1998 gmc sierra k1500 - bad brakes need help

Discussion in 'GMC Truck Forum' started by Billselfjr, Apr 18, 2011.

  1. Billselfjr

    Billselfjr Senior Member

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    I replaced the mastercylinder 3 times, all new not rebuilt all of them Bad i think , i bench bled them as i was supposed to then i put them on the truck bled the lines several times still no peddle only thing is that when i put the plugs back in to bench bleed it again i get a little air then i put it back on and it does it again just air on the back side not on the front one looks like a million little bubbles. I just don't get it i can even bleed it from the abs box by taking one line off at a time still get bubbles in the tank like its back feeding but where is the air coming from somebody please help Quick i need my truck

    ps the mastercylinders were all new Cardone select 13-2352 and bought at advanced auto
     
  2. chevychase

    chevychase Senior Moderator Staff Member

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    Well .... i have seen this brake lines were perforated... real rust micro holes.
    Had to hunt and watch while someone pumped brakes .
    Could see a little fluid being pushed out then sucked in through the rust.
    Never did drip any fluid .. but was sucking air in.
    About drove us crazy till we found it. Replaced lines good to go.
    P.S ADVANCED PARTS ARE USELESS AS TEATS ON A BOAR HOG LOL.
     
  3. Billselfjr

    Billselfjr Senior Member

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    I did that i had my wife to push while i looked and still nothing the bubbles look like there just coming from under the master cylinder reservoir where the rubber washer are but the guy at advanced said that would be unlikely . All i know is i'm tired of changing master cylinders. and i've checked everything that i can think of including checking the lines the pads replacing the wheel cylinder, brake calipers and 3 master cylinder's and bled almost 3 gal. of fluid threw and also i bench bled it i don't know how many times. but there has to be something i missed but I just can't figure out what it is and man it's driving me nuts. One guy said the booster was bad but that don't make sense if it was bad wouldn't it quit working or give me a clue like hard to push brakes or stumble in the engine when i push the peddle. if you can think of anything else please feel free to tell me i've also called a couple of garages around and there stumped to they said just replace every thing again to eleminate all possible problems but i don't have that kinda money or time
     
  4. Billselfjr

    Billselfjr Senior Member

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    well today i replaced the back line no hole just rusty and then replaced the mastercylinder one more time this time got it at napa (new not reman) and still nothing so i blocked off the back line and one front line to see if had peddle then put the other front line on and still had peddle so i put the back brake line on and know more peddle i think the abs is bad because if i plug the back line where it can't recirculate back to master cylinder then i have brake or at least it sounds good until someone smarter that me corrects me which should be any second now because i really don't know i'm just guessing
     
  5. Billselfjr

    Billselfjr Senior Member

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    well know one want anything to do with this so what i've done so i decided to remove the abs from the lines so i just put a T in the front and a adjustable block for the back and leave everything except the lines on the abs so won't mess up the computer or abs lights so thats what i did if i did something wrong please let me know thanks.
     
  6. chevychase

    chevychase Senior Moderator Staff Member

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    Wow this is a tough one. Researched some.. only thing i came up with was abs pump... or rod not long enough in booster to get pedal... said you can adjust length
     
  7. Billselfjr

    Billselfjr Senior Member

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    I took the lines off at the abs one at a time and seem to point in the direction of the abs going bad the two front lines i left hooked up and then i blocked the out going back brakes and now i seem to have front brakes with out going clear to the floor. So i assume the abs is bad ,if i leave all hooked up they seem to return to the mastercylinder and pedal goes to the floor like a check valve or something isn't working like it's putting it back in the MC instead of putting it to the brakes so i guess the only thing to do is replace the abs. Yea like i got that kind of money.Or just leave it there and plumb around it using a T and a adjustable valve for the back brakes . Does this sound like it will work or am i just letting my wheels spin ha ha .?

    As far as the rod from the booster I think its ok it seems to be adjusted fine the pedal is up far enough. When i first hit the brakes you can feel when it comes in good contact with the MC so i guess its all good there .
     
  8. zombie1969

    zombie1969 Senior Member

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    Vehicle Application:1991 GMC S15 Jimmy 4.3L1997 Chevrolet K1500 5.0L, GAS, Vin M, Eng Cfg V81994 GMC G2500 Rally 5.7L, GAS, Vin K, Eng Cfg V81998 Chevrolet Blazer 4.3L1994 GMC Sonoma 4.3L, Vin Z, Eng Cfg V61998 Chevrolet K1500 5.7L, GAS, Vin R, Eng Cfg V81995 Buick Park Avenue 3.8L1998 Chevrolet K2500 5.7L, GAS, Vin R, USA/Canada1995 Chevrolet Blazer 4.3L1998 GMC C1500 4.3L, Vin W, Eng Cfg V61995 Chevrolet C1500 Suburban 5.7L, GAS, Vin K1999 Chevrolet Blazer 4.3L1995 Chevrolet K2500 5.7L, GAS, Vin K, Eng Cfg V81999 Chevrolet C2500 5.7L, GAS, Vin R1995 Chevrolet S10 4.3L, Vin Z, Eng Cfg V62000 Chevrolet Silverado 2500 6.0L, Vin U1995 GMC Sonoma 4.3L, Vin Z, Eng Cfg V62001 Chevrolet Blazer 4.3L1995 Pontiac Bonneville SE 3.8L2001 Chevrolet Silverado 3500 8.1L, GAS, Vin G1996 Chevrolet C1500 5.0L, GAS, Vin M, Eng Cfg V82002 GMC Yukon 5.3L, FLEX, Vin Z1996 Chevrolet K1500 5.7L, GAS, Vin R, Eng Cfg V82003 Chevrolet Express 2500 4.8L, GAS, Vin V, Eng Cfg V8, USA/Canada1996 Chevrolet S10 4.3L, Vin W, Eng Cfg V62003 Chevrolet Silverado 3500 6.0L, GAS, Vin U1996 GMC Sonoma 4.3L, Vin X, Eng Cfg V62003 GMC Savana 2500 6.0L, GAS, Vin U, Eng Cfg V8, USA/Canada1997 Chevrolet Blazer 4.3L2005 GMC Savana 1500 5.3L, Vin T, Eng Cfg V81997 Chevrolet C1500 5.7L, GAS, Vin R, Eng Cfg V8Customer Concern:The brake pedal is spongy. Brake hoses check OK. Has bled the brake system numerous times. A new master cylinder was tried.
    Tests/Procedures:1. Check the brake calipers for excessive movement during brake apply.

    2. Bypass the Antilock Brake System (ABS) Brake Pressure Modulator Valve (BPMV) with fittings so that the ABS modulator is removed from the system.

    3. This is for a brake pedal feel test only, do not leave the system bypassed.

    4. Bleed the brakes at the wheels.

    5. If now OK, replace the BPMV.
    Potential Causes:Brake Master Cylinder
    Brake Pressure Modulator Valve (BPMV)

    Diagnostic Codes:None
    Author:HomeAverage Reported Mileage:162234
    [​IMG]Confirmed Fix Summary[​IMG] [​IMG]
    [​IMG] Confirmed Fix18 - Brake Pressure Modulator Valve (BPMV)8 - Brake Bleeding Procedure4 - Brake Master Cylinder3 - ABS Bleeding Procedure1 - ABS Bleeding Procedure, Brake Bleeding Procedure1 - Both Front Brake Calipers, Brake Caliper Guide Pins, Front Brake Pads, Rear Brake Pads1 - Both Front Brake Rotors, Brake Caliper Guide Pins, Front Brake Pads1 - Both Rear Brake Calipers1 - Front Brake Pads1 - Hydraulic Brake Line1 - Power Assist Module

    Looks like the BPMV might be something to take a close look at.
     
  9. Billselfjr

    Billselfjr Senior Member

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    I know you are not gonna believe this but i bypassed the abs today just to see if i had any pedal and still nothing so to recap. i've put all new wheel cylinders new brake calipers new hoses for the front 4 master cylinders bled over 3 gallon of fluid and a new line for the back because it looked a little rusty also i bled two diff. ways pump,hold,bleed then i've bled using a mighty vac suction device. tried several diff ways of bleeding like rr,rd, then rf then df and diff. ways still nothing i really believe i got the air out i may be wrong but over 3 gal. of fluid man thats alot of bleeding so. what else could i do besides replace what i've done already any help no matter how wild it might be i'll still try it??????

    PS i put a T in for the front brakes and put a summit adjustable valve for the back and still know pedal.
     
  10. chevychase

    chevychase Senior Moderator Staff Member

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