2000 Silverado NO brakes


bluebowtie67
12-27-2010, 02:56 PM
2000 Silverado 1500, 4x4, 5.3L, (I assume it has ABS)
My dad recently bought this pickup and was told upfront by the previous owner that it 'probably needed bled' because they had done some brake work or something.. very vague.
The brake pedal was very mushy and basically no resistance until the very end of the throw, when there was a little pressure to stop the truck. Not ideal by any means, but alright for putting around our farm, etc.
We were going to bleed the brakes and for starters the fluid in the reservoir was dark and disgusting- separations between brake fluid and dark slime- didn't really look like any standing water but not sure if that would separate. So we sucked that fluid out and cleaned the reservoir out. Took the two lines off and ran some fluid through as well. Hooked the lines back up, filled the reservoir and started bleeding, RR, RL, FR, FL. All the same: Pedal was pumped up (which after reading on here I realize is not the proper way, which we'll correct next time) and then cracked the lines. The pedal would never get any real 'feeling' in it- pretty much to the floor each time- and no fluid would squirt out of any bleeder. They were, however, all identical in that with the bleeder open, fluid would start seeping out- about a drop every few seconds.
It seems that there is no pressure being built up at all. The fluid level has never been an issue before, and there seem to be no leaks. Haven't thoroughly inspected for leaks, but during our bleeding there was no fluid shooting out of anywhere so that doesn't seem very suspect.
I've read all the other posts I could find about this and didn't see anything quite like this, with no pressure at all while pumping. I'm not new pickup savvy, so please give me any input. I replaced my 67 C10 master cylinder for basically the same problem and it worked, but I realize the 33 year difference. Thanks for any help everyone!

j cAT
12-27-2010, 07:05 PM
since the fluid was contaminated ,this is going to need lots of parts.

water or the wrong fluid used will damage the metal as well as the rubber.

the Abs UNIT HAS VALVES AS WELL.

since no pressure check for brake line failure. the line to rear brake calipers next to the fuel tank is a very BIG failure item..very hard to see..

the master maybe damaged. I would replace ////pedal to floor is master...or a leak !

bleed first then install..

remove the bleed screws if no fluid comes out..
I would pop the pistons on calipers and check the piston bores..

never allow abs unit to get air in it if so you will need a GM abs control bleeder...

plug lines when checking the calipers for proper operation..the rear calipers are a defective designed unit.


when the brake pedal is depressed with bleeding do not go to the floor..small slow pumps..if you go to floor the master can get damaged...


the abs unit can cause this problem if the alves are stuck / leaking.. go to the scrap yard to get another.

did a repair shop work on the brakes or some hack ?

kahjdh
12-28-2010, 10:12 PM
Did you take the two lines off of the master? If you did prob have to take it off and bench bleed it. I have had luck getting air out of the abs module by doing some extended gravity bleeding. But I really think you need to bench bleed the master to start off.

ukrkoz
12-28-2010, 10:58 PM
well, i have 2000 silverado 1500 4x4. 120 000 miles. yeah, brake fluid is getting there, sorta slimy.
if you have ABS, ABS light will come up every time you start the engine, for about 5 seconds. also, ABS unit is right underneath the driver seat. best bet is to note VIN and call dealer. GM and Ford are mindbogglingly procreative in optioizing their cars.

anyhow. if pedal goes down to the metal, and nothing comes out of bleeding screws, you have no pressure in the lines. i ABSOLUTELY doubt all four lines got bent or plugged.

btw, keep in mind, Silverados are known for having mushy, soft brakes.

my bet is - one of the seals inside master cylinder is bad. or both. hence, it is not pumping up.

here's suggestion. remove bleeder screws, as of now, they are useless anyway. run compressed air to master, if no compressor - maybe find a buddy with surge tank and high pressure nozzle attached to it. disconnect brake lines from master, and blow them with compressed air. if they check out, remove master. if you just want to buy a refurbished one, it's your call. repair kits are sold everywhere, and it is very easy to refurbish yourself.

when done, bench bleed master. master bleeding kits are sold for pennies. reconnect brake lines, and reinstall bleeder screws. bleed system. have PLENTY of brake fluid on hand. we bled inlaw's work van not so long ago, it took quite a bit of fluid in.

i hope, you do not turn engine on to bleed. also, i have bled lost count how many times, never had any issues with pedal to the metal range. yes, you do have the right order.

if you do have ABS, then tough, you need to follow bleeding procedure for ABS systems.

http://www.aa1car.com/library/abs_bleeding.htm

i just checked with my repair manual. they do not caution from pedal going to the floor; if you have ABS, when you done with bleeding, ABS light should come up when you start the engine, and go away in about 10 seconds; if it stays, you screwed and ABS must be diagnosed with special tool. and no, they do not specify any special procedure for bleeding after master re-installation, for ABS. bench bleed/reinstall/bleed master when installed/reconnect lines/bleed lines.

bluebowtie67
12-29-2010, 03:42 PM
My dad bought the pickup from a local farmer who is notorious for not maintaining vehicles but he only had it for 13,000 of the 300,000+ miles and it was maintained at a shop regularly until then.. anyway....

ukrkoz:

So, if i'm following you correctly, you only need to bleed ABS if the light stays on upon startup? If that's the case everything makes sense. I'm finally going to get back to it tonight hopefully and I'll report my findings when I do. Thanks for the help so far guys!

ukrkoz
12-29-2010, 04:15 PM
no, what manual said was if the light stays up for more than 10 seconds, you must TOW vehicle to a dealer to have them ABS DIAGNOSED. they deam it undriveable with that light up.

300 000 miles? that master is due for overhaul long time.

j cAT
12-29-2010, 07:59 PM
your problem may be that the ABS has air in it or the damaged fluid is causing your no brake pressure problems..as well as leaks and a damaged master cylinder.

the ABS is not required on this vehicle. many have pulled the abs 60amp fuse and operate with the ABS light on.
the ABS light on means that the ABS will not work . this causes the brakes to be ALWAYS ON WHEN YOU STEP ON THE BRAKE PEDAL, with the wheels sliding or not !

some have removed the complete ABS module ,and bypassed the unit all together .

follow the standard bleeding proceedures. do not use any air pressure to work on this problem.. buy a vacuum brake bleeder if it is necessary.

If your on a farm this tool will get lots of use anyway.

Elbert
12-30-2010, 11:37 PM
I would remove the master cylinder, dump all the fluid out, fill with new fluid, bench bled maste cylinder, reinstall and then bled the brakes from all four corners without letting the master cylinder run dry.

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