Brake Pad to Rotor Relationship

Khan,

Rotate the piston 45* (the piston with the groove) and compress it as much as you can. When you do this, make sure that the e-brake cable is not pulling on the lever on the indirect (inboard) piston. The lever should be resting on the plastic stop. There should be minimal drag on the rotor and you should be able to easily rotate it (the rotor) by hand.

Also check the clearance between the rotor and the caliper. This is adjusted with shims between the caliper mounting tabs and the upright mounting tabs.

John

I have the piston orientated so that the tab on the pad matches the slot on the piston. I checked the piston and it wouldn't go in any further. I already have two shims on the caliper. What should the distance be?

I took a picture of the piston; does it look like it is all the way in?

Khan,

No its not IN all the way .. rotate the slot to 45 degrees and it will go in further ..enough for the pad to slide in with no bind ..obviously rotate it abck after its all the way in to line up with the pad again,

Ron

Khan,

Your piston is not in far enough. Rotate the piston to the right or left approximately 45*. Use a flat blade screw driver (or a piece of flat stock) to rotate the piston.

There are two pistons in the caliper. The one in your pic is the "direct" piston (it pushes directly on the brake pad), and the other is the indirect piston (it has the e-brake arm). After rotating the direct piston 45*, push the two pistons together. Then push back (towards the outside of the car) on the indirect piston (the one with the e-brake arm) and the yoke (the big metal "plate" that spans the rotor. You may have to pry between the outer surface of the rotor and the inner edge of the yoke, being careful not to damage the rotor surface. Next, rotate the direct piston back to its original position and insert the direct pad first. This should get you going in the right direction.

John

quote:

I already have two shims on the caliper. What should the distance be?

There is no specified clearance. Just make sure that the caliper does not contact the rotor when installed. If you have too many shims, you may not be able to install the outer brake pad.

I replaced one of my stock calipers with another stock caliper and I had to add another shim to the two that were on the car...total of 3 shims.

John

Thanks acccobra and jb1490 for the great and detailed directions. I appreciate it.

Oh one more question since you guys know a lot about these brakes: is there any lubrication required on rods that hold the brake pads in place?

Lubrication ?

I use HIGH TACK on the back of the pads so they dont squeek and never sieze on the bolts and moving components.

Ron

quote:

is there any lubrication required on rods that hold the brake pads in place?

None is required, but some people do. The problem is that when the brakes get hot, most lubes will melt and drip on the pads.

John

Likewise I use anti-seize on the threads. Also be sure to install new (or good used) locking tabs on the caliper bolts or better still drill and safety wire them. I know of two owners that had caliper bolts back out and the caliper drop onto the wheel, making for a nasty mess of both caliper and wheel.

Julian

In case you were wondering about what lives inside the indirect piston. This is what makes the e brake work.

Mine didn't and it was due to the circlip marked "was loose" coming out of it's groove.

There is also an O ring seal in the back of the indirect piston around the e brake actuating plunger that is exposed to brake system operating pressures. It seals on the shiny surface of the part just above the holes of the "was loose" circlip. The O ring (not shown) that seals it lives in a groove machined into the indirect piston.

It's a bit tricky to get at and you'll have to match one up at the parts counter as I've not seen it included in the rebuild kits.

quote:

Originally posted by Joules5:
Likewise I use anti-seize on the threads. Also be sure to install new (or good used) locking tabs on the caliper bolts or better still drill and safety wire them. I know of two owners that had caliper bolts back out and the caliper drop onto the wheel, making for a nasty mess of both caliper and wheel.

Julian

Do you know if the locking tabs and shims are a more common part available at the autopart store or do I need to special order from a vendor?

quote:

Originally posted by accobra:
Khan,

No its not IN all the way .. rotate the slot to 45 degrees and it will go in further ..enough for the pad to slide in with no bind ..obviously rotate it abck after its all the way in to line up with the pad again,

Ron

I got it rotated and the piston pushed in just like you said it would! Thanks! Only issue now is that I can't get it to rotate back? Any trick to this? Don't want to harm the piston but I was putting a lot of pressure and it didn't budge.

Check to be sure there is no tension at all on your e brake cable or you won't be able to rotate the piston back to 90 degrees.

I checked for tension, made sure all was out and tried again. Well...my screw driver slipped and it tore the outer seal. I guess I have to take everything out, order a rebuild kit and start from the begining.....crap.

Well, it might be a blessing in disguise. My expectations for the replacement parts didn't meet reality anyway; this could be a good chance for me to learn more in-depth about the braking system if I rebuild everything. With a rebuild kit and two sets of calipers, I should be set to frankenstein together a great set! Unless I go jabbing my screw driver around