Brake Fluid Question - Taking my calipers off

[325_driver 422]

So i'm looking to add a few HP by taking my calipers off to paint them, and i thought i would clarify a few things

1. Jamming something up against the brake pedal - does that actually stop the fluid from draining out the lines? I've never done it before, and don't want to clamp brake lines. Want to avoid having to do the ABS bleed procedure from taking calipers off.

2. Brake fluid - it's just a daily driver, I have some penrite Super Dot 4, will that suffice to top up the reservoir when i bleed the lines ? If there are specific BMW specifications that need  to be met, I can't seem to find them.

Cheers

[zero 1162]

Brake fluid will come out when you remove the calipers.

No matter what you do you will need to bleed the brakes if you disconnect the caliper.

 

Another option is to remove the caliper from the rotor, but leave the brake hose connected, and paint them on the car. Just mask up the surrounding areas.

[325_driver 422]

@zero i know brake fluid is coming out, i'm talking about stopping it  continually draining through the lines from the reservoir 

i heard pushing the pedal in is a trick to stopping it from emptying the rest of the system

just never done it before

[KwS 2425]

I use a rubber glove palm stretched over the top of the res and a rubber band around it to seal it. This creates a vacuum in the system to stop it completely draining (the cap has a vent so won't do the same). 

Just clamp the lines though. You don't need to hulk clamp them, just get the plastic clamps that look like big scissors and you'll be fine. 

[Eagle 1662]

I got brass brake caps for lines and calipers but as above i just use varying brake clamps most of the time

[325_driver 422]

@KwS thats a good idea. I have a box of latex gloves I could use. Thanks for that !

If I took the pistons out of the calipers do I need a tool to put them back in? Or can they be pressed back in easily enough.

Just Making sure I don't get stuck half way through the task lol

[M3AN 4016]

1 hour ago, 325_driver said:

If I took the pistons out of the calipers do I need a tool to put them back in? Or can they be pressed back in easily enough.

If being the operative word here. Mine were harder to get out with old seals than they were to put back in with new seals.

So I took the calipers to the local service station workshop and he blew them out with air for me for free (but I gave him change for a pint). Make sure you put a block of wood or something in there if you're blowing them out so you don't fire one across the room and damage it.

Putting them back in was easy with some assembly lube (assuming you've cleaned the pistons and barrels up properly).

[325_driver 422]

@M3AN thanks, good to know.

 

 

[325_driver 422]

Does BMW have a list of approved brake fluids? Or just any decent dot 4, hoping I can use that penrite super dot 4

[Eagle 1662]

Probably just DOT 4. Penrite is what i use now, i wish the 4.4L was around back in the day as it would of saved me a sh*t tonne of $

[KwS 2425]

If you're just painting the calipers you don't need to remove the pistons. Only remove the pistons if you intend to rebuild them with new seals. Just thoroughly mask the inside of the calipers, and the mounting flanges, you don't want paint on there. 

[325_driver 422]

@KwS yeah that's what I'm thinking, I didn't really want to remove the pistons but I like doing a pro job. Masking round that area just gunna take a bit of time.

Guess no way I'll notice the difference between the brake pads lol.

Thanks @Eagle going to use my penrite super dot 4. Wasn't in the mood to buy more.

[zero 1162]

You can also plug the brake hoses with a small bolt - m6 i think. 

 

I wouldnt remove the pistons unless you are replacing the seals, especially when you will have to mask the cylinder if you take them out. 

 

Pistons are not hard to put back in, but the seals can sometimes be fiddly.

Edited September 6, 2019 by zero