Brake Master Cylinder Upgrade...confused. Tii, Stock, 320i?

[etk2002]

Hi All,

I'm refreshing my brake setup on my '74 2002. I'm ordered a BMC (brake master cylinder) and wanted to know if this may be a good time to upgrade to a more powerful one.

I'm planning on keeping the rest of the brake parts stock so the upgrade would only be for the BMC. I read through all the threads and there's lots of contaminated talk about different setups and such. I'm only looking to see if an upgrade of the BMC for the stock setup exists and if it's a direct bolt on that won't effect safety or reliability in the long term.

I've read that I can get a Tii BMC, a 320i BMC, or just stay stock because it's not too bad.

Thanks in advance!

[Cyclone101]

Well, what do you mean by upgrade?

I suspect you want a bit harder and firmer pedal with more feel? If so, go with the tii mc. But the stock system has quite a nice feel to it already, so I would say stock.

Regards

Jacques

[etk2002]

Well, what do you mean by upgrade?

I suspect you want a bit harder and firmer pedal with more feel? If so, go with the tii mc. But the stock system has quite a nice feel to it already, so I would say stock.

Regards

Jacques

I would like a firmer feel without sacrificing reliability and safety of the entire system.

Is the Tii version and direct install or do I have to do something different with it?

[Guest_anonymous]

With a stock refresh meaning rebuilt calipers, rear drum cylinders, front pads, rear shoes, SS braided flex hoses, fresh fluid, proper bleed, rear shoes adjusted correctly, the pedal feel should be quite adequate and substatially more responsive than what you are experiencing, keeping the MC you have, given it is not compromised. If you are changing the MC due to blown seals and are looking for an "upgrade" you are correct, there is some chatter concerning this issue. The difference between the Tii and standard MC is the push rod being different for the Tii, this will change the feel of the stroke in the pedal, This also will be true of any other MC you try to use. Most "upgrade" is to compliment a BBK where the fluid proprtion has changed.

*non 02 MC's do not have the correct threaded port for the rear pre-pressure check valve.

[Chris_B]

The tii MC is not an "upgrade" per se to the standard 02 M/C. Guess it depends on what you mean by "upgrade." There are a number of issues to consider in this question: pedal torque (i.e., how hard you have to push), travel and feel among the most significant. Since the Tii MC volume is bigger than the non-tii version, the torque (pedal effort) will be higher than the non-tiii version, but the pedal travel (and perhaps, breaking controlailibility) will be better with the tii M/C.

[AceAndrew]

To answer your question on the E21 BMC, It's to be used on single line calipers, so it's nice if you plan on running a Wilwood (or other) Big brake kit (since the E21 runs single line brakes).

[c.d.iesel]

buy a master cylinder for a 1974 2002 - like your original.

You'll shoiuld have like-new thick brake rotors, new pads,

free operating caliper pistons, new fluid hoses,

like-new rear drums and shoes, and most

importantly adjust the rear shoes properly.

STOCK bmw parts perfect tolerance and working order

will lock up yer brakes, straight and firm.

Your misled by some notion that tii or other parts

from standard will give you 130HP brakes? or something?

Fix the present sad brake condition - restoring it to

the designers original excellent performance.

That's all you need. NEW STOCK brakes.

[M3M3]

a tii MC is not an upgrade, it is a change. it does not make the car stop any better/faster. it actually decreases the ability to modulate the brakes at threshold. it has a bigger diameter, so it pushes more fluid to the calipers for a given distance of pedal travel. this means if you are using stock caliipers, you have to push harder on the pedal to achieve the same effect as with a stock MC. some people percieve this as "better", but really it is not. bigger diameter MC's should be paired with calipers that are higher volume.

if you have stock brake systems and use this car on street, just get a stock MC. if you refresh everything as several others have suggested, you will be pleasantly surprised with the results.

[bnam]

it has a bigger diameter, so it pushes more fluid to the calipers for a given distance of pedal travel. this means if you are using stock caliipers, you have to push harder on the pedal to achieve the same effect as with a stock MC.

Isn't the mechanical leverage of the brake proportional to the area of the caliper pistons divided by that of the master cylinder. So bigger MC dia with stock calipers decreases leverage and so you have to apply more force but with less travel. On a Tii the caliper piston area increases as well so leverage is not impacted.

[M3M3]

that is exactly what i said, you are correct. OP does not have tii calipers, he has stock 02 stuff.