kamikazuki
Member
this is really a great mod, thanks!
Bolt On Subaru Master Cylinder Upgrade
- Thread starter Crow Horse
- Start date
ArtByScars
Well-known member
ArtByScars said:
anyone??
ArtByScars said:
ArtByScars said:
http://bbs.zuwharrie.com/content/topic,96394.msg997035.html#msg997035
i think you well have to do all of it what you was ask about.
when i got mine the subie m/c the booster look to me being fater and taller.
i would try this one http://bbs.zuwharrie.com/content/topic,96394.msg997035.html#msg997035
whitfimb
Well-known member
WoW! Lots of great information.
The one thing I see missing is Why?
Basic Hydraulic System Theory:
Your pump (Master Cyl) to your cylinder (Caliper / Wheel cylinder) gives a mechanical advantage by volume / ratio.
In order to understand this better. Look at it like a Transmission or even simpler a 10 speed bike. The small front sprocket makes it easy to pedal but turns the wheel slower. Just like the smaller bore MC has a greater mechanical advantage over the brakes at the wheels.
This mechanical advantage must be maintained when you swap parts. If you install a large bore MC with small bore cylinders (Caliper / Wheel Cylinder) then you will loose some of your mechanical advantage and require more force to lock your wheels. If you have already upgraded to larger Calipers / Wheel Cyls ~ then the larger bore Master cylinder is a great upgrade to keep everything proportional.
Likewise on the other end if you install a Small bore MC and large bore cylinders (Caliper / Wheel cyl) then you may run out of piston travel / fluid displacement before you lock the wheels. OR you may lock the wheels too easily.
While Brake system power is a scientific calculation, using similar size pieces (Subaru) can get the results you seek.
Also remember that calipers generally require more fluid then wheel cyls, and Disk Disk MC's should be kept with Disk Disk applications.
The one thing I see missing is Why?
Basic Hydraulic System Theory:
Your pump (Master Cyl) to your cylinder (Caliper / Wheel cylinder) gives a mechanical advantage by volume / ratio.
In order to understand this better. Look at it like a Transmission or even simpler a 10 speed bike. The small front sprocket makes it easy to pedal but turns the wheel slower. Just like the smaller bore MC has a greater mechanical advantage over the brakes at the wheels.
This mechanical advantage must be maintained when you swap parts. If you install a large bore MC with small bore cylinders (Caliper / Wheel Cylinder) then you will loose some of your mechanical advantage and require more force to lock your wheels. If you have already upgraded to larger Calipers / Wheel Cyls ~ then the larger bore Master cylinder is a great upgrade to keep everything proportional.
Likewise on the other end if you install a Small bore MC and large bore cylinders (Caliper / Wheel cyl) then you may run out of piston travel / fluid displacement before you lock the wheels. OR you may lock the wheels too easily.
While Brake system power is a scientific calculation, using similar size pieces (Subaru) can get the results you seek.
Also remember that calipers generally require more fluid then wheel cyls, and Disk Disk MC's should be kept with Disk Disk applications.
Whitfield said:
I think you got this backwards. A Larger MC will product more volume and thus more pressure with less pedal movement. And since we are talking 1/16 or 1/8 of an inch. The results are better pedal pressure and better braking.
The reason most folks run larger calipers is so they can also run larger pads and reduce fade in their brakes giving them better brakes.
Barlytreat
Well-known member
I just did the swap into a 94 sami with a 96 legacy outback MC the was 1 1/16th. thanks for the tech info.
Yankee Tim
Well-known member
Barlytreat said:
How did you get your M/C to seal on the booster? That was my problem.
Barlytreat
Well-known member
I used black RVT, it took me two times to get it right though. Also use a hose that is not prone to collapse on it's self, under vacuum to connect the brake booster. Also if you have drum rear like I do, I adjusted the pads out a little to get the booster in the "sweet spot" as far a travel goes. good luck
This is a great thread! I've already added the 4 door calipers to my 95 2 door Tracker a while ago. Like the better stronger braking, but pedal travel has always been too far for my tastes since the swap over. I also seem to go thru rear pads and wheel cylinders fairly regularly.
Could this be the result of too much pedal travel pushing the rear wheel cylinders too far, in relation to the bigger front calipers? Or just too much deep water and mud!
I would like to do this upgrade, but after looking at my master cylinder, I've got questions about the ABS set up on mine. I no longer have the tone ring in the rear diff due to ARB install, so I don't even think the ABS works. The plumbing is all there still though, at the stock master cylinder. A brass looking splitter of some kind, with the brake lines attached to that, then from there to the MC.
How would I go about swapping in the SUB MC, with all this additional ABS plumbing? I want to make this as simple as possible without having to make all kinds of new lines. Sorry for the long post, Thanks Mike.
Could this be the result of too much pedal travel pushing the rear wheel cylinders too far, in relation to the bigger front calipers? Or just too much deep water and mud!
I would like to do this upgrade, but after looking at my master cylinder, I've got questions about the ABS set up on mine. I no longer have the tone ring in the rear diff due to ARB install, so I don't even think the ABS works. The plumbing is all there still though, at the stock master cylinder. A brass looking splitter of some kind, with the brake lines attached to that, then from there to the MC.
How would I go about swapping in the SUB MC, with all this additional ABS plumbing? I want to make this as simple as possible without having to make all kinds of new lines. Sorry for the long post, Thanks Mike.
Yankee Tim
Well-known member
I cheated. I got my few, brand new, from a friend when Subaru did a recall. Only a few were bad, but they were supposed to replace all of them. The mechanics figured out how to determine the bad ones, and then cleaned the ones that were still good so they looked new, claimed they replaced them, and pocketed the actual new one in the box, usually selling them on ebay. I know, disturbing, but if you had any idea exactly how bad dealer service can be, you'd never buy a new auto again.
Oh well, I've got new M/Cs and no Subie, so I'm not too concerned.
Those new onse have the res on them. The dealer price is fairly cheap for new, as Subaru dropped the price when the recall started so they wouldn't have to reimburse the dealers as much money. I'd buy new.
You'll still need a pig tail off a donor auto to make the brake fluid light work.
Oh well, I've got new M/Cs and no Subie, so I'm not too concerned.
Those new onse have the res on them. The dealer price is fairly cheap for new, as Subaru dropped the price when the recall started so they wouldn't have to reimburse the dealers as much money. I'd buy new.
You'll still need a pig tail off a donor auto to make the brake fluid light work.
Biggerhammer
Well-known member
wolverine said:
There is a Subie dealer in Rockwood, TN. I happen to run past it from time to time...
Biggerhammer
Well-known member
I'll see what I can do. Don't know whats going on tommorrow but may go that way may not. :
wolverine
Well-known member
ok got my subaru master cylinder. (sorry kirk was gonna call ya let you know just got it in) ok got it all hooked up the but my pedal after the sammy is running is tight like there is no power behind it. you push the pedal and it don't hardly move any. can it be the bolt is to long. need help quick have a ride tommorrow.
Biggerhammer
Well-known member
I would pull it and check the length of the pushrod. I think the correct measurement is in this thread... Somewhere. :
