Pressure Brake Bleeding Question

[Kilian]

Hey folks, got a question on bleeding the brakes on my 83 GMC 3/4 ton. I've replaced all of the brake lines as part of my project and now looking to bleed things in preparation to getting the truck in motion. When I read the shop manual, the bleeding procedure seems like it's going to take two people and a lot of time to push pedal, hold, crack the bleeder screw, tighten screw, wait, repeat, etc.

There's a section in the shop manual about pressure bleeding using a special tool. The PNs given show up on ebay (J-26819 and related). Has anyone tried it using this tool or something similar? Sounds like it will keep the fluid flowing and not require the pedal push, etc. Any help would be appreciated as I don't want to spend days bleeding.

In case the question comes up, I've replaced the MC and bench bled it before installing to make sure there is no air in the MC pistons. I also have the special tool to use in the proportional valve up front to make sure that front/rear lines can be bled. Thanks!

 

[legopnuematic]

I just borrowed a friends motive pressure bleeder, like a weed sprayer jug, and a large aluminum plate that clamps onto the master (or appropriate adapter for other types of masters).

Fill it with 2qts of fluid, pump to 15psi and crack each bleeder until solid flow, release pressure from jug and remove from master and that’s about it.

A good way to do it solo, better than vacuum imo as most bleeders leak too much at the threads to get a good read.

 

[straydog371]

https://www.gmsquarebody.com/threads/lets-talk-one-man-brake-bleeder.48462/#post-1037100

 

[straydog371]

I use a "Motive Power Bleeder"

Brake Bleeder Kits

Shop the original one-person power brake bleeder kits, trusted by pros and DIYers since 1998. Kits for domestic, European, import, classic & racing vehicles — bleed brakes solo in minutes.

www.motiveproducts.com

Picked it up on Amazon for around $80.
Plenty of YouTube videos showing how to use it.

 

[Kilian]

Do you also use the type with the aluminum plate that clamps on the master cylinder?

 

[straydog371]

Yep, it's a bit fiddly to get it set up.
Pump it up to 10 PSI or so and make sure it holds pressure before opening any bleeders.
It works slick!

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[legopnuematic]

@straydog371 my buddy that I borrowed his unit from, when I asked about the chains and hooks he said he ditched them and uses a large c clamp.

That is what I did when I used it and no issues with it sealing to the master.

 

[straydog371]

Great idea and thanks for that tip!

 

[Ricko1966]

I have a Snap On one I bought 40? years ago, made a more modern one a few years ago, cheap. I've also bled clutch slaves 1 man,by attaching a vaccum hose to the bleeder nipple and hooking it to the intake manifold. Start the truck, let it idle, crack the bleeder. When the idle changes its getting fluid. Tighten the bleeder and move on. Have often thought of buying a spool of nylon tubing , put short rubber couplers on each end and having the world's most bad ass vacuum bleeder. I prefer 2 man to pressure bleeder, if I have I helper available. One time deal, I'd 2 man them. Build a cheap one man bleeder,copying a performance tool one man bleeder, or vacuum bleed them. I'll post a link to a homemade 1 man and tell you how to improve it, if you decide to build it.

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[YakkoWarner]

I have a Snap On one I bought 40? years ago made a more modern one a few years ago cheap. I've also bleed clutch slaves 1 man by attaching a vaccum hose to the bleeder nipple and hooking it to the intake manifold. Start the truck, let it idle, crack the bleeder. When the idle changes its getting fluid. Tighten the bleeder and move on. Have often thought of buying a spool of nylon tubing , put short rubber couplers on each end and having the world's most bad ass vacuum bleeder. I prefer 2 man to pressure bleeder, if I have I helper available. One time deal I'd 2 man them. Build a cheap one man bleeder copying a performance tool one man bleeder, or vacuum bleed them. I'll post a link to a homemade 1 man and tell you how to improve it, if you decide to build it.

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I always wanted to try (but don't have anywhere near the kind of spare cash to buy) an aviation-style bleed system. From what I've seen on TV, planes bleed in reverse where you draw out the contents of the master, put pressurized fluid to the fitting down at the wheel and when the master is full again you're done. It pushes any and all air up and out thru the master with a very strong potential for making a fantastic mess on the cockpit floor if you don't watch the master carefully.

I'm always on the lookout for better ways to do solo bleeding, since I only have me, myself and I to do the work (and 2 of them are slackers who do nothing). I'll keep this intake suction trick in mind, the logic is sound as long as you can get enough suction to overcome the leakage at the bleeder threads (or pack some kind of removable putty around them to seal up better maybe?). I never could get the little hand Mity-Vac style vacuum pumps to do much for bleeding because they can't suck fast enough to overcome the air leaking in around the threads.

 

[Ricko1966]

I always wanted to try (but don't have anywhere near the kind of spare cash to buy) an aviation-style bleed system. From what I've seen on TV, planes bleed in reverse where you draw out the contents of the master, put pressurized fluid to the fitting down at the wheel and when the master is full again you're done. It pushes any and all air up and out thru the master with a very strong potential for making a fantastic mess on the cockpit floor if you don't watch the master carefully.

I'm always on the lookout for better ways to do solo bleeding, since I only have me, myself and I to do the work (and 2 of them are slackers who do nothing). I'll keep this intake suction trick in mind, the logic is sound as long as you can get enough suction to overcome the leakage at the bleeder threads (or pack some kind of removable putty around them to seal up better maybe?). I never could get the little hand Mity-Vac style vacuum pumps to do much for bleeding because they can't suck fast enough to overcome the air leaking in around the threads.

They make reverse bleeders that aren't that expensive. Our service writer bought a good one, a Phoenix injector on for shop use. Non of us used it, which is actually stupid on our part. I already had my SnapOn pressure bleeder, or 2 man it. Every one already had a method, so we kept doing what we always did. Stupid because I could have found out on someone else's dime if it was easier. I do not like the pressure bleeder for the fact you need multiple caps and the GM truck one is a PITA where as a Volkswagen it just screws on in place of the cap. Vacuum or 1 man bleeder or even reverse bleeder is 1 size fits all. I think NAPA and others now sell reverse bleeders under 50 or 60 bucks. Okay just looked Autozone 65 for name brand one. Cheaper than buying a pressure bleeder and more versatile. But look at a performance tool one man bleeder and the use instructions online, then the you tube video I posted. Graft that video into a home made version of the performance tool version. Use a magnet with strap for hold a work light to hold the bottle assembly. I'd put a bolt in the end of the tube in the brake fluid bottle. The weight will keep it submerged cut a slit in the tubing above the bolt which would further act as a one way valve. Pressure blows the slit open vacuum sucks the slit back closed.

 

[YakkoWarner]

Ahh good to know an affordable version exists. I assumed (and we all know how that goes) that since it was normally an aviation tool, the price would start at 4 digits and go up from there.

 

[Ricko1966]

I always wanted to try (but don't have anywhere near the kind of spare cash to buy) an aviation-style bleed system. From what I've seen on TV, planes bleed in reverse where you draw out the contents of the master, put pressurized fluid to the fitting down at the wheel and when the master is full again you're done. It pushes any and all air up and out thru the master with a very strong potential for making a fantastic mess on the cockpit floor if you don't watch the master carefully.

I'm always on the lookout for better ways to do solo bleeding, since I only have me, myself and I to do the work (and 2 of them are slackers who do nothing). I'll keep this intake suction trick in mind, the logic is sound as long as you can get enough suction to overcome the leakage at the bleeder threads (or pack some kind of removable putty around them to seal up better maybe?). I never could get the little hand Mity-Vac style vacuum pumps to do much for bleeding because they can't suck fast enough to overcome the air leaking in around the threads.

Intake vacuum works awesome on clutch slaves and volume of suction I didn't have a problem with air leaking past the threads, plus the bleeder and brake system are under a constant vacuum until you shut the bleeder, even if some vacuum is leaking past the threads, it's not all leaking past the threads and air can't get in the wheel cylinder or caliper. If you are having trouble with your mighty vac, back the bleeders out several turns, wrap them with Teflon tape to the base of the exposed threads then tighten them back, don't crack the bleeders too far. I only did the clutch slave because I was lazy. Didn't have the right pressure cap, didn't have anyone around to help and noticed how close the bleeder was to an intake source. It worked good, now it's my go to on clutch slaves.