dealer tool is available for ±$150 now, down quite a bit from years ago. Dealer cost is $119 plus whatever markup they're using on tools.

202-589-00-43-00

The SG version is a few bucks less:
http://www.ebay.com/itm/351137411614

[7delta]

Sg version looks to be identical to Baum Tools. I cannot recall the price off hand..

Sent from my SM-G900V using Tapatalk

[vatc5637]

Just thought I'd check before springing for one of these rear carrier bushing installation tools, but if anyone has one for sale, please let me know as I'm about to tackle this project. Thanks.

[emerydc8]

I just did this job on both my cars (94 & 95 E420s). Maybe it's overkill, but Trae asked me to take some pictures along the way, so I wanted to share my experience with this before I forget it.

I ordered the factory tool (202 589 00 43 00) from Napperville, which was $145.20. The bushings (204 352 00 27) were $40.70 each (I ordered four to do both cars). I took advantage of the free shipping promo.

This only requires removal of the rear tires, brake calipers and plastic underguard for the control arm. You do not need to compress the spring or remove the rotor (at least on my cars with the large dust guards).

I chocked the front wheels and jacked my car up from the rear differential with a floor jack and lowered it onto two jack stands at the rear jacking posts, leaving the floor jack in place and under a slight load so I had three things holding up the car (GVZ style). I hung the brake calipers from the spring by a coat hanger and removed the lower plastic control arm guards as well. Both my cars have the large rotor dust guards and I only had to bend them a bit to access the nut for the bushing. I used vice grips to bend the guard.

You will need a 17mm socket for the brake caliper bolts, a 10mm socket for the two bolts holding the plastic underguard and a large 22mm socket for the bushing bolt. I also used a 22mm box end wrench to hold the head of the bushing bolt. I used an electric impact driver to remove the 22mm bushing nut, but I think I could have just as easily used a breaker bar.

I used a jack under the control arm just in case, but even if you don't, it won't kick down once you remove the bushing bolt. Actually, the part connected to the rotor will pop up a few inches. Getting it back down into the control arm once you replace the bushing will be the most difficult part of this job.

A couple of areas that took a while to figure out are posted below (sorry I don't know how to insert writing in between the pics, so this is no GVZ HOW-TO by any means!):

1. The bushing bolt heads always go towards the front on both sides. Once the nut was removed and the control arm was supported with a small jack, I used a long 3/8" extension and hammer to drive out the bolt towards the front. Once the bolt and 3/8" extension are removed from the bolt hole, you can expect the part connected to the rotor to pull up a few inches away from the control arm. Actually, mine stayed as they were until I pushed the brake rotor and it dislodged from the control arm, but there wasn't much tension to begin with.

2. For bushing removal, the large diameter part of the tool and the head of the bolt for the tool always go towards the back -- actually this applies to both removal and installation. You will pull the bushing through from front to back to remove it and install the new bushing from front to back. I used some Gleitpaste on the rubber just to help it slide through and not get hung up while pulling it through.

3. For bushing installation, be careful that you don't pull the bushing through too far to the rear. This may require that you check it a few times while tightening the tool to ensure that the bushing housing is evenly spaced in the hole.

4. Once the bushing is installed, you will need to put all your weight on the rotor to get the bushing back down into the control arm. Be careful that the rubber part doesn't catch. This is where you can raise the control arm with the jack a bit to help. I had a screwdriver and a long 3/8" extension in one hand and when I got it down far enough that there was some space between the control arm hole and the bushing, I stuck the screwdriver in the hole and opened it up enough to remove the screwdriver and replace it with the long 3/8" extension (keep weight on the rotor while you do this or it will spring back up out of the hole). The extension allowed me to move the bushing center around so I could get the hole aligned and the bolt started into the control arm from front to back. Once it was started, I used a hammer and another extension to tap it through the hole.

The pics below are of the right rear wheel and were taken in chronological order. They were taken from behind looking forward. I used Locktite on the bushing bolt and brake caliper bolts. This isn't a tough job but as was mentioned above, it just takes some time to figure it out. Most of my time was taken trying to get the holes aligned to re-insert the bushing bolts. Obviously, after 25 years, the bushings on my cars were toast. There was an awful lot of play in the old bushings. Hope this helps. I'll do a part 2 to get the rest of the pics uploaded.

[emerydc8]

More pics in chronological order.

[Trae]

It was NOT overkill. I need all the help I can find when attempting most of these jobs.

Many thanks to Jon for your excellent write up and adding to the "Collective"!

[emerydc8]

Many thanks to Jon for your excellent write up and adding to the "Collective"!

Thanks, Trae. As long as that doesn't make me a "collectivist"!

[500AMM]

Well done, Jon!

That honeycomb support block must be a handy thing, never seen it before. Could you post some info about that please?

[emerydc8]

Hi Arnt and sorry for the late reply. That's just a piece of 2 x 6 that was painted Boeing brown and was temporarily used in a 747 flight simulator that I built. The edge has Velcro on it. But now that you mention it, I guess it does look pretty cool. Maybe the chicks would dig it.