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Gary
Gary, Technician
Category: Car
Satisfied Customers: 16769
Experience:  GM master tech for 15 years/ASE master tech for 20 years
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Gmc jimmy: 94 jimmy brake petal goes down inch gets hard a

Customer Question

94 jimmy brake petal goes down inch gets hard a rock and barly slows down
Submitted: 1 year ago.
Category: Car
Expert:  Gary replied 1 year ago.
is this acting like the brake booster assist is not working as it should ?if this brake pedal goes down 1 inch then gets rock hard and will not stop the truck good these kind of issues are usually brake booster or vacuum to the brake booster being too lowdoes it do this all the time ?
Customer: replied 1 year ago.
this happened after changing the master cyl and repairing a rusted brake line
Expert:  Gary replied 1 year ago.
when bleeding the brakes is the fluid pressure very good at all 4 wheels ?was it bled with a scan tool ?
Customer: replied 1 year ago.
all lines were bled by an expert mech who said he tried bleeding every way you can
Customer: replied 1 year ago.
mech sid the booster was fie
Expert:  Gary replied 1 year ago.
where these tools used to bleed the brake system ?Tools Required:J 39177 Combination Valve Pressure Bleeding Tool (Three required)TK 00000 Tech-1 Scan ToolTK 02650 RWAL/4WAL Cartridge Kit or(###) ###-####Mass Storage CartridgeA modified J 35856 Combination Valve Pressure Bleeding Tool can be used in place of J 39177 providing you remove the dimple from it first.
Customer: replied 1 year ago.
I think he said he did
Expert:  Gary replied 1 year ago.
you need all of those to bleed these old style systemsif this did this after the master cylinder was changed and a brake like there has to be air in that ABS system stillthis here has to be followed 100 % and even done possibly 2 times the procedure to get the air outthese brake systems where one of the worst to get air of of them and required a lot of time to do soOpen the internal bleed valves on the sides of the BPMV 1/4 to 1/2 turn each (A).Install J 39177 on the left high pressure accumulator bleed stem (C) of the BPMV.Install J 39177 on the right high pressure accumulator bleed stem (C) of the BPMV.Install J 39177 on the combination valve.Check the master cylinder reservoir fluid level and fill if needed.Bleed the brakes as described under Pressure Bleeding.NOTICE: Always use the correct fastener in the proper location. When you replace a fastener, use ONLY the exact part number for that application. General Motors will call out those fasteners that require a replacement after removal. General Motors will also call out the fasteners that require thread lockers or thread sealant. UNLESS OTHERWISE SPECIFIED, do not use supplemental coatings (paints, greases, or other corrosion inhibitors) on threaded fasteners or fastener joint interfaces. Generally, such coatings adversely affect the fastener torque and the joint clamping force, and may damage the fastener. When you install fasteners, use the correct tightening sequence and specifications. Following these instructions can help you avoid damage to parts and systems. Close the internal bleed valves. Tighten Internal bleed valves (A) to 7 Nm (60 lbs. in.).Remove the three J 39177 tools.Check the master cylinder reservoir fluid level and fill if needed.With the ignition switch "ON" and the engine off, do six function tests with the Tech-1 scan tool.Repeat the wheel cylinder and caliper bleed procedure to remove the air that purged from the BPMV during the function tests.Apply firm pressure to the brake pedal and evaluate brake pedal feel.Repeat the bleed procedure if needed.Make sure you have a good, hard brake pedal before starting the engine and moving the vehicle.
Expert:  Gary replied 1 year ago.
how are you making out ?