DIY tips for rotors? - Page 2 - PeachParts Mercedes-Benz Forum

95E320cab · #16 11-28-2002, 11:28 PM

Thanks Haas. No room for a long cheater. Going in search of an impact wrench and a 6-sided, 19 mm socket tomorrow. Either that or i'm taking it to the shop for the first time.

haasman · #17 11-29-2002, 01:42 AM

Are you trying to remove the caliper or the retaining bolt for the pad?

SoCalSwami · #18 11-29-2002, 02:16 AM

It took me 2.5 days of penetrating oil and 3 - 4 hours of sledge hammer'n on my 1995 E320 to brake my right front rotor loose, the thing had rusted on. I finally resorted to prying the rotor loose with a prybar braced against the ball joint.

My left came off after 20 minutes of easy swats with the sledge. Don't worry about damaging the rotors coming off, your only going to be throwing them away.

As for hanging the calipers, just replace your hoses and you don't have to worry about letting them hang loose.

After all that, and a good brake fluid flush, my ride was better than ever.

P.S. I went with the 'grooved' rotors, and I am not sure I can tell the difference. They are meant to remove the gases generated by the pads faster. Can't say for sure they stop the car any better, but they look cool.

#19 11-30-2002, 09:37 AM

Not sure which bolt is frozen, but if it's one holding on the caliper you should be able to use the soak in penetrating oil and breaker bar technique. I have never snapped anything over 17mm. I have an 18 inch long 1/2 breaker bar. Have not come accross anything I can't free. Try the penetrating oil technique, it does work, and with a good breaker bar should be no problem. Siz sided socket good idea.

As a last ditch effort you could always cut the head off with a cutting tool (dremel) and then trhead out the stud. Drill out as absolute last ditch effort.

Good luck, be patient,
Joel

brookspw · #20 07-30-2003, 11:16 AM

Quote:

Originally posted by haasman
A couple of additional thoughts regarding the DIY brake job-

-It is a good idea to compress the caliper puck into the caliper. It makes the installation of the pads and the new thicker rotor (disk) easier but also cleans and "lubes" it.

One caution though: Take a closer look at the master cylinder. If it is full, you will need to remove some brake fluid so it doesn't spill out and curdle your paint.

-Never pry against the rotor ..... NEVER

-I use extra-large channel lock plyers to compress the puck into the caliper. I use either an old brake pad for one side and the out housing of the caliper on the other.

-If you clean the rotor (some don't require this, so be *absolutely* sure which is required of your new rotors) make sure they are completely clean. Twice in the past I have *thought* the new rotors were clean. Just a little grease, oil, residue will cause eventual "high-spot" resulting in pulsating rotors and brake pedal. If in doubt, clean them again, both sides before installing. BTW, a simple dot of pad lube the size of the period at the end of this sentence can cause a problem.

-Break squeak: Typically pads come with shims and some with anti-sqeak paste. You should put the paste (lube) on the "upper and lower" edges and the back of the pads, only. Be careful of this lube in that it will lube the braking friction surfaces (which you don't want).

-If your brake pad sensors have any wear on them, replace them.

-I have found that if you turn the steering wheel full lock, it is much easier to access the caliper.

-The retaining bolt is straightforward but it often will turn unless you also hold its respective nut. The catch here is that the nut requires a thin wrench. You can substitute with another tool (vise grips etc) but ideally you want to use a thin headed wrench.

Haasman

Great post. Haasman is always full of it. Good DIY advice, I mean:p

Question: When I purchased my car (1/02) the front rotors were warped. Purchased ATE rotors and Textar pads. I was very careful about the installation and made sure the hub face was very clean and the rotor had a flush seat. Worked like a charm.

2-3 months ago, rotors (1 at least) is somewhat warped and pulsates at breaking from high speed. The left front, when I looked at it, has a couple of spots that are about 2 inches, and are lines that are concentric with the circle of the rotor. They seem to be the "high" spots that pad catches on when you turn the rotor.

Now, I know that the lugs and wheel actually snug the rotor up. SO, how can I tell if what I am seeing with the wheel off (rotor not tight) is what is actually happening with the wheel on.

Also, I did not know about cleaning the rotor. With what should I clean it? Alcohol?

Thanks, Phillip

md21722 · #21 07-30-2003, 11:54 AM

There should be a screw with a 5 mm hex head that holds the disc in place when the wheel is off. Lots of Mercedes warp discs and some say they've never warped a disc. Changing brake lines and calipers helped me reduce disc warping.

csnow · #22 07-30-2003, 12:25 PM

Clean with Brake cleaner.
Good stuff. Wear rubber gloves, and avoid fumes.

brookspw · #23 07-30-2003, 05:31 PM

Quote:

Originally posted by md21722
There should be a screw with a 5 mm hex head that holds the disc in place when the wheel is off. Lots of Mercedes warp discs and some say they've never warped a disc. Changing brake lines and calipers helped me reduce disc warping.

Thanks, but I'm not sure how this applies to my question. The little hex screw just holds it in place lightly. It doesn't apply the actual mounting force.

I can understand how changing a caliper would help, how would the brake line replacement help?

md21722 · #24 07-30-2003, 07:41 PM

Maybe I didn't understand your question. As the lines get old they swell internally prevent fluid from flowing properly. Particuarly they may drag because fluid does not flow out of the calipers. For this reason, its recommended to change lines when changing calipers and many places won't warranty a caliper unless the line is replaced at the same time. But if your problem is dirt or otherwise on the discs, then changing the calipers won't help.

haasman · #25 07-31-2003, 12:52 AM

Phillip

You are correct in that the little 5mm bolt only holds the rotor to the hub, nothing more. It is the actually tightening of the wheel against the rotor and thus against the hub that makes it fully seat.

That is why torquing the lug bolts in a star pattern is so important. This process pulls the parts together evenly.

It is not that uncommon to have a wave or a high sport after replacing rotors and pads. I just think many don't bring it up. One simply small blot of grease is all it takes. Try BrakeKleen or other brake part spray cleaner, but my guess is that if you are already feeling it in the pedal, you will need to turn the rotors. It is rare in my experience of rotors that are waved to cure themselves.

If you are game, you can try multiple very light brake applications to take off the high spots, but I think you are headed for a rotor turn.

You can also try sanding the obvious spot on the rotor. You want to use an emery cloth or other similar type abrasive. Be sure to check the inner side.

As a tip, whenever I replace rotors, I always make sure the mounting surfaces are clean and smooth. I then apply a light covering of these mounting surfaces with anti-seize.

Keep us posted,

Haasman

brookspw · #26 08-03-2003, 05:33 PM

Thanks. Give me your thoughts on this:

-- I replaced the pads and rotors about 25k ago
-- Smooth until about 5k ago
-- Pads are fine and thick
-- Left rotor has obvious high spot- you can see lines across one side of the rotor (the direction of the slice in a slice of pie) in a section about 1-2 inches wide.

-- When I replaced, I did everything you just mention -- EXCEPT cleaning the rotors with brake cleaner. I removed the plastic coating and wiped them, but who is to say that I didn't get anything on them.

My question is: Would a grease spot have the effect you describe after 20k, or wouldn't that show up much sooner?

haasman · #27 08-03-2003, 05:58 PM

My first reaction is that residual grease would show up quite quickly after doing the brakes and rotors. Funny that it took 25k to appear. But a blob of grease, oil or whatever that got onto a rotor later could contribute to the problem.

Question- is the ridge between the bad spot and the rest of the rotor surface high enough that you could catch a finger nail on it? Just trying to imagine what it looks like.

This is what I conclude: You didn't do anything that contributed to this problem, at least as far as the original brake and pad work. If you had, my guess is it would have shown up a lot earlier.

One quick thought- did you or anyone lube your wheel lug bolts? Maybe some of the lube got flung onto the rotor.

Pull the disks, yes both, have them checked to see if you can turn them. If so do it, around here I get them turned for anywhere from $15-20 a rotor. Reinstall everything and chalk it up to one of the great mysteries of owning a car.

Haasman