Wow! I had to do that with my Bug several years ago! But I would have to loosen the bolt on the master cylinder piston in order to relieve pressure!

Turned out that the wheel cylinders (drum brakes) were too incorrect. Accidentally installed VW bus parts instead of bug parts...

Picked up a set of pads wile ML was in the shop. Checked with service advisor to find out when I last had pads changed and it turned out to be around 15K miles ago, not 5K as I originally thought. So maybe the wear is actually normal for my now frequent stop-and-go commuting I get to enjoy daily.

Well, new pads are going in this weekend...

I would still think that 15k is a bit soon for your type of driving. I would expect 25-30k minimum. I have noticed that the sensors used on these pads have always indicated (for me at least) pad replacement long before they actually needed replacement.

This is because there was a ridge of rotor developing in a minute area where the pad was not contacting. The ridge was however in line with the wear sensor. As the pads wear and come closer to the rotor, the sensor comes closer to the ridge until they meet. The sensor is grounded out and lights up.

I don't replace the sensors anymore.

When I talked to the service tech, he told me the EXACT same thing about the ridge and the sensors.

I suppose I could get the rotors turned as well, but with the miles I've got on the originals, I probably should spring for a set of rotors on the next pad replacement shedule.

G-Benz

I couldn't resist replying to your post with a couple extreme examples. My daughter and I used up a set of front brake pads on a single tank of gas which was likely less than 200 miles. My wife routinely gets 125,000 miles on the front pads of her 604 Peugeot.

It is all in how you drive. I should explain that when my older daughter and I used a set of pads in less than 200 miles we had our 2.3-16 at Summit Point Raceway. She would drive for 20 min, park the car for 20 min then I'd drive it for 20 min, park it for 20 min and so forth. I was using 1/4 tank of gas per 20 min run. She used a bit less. :D

Swapped out the pads this morning. Old pads had about 1/3 of the material left. I am going to have to find a different route to work in the mornings!

Had to loosen the bleeder valve to get the caliper pistons pushed in far enough to get the new pads in. Had to top off the reservoir afterwards, but there was enough in there to not worry about air entering the system.

I am guessing bleeding is not necessary, but the braking still seems a bit soft. Is it due to the ABS system or should I consider getting the system bled?

Bleed your system!
 

I know of no reason why you would ever crack a bleeder valve for anything other than bleeding. PEOPLE, PLEASE DO NOT DO THIS:mad: ! In doing so you are breaching a high pressure hydraulic system, and that's bad. Sorry to shout, but I've read a few posts here regarding this practice and it bothers me. I used to work on helicopters, and such a procedure could have you falling out of the sky. In the first place, your pistons should compress fairly easily; if not, your technique needs a little work. I either use a Channel Lock pliers to squeeze the old pad against the piston(s), or remove just one old pad and use the rubberized end of that same ChannelLock to lever against the piston (no damage to the rotor that way). Doing a pad change, you should never have to add fluid, since you're pushing quite a bit of fluid back into the master cylinder...it's more of a concern that you don't overflow the master.

You need to bleed your system, unquestionably. When you cracked the bleeder, you likely let a bit of air in. And frankly if the system DID ingest some air, it may have also ingested any corrosion or dirt particulates that were in/around your bleeder valve when you cracked it open(more of a concern for older cars). Get the air out of there and you'll be fine:)

I'd agree. You should never have to crack a bleeder to push in a piston into the caliper. You most likely let some air into the system. If you resevoir was low, this might also let some air in.

I now use a set of welding vise grips. These ate the ones with the extra long arms. The one that I bought has a large flat swivel ends. I think they are called locking C-clamps. This gives a larger safe surface area for the force needed to press the piston back in. One tong will fit right into the piston, the other can go behind the caliper body. Press the handle together, readjust the threaded adjusting screw and do it over and over.

If the pistons were that hard to press back in, you may have a master cylinder problem. It is not letting the brake fluid back into the system and releiving pressure. You may have slight braking pressure applied to the pads at all times. It may not be noticable at this time, but it will cause your pads to wear much quicker. After driving at least 10-15 miles, put your hand on the outside of front wheels by the lug nuts and notice the temperature. Now do the the same for the rear wheels. If the fronts are noticably hotter, this may be your problem.

A couple of observations:

There are several things that will cause disk brakes to drag -- residual pressure in the master cylider, sticking pistons (usually more noticable on one pad), bad brake lines that retain pressure, and so on.

One thing to remember when replacing pads -- take the cap off the master cylinder reservior! The air orifice in the cap is very small to reduce the amount of water the brake fluid absorbs from the air, and stuffing all the displaced air out that hole takes quite a bit of pressure and time. I've know people to think their calipers were locked up!

ABS brake systems tend to have a slightly spongy pedal -- a sort of mushy zone between initial brake effect and hard pedal -- that can be disconcerting the first time you drive one. It's normal, and doesn't have the "air spring" feeling of air in the brake lines, more like a "remote control" effect where pedal travel gives additional brake response without addition pressure for a short amount of travel.

And if it has been a while since you changed the brake fluid, I'd flush in new while bleeding the brakes. Cheap insurance for that long hill on the interstate when you really NEED those brakes to stay alive!

Peter

Great tips on the brakes! Will do so from now on!

I am scheduling a brake bleed and and a good Hunter tire balancing!

How many miles do you get out of your pads?
 

Depends on how strong the flow is!:D

Re: How many miles do you get out of your pads?
 

I don't think I understand this?

(Or am I just that dumb... is it a joke!?) :eek: :eek: :p

The brakes on the front of my 300E 4matic have been replaced 3 times in 208,000 miles-and the rear ones have been done twice...combo of city and highway driving . And yes, I replace the rotors each time (and sensors too)-I also have the brake fluid flushed and re-filled every 60,000 miles (not necessairily co-inciding with the brake job)

My 300D gets about 12K on front pads
and about 35-40K on rear pads.
I just changed the rear pads and
rotors only because the rotors had
concentric scoring. There was still meat on the pads, good for another 5K. The car stops much better now (the front pads and rotors
were replaced about 6 months ago).
Safety first!
San Francisco hills.

Mean or just careful?
 

A set of OEM front pads for my 190E cost about 12 pounds ($18) and the discs (rotors) about 7 pounds ($11) each. It takes me about 20 minutes to change the pads.

I think that is excellent value for money, and I don't worry that I get 10k out of my pads.

If you guys are getting 25k out of your pads, then you must use a lot of long straight roads!