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I've bled brakes successfully many times over many decades. What's the rationale for why the engine should be running?
This has the potential to be a " brand of oil" thread.
Like you , I have bled many brakes and many brake systems over the years. Manual, boosted, full power brakes, motorcycle, truck, etc. My rationale is admittedly multi-faceted.
1. I've discovered that when the brakes are bled in their "working state", I push more fluid faster, thereby reducing the chance of air bubbles, that might have to go over then down a tube, won't have the chance to get caught in a high bend. ( that makes sense...right?) This "engine running" is obviously only when the system has a vacuum or hydraulic assist set up.
2. probably the most significant reason...my wife is usually pushing the pedal....I'm more assured that the peddle goes to the floor..if she has help.
(I do use a flashlight to check for micro bubbles and I usually go through about 1.5 large bottles of fluid during a bleed.)
Last edited by Killerkaw; Sep 13, 2023 at 09:51 PM.
You can activate activate the ABS/TC pump by removing the ABS relay in the fusebox and shorting it through a switch. I took an old light switch, put 2 15' leads on it with spade terminals. When it's time to bleed the brakes I remove the ABS relay, put in the spade terminals, crack the bleeder screw and flip the switch.
You can activate activate the ABS/TC pump by removing the ABS relay in the fusebox and shorting it through a switch. I took an old light switch, put 2 15' leads on it with spade terminals. When it's time to bleed the brakes I remove the ABS relay, put in the spade terminals, crack the bleeder screw and flip the switch.
that's cheating😁
Looks like I'll be fabbing up a switch now, as if i didn't have anything else to do. I'm thinking a momentary palm sized button.
that's cheating😁
Looks like I'll be fabbing up a switch now, as if i didn't have anything else to do. I'm thinking a momentary palm sized button.
Haha! A momentary or a latching switch will work. I wanted the ability to use both of my hands while it was running in case I ever had a need to do so, but so far I haven't. I don't like to run mine for more than 10-15 seconds at a time, but I think that's just me being paranoid. The important thing is that your leads are long enough to reach from the fuse box to the drivers side rear wheel. When I made mine I just "eyeballed" it and added some extra and it just barely reaches. Its longer than it looks, especially because you want to be able to run the wires around the truck and not underneath!
It shows the recesses in the under bonnet fusebox into which the spades should be inserted, although he pictured the upside-down relay so the positions are reversed. His other pic shows the switch he used, the lamp cord used, and the spade terminals at the other end. Lamp cord is inexpensive, easily available in lengths, and does the job just fine.
So if I understand this little bad boy correctly, You plug into ABS relay with power on (engine running or just key position 2) flip the switch and it activates the ABS?
You remove the ABS relay and plug the spade terminals into to two larger recesses.
You really don't need the spade terminals or even the switch. You could just strip ~½ inch and twist the copper tight and insert it into the recesses, and at the other end just touch the two exposed leads together to close the circuit and activate the ABS pump. It's just "tidier" with the spade terminals and the switch.
I don't recall whether or not the key even needs to be in Position 2, but the engine certainly doesn't need to be running.
