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Old 07-12-2003, 07:13 PM   #1
stimpy
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Default 1 1/16" Master Cylinder Installed

A very popular upgrade for the older Subarus is to upgrade the brake system with newer brake configurations. In my case, I upgraded my 1996 Impreza L wagon from single-pot calipers up front and drums in the rear to the full WRX brakes with two-pot calipers up front and single-pot calipers in the rear. For those with any type of engineering or physics background, you will know that if you increase the fluid requirements of the brake system and keep all other fluid moving components constant, the movement required to get the same performance is going to increase. What I am really talking about is pedal travel. I nearly doubled the fluid requirements of my brake system but I kept the stock 15/16" master cylinder in place. For me and legacy777, our pedal travel increased with the upgrade. Many others are either ok with this increase or didn't notice it.

In all reality, it is totally livable and, by no means, detrimental to the functionality of the brake system. It did bug me that I had about one and a half inches of dead pedal before the brakes started grabbing. Once they did grab, though, it was firm and the stopping power was good (and there was much rejoicing).

legacy777 has had a few rathy lengthy and very in-depth threads regarding some of the issues related to doing brake upgrades on the older Subarus.
You can read about that here.

To sum it up, the pedal travel was unacceptable, and a replacement master cylinder was researched and found. The idea was to increase the fluid displacement for a given piston (pedal) distance.

There are three master cylinders sizes out there: 15/16", 1", and 1 1/16". The 15/16" MCs are only available on non-abs Imprezas. The 1" MCs are available in the abs equipped Imprezas and the non-abs equipped Legacies. The 1 1/16" MCs are found on the abs equipped Legacies and new-age Imprezas and WRXs. The abs MCs have only two ports for fluid while the non-abs MCs have four ports. There are numerous 1 1/16" MCs for abs cars, but in both of our cases, our cars were without abs. The only 1 1/16" non-abs MC was from a 1991-1995 FWD non-abs SVX. The Subaru part number is
26410PA001, however I bought the last one in the country. The master cylinder is still available as a non-OEM part from Schucks (Checker) and Autozone as a special order part. I bought my MC for $100 and the non-OEM parts are available between $130-160.

The installation took two hours from start to finish, including bleeding. To remove the old MC, you need to drain the fluid reservoir, remove the phillips screw holding the reservoir in place, remove the reservoir, unclip the wire connector, undo the brake lines with a 10mm flarenut wrench, undo the two 14mm nuts holding the MC to the brake booster, then remove. To install, reverse the procedure. The FSM calls for bleeding the MC, however it is possible to achieve good results without doing this messy procedure. I took the opportunity to install speed bleeders at this time, so the bleeding procedure was done by myself. I followed the FSM brake bleeding procedure of RF, LR, RR, LF. I very slowly pressed the pedal down, held, then released fifteen times for each corner, then repeated again. The speed bleeders were a very good aid for this install.

Before starting the car, just pressing the brake pedal yields an immediately solid pedal. With the car running, the brakes are immediately actuating, but the stopping power doesn't really get going until about an inch into the pedal travel. It doesn't sound like much of an improvement, but there does not feel like there is a deadspot where nothing is happening. You push the brake pedal and things start happening. Going back to the physics books you will notice that the pedal effort should increase and it definitely does this. The increase in effort was surprisingly apparant, but the overall feel is superb. This was a very worthwhile mod to my brake system.

Here is a picture of the two MCs. The stock 15/16" is on the left, the new 1 1/16" is on the right. Notice the size difference



Special thanks goes out to subysouth and legacy777 for all their ideas. I can't take any credit for this mod except that I was the test pilot...

-Jon
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Last edited by stimpy; 07-12-2003 at 07:19 PM.
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Old 07-13-2003, 02:04 AM   #2
subysouth
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Nice job Jon! Sounds like you got just the improvement you wanted.

I like how the size of the MC is cast right into the side - nice touch. If only everything was so clearly labeled.


ss
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Old 07-13-2003, 02:07 PM   #3
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Very cool Jon,

Glad this worked out so well. I'm sure this replacement will have the same results in my car. I just wish I had time to do it. I've got all the parts, just need time and place. It sucks having mods to put in and can't put them in....

Josh
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Old 07-14-2003, 03:34 AM   #4
NicGordon
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Now the real question is. Were there ever any 1 1/16" ABS MCs that bolt up to a single stage booster? Because from what I can find, all ABS MCs used a dual-stage booster. Yes? This is what I want:

-1 1/16" MC to work with my ABS
-Single stage booster
-eleventy billion dollars
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Old 07-14-2003, 08:35 AM   #5
Legacy777
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Quote:
Originally posted by NicGordon
Now the real question is. Were there ever any 1 1/16" ABS MCs that bolt up to a single stage booster? Because from what I can find, all ABS MCs used a dual-stage booster. Yes? This is what I want:

-1 1/16" MC to work with my ABS
-Single stage booster
-eleventy billion dollars
I've got one sitting in my apt as we speak.

1 1/16" MC for ABS models. It has the two ports on the side. It came from a 90 legacy wagon.

Whether the MC came with a tandem or single booster doesn't matter. What matters is that you match the same style MC to the same style booster. The single stage booster uses the older style MC's, so any of the round resevoir MC's should work.

If you're interested in the MC, I don't need it. I bought it from a buddy when I was still researching things, and didn't know any better.
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Old 07-14-2003, 10:15 AM   #6
stimpy
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I have a couple other notes worth mentioning.

My car was equipped with a single, non-tandem, brake booster. This helps to reduce any sponginess but also is going to increase the effort a little more. This effort is perfect for me, but I can understand why it didn't come from the factory with this configuration; it definitely takes more effort.

With the 15/16" MC, my brakes went to the threshold of locking almost at the floor. The tires could be locked up, most assuredly, but it happens so low that it makes me wonder if it would be still possible to lock very sticky tires. Having the threshold so low also made it very difficult to heel-toe since the accelerator pedal was higher than the brake pedal. The 1 1/16" MC is very different in this regard. When bleeding, you can feel the transition between ports. If the outer port is sealed, you cannot press the MC beyond 2/3 travel; period. In testing, the threshold of locking is now found at about half pedal travel. Heel-toe is now much easier and I have no doubt that there is enough room to increase the pressure and lock R-compounds. I can also upgrade to 4-pot/2-pot calipers without worrying about exceeding the capacity of my MC.

One little note that isn't directly related: the backing plates that the calipers mount to have a lot of flex either due to a poor design or the unopposed, floating caliper piston design. Brake feel could, no doubt, be improved with a better caliper design which keeps itself centered properly over the rotor.

NicGordon, if I remember correctly, the single boosters were dropped in 1997 in favor of the tandem boosters. I don't have my FSMs here to verify this though. To be safe, you would want to purchase a 1 1/16" booster from either an SVX or a Legacy turbo.

-Jon

PS, personally, I'd take a gabillion dollars over eleventy billion...
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Old 09-08-2009, 11:33 PM   #7
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i have wrx two pot up front and single pot in the rear in my 93 L wagon. i have the same problem with the brake travil. a friend of mine has a wrx mc. would i have a prablems putting the wrx mc in my 93 L. thanks for the help
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Old 09-09-2009, 01:54 PM   #8
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1: points for at least trying to search
2: however, this thread is 6 years old (minus points)

3: to answer your question you will have problems because as mentioned above in the thread, you have a non-abs MC and the WRX MC is an abs one. Optimally, you will want to get a non-abs SVX master cylinder.

Last edited by kumanchu; 09-10-2009 at 01:19 PM.
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Old 09-11-2009, 11:06 PM   #9
Legacy777
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Like mentioned, if you don't have ABS, the only MC that will work is the SVX non-abs 4-port MC.
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Old 09-12-2009, 09:12 PM   #10
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cool thanks. i just had a wrx one
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Old 09-12-2009, 10:59 PM   #11
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Can you T 2 lines together and hook them up to one port? Isn't that how most manufacturers did it? I guess it would be easier to get the proper master cylinder though.
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Old 09-14-2009, 12:39 PM   #12
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If you do that, you will lose the diagonal brake circuit which is designed to provide a fail safe in the event you have leak in a brake line or similar which causes you to lose fluid.

I would not recommend putting a tee in.

Josh
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Old 02-19-2010, 07:16 PM   #13
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Quote:
Originally Posted by Legacy777 View Post
If you do that, you will lose the diagonal brake circuit which is designed to provide a fail safe in the event you have leak in a brake line or similar which causes you to lose fluid.

I would not recommend putting a tee in.

Josh
I'm wondering if someone could explain how a T would take away the diagonal?

Looking at the 4 port MC the two front ports come out of the same area, therefore how would a T outside the MC be any different? Maybe there's more going on inside the MC than I know about.

I'm thinking you'd have two T's. One on the front and one on the rear (of the MC). Then keep the same line patter as with the 4 port(which is diagonal).
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Old 02-21-2010, 07:12 PM   #14
Legacy777
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If you tee it that way, you should be alright.

I may have misunderstood the original poster's comments.
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Old 06-03-2015, 03:41 PM   #15
bue car
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Just for future searches, Centric Brakes makes makes an exact replacement:

130.47019

Shows NABCO - made in Japan too!







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Old 06-03-2015, 08:08 PM   #16
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The OEM I bought for my car from subaruparts.com was $153. On Amazon this centric part isn't that much cheaper. e.g. $144 + 9 shipping.

So either will work, as they are roughly the same price.
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Old 06-03-2015, 08:57 PM   #17
bue car
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I was told I bought the last OEM in the states. It shows as discontinued on searches. Running 2 separate older race cars I needed 2, and was very happy to find the centric unit matched the oem one I bought as well.
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Old 06-04-2015, 11:39 PM   #18
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Old thread but great info, thanks for updating with that Centric part number. I would add that some of the non-abs cylinders have 3 ports, at least my 15/16 with the hill-holder contraption did. I removed that and rerouted one of the lines to my 1" Legacy cylinder, but want to upgrade to this SVX one.
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Old 06-27-2015, 10:15 AM   #19
kimokalihi
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Is that centric master the svx 1 1/16"?
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Old 06-27-2015, 10:46 AM   #20
Legacy777
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Thanks for updating this thread with the Centric info, that's a great find!


Kimo,

from what I can tell, that looks like the SVX 1-1/16" non-ABS MC.

Josh
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Old 06-27-2015, 07:25 PM   #21
bue car
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Yes it's the SVX model.

Most welcome, i love to help

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