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Discussion Starter · #1 ·
I'm wanting to remove all 4 calipers completely from the car for painting. I'll also be changing pads/rotors (HPS/Centrics), and when all finished I'll be bleeding/flushing the brake lines and clutch. The car will be up on stands for probably a couple days, as I'm likely to work on this in stages over a weekend around other life obligations.

During that time, with calipers removed, I do NOT want to drain the master cylinder, as I am not equipped (or knowledgable enough) for a bench bleed.

1. Should I be:
A: disconnecting the brake flex line from the calipers?
or
B: disconnecting the brake flex line from the brake hard line (and leaving the flex line connected to the caliper)?

2. Then, what caps/plugs do I then use to prevent the lines from draining out over a day or two? I've read so many different things about the fittings on the flex lines, and I'm so confused (3/16, M10x1.0, bubble flare, banjo, vacuum caps, etc.). Depending on whether I should detach at the caliper end of the flex line (A) or the end of the hard line (B), what hardware do I need to effectively/safely cap/plug the end point of the brake lines? It doesn't have to withstand massive pressure- just prevent gravity from draining out of the MC.

Surely I'm not the first person to want to do this, and it seems like it would be simple/straightforward. However, I have spent hours and hours searching for an answer online, and I'm yet to see anyone specifically cover this. Am I just missing something obvious?

BTW, this will be my first time doing any of these things (on any car). I'm feeling reasonably confident and prepared though, thanks to the FocusST.org and greater automotive communities. Thanks in advance for helping me get this figured out.
 

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First, draining the master cyl reservoir does not necessitate a bench bleed. Every time I flush my system to change the fluid, I completely siphon the reservoir to get as much old fluid out as physically possible, refill with new fluid, and then bleed the system as normal. Second, removing all the lines will not completely drain the reservoir. With the lid on, the system will act like a vacuum and the fluid will stay in the lines; think finger over a straw full of liquid...the liquid stays. If it did drain some, it still would not necessitate a bench bleed.
 

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Discussion Starter · #3 ·
Thanks for the response, galaxy7. Much appreciated.

I was under the impression that if levels dropped too low and the MC chamber was devoid of fluid (from having "bled out"), the MC itself would then need to be bench bled. I'd love to be wrong- it's just what I've read from everyone else ("whatever you do, don't...", etc.).

So you're saying that as long as I leave the reservoir cap on/sealed, letting all 4 lines hang open without restriction won't cause a level/MC problem? Even if the car is in that state for a few days (thinking worst-case scenario on my end)? If so, that would be great- I'd just need to have something collecting fluid at each brake line to avoid a mess. I do get the straw/liquid analogy, and it makes sense, but I haven't experienced this first hand and want to be sure rather than learning "the hard way."

Also-
Any reason it'd be better/easier to detach the flex line from the hard line as opposed to separating the flex line from the caliper? Does it matter where I detach? I can't seem to find much on that either way. For painting purposes, it'd seem like removing the flex line from the caliper would be better, as well as being less messy (no need to dump out the flex line fluid, as it can just stay in the flex line)- but I don't want to do something stupid there if I'm overlooking a problem that might cause.

Thanks again.
 

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Yes, that is what I'm saying. The need for a bench bleed stems from having the piston/actuator in the MC void of fluid. You can have the reservoir bone dry. Just don't go pumping the pedal with the reservoir empty.

I'd think you'd need the line off the caliper for painting, but from a system standpoint, where you disconnect the line is irrelevant; you're still left with the same issue. And when you put it all back together, you still have to bleed the whole system.

This is a perfect, and ideal opportunity to flush and replace all your brake fluid. For which you'd want to do what I recommended in the first place....after you have the painted calipers reconnected, suck empty the reservoir, immediately refill the reservoir with your chosen favorite flavoring of fluid, and bleed via whichever method you're a fan of. You are overthinking this bench bleed thing. As long as you don't pump the brake pedal while it's empty, you are good to go.
 

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Discussion Starter · #5 ·
I was planning on flushing the brake fluid at the end of all this anyway- I'm all set for that. I've got a Motive Bleeder (pressure bleeder) and the fluid ready to go.

I appreciate the explanations. I still keep reading horror stories about having a dry master cylinder, but perhaps all those horror stories are when someone has been working the brake pedal without making sure the reservoir has had sufficient fluid in it. It seems such a disaster can be avoided as long as I don't touch the pedal (which would move the cylinder and suck air into the system) as the lines bleed out (if they somehow did so despite the vacuum from the reservoir cap). I'll be sure not to touch the pedal or the reservoir cap while the calipers are detached.

One last (dumber) question... Does our reservoir location allow for a straight syringe/baster? Or does it require a syringe with a hose attachment? I don't have an extractor either way- just looking at what I might need to pick up.

Thanks a bunch. Will cross my fingers and go for it here in the next weekend or two.
 

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Buy new calipers. Painting will be much less labor intensive and you'll get a much better job in the end.

If you prefer spending a lot of time cleaning the existing calipers, Todd at TCE sells a cap set for the brake lines. Double check with him that the caps fit on the OEM lines.
 
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