Need to bleed MC after running it dry?

[cstamm81]

This is an addition to my post regarding leaky Slee SS lines, which are probably in fact boogered up factory hard lines. In installing my new lines I let the MC go dry. I filled it up and gravity bled the crap out of all four corners and LSPV. I let them each drip all together and then sequentially for over an hour. I have a pretty good feel to my brake pedal, but there seems to be a notch that is felt on the first quarter push of the pedal. I can definitely feel it with my hand, not sure if it was always there or not. My brother (mechanic) wants to bleed everything the old fashioned way, one man on the pedal and one on the bleeders; but I am hesitant due to the old MC. I'm trying to avoid pushing the MC past where it's been for years and wrecking it. Question is, do I necessarily need to bleed my MC since I let it go dry? Or do I continue the bleed sequence RR, LR, RF, LF, LSPV until I get all the air out?

[35inchoverdrive]

When you say, "gravity bleed," do you mean that you're letting brake fluid seep out of each of the bleed screws, and air seep in?

[cstamm81]

yeah gravity bleed meaning crack the bleeder and let the fluid seep out. In theory no air enters as the fluid pushes it out. There is no vaccum sucking air back into the beeders, and I have done and helped do this on tons of vehicles, with great results.

[-Spike-]

Only if you want brakes.

If your MC is gonna fail, better it fail in the shop. I've never seen anything fail in the manner you're describing- if something was worn, the thing is junk anyway. The seals don't care where they ride, the bore should be smooth, there's no reason to avoid bleeding the MC and every reason to do it.

-Spike

[98 SNAKE EATER]

Originally Posted by cstamm81

My brother (mechanic) wants to bleed everything the old fashioned way, one man on the pedal and one on the bleeders; but I am hesitant due to the old MC. I'm trying to avoid pushing the MC past where it's been for years and wrecking it.

If you don't think your MC can handle a simple bleeding, what makes you think it will be safe for the road

Bleed it the right way

If it breaks, at least it will be in the safety of your driveway instead of the highway during a panic stop

[98 SNAKE EATER]

Spike beat me to it

[cstamm81]

I've read accounts on here of it failing for that very reason, bore has buildup behind the normal operating range, bleed them with pedal to the floor and the seals go... makes sense to me. Good reasoning though in thinking good way to find out if it's junk anyway. What the he**, I will bleed them the old fashioned way and hope for no MC failure. Back to the original question, do I necessarily have to bleed the MC separately seeing as though I let it go dry?

[-Spike-]

Originally Posted by cstamm81

I've read accounts on here of it failing for that very reason, bore has buildup behind the normal operating range, bleed them with pedal to the floor and the seals go... makes sense to me. Good reasoning though in thinking good way to find out if it's junk anyway. What the he**, I will bleed them the old fashioned way and hope for no MC failure. Back to the original question, do I necessarily have to bleed the MC separately seeing as though I let it go dry?

If you're truly worried about buildup, take it apart and clean it. You're gonna bleed it anyway, which is the PITA part of the job.

-Spike

[98 SNAKE EATER]

Originally Posted by cstamm81

I've read accounts on here of it failing for that very reason, bore has buildup behind the normal operating range, bleed them with pedal to the floor and the seals go... makes sense to me. Good reasoning though in thinking good way to find out if it's junk anyway. What the he**, I will bleed them the old fashioned way and hope for no MC failure. Back to the original question, do I necessarily have to bleed the MC separately seeing as though I let it go dry?

It's always best to bench bleed a dry master, but you shouldn't have to....

After letting an M/C go dry, it usually means you'll have to do 2 to 3 times as much bleeding than normal, so be prepared with extra fluid and some choice words from your bleeding buddy and his sore leg

[chtucker]

If you are going to gravity bleed have a hose sitting in fluid and bleeder. It took me a few hours till one big bubble got out of the MC when I gravity bled my whole system ( I wanted to to a flush)

[cstamm81]

I've got plenty of fluid and I will bleed the old fashioned way, working in sequence multiple times around the truck. Thanks for the advice, this forum is the best.