What to consider when buying Brake MC?

[Earendil]

After rebuilding calipers, changing pads, and flushing the system, I have better brakes but the same soft pedal. Since rapidly depressing the pedal causes a stiff feel, and a slow application of the pedal allows it to sink twice as far, I'm assuming a bad MC.

From what I gather, no one makes a rebuild for these things? Sad, because I actually have a spare MC that I had intended on rebuilding and swapping in at some point. I'm loath to just toss a random MC in my car though. Am I wrong about there being no rebuild options?

It looks like I'm down to "professional" rebuild options. The two common brands appear to be ATE and TRW. I've honestly never heard of TRW, which would be okay if they were also cheaper than ATE. But it seems they cost 15%-25% more than the ATE at every site I look at, leading me to believe they might be better? Does anyone know the difference? Are there compatibility issues? My car currently has a Girling MC.

I've not going to enjoy spending the equivalent of a track day on an MC, but I suppose I do enjoy the ability to stop at said track days ;D

[jlevie]

The only master cylinder I will use is a new aftermarket or OE part.

[Earendil]

The only master cylinder I will use is a new aftermarket or OE part.

After my research turned up people complaining about $500-$700 new ones, and rebuilt ones for $200-$300, I sort of assumed I was looking at rebuilt ones. However, on the websites I'm looking at I don't see any sign that they are anything but new.

So, all the same questions, just assume we're talking about new ones :)

[jlevie]

A new ATE MC (if your car has the ATE booster) will run about $250. The OE part from a dealer will be a bit more expensive. Either are fine.

[Madhatter]

nobody does cylinder resleeving over there? really common here. Usually results in a better product than the original part. Much cheaper cost too.

[Earendil]

A new ATE MC (if your car has the ATE booster) will run about $250. The OE part from a dealer will be a bit more expensive. Either are fine.

So the E30 used two very different brake master cylinders that are not compatibly with each other, ATE and Girling? I knew that they each made different but compatibly calipers, but the MC is incompatible? :(
I can only find one thread, a recent one, where an issue with braking might be traced to attaching an ATE MC to a Girling booster.

I want to clarify compatibility because I'm seeing a lot of "out of stock" Girling and Girling equiv MCs. BluntTech lists one as being "NLA 10.13" and is selling remaining stock for $370. Yet an ATE MC can be had for $200-$220.

I just don't want to pay double for an MC if it's the same situation as the calipers, a technical difference but no consequential functional one.

[Yonkers320is]

I am on the same boat, I checked bavauto and they show only one MC for $309.00, for cars with ABS. doesn't specify ate or girling.
rockauto.com have a MC for the ATE system from $96 to $160, and the ones for Girling from $177 to $355. plus there are 2 bore sizes: 7/8" and 13/16"

I guess I will have to remove it, check what size bore (I have girling calipers)and see what is the difference between the two units. (the pros of having a repair shop to order parts for you)

[jlevie]

The master cylinder and booster must be from the same manufacturer. You can use either pair.

[nando]

I am on the same boat, I checked bavauto and they show only one MC for $309.00, for cars with ABS. doesn't specify ate or girling.
rockauto.com have a MC for the ATE system from $96 to $160, and the ones for Girling from $177 to $355. plus there are 2 bore sizes: 7/8" and 13/16"

I guess I will have to remove it, check what size bore (I have girling calipers)and see what is the difference between the two units. (the pros of having a repair shop to order parts for you)

are you sure there are two bore sizes? that's usually function of the caliper pistons and they're all the same. the only one I could see being differen't would be early E30s that had drum rear brakes and solid front rotors with the smaller diameter strut housings.

[Yonkers320is]

are you sure there are two bore sizes? that's usually function of the caliper pistons and they're all the same. the only one I could see being differen't would be early E30s that had drum rear brakes and solid front rotors with the smaller diameter strut housings.

that is what it says on the parts website, unless they are bored out and rebuilt using bigger piston.

[nando]

Its probably from another BMW.

[TobyB]

are you sure there are two bore sizes?

the non- abs and abs masters are very different- the abs is stepped, with
a smaller bore for the rears...

t