Mazdax605

iTrader: (5)

Hey guys,

I am having a slight issue with my 79 that I am not sure is really a problem,but you guys can probably help. I have owned the car for three years or so,and having never owned a SA before I am unsure of the brake feel from them. Just a few weeks ago I replaced the master cylinder that was leaking into the brake booster,and the brakes do feel a bit better,but no as I remember them on my FB. It seems like the pedal moves a lot more than on my FB,and the brakes don't feel real firm. I know I bled the system real good,and bench bled the MC before installation. If I pump the pedal while braking the pedal gets nice,and firm,and the brakes feel great. Could this be an issue with the brake booster,or elsewhere? Could it be I didn't bleed the system enough? The brakes feel about the same as before the MC replacement,but now I am not loosing any fluid like I was before(it was a very slow leak). Any help on thi subject would be greatly appreciated.

djessence

If you pump the brakes and it gets firmer it does sound like a bleed problem if you just replaced the master.

Did you bleed all 4 wheels in the correct order (meaning furthest away from master to the closest)?

j9fd3s

iTrader: (3)

my SA had a mushy pedal too, or it seemed like pedal travel was kinda long. brakes actually stop the car pretty well though, it just feels odd

couple things to check.

1. rear brakes adjusted right? makes a huge difference, and its very easy to do, in my experience even self adjusting drums, arent.

2. the 79 wedge calipers are kinda crap, but they do need to move around, lube here is good

3. if the wheel bearings are too loose, then it pushes the caliper pistons further in then they need to be, and then they need to move further than they should to make the car stop, which makes for a soft pedal on the first stop, and a firm one on the second.

4. its an old car, even though its a mazda, you might have a bad hose or something

Box_Man

It's normal for the pedal to feel more resistant when you pump the pedal due to the brake booster not getting sufficient vacuum to assist you. As for the pedal travel, change your brake shoes out back, it'll make a huge difference (assuming you have drums) and while your at it, fab up a master cylinder brace and add braided stainless lines.

Hyper4mance2k

iTrader: (40)

lol my car does the exact same thing. i rebuilt all the calipers, and rear pistons, put all new hardware and pads in. And they stop awesome, on the secong pump. or if the ebrake is pulled all the way up. oh and the e-brake doesn't work either. I honestly think I just need to take it to midas and have them adjust 'em I'm tiard of trying.

Mazdax605

iTrader: (5)

Thanks for the replies guys. My e brake works great,and when I was bleeding the brakes I did it in this order: Rear,front right,front left,and I also bled it at the MC as well. The rear brakes seem to be adjusted correctly,and the E-brake works great. The brakes feel about the same as my 74 REPU which I think uses a similar brake caliper,so maybe that is just the way they are supposed to feel. I really wish the pedal was as firm as it is on the second pump all the time though. I will try to bleed the system again,and maybe I will open the rear drums up,but I doubt they are the issue.

t_g_farrell

iTrader: (1)

Did you bleed in this order; master cylinder ( theres a bleed screw on the master itself for the SAs), right rear, right front, left front?

Also, if you don't have a bleed screw on the side of the master, its not an SA master.

It could also be your booster. Has it ever been replaced? Once a master leaks fluid into the booster it can kill it. Ask me how I know

Mazdax605

iTrader: (5)

I bled in this order MC(yes it is an SA MC),and yes I did bench bleed it as well. Rear was next which only has one bleeder,next was right front (pass side),and then finally left front(drivers side). The MC was leaking into the booster,but the brakes don't feel any different travel wise from the old slowly leaking MC to the new one. It very well could be the booster,but I have no idea what the syptoms are when one is bad. Can I replace the booster without breaking the hydralic system apart? What is the best source for a new booster if I need one?