93 C1500 Drum-Disc brake system bleed

[Ryline]

Good afternoon,

I have a 1993 Chevy C1500 2wd ext cab 5.7L. I did the brake conversion to remove factory drum brakes and install disc brakes. Also I installed a new I guess to say performance style master cylinder for a couple key reasons. But I’ve never done this big of a brake fluid bleed.

How does anyone recommend I go about this? Just bleed with a partner through the brake pump method or go buy a bleeder? Also whether I do the brake or bleeder method. I never remember but does the truck need to being running or does the key need to be forward with just the ignition on or key completely off?

Also, How did you cycle the ABS to get the fluid through the ABS module? I came across this in an article but the guy didn’t mention a method. Is this going to be something I’ll run into since most the system is going to be flushed & if so, how do I go about doing this properly.

Thank you so much for your time. I’m going to start bleeding in about an hour. Huge huge thank you if anyone comes across this tonight.

Ryan

 

[Ryline]

Good afternoon,

I have a 1993 Chevy C1500 2wd ext cab 5.7L. I did the brake conversion to remove factory drum brakes and install disc brakes. Also I installed a new I guess to say performance style master cylinder for a couple key reasons. But I’ve never done this big of a brake fluid bleed.

How does anyone recommend I go about this? Just bleed with a partner through the brake pump method or go buy a bleeder? Also whether I do the brake or bleeder method. I never remember but does the truck need to being running or does the key need to be forward with just the ignition on or key completely off?

Also, How did you cycle the ABS to get the fluid through the ABS module? I came across this in an article but the guy didn’t mention a method. Is this going to be something I’ll run into since most the system is going to be flushed & if so, how do I go about doing this properly.

Thank you so much for your time. I’m going to start bleeding in about an hour. Huge huge thank you if anyone comes across this tonight.

Ryan

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Just picked up the new brake lines for the rear & I happened to come across this handy fella. Called LiquiVac 8 quart oil changing system. It states it’s for use of all types of oils, grease, etc… But absolutely no gasoline. I added and changed around the hoses so it’ll fit right over a bleeder valve snug as a bug. Best thing is it doesn’t need a compressor nor electricity. it’s a manual pump style setup for creating a vacuum which I feel is great & very versatile for a wide range of uses. I was just curious on the most efficient way to go about doing this Or if anyone has tried using something like this and their opinion on it.

 

[Ryline]

Right after I pressed to post this last message I had an idea. no Idea if it’s a good idea or not. But if I wait until morning and take all the correct measurements. would it be more beneficial to get enough properly snug hosing to come off from a 4 way adapter to reach all 4 bleeder valves and perform a bleed of all 4 calipers at the same time? Now my mind is racing on what to do. Any opinions are welcome. Thank you in advance.

 

[Drunkcanuk]

I've never used a fancy machine like that, just the old fashioned way.
Key off, don't know if that's a thing or not. Have someone pump the brakes until hard, crack the bleeder.
If you haven't already bench bleed the master cylinder, that would be the first thing to do or you will be chasing bubbles for a while.
A tip I got from old GM mechanic was to put a block of 2x4 under the pedal so it doesn't go to the floor. Said you would tear the seals up or something like that.
As for the abs, Harley riders just find a gravel road and jam on the brakes to cycle the abs, should work for our trucks if you don't have the magic box to cycle it.
Good luck.

 

[Erik the Awful]

That thingawhichit will suck the fluid out of the reservoir, but it won't bleed your brakes. I've made plenty of one-man brake bleeders on the fly at the track, although we typically use two people to bleed. It just makes it easier.

Take a gatorade bottle that your teammate just guzzled and clean it out with a shop towel on the end of a screwdriver. Nab two feet of vacuum hose and two zip ties. Stab a hole in the gatorade lid - it doesn't have to be perfect nor airtight. Stick the vacuum hose through the lid so that it ends about 1/2" above the bottom of the bottle. Zip tie above and below the lid to keep the hose in place. If your hole in the lid isn't imperfect enough, punch a hole to allow air out. Put at least an inch of brake fluid in the bottom of the bottle. Go to the right rear brake and slip the end of the vacuum hose over the bleed nipple. Take a new bottle of brake fluid, open it, take your smallest screwdriver, and punch a small hole in the seal. Invert the bottle onto the top of the master cylinder. It won't overfill the master cylinder, but if the fluid level drops below the level of the opening, it'll dribble in to fill the master cylinder. Go back to the right rear brake and crack the line loose with a line wrench. Pump the pedal ten times. If you don't have anyone to check for bubbles, gauge the pedal feel. If it's still improving, pump ten more times. If it's good, tighten and move to the left rear, then right front, then left front. Don't forget to check if the bottle's too full and if the bottle in the master cylinder is empty.

I don't have the tool for opening up the ABS for bleeding and haven't done that, but bleeding it by stomping the brakes should be moderately effective.

 

[Schurkey]

You MUST have a scan tool to cycle the valves on the ABS.

Some folks take the vehicle to a dirt or gravel road, smash the brake pedal, and hope the ABS cycles. But then you've gotta drive back to the shop and bleed at each wheel cylinder again, AND hope that all three channels of the ABS unit were chattering, not just one or two.

Don't get me started on crappy rear disc conversions using poorly-engineered flat brackets, or trying to use a two-chamber master cylinder with low-drag front calipers (the calipers used on virtually all 5- and 6-lug GMT400s.) Suffice to say that you almost certainly have the wrong master cylinder.