Rear drum brakes

[Pistonbroke]

Here's hoping you guys can help a new boy with some info. I am rebuilding a 1969 2800CS manual which has been sadly abused. Some stuff is missing and I will be asking youall to fill in the blanks with maybe some pictures of what various bits should look like. First question is what other BMW models can provide the parts needed to convert the rear drums to disc brakes. The obvious bits are the hubs (rotors with integral handbrake drums?), calipers and pressure regulating valve. Is this a straight swop job or not so simple?
Can I just use E28 bits from a 528i or something similar?

 

[bmwmadman]

Welcome to the group .

I have done this exact conversion. While there might be several ways and different parts that can be used to complete the job, I think the easist is to find a 3.0cs with stock rear brakes. Take the complete rear suspension arms with all brake componants. (disc, cables, calipers). If the parts car is in good shape hopeful there is very little you have to purchase new. I would recommend though getting new cables and I think the master cylinder is a different style that you might also get new as well. Otherwise it is a bolts on..

I noticed a big different between systems. Not to mention the parts for drum brakes on a 2800 are getting hard to find... After you get done with the rear, consider upgrading to the front 3.0cs brakes - there vented discs...

 

[Pistonbroke]

Thanks for the dope. I should have said more about why I'm looking at other models. In South Africa, there are literally a handful of E9 coupes and I have more chance of falling pregnant than finding a 3.0CS or later model, as a spares donor. The saloon models,from the '80's are much more plentiful - hence my question.

 

[x_atlas0]

What about the saloon models of the time? (the E3) Those parts would work well, too.

If you are trying to use a newer BMW, (say, an E28, specifically) you can use the entire rear subframe assembly, including the diff, arms, hubs, the lot. I am afraid only someone that has actually performed the conversion (like Carl Nelson of LaJolla, as an example, you can find his contact info in the links section) would be able to tell you more.

Finding the 3.0 CS fronts are nice, however, as they use quad piston fronts, rather than dual piston like almost every other BMW since. The thing has some serious stoppers. I don't know if the 2800 CS used the same front brakes or not.

 

[bmwmadman]

Front capilers on a 2800 are 4 piston but they do not have the width for the vented 3.0 discs. 2800 frts are not vented and therefore thinner..