Hi Guys,

I've had my front brakes upgraded to FC calipers and some nice big discs... the new calipers are 4 spot. The old ones were single piston. The problem with this is when you brake, you don't feel the front brakes come in until you have pushed the pedal down a bit... which makes sense.

Because a lot more fluid needs to move in order to compress the front brakes the same distance as the back, with the current master cyl setup the rears are coming in first...

This could be bad from a handling point of view... like slowing down in wet corners!!

Some options I am aware of are getting a brake-bias adjuster, or I think I can swap to a S4 master and booster( not sure if i need both )....

I am open to suggestions to resolve this... and any pro's and cons... personally i think the s4 brake master/booster would be a neater fix... but i'm open to suggestions

Thanks in advance!

Paul.

 

It's hard to tell, is that one of our caliper brackets?

Was the car a rear drum car at any point? We have not seen adverse effects from the front 4 piston unless the master was a drum.

-billy

 

I swapped my drum unit out for an FD unit. I will probably need to adjust it once I can actually use it, but I had an extra one and figured I needed more power for the bigger brakes.

 

Hmm I'm not sure if its one of yours- someone else did the work.. but I guess if you have noticed no problems, then it should basically be the same... Is there anything special you do when you set them up?

I'm pretty sure that the car has always been standard disc brakes.

Thanks for your help,

Paul.

 

The only reason I asked if it was our bracket is due to the picture showing what I believe to be a welded spacer on the caliper mounting ear. If it was our bracket then the spacer side of the bracket should be opposite the caliper ear and using a separate washer to obtain the spacing. That spacer is a top hat style that is welded into the hole simply to keep it from turning. It should not be mounted where the welds are used to secure the caliper in place.

There are some guys who have played with mounting 1" bore, 929 master cylinders. Not sure what it was called on your side of the pond. As posted above, some use the FC or FC master as well.

-billy

 

I didn't really have a problem with my kit until I installed the rear T2 brakes. At that point the pedal was quite a bit further down than I liked. My quick fix was a cmplete T2 booster, master cylinder, and p valve. $50 used. I had to stack a 1/2 inch spacer between the back of the booster and the fire wall. I also ground the clutch master cylinder with an angle grinder. Now the pedal is way back up there and Iam rocking T2 brake componnents everywhere. Its a few hours worth of swapping and fabbing then your done.

BTW my car was an original a rear drum model. I believe mazda had 4 different master cylinder from 79 -85

 

I'm wondering if you are using the Same Proportional Valve and Master/booster that was on the car originally(the FB)?.If so,In My opinion,you would be Better of to Run a GX master/booster and proportional valve..(I Did a five lug swap.using the Gx brake set-up on the FC TII brakes.No problems.I have Also Sold the GX Booster/master Proportioning valve to 2 members For their FB TII brake conversions,and they are runniing them with no "side effects")..That is my Take on it.I hope that may help.

 

sorry, off topic but relevant: iirc you can use fd calipers in place of the tII units?

 

noticed your brake hose looks abit twisted, that can cause issues aswell, hoses can't be twisted like in your pic, it can twist further when you turn your wheels side to side causing a failure of the line or pinching of the line (no pressure)

back to the main problem, try swaping in the t2 master/booster/pp valve and go from there.

 

ok, we have reassessed the situation, i was wrong in thinking i am rear biassed now.. moreso i am a bit more front biassed.. which is better than rear bias

I think the photo from that angle makes the hose look more twisted than it is.. it seems quite fine going from lock to lock, no pinching... i will keep an eye on it for any signs of wear though, thanks for pointing it out.

I've taken it for some test drives and it is feeling good now- we adjusted the brake pedal so the brakes come right on as soon as you touch it pretty much

Thanks!

Paul.