On a typical single piston caliper the bleed valve usually is located at the top of the caliper near the brake hose attachment point. When bleeding brakes does the brake fluid flow from the hose connection right to the bleed valve leaving the majority of old fluid sitting in the caliper? I assume it does so I bleed brakes first, then compress the caliper piston with the bleed valve open to push out the old fluid. Not sure if that is overkill but feel better knowing the caliper gets refilled with fresh fluid. I would guess that calipers that have the brake hose attach to the bottom of the caliper with the bleed valve on top might be "self flushing" due to the design/fluid path. Anyone know for sure?
Bleeding brake calipers - fluid flow?
- Thread starter cos
- Start date
- Status
The bleed screw is on the top to get rid of air. It's lighter than the fluid
If it were on the bottom you'd never be able to get air out of it
If it were on the bottom you'd never be able to get air out of it
If the bleed screw is on the bottom, you put a left caliper on the right or vice versa.... I "read that" lol.
I used to always pressure bled the brakes with someone stepping on the pedal. But if they screwed up and lifted their foot before you closed the bleed screw, air might get sucked in.
I use a vacuum bleeder now, faster too. Since the car was not done since new, I'll do it every 2 years for the next 6 yrs to eventually get it all out, then I'll do it every 3 yrs.
CRITICAL: Always be sure the master cylinder never runs empty - cars /trucks with ABS will be all screwed up if air gets into the ABS pump/valve assy. For most GMs, there's a special dealer scan tool that commands all the valves to open to bleed out air when new or replaced. You don't want to go down that road accidentally!
I use a vacuum bleeder now, faster too. Since the car was not done since new, I'll do it every 2 years for the next 6 yrs to eventually get it all out, then I'll do it every 3 yrs.
CRITICAL: Always be sure the master cylinder never runs empty - cars /trucks with ABS will be all screwed up if air gets into the ABS pump/valve assy. For most GMs, there's a special dealer scan tool that commands all the valves to open to bleed out air when new or replaced. You don't want to go down that road accidentally!
speed bleeders are awesome
Use turkey baster & exchange as much fluid out of the master cylinder as you can. Unbolt the caliper & compress the piston with the bleeder open to get all the old fluid out, then reassemble everything & bleed the lines out.
Originally Posted By: slacktide_bitog
speed bleeders are awesome
Yup, they work pretty good. Just make sure to get the correct size- triple check the sizes.
speed bleeders are awesome
Yup, they work pretty good. Just make sure to get the correct size- triple check the sizes.
Originally Posted By: SnowDrifter
The bleed screw is on the top to get rid of air. It's lighter than the fluid
If it were on the bottom you'd never be able to get air out of it
I have a motorcycle with the bleed screw on the bottom
Proper bleed procedure for this motorcycle is to remove the caliper and hang it upside down with a special tool before bleeding.
The tool is quite expensive , so bungee cords are typically used. Even so its notoriously hard to bleed.
The bleed screw is on the top to get rid of air. It's lighter than the fluid
If it were on the bottom you'd never be able to get air out of it
I have a motorcycle with the bleed screw on the bottom
The tool is quite expensive , so bungee cords are typically used. Even so its notoriously hard to bleed.
Last edited:
Of all the posts in this thread, mehullica's was the only one that addressed the OP's question. The others were posting what they wanted to post, not replying to the topic.
Reminds me of an old story, about a guy dropping something on the ground and searching for it. A friend comes along and helps him look for the object
Guy - Why are you looking over there? I dropped the item here.
Friend - I know, but the light is better over there.
Reminds me of an old story, about a guy dropping something on the ground and searching for it. A friend comes along and helps him look for the object
Guy - Why are you looking over there? I dropped the item here.
Friend - I know, but the light is better over there.
Originally Posted By: rubberchicken
Originally Posted By: SnowDrifter
The bleed screw is on the top to get rid of air. It's lighter than the fluid
If it were on the bottom you'd never be able to get air out of it
I have a motorcycle with the bleed screw on the bottom
Proper bleed procedure for this motorcycle is to remove the caliper and hang it upside down with a special tool before bleeding.
The tool is quite expensive , so bungee cords are typically used. Even so its notoriously hard to bleed.
Early Minis with front drum brkes also had the blled nipple at the bottom. Surprisingly, gravity bleeding worked fine as long as you removed the M/C lid.
Claud.
Originally Posted By: SnowDrifter
The bleed screw is on the top to get rid of air. It's lighter than the fluid
If it were on the bottom you'd never be able to get air out of it
I have a motorcycle with the bleed screw on the bottom
The tool is quite expensive , so bungee cords are typically used. Even so its notoriously hard to bleed.
Early Minis with front drum brkes also had the blled nipple at the bottom. Surprisingly, gravity bleeding worked fine as long as you removed the M/C lid.
Claud.
George7941,
Yep. I guess I wasn't clear enough - I just wanted to confirm the actual routing/plumbing of the fluid as it travels through a caliper.
mehullica,
Thanks for tip but you might might want to reverse the way you do it - bleed the lines first so the fresh fluid is at the calipers, then compress your piston with the bleed valve open. Then, when you eventually step on the brake pedal you will fill the calipers with fresh fluid.
Yep. I guess I wasn't clear enough - I just wanted to confirm the actual routing/plumbing of the fluid as it travels through a caliper.
mehullica,
Thanks for tip but you might might want to reverse the way you do it - bleed the lines first so the fresh fluid is at the calipers, then compress your piston with the bleed valve open. Then, when you eventually step on the brake pedal you will fill the calipers with fresh fluid.
- Status
Similar threads
