 
     |
| Brake System Issues (Page 1/3) |
|
WaterInYuhDish
|
DEC 17, 11:51 AM
|
|
I replaced the two rear hoses.
I overhauled my rear calipers.
The front hoses and calipers are in "good enough" condition.
I double and triple checked that I bled all the old fluid and air out from each of the calipers.
With the car OFF, and a few pumps, the brake pedal stiffens.
When the car is RUNNING, I hear a hiss and the pedal can be pushed straight to the floor with ease indefinitely.
I notice what appears to be "splashing" going on in the MC reservoir when pushing the brake pedal whether the car is running or not.
I've read it could be a booster and a MC issue.
Last night I bench bled the MC and put it back on the car. Had a friend press on the pedal, I cracked open and then closed the front line, my friend depressed the pedal and repeat for rear line.
I'm still facing the same symptoms.
What would you do next to figure this out? Should i plug the MC lines and see how the pedal feels to narrow down the window of failure? Should i buy a MC overhaul kit and do that next? Replace the booster? Thanks yall.
|
|
|
|
theogre
|
DEC 17, 02:21 PM
|
|
MC is bad. Likely bad before then pedal bleeding did the rest. Replace it, Do Not rebuild.
Rear calipers may still have problems making more low/floored pedal problems. DIY Rebuilding Fiero rears is often a wast of time and money.
See my Cave, Brake Service and rest of brake section.
Booster is Not your problem. Air Noise is just Air moving in the booster when you floor the pedal and engine off will get very hard pedal as booster Vacuum runs out. The white Check valve on the booster is ok too because you can push pedal 1 to several times w/ engine off. (Floored pedal problems then vacuum reserve runs out faster.)
------------------
Dr. Ian Malcolm: Yeah, but your scientists were so preoccupied with whether or not they could, they didn't stop to think if they should.
(Jurassic Park)
The Ogre's Fiero Cave[This message has been edited by theogre (edited 12-17-2021).]
|
|
|
|
WaterInYuhDish
|
DEC 17, 03:39 PM
|
|
| quote | Originally posted by theogre:
MC is bad. Likely bad before then pedal bleeding did the rest. Replace it, Do Not rebuild.
Rear calipers may still have problems making more low/floored pedal problems. DIY Rebuilding Fiero rears is often a wast of time and money.
See my Cave, Brake Service and rest of brake section.
Booster is Not your problem. Air Noise is just Air moving in the booster when you floor the pedal and engine off will get very hard pedal as booster Vacuum runs out. The white Check valve on the booster is ok too because you can push pedal 1 to several times w/ engine off. (Floored pedal problems then vacuum reserve runs out faster.)
|
|
Thanks for the response! I have read through a few sections of the Cave, it's been helpful! Thank you for your service! Advanced Auto Parts has the MC in stock about 20 minutes from me for $80, it's cast iron... Is there a better online option you suggest for the MC? I don't think there's any fieros in junk yards that I can pull parts from. Few and far between in Utah.[This message has been edited by WaterInYuhDish (edited 12-17-2021).]
|
|
|
|
theogre
|
DEC 19, 04:44 AM
|
|
That listing is wrong. Either wrong part total or wrong entry on the web site etc.
All Fiero MC are aluminum.
Pic looks right but description say cast...
Can buy online from AA web, and AZ web, and return core to nearest store. If can't use, return new unit to store too.
AZ has New MC for 84-87 that doesn't core charge
They say "Master Cylinder Material Aluminum or Cast Iron"
Used MC is likely bad. Don't bother.
|
|
|
|
WaterInYuhDish
|
JAN 06, 07:29 PM
|
|
| quote | Originally posted by theogre:
That listing is wrong. Either wrong part total or wrong entry on the web site etc.
All Fiero MC are aluminum.
Pic looks right but description say cast...
Can buy online from AA web, and AZ web, and return core to nearest store. If can't use, return new unit to store too.
AZ has New MC for 84-87 that doesn't core charge
They say "Master Cylinder Material Aluminum or Cast Iron"
Used MC is likely bad. Don't bother. |
|
Finally got around to changing out the old MC and put in a new one. Same issues as with the old MC, yay... is the brake booster the next culprit? Someone told me it could be a vacuum leak but I'm unfamiliar.
|
|
|
|
Neils88
|
JAN 06, 08:09 PM
|
|
It shouldn't be the booster since it's a hydraulic system and despite being easier to push, it should never go to the floor. I have a feeling (having ruled out the master cylinder) that you either have air in the system that is being really stubborn, or a bad hose (check the front hoses since you already swapped out the rear ones).
Fieros are known for being very difficult to properly bleed. Many people swear that they've properly bleed the system yet ultimately they find trapped air after days of cursing.
|
|
|
|
Mike in Sydney
|
JAN 07, 03:03 AM
|
|
Did you bench bleed the new MC before you installed it? If not, you may want to redo it to make sure there is no air in the new MC.
I agree with another poster, change out the front hoses and re-bleed the entire system. Start with the caliper furtherest from the MC and work inward. If you have a manual, forget the order it suggests. The correct order is LR, RR, RF, LF. I've been "gently" corrected on this several times (Thanks, Patrick ;-D) .[This message has been edited by Mike in Sydney (edited 01-07-2022).]
|
|
|
|
Australian
|
JAN 07, 06:08 AM
|
|
|
Master or slave is leaking. Get a rebuild kit for each.
|
|
|
|
ArthurPeale
|
JAN 07, 05:33 PM
|
|
If memory serves, if the rear brake pistons aren't adjusted properly, this can cause the issue you're describing.
I've got two Fieros, and what you're describing is what's happening with my project car.
I'm not going to bother to install them properly until I can replace the cradle, since I'd have to replace the ebrake line through the cradle, that would just be added work
|
|
|
|
WaterInYuhDish
|
JAN 10, 04:34 PM
|
|
| quote | Originally posted by Mike in Sydney:
Did you bench bleed the new MC before you installed it? If not, you may want to redo it to make sure there is no air in the new MC.
I agree with another poster, change out the front hoses and re-bleed the entire system. Start with the caliper furtherest from the MC and work inward. If you have a manual, forget the order it suggests. The correct order is LR, RR, RF, LF. I've been "gently" corrected on this several times (Thanks, Patrick ;-D) .
|
|
I did bench bleed before putting the new one on. And I have bled in the proper order for the manual trans. I rebled the lines again yesterday and still nothing. Another post suggests the rear brakes not being set properly could be the issue which I know I haven't reset the calipers/ebrake properly since overhauling those calipers, the cable on the driver side is pretty deep in the spring so it was a pain to get to after putting everything back together in one go so I put it off for another day. I guess that time has come. It sounds like the pads are dragging now too.[This message has been edited by WaterInYuhDish (edited 01-10-2022).]
|
|
|
|