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master cylinder
vinnievector - 4/5/09 at 04:04 PM

Hi all ,
I have a sierra duel curciut master cyl and just want to confirm that the out let nearest the pedals goses to the front brakes and furthest to the rears for the correct brake balance .

40inches - 4/5/09 at 04:35 PM

Front to front, rear to rear, strangely enough.
However i would hold off fitting the brake pipes just now, because there is a possibility that the Sierra master cylinder will not pass IVA due to the requirement for the brakes to be split diagonally We will all know better after a few have gone through.

MikeR - 4/5/09 at 04:40 PM

requirement isn't for a diagonal split, but for if one circuit fails, the other circuit to provide at least 30% braking power.

The issue, as i read it on here, with the sierra m/c is that if you get a failure then the car, when braked, will pull heavily to the side with working brakes.

theconrodkid - 4/5/09 at 05:13 PM

they dont have to be diagonal,no other motor manufacturer makes them that way.
the port nearest the pedal is normally front,see if its marked "P" if so its deffo front,didnt you make a note when you took the doner to bits?

40inches - 4/5/09 at 06:07 PM

quote:
Originally posted by MikeR
requirement isn't for a diagonal split, but for if one circuit fails, the other circuit to provide at least 30% braking power.

The issue, as i read it on here, with the sierra m/c is that if you get a failure then the car, when braked, will pull heavily to the side with working brakes.


Yea, you're right, my bad;

"09E Brake performance
2.
The service brake performance must be at least 60%, (of the CLW or DGW as determined to be the highest) or more than half the road wheels lock.
3.
The secondary brake performance must be at least 30%,(of the CLW or DGW as determined to be the highest) for each half of the split system."

That will teach me to speed read documents
so,the Sierra system is split front and rear and reading the above paragraphs s.l.o.w.l.y, am I right in assuming the problem will be if the Sierra rear drums can provide 30% of the total braking force? or am I being incredibly thick here???

40inches - 4/5/09 at 06:15 PM

quote:
Originally posted by theconrodkid
they dont have to be diagonal,no other motor manufacturer makes them that way.
the port nearest the pedal is normally front,see if its marked "P" if so its deffo front,didnt you make a note when you took the doner to bits?


All the Sierra duel master cylinders I have seen, have had two outlets at the the front for the front brakes and one outlet at the rear (nearest the pedal) for the rear brakes, using a 't' junction near the diff.
Although I stand to be corrected

l0rd - 4/5/09 at 06:19 PM

quote:
Originally posted by theconrodkid
they dont have to be diagonal,no other motor manufacturer makes them that way.
the port nearest the pedal is normally front,see if its marked "P" if so its deffo front,didnt you make a note when you took the doner to bits?



I am 99% sure that Renault use that system in their cars.

prawnabie - 4/5/09 at 06:24 PM

Older Renaults use that system, pretty much anything that has abs, or can have abs as an option uses front/rear split.

britishtrident - 4/5/09 at 07:08 PM

Quite a few manufacturers used it back in the 70s but abandoned it.

bob - 4/5/09 at 07:35 PM

quote:
Originally posted by 40inches
quote:
Originally posted by theconrodkid
they dont have to be diagonal,no other motor manufacturer makes them that way.
the port nearest the pedal is normally front,see if its marked "P" if so its deffo front,didnt you make a note when you took the doner to bits?


All the Sierra duel master cylinders I have seen, have had two outlets at the the front for the front brakes and one outlet at the rear (nearest the pedal) for the rear brakes, using a 't' junction near the diff.
Although I stand to be corrected



Seen some with four outlets but most have three, as you say front two for the front brakes and middle or rear nearest pedal for rear with a split T junction at rear. (well mine are like that)

vinnievector - 5/5/09 at 07:47 PM

sorry for late post ,

The master cylinder was purchased new ,look through the hynes manual but no symatic for the brakes in there .wot i will do is to remove the connections and take a look at the port sizes and see if i can see some markings thanks for the help .Vin