Front calipers, 1991 n/a "Coupe"

 

bump

 

I am pretty sure they are 4-piston. The 4-piston calipers are long, and say MAZDA down the long side of the caliper.

 

Nice. I got 4 piston then! I am buying Hawk pads, and I am too lazy to pull off the damn thing and check right now!

 

They do not say "Mazda" on the outside, but they are twice as long as the rear ones, so I assume they are 4.

 

you can see how many pistons just by taking the pads off. Takes 2 mins to yank the pads. Just undo the clips.

 

There were no 4 lug cars after 88. All 5 lug cars have 4 piston front calipers.

 

No that is not correct. The 4 piston brakes were very uncommon on the 91 models. Only the vert and T2 came standard with them.

Single piston brakes with 5 lugs were found on the 89-90 GTU as well.

If you have the PP (power windows-locks) and leather, chances are that the brakes are the 4-piston option, but if you don't it is very very very rare to have 4 piston front brakes on a 91.

Can't you go look? I mean its not hard to see if you have one or two bulges in the brake caliper and whether or not there is Mazda written on the caliper (two bulges and Mazda- is the dual piston brake caliper).

 

What about the 86 gxl
and the 88 gtu.

 

Ok, I do have power everything, but no leather. The calipers are twice as big as the rear ones, and there is one big bulge on the outside. But if they are only 1 piston, then why are they bigger than the rear calipers???

 

I was refering to the 91 model year.

Okay 4 piston brakes (also called dual pot or dual piston) are normally found on:

86-87 Sport (or GS)
86-90 GXL
87-92 T2
88 GTU
89-90 GTUs
88-92 Vert

In addition there were some 91 coupes (there were only coupes, T2, and 'Verts available in 91, there were no letter designation models) that got 4 piston or Dual Pot brakes, generally these were models with the power package and LSD and leather (in other words a GXL trim level).

Everything else FC got single piston brakes, front and rear, regardless of whether or not there were 4 lug or 5 lug wheel hubs.

Just because it has 5 lug wheels doesn't mean it got dual piston front brakes.

 

because the have to stop the car, front brakes are almost always bigger due to the weight transfer when a car slows down.

If you are not sure, pull the wheel and look. If it doesn't have Mazda on the caliper in nice big bold lettering that is normally visable with the wheel on, then it is not a dual piston brake.

 

Oh well, no 4 pistons for me. That's ok, she still stops good enough for me!

 

Here is a picture of the dual piston brakes:

 

Is there a way of getting better rear calipers?
w/o shelling out alot of money.

 

Will the slotted cross drilled/slotted rotors make a difference?

 

Well I'm glad I don't like S5 cars that much. Single pistons with 5 lug rotors?

 

My 90 GTU came with single piston up front, so I upgraded to 4-piston. And no they aren't normally blue, and I didn't paint them either.

 

For the rear, even the upgraded calipers and rotors (from like a T2 or 'vert or GTUs) are only 1/2 inch bigger. There is no big difference in stoping. It is generally not cost effective.

Slotted rotors will help, as will cross drilled, but I have seen quite a few poorly drilled cross drilled brake rotors explode from being overheated. Well I shouldn't say "explode" I should say shatter or develop cracks. IMO most cross drilled rotors are not the best choice for street driving. Great for track or road course racing though where you replace them often.

 

you dont want "better" rear calipers in the back and you dont want the stopping power on front to back to be the same. if your back braakes lock up before your front then you will quickly have your @ss where your head should be...

Justin

 

that wasnt too clear... there is more weight in the front during braking so the back brakes lock up easier..

there,
Justin

 

If you are braking in a straight or near straight line most of the weight transfers to the front end of the car, with the rear end lifting slightly (depending on the suspension's condition).

If you don't have ABS and the front and rear are poorly matched for this weight transfer yes, you will either overheat the front brakes, or the rears will lock up. Both of which are very bad of course.

In an ideal world the brakes should compensate either in size (for braking efficiency, and unsprung weight) or pressure so that you do not lock up the rear before you lock up the front. In some cases a brake-proportioning valve may be used to fix this (as this was a common add on in the '70 and '80s).

What throws a loop in this is braking while turning, which weight can transfer forward and sideways. Which again brings back the suspension and body weight distribution into play controlling the lift side to side.

So what does this mean? The rear brakes are fine unless you want to upgrade all four corners with substantially bigger brakes (more than 1" increase in rotor diameter, and the corresponding calipers to allow increased pad size). Just making the rears bigger throws off the balance. Just adding bigger fronts throws off the balance.

 

I'm going to be recieving crossdrilled/slottted rotors in the mail. Should I be worried abouth them ******* up? I'm not that hard on my car.

 

I've been pretty hard on mine for about a year with them on. 6-7 auto-x's. Lots of HARD road driving for periods of up to an hour, etc...No problems yet.

 

Good deal.