What car did the 23mm master cylinder that will bolt into our cars come out of?
John
Early Mercedes. You'll need the alloy front end support or what ever it is called as it is too long for the steel tube one, although I have seen a picture where someone put a dent in the tube with a BFH?
I believe it was a Mercedes truck. It's an ATE master cylinder. A search of the forum should give you a part number.
plain ol' Mercedes passenger sedan.
a few places have them (or claim to). i dealt with a couple of places that claimed to have them, but they meant they "could get" them. DART (they advertise in Pano and Excellence) had 'em in stock and will know what you need. you will need to mod the pushrod a little, has to be a little longer or shorter, i don't recall which. you can easily make one out of a cylinder stud by grinding a full ball radius on the 'working' end.
gotta ask: what are you doing to/with your calipers that makes you think you need such a thing? (there *are* correct answers to this question! but it's not something that everybody needs and it is NOT a "standard upgrade" to an otherwise stock brake system - even in a 914.6)
i've heard the stories of suspension crossmember mods too but i know for a fact i did NOT have to do that when i put my Mercedes MC in my 914/6 25 years ago. we'll see what happens when i p[op one into the 911 ...
I think the 914/6's came with the I-beam type front end support if I remember correctly? The 23mm m/c fits in there okay with that but not the 914/4 steel tube support. When I put mine in the 1973 race car I had to do a replacement. There is also an issue with the front line that feeds the brake fluid from above that it hits the bottom of the gas tank and the one I bought came with a short, bent adapter so the lines fit okay. I also had to lengthen the rod from the pedal to the back of the m/c.
John (stock93) will be my guinea pig for a Volvo brake upgrade. Want to test the 19mm and 23mm masters. Will probably be running Volvo vented calipers on the front and 320 calipers in the rear. Might do all Volvo calipers all the way around.
QUOTE (john rogers @ Feb 14 2005, 04:11 PM) |
I think the 914/6's came with the I-beam type front end support if I remember correctly? |
Brett,
I think that the Volvo 240 used a 22 or 23mm MC with the 4-piston calipers--but they also had a vacuum assist. Wouldn't the 23 give you an awfully hard pedal?
I've got a set of vented volvo calipers and a MC hiding in garage somewhere if you need any dimensions (piston size, etc.).
Lemme know . . .
Best,
Steve A-
the 6 i parted out had a tubular crossmember
Thanks for the offer. I already have the calipers and stuff. just need the 23mm master.
With the proper proportions the pedal should feel like the stock brakes.
I've been looking at this on ebay for quite a time...the guy seems to sell these regularly...http://cgi.ebay.com/ebaymotors/ws/eBayISAPI.dll?ViewItem&item=7943123843&rd=1&sspagename=STRK%3AMEWA%3AIT
if anyone knows about these what modification for 75 914 1.8
What type of brake system do you think would require a 23mm master cylinder. I have all Carrera brakes on my 912 and I also have a 23mm master cylinder that I have not yet installed. Do you think that this is overkill or would it feel just fine?
-Britain
Britain,
Read Brett W's replys.
Ok guys, I got a mer truck or passanger sedan. I have access to several older Mercedes cars for parts. What does anyone know specifically what model this MC is out of?
QUOTE (rj777 @ Feb 15 2005, 02:19 PM) |
if anyone knows about these what modification for 75 914 1.8 |
QUOTE (stock93 @ Feb 15 2005, 12:58 PM) |
Britain, Read Brett W's replys. Ok guys, I got a mer truck or passanger sedan. I have access to several older Mercedes cars for parts. What does anyone know specifically what model this MC is out of? |
Adding a 23mm MC to a stock system is actually a BAD thing. You get a harder pedal and less pedal modulation of the brakes. Unless you get larger calipers it will be a lot of work for a less desireable result.
George
QUOTE (Brett W @ Feb 14 2005, 02:46 PM) |
John (stock93) will be my guinea pig for a Volvo brake upgrade. Want to test the 19mm and 23mm masters. Will probably be running Volvo vented calipers on the front and 320 calipers in the rear. Might do all Volvo calipers all the way around. |
I'm working up a spreadsheet now to help work out the ratios for MC/calipers. I need the following to finish it:
What is the diameter of one caliper piston on the Volvo 4-piston calipers?
How about the Carrera calipers, Britain? How many pistons are there per caliper?
Mike, what's the size of the caliper pistons on those 4-piston RX-7 calipers you have?
If anyone else has any calipers they'd like added, let me know. I just need the size of one piston and how many are in the caliper.
Carrera calipers (wide-A)
Fronts: 48mm piston bore (2 pistons per caliper)
Rears: 42mm pistons bore (2 pistons per caliper)
-Britain
Caliper
Piston Diameter
914-4
42 mm
BMW 320i
48 mm
911 - M caliper
48 mm
RX7=36mm (ea)
Big Reds=36/40
Boxster(F)=35
M-Caliper (early rear)=38
Everybody follow alonge here:
The 23mm master cylinder is not going in anything stock. I am well aware of the problem with upgrading the master on stock system.
I will get the Volvo piston sizes later tonight.
QUOTE (Brett W @ Feb 15 2005, 05:28 PM) |
Everybody follow along here: The 23mm master cylinder is not going in anything stock. I am well aware of the problem with upgrading the master on stock system. |
QUOTE (Brett W @ Feb 15 2005, 03:28 PM) |
Everybody follow alonge here: The 23mm master cylinder is not going in anything stock. I am well aware of the problem with upgrading the master on stock system. I will get the Volvo piston sizes later tonight. |
got a volvo caliper question....
they bolt up fine. they can be centered on the rotor with a washer.... how much of the pad over hangs the edge of a rotor?
QUOTE (Aaron Cox @ Feb 15 2005, 03:40 PM) |
how much of the pad over hangs the edge of a rotor? |
QUOTE (Mueller @ Feb 15 2005, 03:45 PM) | ||
something like 1/8" or a tad bit more...nothing to worry about unless you put on new pads and wear them down enough for the overhanging material to touch each other when you hit the brakes...you can always add a bevel to the edge to help minimize/eliminate the overhang |
CODE |
914/4 & A rear 320i/M front RX-7 4piston Boxster front M rear 42x4 48x4 36x8 35x8 36x4 stock 914/4 17 24 32 36 34 18 stock early 911 19 20 26 29 27 14 mercedes 23 13 17 20 19 10 |
QUOTE (ArtechnikA @ Feb 15 2005, 03:24 PM) |
you are going to need to change the hard lines to the front and possibly to the first junction to the back. |
caliper spec sheet
and brake bias sheet
QUOTE (ein 6er @ Feb 15 2005, 04:34 PM) |
and brake bias sheet |
QUOTE (nsyr @ Feb 15 2005, 05:55 PM) | ||
why would you need to do this? |
second pdf file screen shot:
Attached image(s)
I installed a 23mm M/C this winter and have one test day at Willow to evaluate the difference. Previously I was running a 19mm and always had too much pedal travel when the pads wore anything beyond about 75%. I would only have a good firm pedal after a new pad change. Calipers are Carrera front and SC rears so I was on that margin between the 19 being too smalll and the 23mm too large. After a couple of hours testing, I can modulate this combination of the 23mm and the Carrera/SC calipers OK, but its probably not for everyone. Pedal pressure is significantly higher. I plan to upgrade to Boxster fronts so this should bring the overall ratio into a more optimal range. My first race with this setup (23mm, Carrera/SC) is this coming weekend in Phoenix (if we don't get rained out). I let you know how it went.
BTW, I did install with the steel crossmember, but had to take off about 1/8 inch dimple with my grinder and and another 1/8 inch off the casting bump on the M/C. It fit but had me exercising my four letter word vocabulary. Not a fun job - the fluid supply lines were tricky to insert into the M/C. I loosened the crossmember and dropped it and the front suspension arms about 2 inches to get the M/C in.
Steve
QUOTE (lapuwali @ Feb 15 2005, 05:54 PM) |
...I would think a 21mm MC (if such a beast exists or could be made) would be about ideal for these calipers. ... |
Just a note here, the master cylinder sizes are actually in increments of 1/16 of an inch, they are not metric. The '19' mm is actually 3/4 inch. Moreover, the 911S used a 20 mm master with the aluminum 'S' calipers. It would be really nice if it was still available.
17.46=11/16
19.05=3/4
20.46=13/16
23.81=15/16
QUOTE (slivel @ Feb 15 2005, 06:43 PM) |
...the fluid supply lines were tricky to insert into the M/C.... |
QUOTE (ArtechnikA @ Feb 15 2005, 03:47 PM) | ||
there *used to be* a 20,5mm MC used with the early 911E and 911S with aluminum calipers front but the rear brakes unchanged. those have been NLA for years. BTW - we call these MC sizes by their nearest metric equivalents, but they're *actually* English-system measurements. 19mm is really 3/4", that 20,5 is really 13/16", and the 17mm is really 11/16" (11, 12, and 13/16") |
I have Carrera (wide-A) calipers all around and according to that link above the stock set-up was a 20.64mm MC vaccum assisted. Do you think that a 23mm MC would be too large for this set-up when not using vaccum assist? Also, should a proportioning valve be used?
-Britain
QUOTE (Britain Smith @ Feb 15 2005, 04:20 PM) |
I have Carrera (wide-A) calipers all around and according to that link above the stock set-up was a 20.64mm MC vaccum assisted. Do you think that a 23mm MC would be too large for this set-up when not using vaccum assist? Also, should a proportioning valve be used? -Britain |
Sorry Mike, didn't mean to jump your shit.
My hats are off the shelf bolt on. Have to drill the lub holes though. With the vented rotor and vented caliper the caliper will need about .75-.100 off the inside mounting ears. I beleive. I need to machine and measure and machine an measure.
The Hat is something like 50 and the rotor is about the same. Calipers are 13 apeice. Haven't priced studs yet.
For the guys running Fuchs or other hub centric wheels then the hat will have to be machined slightly otherwise I am going to turn the ring off all together.
Audi RS2 and some Quattros has 23 and 25mm masters. I have Quattro version from -92. It has two different size of pistons. other is 25,5mm and the other is 19,8mm. Bigger is for rear and smaller for front calibers. It's quite hard to use but with 996 monoblocks it is awesome in 914...
lower part is somekind of pressure balancer between rear and front
I have a 23 mm master and a 19 mm master for sale both are new. they come with the matching pus rod for the pedal.
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