Quote:
Originally Posted by 97 SL320
Each brake shoe has an anchor pivot on one end and the wheel cylinder on the other. The adjusters center the shoe vertically for proper concentric contact with the drum. The adjuster also moves the anchored portion of the shoe outward for the brake adjustment we are typically accustomed to.
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This describes the rear brakes. The front brakes have two wheel cylinders on each wheel. For the rear brakes the position of the anchor is adjusted using the eccentric bolt with the lock nut. There is a repeated pattern of adjusting the rear brakes such that you adjust the bottom adjustments such that it is just about to cause friction, then you back off, the you adjust the top ones so they are about to cause friction and leave them causing friction. Then you attempt to release the friction using the bottom ones again, then back to the top. When you can no longer release the friction with the bottom adjustment then it is set correctly and you adjust the top adjustments so that the friction is released.
The front brakes have two cylinders per wheel, one on bottom and one on top. In this case there isn't an anchor point that gets adjusted, only the one adjustment for each shoe for that wheel. Adjust until some friction then back off, then adjust the other one until some friction then back off.
Quote:
Originally Posted by 97 SL320
Given the shoes can be adjusted for proper concentric contact, the need to arc a shoe is reduced but might be of some benefit.
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It would seem that I cannot adjust for proper concentric contact and that arcing is needed. I strongly believe at least the rear shoes are new. I have not seen the front shoes because I don't have the special tool to remove the center hub cover (it unscrews somehow).
Quote:
Originally Posted by 97 SL320
A firm ish and long peddle travel is usually due to swelling brake hoses / too small a master cylinder bore diameter / too large a wheel cylinder diameter / brake drum flex / backing plate flex / brake master push rod too short.
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Does the brake master push rod need to be adjusted with respect to the pedal location? I should go look at this and see if I can see it. I believe everything to be stock and the hoses are new, although the front hoses are too long. It very much DOES feel as I would imagine for swelling brake hoses. I do not know what backing plate flex or brake drum flex mean.
Quote:
Originally Posted by 97 SL320
Not getting much braking effectiveness may be from the shoes not making full contact with the drum. Do the shoes show wear along their entire face? ( not having wear in the last 1/2" top / bottom isn't an issue. )
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I have verified that the rear brake shoes are wearing on approximately 50% of their faces. That was observed prior to adjust the brakes.
Quote:
Originally Posted by 97 SL320
Do you know what the bore sizes should be?
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According to the manual, the master brake cylinder has a bore of 25.4 mm and a stroke of 36 mm. The front cylinders have a bore of 28.57 mm and the rear cylinder has a bore of 22.2 mm.
Quote:
Originally Posted by 97 SL320
Does this car still have a single circuit master cylinder? While not related to the braking issue, I'd be putting a dual circuit master cylinder on this car for safety.
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Yes, single circuit. I'll be happy if I can get that working for now. Picture of strange hub to be removed shown in attached picture. I have since been told by the Germans that it unscrews in a normal manner. hah.