5k e-brake operation, zerk fittings in caliper

[Kneale Brownson]

I believe the spring you describe acts to push the threaded rod on which 
the piston rides back into the bore when the "bullet" that applies the 
brake is released.  If I remember correctly from when I stripped out a rear 
caliper off my 200q20v, the spring was located between the circlip that 
holds the inner workings of the cylinder in place and the flare at the 
bottom of the threaded rod.  I didn't notice the pressed-in bearing, but if 
it goes into the cavity occupied by the parking brake lever assembly, then 
it would be a handy place to insert a zerk.  Have you seen high-temp brake 
grease in a form that could be pumped through a zerk?  I'd be a bit 
concerned that too much pressure from a grease gun would force grease past 
the "bullet" and into the cylinder itself.  I'm not sure you'd want the 
grease in the cylinder.


At 01:26 AM 12/22/2000 -0500, S. Jaworski wrote:

>I was musing thru the archives a while back and found an article about
>adding zerk fittings to the rear calipers. The purpose of which was to keep
>the e-brake internals from seizing up. I cant find that article. Anyone know
>anything about this?
>
>I just took apart a rear caliper (donated by RPM Parts) to see how the
>e-brake worked. Pretty simple concept.
>1. e-brake lever attached to 1/2" dia X 2.0" pin
>2. pin is drilled off-center halfway thru . .forming an off center "pocket"
>in the side of the pin
>3. in this "pocket" sits a steel dowel 3/4" long, rounded on both ends
>4. other end of dowel fits inside the threaded rod that is inside the
>caliper
>5. threaded rod has a cup machined into its base to accept the 3/4 dowel
>6. the 3/4 dowel prevents any binding as it wobbles and adjusts to angles
>produced by the lever pin
>7. the threaded rod is sealed from the outside e-brake area with o-rings,
>and it has some back and forth play in it
>
>How it works > - - move the e-brake lever . . rotates the 1/2" dia pin . . .
>off-center hole in pin moves 3/4" dowel . .. which pushes on the threaded
>rod . . . which pushes on the piston that is screwed onto the rod . . piston
>pushes on pads . . . wheels locked.
>
>The threaded rod and the mating threaded female part inside the piston are
>finely machined parts. Held vertically, the rod will screw itself into the
>mating part all by itself just from gravity. Slicker than snot.
>Its a cinch for hydraulic pressure to push against the piston and thus
>rotate it . . and thus eliminate any play between brake shoes and rotor.
>
>Now there is a spring inside the caliper that pushes or pulls on the
>rod - - - I dont know how that works exactly cause it "thwanged" and flew
>across the garage somewhere when I took off the inside circlip. I dont feel
>like finding it.
>
>Inside and at the bottom of the bore where the lever/pin sits is a hole
>drilled to the outside with a steel bearing pressed into it to seal it.
>Could this be a grease lubrication point during manufacture?
>I guess a zerk fitting could be fitted into this area with some drilling and
>tapping. Periodically shooting some high temp brake grease here would keep
>that lever/pin pretty well lubed and keep any water/moisture out.
>If you know something about this, drop me a line.
>
>Any listers live near me?  Northern NJ, Morris county. I do all my own
>repairs and wouldnt mind a "third hand" now and again. Likewise, if you need
>some help . . give me a call.
>
>Syl
>
>85 4000s   sold
>88 5000sq
>90 100sq
>
>