Mazda MVP question

[cruiser88]

Last month i changed the calipers on this 97(ABS) Mazda and ever sense this thing will not get any brake pressure or very little to none.

It has a good vac booster i just put a new 150 dollar master cy. on and still nothing.
I am using on of those pump bleeds(On the bleeder) you use by hand. I get up to 10 psi and that is far as the gauge will go. This new master was bench bled and i used new copper washers and new o-rings ....any ideas before it goes back to the stealership???? No the ABS does not need to be on a computer......

 

[WristPin]

those vacuum pumps are a joke.
you need to get a helper in there.

heres what i would do

clamp the three brake hoses. one on the rear axle and two on each caliper. use specified brake hose clamps or needle nose vice grips. (not too tight)

what you are doing is isolating the trouble area.

push down the pedal.
if the problem is downstream of the clamps, the pedal should be rock solid.

if its a wet noodle, keep the clamps on. have a helper operate the pedal.
crack the line on the master. have helper push down and hold. tighten fitting. do this to all fittings on master.repeat 2x.
check fluid level. if pedal is still soft, have helper pump slowly three times and hold pedal. open fitting. close fitting. repeat 2x on all fittings.

check fluid. if by this time pedal is soft, you have a defective master. i dont care if its new or reman. remans are especially junk. you will have best results from OEM parts.

onto if the pedal is rock solid.

take off one clamp only. check pedal.
when the pedal goes down, you found the trouble area.
bleed in the same manner as above.

your rear drum brakes wont make up much of a differnce for this test. most of what you will feel will come from the calipers.


since i probly will forget about checking back here, if you need help, PM me.

 

[cruiser88]

Thank you wristy.....actually that helps alot. I forgot all about the pinching off the brake line trick.......calipers all the way around

 

[WristPin]

yer welcome!!

that thing has calipers in the rear?! honestly im glad i never had the pleasure of working on one of these things.
ok heres another thing to look for.
(unless it has a drum brake strictly for the parking brake, this isnt going to help.)
assuming the calipers are ratcheting type, you probably didnt have to ratchet them in, since it probably came fully compressed and loaded with pads. there may be a bolt right in the center line of the piston, on the back side of the caliper case. if so, you need to adjust that (tighten). on a jack stand, the spin the wheel till you fell a very slight drag. once you do stop. if there is a set screw, lock it, and recheck drag. put it on the ground, put a block in front and rear of one tire a foot away, start up the engine and engage parking brake then put it in gear. if it works, (and didnt before, granted this was the culprit all along) you should be good to go.

 

[cruiser88]

ok finally got a chance to try again. The rears are fine but when i clamp the passenger side front i get almost full brake pressure...no change when i clamp the drivers front. I have bleed the master cy. to death with no change along with bleeding the fronts and the backs. i am starting to think p. valve might be bad which it sits right under the master. The booster has plenty of vaccum

 

[WristPin]

dont be insulted; are you certain the calipers are on ther correct side? all bleeder screws must be on the top side.

 

[cruiser88]

dont be insulted; are you certain the calipers are on ther correct side? all bleeder screws must be on the top side.

you know i will check ...no of course i am not insulted

 

[Gumby]

Try tapping on the combo valve, if it has one. Sometimes they get stuck

 

[cruiser88]

Where is the idiot emotion































calipers are on wrong..........how dumb can ya get,
Thanks guys for the help

 

[Gumby]

Done the intake manifold gasket yet?

 

[cruiser88]

Done the intake manifold gasket yet?

Not yet ...why? they a sob to do?
I know i have this blasted hard to get to o-ring behind the passenger side head to change. Leaking oil like there is no tomorrow.

 

[WristPin]

good.

and you are whalecum

 

[cruiser88]

good.

and you are whalecum

fawker

 

[Gumby]

Not yet ...why? they a sob to do?
I know i have this blasted hard to get to o-ring behind the passenger side head to change. Leaking oil like there is no tomorrow.

Not too hard, just pretty common. Fortunately it's just the upper plenum. No anti-freeze involved. Do the plugs and wires at the same time.