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View Full Version : Master Cylinder Interchangability



B6T
03-04-2013, 07:14 PM
Not sure about you guys, but one thing I've always noticed about the B5 is that the brake pedal is very numb. It was like this with my two previous 1.8T A4s, as well as my S4. I tried to remedy this with my current (3rd) 1.8T A4 by installing ceramic pads, rotors, stainless lines, and DOT 5 fluid. Regardless, it still feels as though it requires twice the pedal travel to achieve the same braking force as other cars I've driven... even my girlfriend's stock Ford Focus has a more touchy pedal.

I could upgrade to a more aggressive pad, but I'm not sure it will make as drastic of a difference as I'm expecting. It seems as though a larger bore master cylinder might be what I'm looking for.

Does anyone know if there are any other VW/Audi master cylinders that are swappable into the B5?

B6cool
03-04-2013, 07:39 PM
looks like this is not only in b5s but also b6's i have the same feeling...

jvega21
03-05-2013, 12:02 PM
Not sure about you guys, but one thing I've always noticed about the B5 is that the brake pedal is very numb. It was like this with my two previous 1.8T A4s, as well as my S4. I tried to remedy this with my current (3rd) 1.8T A4 by installing ceramic pads, rotors, stainless lines, and DOT 5 fluid. Regardless, it still feels as though it requires twice the pedal travel to achieve the same braking force as other cars I've driven... even my girlfriend's stock Ford Focus has a more touchy pedal.

I could upgrade to a more aggressive pad, but I'm not sure it will make as drastic of a difference as I'm expecting. It seems as though a larger bore master cylinder might be what I'm looking for.

Does anyone know if there are any other VW/Audi master cylinders that are swappable into the B5?

What about this? Would this make a noticable difference for $100
http://www.tyrolsport.com/brakes/tyrolsport-brake-caliper-stiffening-kit-for-vw/audi/

B6T
03-10-2013, 05:47 PM
I looked through some online part catalogs and found that there's basically two diameter master cylinders used in most later model Audis. My A4 uses a 23.81mm diameter cylinder. I checked some other Audis from the same era, and found that the C5 A6, S2 A8, and the B5 S4 use a 25.4mm diameter cylinder.

So a master cylinder swap from a B5 S4 might be a good upgrade. To the used parts classifieds I go...

turbo_bootin
03-10-2013, 06:41 PM
Not sure about you guys, but one thing I've always noticed about the B5 is that the brake pedal is very numb. It was like this with my two previous 1.8T A4s, as well as my S4. I tried to remedy this with my current (3rd) 1.8T A4 by installing ceramic pads, rotors, stainless lines, and DOT 5 fluid. Regardless, it still feels as though it requires twice the pedal travel to achieve the same braking force as other cars I've driven... even my girlfriend's stock Ford Focus has a more touchy pedal.

I could upgrade to a more aggressive pad, but I'm not sure it will make as drastic of a difference as I'm expecting. It seems as though a larger bore master cylinder might be what I'm looking for.

Does anyone know if there are any other VW/Audi master cylinders that are swappable into the B5?

You know you shouldn't be using DOT 5 with ABS systems right? DOT 4 is more than capable.

B6T
03-11-2013, 03:43 PM
My brother, a BMW tech, bled the brakes for me. I may be mistaken on it being DOT 5 though. Either way, if it's compatible with BMWs it's likely compatible with Audi.

Urtorsen
03-11-2013, 09:44 PM
I did the whole steel braided lines, flush, super blue ate fluid, expensive pads, tyrolsport stiffening, A8/TT upgrade up front...bled it a few times, tapped the calipers incase any bubbles stuck to the walls.......the brakes are excellent considering the size but the pedal is still as you say just a little bit too much travel, I was thinking the m.cylinder too but started to wonder if there is any bushings or something related to the mechanics of the pushrod/servo????
The tyrolsport with the lines makes a great difference incase anybody is on the fence about it, I went for the Ecs set of lines. Both these upgrades are child's play, no more than a couple of hours work.

walky_talky20
03-11-2013, 10:12 PM
Just checked ETKA. The B5 A4 and S4 all use the same Lucas 25.4mm bore master cylinder. The same part number is used on the A6, including 2.7T and Allroad models as well as the D2 A8. The only different master I came across was on the D3 A8 which uses a Girling 26.99mm bore master. The ETKA I'm using only goes to 2005, so it is possible other newer models also use this larger bore.

Honestly, after doing the A8/TT upgrade up front, the pedal is plenty sensitive for me. I can kick in the ABS with very little pedal effort. I suppose there is some "travel" to it, but I think it feels good - and I haven't even done stainless lines or anything yet.

Urtorsen
03-12-2013, 05:47 AM
The braking is great alright and for the effort and cost you couldn't do much better. I just remember driving one of my family's brand new b5 way back in 2000, I almost put the guy in the passenger seat through the window because of how little travel there was. And the same with most fairly fresh cars since then. Something gives way over time, I just wish I had the time and money to experiment and find out, but for a 14 yr old car though the brakes are pretty good apart from being easy to cook.
OP..... If you go and replace the M.cyl let us know how much if any of an improvement it makes.