Rear Disc - Locking rear wheels

[MUD-PIGSIERRA]

I have the 1L Master cylinder and run the same calipers for front and back, I am running a good Bendix brake pad on the front and a cheaper Ferodo slotted pad on the rears, whilst I do check my braking force in a safe place on the road every now and then I don't get a rear lock up, but I can get a heavy lock up which makes the back step out on gravel roads. But as I know this happens, in the back of my mind Im prepared for it when it does happen and can counter it, so its not so much of a issue to me, though it occasionally scares passengers who think we are going to crash lol.......

[hyzook]

Hyzook - whats urs adjusted too.

I first followed instructions but then after initially testing in empty street and making lots of small adjustment then after a few days driving in different conditions and wet weather I made further adjustment so exactly what the ratio of front to rear is I dont know as there are no marking on it.

Each vehicle will differ due to weight, tyres, suspension set up etc. Do lots of testing and drive carefully with large gap between you and the car in front untill you are confident its right and get used to the brakes.

[hyzook]

I have the same braking set up although I have Vit Estate discs, calipers and master cyl. I have a proprtioning valve on mine which is engineered is NSW. After some adjusting over a short period of different driving conditions it all good now.

In the pic above is my M/C which is off a 4door vit, I have just been informed that I have the front line connected to the rear port and rear line with prop valve connected to the front port can anyone confirm if this is correct?

they (brake residual valve) were only in sierra's with 4 wheel drums and no booster, anything with factory front discs won't have this item.

So Joe you saying in my M/C there is no brake residual valve for the rear?

[christover1]

All Master Cylinders I've had, the rear brakes run from the front part of MC. But this may not be true for some later 3way split circuits. I know nothing of the one you used.

My 1983 1.0L LWB had discs up front and had the brake residual valve fitted. No idea if it was stock, or maybe LWB came with that option that year?

[built4thrashing]

Has anyone tried to use the Forester master cly. Ive got one and it bolts up to the sierra booster. All that was needed was a longer pushrodand its good to go. Now this master cly was from a car with 4 wheel disc so no proportioning should be needed so im thinking of removing the rear valve when i do the disc and im already running LWB vit brakes up front.

wont know till i get the brackets and lines for the rear diff.

B4T

[nicbeer]

nopes.

with the valve in mine feels heeps safer but a little bit more is needed that the valve can provide. i will either go for bigger % vlave later or live with it i think.

not too bad,

[Gwagensteve]

Now this master cly was from a car with 4 wheel disc so no proportioning should be needed
B4T

What makes you think that? Relative pressure and volume requirements might be just as wrong as with a sierra M/C.

I'm not saying it's not going to be better, just that there's no real reason it will be correct.

Interested to hear how it goes though. We have a car in the build in the club with an impreza cylinder but it hasn't been driven yet. (sierra rear calipers)

Steve.[/i]

[greg]

:stupid question start:

rather than trying to reduce the braking effectiveness of the rear disc, what about trying to increase the effectiveness of the front disc?

i.e. if the sierra disc is say 30% more effective than a sierra drum, then what about installing a disc / caliper setup in the front that is also 30% more effective... wouldn't that solve the problem?

i.e. fitting a master cylinder that can push more fluid, and then fitting a new disc and caliper to the front with more stopping ability.

it would equate to more work though i guess, and still has to squeeze into a 15 or 16" wheel - but wouldn't the finished product be better?

:stupid question end:

[nicbeer]

u must be catching up on the posts now greg or following gwagen

thats sort of what i have done but as the drums pressure is higher afaik why they are more force on the back.

I have the vented vits on the front of mine.

[greg]

any "seat of the pants" estimate on how much better the slotted vitara discs are?

i just found some sierra slotted discs on the www.suzisport.com website that claim "superior stopping" - but i'm not sure exactly how much better that means. They are $350 for the sierra rotors and $380 for the vitara rotors... so they would want to be good.

one ugly suggestion might be a K-i-a* - they are a bigger car that still run a 15" wheel, with a 5 on 5.5 stud pattern (smaller center though)... their caliper / rotor setup might be good.

* - so no one will ever find it when searching

the higher post count is due to a minor part build up that is slowly happening and the nicer weather making me miss being out on the tracks.

[nicbeer]

sorry cant tell, as i went from disc/drum in the old zook to disc/dics in the new zook. can tell thou i can make all 4 lock up with discs all round.

Alien went the vit route on his and afaik he said it was a good difference.

and mine where free with my front cut.

i wonder if the K** run 4w discs or disc drum for the master

other thing is the K** ones would probably need an adapter to fit up to the zook stuff?

[greg]

i've done a bit more reading in the suzuki section and surprisingly if you go back a few months, there was actually some good tech in there

from what i have read in brief:
1. vitara stuff is better than sierra and definately fits with minimal hassle
2. sierra discs are sufficient at the front
3. sierra discs on the rear need less fluid to work than the drums so using a prop valve will probably end up with a good result
4. the other disc rear advantage is the better serviceability - so you still get some good out of it even if you are using a prop valve to limit their effectiveness.

lets never talk about k** again. if we want to talk about ugly cars that run a 5 on 5.5 stud pattern and are good for scavanging parts from we will go back to talking about vitaras and lwb sierras.