PeachParts Mercedes-Benz Forum - Working on brakes: how difficult?

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Quote:

Originally Posted by rino (Post 1427600)

Thanks for your advice... I'll get the jackstands at Sears this weekend (any specific suggestable model I should be on the look for? Preferably economical, reliable, and SMALL, so that I can hide them somewhere after use...) and I will look into all you have suggested, with the help of my Haynes manual to make sure I understand everything correctly, and then report back here soon.
While I am at Sears, what are the other special tools I am going to need that I should get there (I have no tools that are specific to brake work).

Winmutt, I am unclear about your 99_cent solution: does the jar you mentioned imply the use of a power bleeder along with it, or can I just use the jar and do the bleeding myself without the aid of a second person? Thanks...

Rino

The latter. You want to keep the jar ABOVE the bleeder valve. As you press the pedal in it forces the air out, then you release it sucks fluid back in. Just make sure you close the bleeder before you unhook the hose.

Quote:

Originally Posted by vstech (Post 1427229)

I also recommend jackstands... that said, a large block of wood under the frame of the car with the car on a jack is kinda ok... for 50.00 you can get a set of jackstands with a nice 2.5ton floor jack at most auto parts stores, or sears.
as far as bleeding goes, theese cars are so simple. with the cap off the MC suck out the nasty fluid, and fill it with clean fluid, then starting at the back passangers side, open the bleeder screw, it's either 8mm or 10mm, I don't rember... anyway, the system will trickle out gunky fluid, when the gunky stuff stops and you get clear, close her up and move to the closer to the drivers front. RR, LR, RF, then Drivers front. keep filling the resivoir. it is faster with a power bleeder, but not needed on the older MB's.
if you want to just change the brakes, it's also simple. just pull the clips, on bendix calipers, or simply drive out the pins on atx calipers. and pull out the pads.
reverse to install. some put stickey goo to keep the squeel down.
some use a sticky spacer.
ymmv
John

I got the jack stands and floor jack yesterday at Sears... I'm all set to go with the brake job...
How long would it take for the system to trickle out the gunky fluid and to complete the bleeding process using your method, more or less? I am willing to give it a try (if it works, I'd say it is the very best approach to brake fluid bleeding, in that it is done without the need for a power bleeder or the assistance from others...) I'd also like to learn more about what was suggested by winmutt, which process I do not completely understand at this point, but think that perhaps might be usefully used in conjunction with what you have advised...

Thanks,
Rino

Quote:

Originally Posted by winmutt (Post 1427230)

There are actually more downsides to the two person method. It requires that the bleeder valve be frequently opened and closed. This causes wear on it and also opens the sytem to possibilities of air getting sucked back in.

Just find a jar and appropriate sized hose. Fill the jar with some clean fluid and make sure one end of the hose is in the fluid. Attach the other end to the bleeder. Lift said jar above the bleeder (so the air flows up) get in the car and start pumping on the brakes. Keep an eye on the fluid level (remeber the rear reservoir) and try to keep an eye on the jar. I prefer to pump until its a nice clear color. Get out close the bleeder and move on. No reason to spend even $5 on a 99 cent solution.

As I mentioned, I got both the jack stands and the floor jack: I am ready... I want to give your method a try, and yet at this point I would like to understand better how that works before going ahead with it. My understanding (please correct me if I am wrong) is that in order to get the air (and the contaminated fluid) out of the system at the time of doing the bleeding, the new fluid has to flow from the master cylinder all the way through the exit points at the bleeder valves, replacing the old as it travels down. So, has the method you described to be done in conjunction with the process described earlier by vstech, that is, first empty the reservoir, refill with new fluid, start letting the old fluid in the lines out, beginning from the farthest valve, then RL, FR, FL... filling the reservoir with new fluid as it gets low... until all gunky liquid is out? Is it at this point that you do your thing with the jar filled with new fluid held above the bleeder valves and the pumping on the brakes? Otherwise, if you don't do the other part first, how is the old fluid going to be replaced and any air possibly trapped along the lines from the master cylinder to the bleeder valves going to be expelled from the system?

Please pardon my inexperience about the topic at hand and be patient, you guys... Both what you and vstech have suggested seems superior to the other methods posted here involving power bleeders or the traditional use of an assistant (to pump on the breaks - with the resultant wear on the bleeder valves)... but I need to fully understand how it works before I can do it appropriately on my own.

And, if you know of a website that explains this process thoroughly (maybe even with pictures), by all means let me know.

Thanks,
Rino

Agree with The Gears, no need to bleed unless you remove hoses. HOWEVER, brake fluid absorbes water very eaisly. A good maintainence item, as water soaked fluid will eventually rust calipers, then you get to spend even mo money. You may have heard, maintenance, maintence, maintence. This is part of it. This time of year may prohibit this. See three sentances ago. The resevoir has a passage way in the bottom. It is odd, I didn't believe it either. Just keep it topped up.

just dont wait too late. i burned through a pad once and prying it off the disk rotor was probably an 8-10 hour job and infinitely frustrating. i dont know about the w123's but my w126 has pad-wear sensors that need to be purchased & installed as well.

Good point, rektide, 123's have pad wear sensor too. Not a bad idea to replace. Cheap and available from most sites, some of which will alert you to other needed parts when purchasing items for whatever job you're doing.

Just to confirm that, as many of you suggested, it is really very simple... you just need to do it once to realize its simplicity...
This morning I changed the brake fluid (using the gravity method), then took the brake pads out, played around with the caliper, put the brake pads in...
Thank you so much everybody for letting me know how to do it and that I could do it...
It's a wonderful support forum that we have here!

Rino

When replacing the pads, what's the best way to get rid of the brake pad dust that accumulates inside the calipers? It is likely to contain asbestos which is very hazardous to your health... so you don't want to use compressed air, risking to inhale it... I heard of some people washing their brakes as well when they wash their cars... Pouring water over the calipers... does it make sense?

Rino