Caliper pins won't budge on 240D - PeachParts Mercedes-Benz Forum

BodhiBenz1987 · #1 02-09-2009, 05:49 PM

My tradition of turning routine maintenance into bloodsport continues as I am trying to change the brake pads on my 240D. I cannot, for the life of me, get the retaining pins out of the caliper. I used a punch and hammer and couldn't get the top one to budge ... the bottom one budged about a millimeter and no more. It's like they're welded into the caliper. I tried putting some wd40 on them but that didn't do a thing. Any tips on loosening them up? Heat them? It's pretty cold out and I'm guessing that doesn't help. The calipers themselves don't look too great so maybe I have to replace them anyway, but I'd like to put some new pads in and see how it goes (I already flushed the brakes + clutch and that went OK).

vwbuge · #2 02-09-2009, 05:54 PM

I hate to ask this, but are you pushing them the right way?

JonL · #3 02-09-2009, 05:55 PM

WD-40 overnight. Heat, too, but you will be risking the caliper seals if you let it get too hot. Some heat, just a propane torch, will help the WD-40 penetrate, even if it seems to smoke and flame and burn off. Heat, more WD, more heat, more fire, more WD... It'll come loose.

redassag00 · #4 02-09-2009, 06:02 PM

use the new pins to push the old ones out....

winmutt · #5 02-09-2009, 06:07 PM

What are you supporting the caliper with?

BodhiBenz1987 · #6 02-09-2009, 06:39 PM

Quote:

Originally Posted by vwbuge

I hate to ask this, but are you pushing them the right way?

Almost positive ... I took the clip off and hit the outside end to drive it inward, which is what it looks like in the picture of the chiltons manual ... the other end of the pin is wider so there's only one way it could go. I pretty much followed the instructions in the manual: Remove sensors (or break them off, in my case), take off locking clips (and lose them), drive upper pin out using a punch, remove the spring, then drive out the lower pin. I couldn't get the upper pin to budge.

winmutt ... forgive me, but what do you mean? The caliper is still in place on the disc, so I just placed the punch on the caliper, bracing it with my hand, and hit it with a small hammer.

79Mercy · #7 02-09-2009, 07:00 PM

Hit them harder.

I just use a nail and a hammer. I never have any trouble.

JimmyL · #8 02-09-2009, 07:03 PM

Quote:

Originally Posted by BodhiBenz1987

The caliper is still in place on the disc, so I just placed the punch on the caliper, bracing it with my hand, and hit it with a small hammer.

Might I recommend a larger hammer....

BodhiBenz1987 · #9 02-09-2009, 07:14 PM

Quote:

Originally Posted by JimmyL

Might I recommend a larger hammer....

I was a little worried about damaging something ... maybe the calipers are more robust than I think.

79Mercy · #10 02-09-2009, 07:21 PM

your not going to hurt anything.

t walgamuth · #11 02-09-2009, 08:27 PM

Quote:

Originally Posted by JimmyL

Might I recommend a larger hammer....

x2!

no kidding though!

t walgamuth · #12 02-09-2009, 08:29 PM

Quote:

Originally Posted by BodhiBenz1987

I was a little worried about damaging something ... maybe the calipers are more robust than I think.

Indeed they are really tough. I doubt you could damage them by hitting them with a six pound sledge as hard as you can.

(Don't try it though).

They are designed to take a tremendous amount of stress and are forged, high quality steel.

Mark DiSilvestro · #13 02-09-2009, 09:04 PM

You might wind up damaging the pins if you hammer them hard. Try some penetrating oil first, instead of WD40. Sometimes, I've been able to loosen stuck pins by gripping them between the pads, with a Visegrip pliers and rotating them to break them free. Might also want to get some new pins first, just in case you wind up wasting the old ones.

Happy Motoring, Mark

JonL · #14 02-09-2009, 09:08 PM

If you hit the pins and not the caliper you won't harm anything but the pins, which you are saying you will replace anyway. You'll probably mushroom the small end a little, but so what.