For several years now, I've really needed to replace my front brake rotors on my 560SEC. I bought them about 2.5 years ago and stored them up in my attic, and finally this summer got them down and decided to bite the bullet and replace them at the next brake pad change. At the same time, I finally tired of the dusty Textar/Jurid/Pagid pads, and earlier this year ordered a set of Akebono Euro pads for the front of the 560SEC, to use when the time came.
Well, starting about 10 days ago, that time finally came. My brake pad warning light started its tell-tale flickering, which indicated that a pad change was in order. So, I gathered things up, did a bit of research, and decided to do the job in the 90F Houston heat this weekend. Yes, the heat is JUST NOW STARTING to break, with highs only in the low 90s every day rather than in the mid to high 90s as is normal in July and August. So, car-repair season is fast approaching ... when I can do my repairs in (relative) comfort. But that day has not yet arrived, and I needed to do these brakes.
I also decided to replace my front wheel bearings as a proactive maintenance item. The reason for this is that my SEC is still on its original roller bearings, and new Timken bearings are readily available and not all that expensive. The SEC (and SEL) uses the Timken SET3 (outer) and SET5 (inner) bearings, which are common sizes that are shared with many Chevrolet and Ford models.
It is important to note that when bearings are replaced, the races (which come with the bearings) must also be replaced at the same time. You SHOULD NOT re-use the old bearing races with new bearings. The old races are pressed out of the car's wheel hubs, and the new ones are pressed in. More on that later.
This job should take about 4-5 hours to do both sides, for the first-timer. Generally the second side goes much faster.
Items required include:
- Two front brake discs, MB part number 126 421 05 12 (current price $44.40 each via parts.com, ATE aftermarket $58.61 via AutohausAZ.com)
- One 150 gram tube of MB high-temp wheel bearing grease (which is a fluorescent green in color), part number 002 989 00 51 10 ($5.28 via parts.com; $6.95 via AutohausAZ.com)
- Two seals for the rear bearings, MB part number 005 997 44 47 (quality Elring product available on the aftermarket) (current price $13.80 each via parts.com; $2.82 via AutohausAZ.com)
- MB brake paste, MB part number 001 989 47 51 ($11.70 via parts.com)
- One set of four front brake pads, Akebono Euro 1072 (available via Amazon.com)
- Four brake pad wear sensors, MB part number 140 540 12 17 (quality Pex product available on the aftermarket, $3.96 each via parts.com; $0.94 each via AutohausAZ.com)
- Two Timken SET5 inner cone front wheel bearings (available from AutoZone)
- Two Timken SET3 outer cone front wheel bearings (available from AutoZone)
A front wheel bearing repair kit (part number 126 330 00 51, $80.40 for MB via parts.com, $27.25 for SKF kit via AutohausAZ.com, two required) is also available, which contains the following parts:
- inner bearing sealing ring
- inner tapered wheel bearing
- outer tapered wheel bearing
- pinch nut for axle nut (axle nut not included)
- brass suppressor contact piece
- dust cap for end of hub
Tools required include:
- Hydraulic jack
- One and preferably two jack stands
- lug wrench
- drift punches - small and large sizes
- 19mm 1/2" drive socket
- 10mm 1/2" drive Allen socket
- Breaker bar or long-handle 1/2" ratchet
- Bent needle-nose pliers
- Channel-lock pliers
- Large and medium flat-blade screwdrivers
- clothes hanger (to hang brake caliper from sway bar)
- small square block of wood (example, 4" length of a 2x4)
- shop vise
- Cardboard or other item to place underneath brake/rotor assembly
- Brake cleaner, 1 can
- Blue Loctite
The first thing to do is to loosen the lug bolts on the side of the car you want to work on, before jacking it up. I did this job one wheel at a time, rather than jacking up the entire front end. You can see my toasted clear-coat on my Lorinsers, which will be fixed this coming winter. Then, jack up the car and remove the five bolts and remove the wheel.
IMG_3073.JPG IMG_3140.JPG IMG_3142.JPG
Here's what the brake assembly looks like, with the wheel removed from the car.
The next step is to remove the brake pad retaining pins and the anti-rattle spring. Use a small drift punch and a hammer to tap lightly on the two pins, and drive them out of the caliper toward the center of the engine. You can then use your bent needle-nose pliers to remove the pins from the calipers once they are driven as far as the punch will allow. You can see me removing the pin by hand here, as it came out fairly easily. This is not always the case.
Next up is to remove the two brake pad wear sensors (unplug them from their electrical connector and pull them out of the top of the brake pads). After you've removed the sensors, you should inspect them to see which one was causing a brake pad wear warning light on the dashboard. Chances are that one of them is worn down. Also, you can then remove the anti-rattle spring much easier after the pad wear sensors are unplugged and removed. Here you can also see me using my Channel-lock pliers (actually they are Knipex models, made in Germany) to squeeze the pad and caliper together, slowly. This squeezing provides a little slack so that you can easily pull the worn pads out of the calipers.
After that, you need to remove the pads by pulling them straight out of the caliper and setting them aside. From there, you need to get your 1/2" ratchet or breaker bar, and a 19mm socket, and remove the two bolts that hold the caliper onto the car. These bolts are accessed from behind the caliper. Be sure that you are removing the right bolts .. not the ones that hold the two halves of the calipers together! These bolts are on very tight (they use Blue Loctite), so a breaker bar and some effort here will be required.
Next up, after the caliper is removed, is the removal of the hub+rotor assembly from the car. This is fairly easy once the caliper is removed. You first need to remove the dust cap that fits over the end of the hub. MB and a couple of aftermarket German tool makers manufacture a special tool for removing these caps, but you can do this quickly and easily with a medium sized flat-blade screwdriver and a mallet. You just need to tap softly and go around the entire circumference of the dust cap, and it will gradually loosen so you can pull it off. Below you can see the cap coming off, and what the inside looks like (end of the spindle).
Here's what the end of the spindle looks like with the wheel bearing grease cleaned off.
Next, you'll need to remove the retaining axle nut that is threaded onto the end of the spindle. It has a 5mm Allen pinch nut, which is rather easy to loosen and remove. Then you can remove the axle nut by turning it counter-clockwise.
From there, you can just pull the hub+rotor assembly straight off the spindle. The outer bearing will come loose, so be prepared to catch it, and set it aside. You are going to clean it and re-use it, or replace it depending on how proactive you want to be. A careful examination of the bearing and race in the end of the hub will tell you if you need to replace the bearing or not. If you see any pitting, cracks, scoring or major burn marks, the bearing and race MUST be replaced. They are inexpensive parts, as mentioned earlier.
Here's what the end of the spindle looks like, after the hub+rotor assembly has been removed. I am cleaning off the excess wheel bearing grease from the spindle, and also checking the bearing races on the spindle to ensure that they are in good condition. If the spindle shows any type of wear, it MUST be replaced.
Now we move into the next phase of the job ... the separation of the hub and rotor. The rotor and hub are pressed together and held with five bolts, which are inserted from the inside. These five bolts are also secured by Blue Loctite, so you will need to have your Loctite handy when you re-assemble the hub and the new brake rotor.
Here is a view of the assembly removed, and I'm cleaning the outer and inner bearing races carefully with a rag. I didn't show the removal of the grease seal on the inner bearing, which can be removed with a seal puller tool or very carefully with a large flat-blade screwdriver. It is EXTREMELY easy to damage the bearing using this method, so it is a good idea to consider replacing the bearing if you plan to pull the seal. If you don't plan to repalce the bearing, you can leave the seal in place and just clean and re-pack it with new wheel bearing grease. It's advisable to use the green MB High-Temp wheel brearing grease. You can also see a close-up of the inner bearing race, just prior to it being pressed out of the hub.
IMG_3074.JPG IMG_3075.JPG IMG_3076.JPG
The next job is to press the race(s) for the bearing(s) you wish to replace, out of the hub. To do this, I used a large punch with a flat end, and a hammer. There is a flange on the inside of the hub that you can hammer against, in a circular pattern around the circumference of the race, to gradually hammer it downward and out of the hub. Flip the hub/rotor over and do the same for the outer race. Here are a few views of the process of the race being punched out of the hub.
IMG_3077.JPG IMG_3078.JPG IMG_3079.JPG
Next up are the steps to separate the hub from the rotor by unbolting them. To do this, take two spare lugbolts (if you have them, otherwise you can use your regular lug bolts in a pinch) and screw them into the hub, as shown below. Put them in the holes next to one another, or two apart depending on the width of the jaws of your bench vise. Then you will want to clamp the heads of the two bolts into the haws of the vise. This will keep the hub from rotating in the vise, so you can have a stable platform by which to loosen the five bolts that hold the hub to the rotor. See below for details on how this works.
Use your 10mm 1/2" Allen socket and breaker bar to loosen the five bolts, once the hub is clamped into the vise by the lug bolt heads. The bolts will be very tight, so it will take some elbow grease to loosen them.
IMG_3080.JPG IMG_3081.jpg IMG_3082.JPG IMG_3083.JPG IMG_3084.JPG
A couple of final shots showing the process of loosening and removing the five bolts holding the hub and rotor together.
Then, bring the hub and rotor back to your work area, where you will separate them. They are just pressed together, so you will need to insert a large flat-blade screwdriver or other object between them to begin working the two parts apart. See photos below for this process.
IMG_3087.jpg IMG_3088.jpg IMG_3089.jpg
Here are a couple of views of the bare hub, separated from the brake disc, as well as the old disc side by side with the new MB disk (painted gray for corrosion protection).
IMG_3090.JPG IMG_3091.JPG IMG_3092.JPG
Now it's time to install the new bearing race by pressing it into the hub. First of all, here are a few views of the new bearing and race.
IMG_3093.JPG IMG_3094.jpg IMG_3095.JPG IMG_3096.JPG
After scoping out the bearing, it's time to install the race in the hub. This is the larger inner bearing. First of all, you need to test-fit it by placing it into the opening in the hub. It's HIGHLY IMPORTANT that you install the race with the smaller edge facing up, as the cone profile of the inner bearing is going to point OUTWARD toward the wheel. So, you must have the larger end of the race facing down. Once you are sure you have the correct orientation, you should use the OLD race (which you pressed out of the hub) as a drift to press the new race INTO the hub. Do this by lining it up very carefully and evenly on the new race that is test-fit into the hub.
IMG_3097.JPG IMG_3098.JPG IMG_3099.JPG IMG_3100.JPG
Carefully and with only medium blows (softter at first, then a bit harder as the race starts to settle down into the hub) on the old race/drift, carefully hammer continually around the perimeter of the race to apply even pressure on the new race as you drive it gradually downward into the hub. The last photo below is what a fully driven-in race looks like, sitting in the hub. This, again, is the inner bearing race.