On the Sierra, there's a front-rear brake balancer. I reused it on my Tiger Cat. I did installed discs on the rear side. Do I still need to keep the balancer as the rear discs are smaller than the front discs?
tia for clarification

IMHO
Leave it out

The one in the Sierra uses a ball bearing to proportion the front to rear effort and has to be fitted at the same angle as in the donor where it senses the suspension dive. Hopefully your Locost will not sag as much as the Sierra so you should not need it.

I didn't use mine on my supercat. Passed SVA no problem.

I did have drums on the rear but it shouldn't be necassary


Dan

mine passed SVA with no problem with sierra discs all round.

Turned out I needed to put a valve adjuster in as when I took it on a track in the wet, the back end was locking up and causing me to spin.....

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Originally posted by Peteff
The one in the Sierra uses a ball bearing to proportion the front to rear effort and has to be fitted at the same angle as in the donor where it senses the suspension dive. Hopefully your Locost will not sag as much as the Sierra so you should not need it.

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I think you are all missing the point!

1. Do you have two master cylinders (one for the back and one for the front) connected by a Threaded Balance Bar ?

2. Do the front wheels lock up before the back wheels?

If you have a balance bar and two master cylinders then the answer is NO, as you should be able to adjust the front to back ratio on the ballance bar.

If you are using the std Sierra twin circuit master cylinder (or similar), then you MAY need the ballancer in circuit. It will depend if the ballance is within limits with out it.
Remember this is now a Locost and NOT a Sierra (both in weight and distribution wise).

Basically at the end of the day it will need to pass the IVA. This means that the front to back braking ratio needs to be correct or within limits.
As a rule of thumb, the Fronts need to lock up BEFORE the Backs. Anything else is a FAIL. (This is ONLY a ROUGH GUIDE)

Believe me I failed SVA twice on this item.
Both fails were the backs locking before the fronts. I adjusted on the bar, but not enough, second time the bars movement was hampered by the locking nuts hitting the pedal ie the locking nuts were too close to together on the bar. (My bar was adjusted to the max to compensate for the incorrectly matched brakes, so had a large angular movement)

The Brakes are what I call "Mission Critical" parts / system. ie your LIFE (and others) WILL depends on them.
Do not skimp, or do half a job. Its far to important to get wrong.

The size of the discs will be different as there are different braking forces applied to the car to keep it stable, hence the ballancer on the Sierra.

Did your front and back brakes all come of the SAME (model) of car, ie are they ALL off a Sierra 4x4, or 1300cc basic model?

I had std 240mm front discs (off a 1800 sierra, and it should have been matched with drum rears.
I had 4x4 rear discs, and it was a bugger to ballance, as I should have had 260mm discs on the front. (I have since changed to 260's and the matching calipers).

As long as you have the front and rear brakes off the same model, and not different ones (like I had) you should be able to balance it up using the threadded cross bar if you have two mastercylinders.

If not you you need to test and see, then move on from there.

Sorry for the long post.

I use the standard master cyl and the original set of discs. The SVA test revealed higher brake force at front brakes (about the double). As the car is not moving on that test, the original Sierra brake 'balancer' does not function, I think. Hence my assumption that I could possibly do without. So I would assume that the front brakes should lock up first. Right?

Correct
I put one in line and left it fully open for SVA, this found a good balance at he time, hence my response , not necessary
However if you did have issues with imbalance it would be easier if' you'd put one in to start with than to retrofit

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Originally posted by MikeRJ

quote:

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Originally posted by Peteff
The one in the Sierra uses a ball bearing to proportion the front to rear effort and has to be fitted at the same angle as in the donor where it senses the suspension dive. Hopefully your Locost will not sag as much as the Sierra so you should not need it.

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It senses braking effort rather than body angle, though I guess it will be slightly affected by the latter.

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