front brake pads - PeachParts Mercedes-Benz Forum

adiaw83 · #1 04-16-2003, 09:06 PM

I'm going to order the parts I need from fastlane tonight. I'm changing the front brake pads on my 83 300SD. I know I need to by brake pads and brake pad wear sensors but are there any other things i should get. Also while im working on the brakes are there any other maintenece procedures that I should do while i have easy acces to them. If anyone has any little helpful advice id really appreciate that. thanks.

DieselHead · #2 04-16-2003, 09:20 PM

I normally just change the pads and let that be it. Sometimes, while the wheel is off, I shake the suspension parts around to see if anything's loose, and I take a look at the various rubber parts. It's a good time to look for rust also.

With regards to buying stuff online, I usually just get the pads and the pad wear sensors, nothing else. If I have the time, I go through each catagory and look for stuff I might want to have just in case, or for future projects.

Alex

sixto · #3 04-16-2003, 09:24 PM

Consider replacing the flexible brake hoses as well. Not expensive and 250K miles is a lot of use if they're still original.

Pry the hubs and see if you have grease or wax in the wheel bearings.

Sixto
91 300SE
87 300SDL
83 300SD

psfred · #4 04-16-2003, 09:25 PM

You will need some antiseize to put on the pads to keep them from squealing -- some on the back where the piston touches the pad and some on the EDGES of the backing plate, never ever on the friction material!

Check the condition of the rubber boot around the pistons in the caliper. If there is any damage, replace the rubber parts in the caliper (called rebuilding) -- otherwise, if the dust boot fails, the caliper will stick, causing more problems.

While you are in there, this is a good time to change the brake fluid if you have not done so in the last couple years. Check the condition of the hoses, replace any with cracks or bulges. Clean the slots in the caliper where the pads fit, or they can stick instead of sliding freely, also crud in there can make them squeal.

Push the calipers back with something like a large screwdriver or heavy putty knife. One of those small prybars with a screwdriver handle is the ticket here, you want to push back in the center of the pad.

If it is very difficult to push the pad back, just get it loose enough to pull out and use a deep C-clamp to push the piston back.

Check the rotor thickness before replacing pads, though -- if there is a distinct lip around the outer edge, the rotor is worn out and must be replaced -- new pads on a too-thin rotor will result in the backing plate contacting the anti-rattle spring. This causes the pistons to be forced crooked in the caliper bore, and they stick, overheating the caiper and cooking the rubber parts. If the backing plate is already very close to or touching the antirattle spring on your current pads, get rotors too.

Check the tire rod ends and suspension parts for cracked or torn boots and any loose parts. Check tires for even wear and damage, since you have them off.

Check ball joints for play and stiffness, check play in steering parts.

Clean the wheels.

Check wheel bearing play, correct if excessive.

Peter

adiaw83 · #5 04-17-2003, 12:02 AM

wow thanks a lot for all the info.

adiaw83 · #6 04-17-2003, 12:16 AM

what brand would you recomend from fastlane. They have: Pagid, PBR, ATE (TEVES), Textar and Jurid. Thanks

DieselHead · #7 04-17-2003, 12:25 AM

I always get Textar. I don't have much to compare them to, but they've never been bad, so I stick with what I know.

Alex

adiaw83 · #8 04-17-2003, 12:38 AM

thanks i was just looking at some other posts and the textars seemed like the best bet . I'm gonna go with those.

edge · #9 04-19-2003, 01:16 AM

I just buy the cheapest OEM pads at the time I am ordering. Just bought Textar for the rear and ATE for the front.

Thomaspin · #10 04-19-2003, 10:33 AM

Go to Cars - Technical - Chassis.

if you change them you should check run-out and end-play also.

adiaw83 · #11 04-19-2003, 12:46 PM

Thanks for that site its really great. How do i change my break fluid. I bought a litre of ATE original brake fluid but I'm not sure how to change it.

edge · #12 04-19-2003, 01:34 PM

Changing the brake fluid is on Thomaspin's site, very informative.

adiaw83 · #13 04-19-2003, 04:39 PM

is there any way to get the pads out without a brake caliper spreader?

JimSmith · #14 04-19-2003, 05:49 PM

adiaw83,

I have posted a method in the past. But the idea is to change the brake fluid when you do the pads, so put a 9mm box end wrench over the vent fitting on the caliper, then put small, say 1/4" inside diameter rubber hose (like the line going to the prefilter on the the way to the fuel injection pump - I have a spare length I use for this) over the nipple. Then run the other end of the line to a jar, and open the vent. Use a large screw driver (I use a large Craftsman slot head screwdriver from Sears) positioned between the disc and the pad, with the end of the screwdriver about the middle of the pad, and then pry it away from the disc. Go ahead and chew up the pad as you are not going to use it again. I try not to damage the disc or pry against it in the area the pad sweeps. Once the pad begins to move, with no back pressure it will go all the way back, driving the piston all the way into its cylinder bore. Once the pad is all the way back against the caliper guide surfaces, close the vent line.

Remember to replace the pad with a new one before going to the other side, or you may pop the piston you just pushed in back out a little. With the vent open, you don't generate much pressure so it is unlikely you will really pop it out.

As noted above, really clean the crud out of the cavity the pads go back into. If you leave old burned pad material and disc grindings, it will make the fitting of new pads very difficult, and could contribute to binding or other brake system functional problems.

When I am done on each side, I bleed each brake out through the vent lines before going to the next caliper. I am always in awe of how dirty the stuff looks compared to the clean stuff that goes in the reservoir. I flush until the clean stuff comes out and then I just make sure no air leaked back in.

Hope this helps, Jim

adiaw83 · #15 04-19-2003, 06:19 PM

Thanks a lot looks like i have all the info i need. Unfortuantely, the discs look like they need to be replaced. They have somewhat of a lip and there is rust running along their width. I'll order these and try and go at it again next weekend. Which discs are most reliable?