On my 406, I went to work on the the emergency brake cables which will have to be replaced but, I got them free. On one of the calipers however, the arm the actuates the emergency brake is not moving freely and is too tight to return with spring pressure. I sprayed the joint and worked the arm for a while which helped but, not enough. Is this serviceable or, am I looking at replacing the caliper?
The eccentric shaft, on the e-brake arm, runs on sealed needle bearings, yours sounds rusty. The book says you have to split the caliper halves, to compress the spring on the adjusting drive screw (with a special tool), to remove the retaining snap-ring (while the spring is held compressed), then you get the whole adjuster out,... then get the big end disk plug out to get the clip off the back of the shaft.
It looks tough.
There is a Note: Fixed calipers are to be disassembled by authorized workshop only.
Plus the possibility of pitting of the needle bearings or shaft.
However I considered the possibility that the end disk plug could be removed, and the clip and washer taken off the shaft (easily without separating the caliper halves). The shaft is drilled through for lubricating the bearings during assembly and might be freed up better this way.
There are no pictures of the eccentric shaft itself, but since the adjuster drive screw (under spring pressure) rides the shaft on a pill shaped tappet, the shaft is probably grooved to hold the tappet and cannot be removed this way.
Of course this means you can't get at the seal under the arm that probably let the moisture in, or get realy clean at the needle bearings nearest the seal.
Depends on how it moves,... if stiff but smooth I'ld go for trying to flush the needle bearings through the hole in the eccentric shaft using brake clean. Then then force them full "of special fluid from repair set" which I would assume is silicon grease.
The seal beween the mechanical and hydraulic side of the caliper is part of the drive screw.
I took mine all apart and rebuilt them and they now work great. What you can do is take the calipers off and do the electronic rust removeal on them. This helped big time on mine to free them up. Of course mine were split when I did this. Then I just honed them out and replaced the seals. Now all my brakes work great, and mine were nothing but rust when I got it. Von
Crash and Von, Thanks for taking the time to respond! You guys are great mechanics and I am a great cabinetmaker, builder and plasterer! To illustrate this, I have never heard of electronic rust removal. Is this something you take somewhere to have done? Are the rebuild parts available at Mercedes?
Daniel, The ERR you can do at home. Here is a link to learn all about it.
http://www.davidbradley.net/ERR.html
And it does work great! I used in on lots of my mog restoration. I did all my brakes, axles, springs and lotts of other parts. Von
So, does this just remove rust, or if a piece was left in for too long would it eventaully be completely consumed? What about bits of old paint? I'm curious how fast it might eat away at sufaces where tolerances are critical, (wheel cylinders, cylinder heads, etc.} Von, do you feel that the bores on your calipers were affected at all? Seth
PS. If this works as well as I think, the bead blast cabinet goes to ebay heaven.
Seth, It does not take away any metal, in fact it will replace it if you left it in long enough! But it would take weeks to do that. What it does is remove just the rust and will take off the paint as well. As for machined surfaces, it will not harm them at all, that is one of the reasons I like using this method so much. What I like to do after using ERR is to pop the part into the beadblast cab. just to etch the surface for new paint. But only on parts that the blaster will not harm. I did my whole axles with this method. It took awaile, but I sure didn't want to be putting them into a blast cab. Von
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