Chevrolet Repair Questions? Ask a Mechanic for Answers ASAP
Hi Im David, when you vac bled the rear brakes did you get fluid out?
did you also bleed the fronts?
do you have a dual master cylinder or a single bowl?
ok. bleed the brakes again. rr rl fr fl. do it with the engine running.. if there is still no pressure to the rear brakes, then adjust the shoes up with the thumbwheel and see if they improve.
4 wheel abs?
if it was me, i would bleed them the conventional way with a second person. engine running. bleed those suckers 4 or 5 times if you have to. i have had to bleed a few vehicles brakes 8 or 9 times... doesnt make sense, but it worked.......
oh yea, thats right. the rear runs off the axle for both. if bleeding them conventionally the way i described doesnt help, you will probably need to take it to a shop and have the abs module bled. the system is bled with a diagnostic scan tool with abs module bleeding capability.
yes, or until you get pressure
hows it going?
BECAUSE IT TIMED OUT. I DIDNT CLOSE IT. THE SITE DID
With the pedal pumped up with vehicle shut off start the vehicle. does the pedal sink?
pump the pedal up up with engine off. keep your foot on the pedal with pressure. start the vehicle and pedal should sink.
how much travel would you say?
that sounds like a booster to me
ckeck the check valve that goes into the booster. make sure its seated all the way and that you cant blow through it both ways.
ok....let me think
do the back wheels still turn with the brakes applied?
what model chevy and size engine?
ok. im going to see if it has an accumulator or proportioning valve. gimme a sec
i got really busy at the shop.. sorry. ill get on that now.
its a combination brake proportioning/modulator assembly. you may need to have the system bled by the dealer with a scan tool.
then all i can tell you is adjust the back brakes up a little more. if that dont help, theres nothing left other than to replace that unit
im going to opt out and seei f anyone else has any ideas.
Hi, My name is ***** ***** for the delay.
I will do my best to assist you.
did you bleed the brakes using a scanner to operate the ABS solenoid?
first,,be sure the rear brke shoes are adjusted up against the rear hubs.
then use a scan tool to bleed the abs system
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if you have already tried to bleed with a scanner and you still have no pressure,,
i would think your problem here is the ABS module itself..
there is nothing else left
still sounds as if the rear shoes are too loose or it still has air in the abs..
i dont think there is anything wrong with the booster itself
do you hear a vacuum loss near the booster?
i know you have replaced the master,,but if it has no air in the system and from the way you explain,this still sounds as if the master is bypassing the fluid and loosing pressure..
yes,,it is possible for it to be bad causing the fluid to loop back
Parts InformationOEM Part #Price
Brake Proportioning/Combination Valve
Hydraulic System, Brakes
Pressure Metering Valve
Order By Description.