Bleeding air out of front caliper

Energy One

No H2O

Active Member
1. You burned any grease off that made the squeak.
2. The pad is mixed with metal so a harmonic high-spot set-in until worn.
3. The removal of the caliper, then bolted into a new position; cut into unworn disc area.
I thoroughly felt the rotor for any signs of fluid/slickness, didn't feel like any grease or brake fluid was on it and I never removed the caliper so it's most likely #2, thanks
 

No H2O

Active Member
Took it to the mechanic.
Said it was the matter cylinder piston that needed to be rebuilt and that there was no air and everything else was fine.
That also allowed the piston on the caliper to retract so we solved three issues:
1. The squealching noise
2. The loose brake lever
3. The difficulty moving the bike manually
 

bdm7250

Guru
Supporting Member
Took it to the mechanic.
Said it was the matter cylinder piston that needed to be rebuilt and that there was no air and everything else was fine.
That also allowed the piston on the caliper to retract so we solved three issues:
1. The squealching noise
2. The loose brake lever
3. The difficulty moving the bike manually
Thanks for updating..
 

No H2O

Active Member
Took it to the mechanic.
Said it was the master cylinder piston that needed to be rebuilt and that there was no air and everything else was fine.
That also allowed the piston on the caliper to retract so we solved three issues:
1. The squealching noise
2. The loose brake lever
3. The difficulty moving the bike manually
So about a week ago I pretty much lost all stopping power in the front brake. It happened over the course of 2 or three days. in other words, day 1 had full stopping power which btw was never that great to begin with, then by day 3 I had a completely flimsy (zero tension) lever.

I rebuilt the front caliper, not leaks. When changing the brake fluid, the lever handle went from 100% flimsy only to very slight tension but nowhere close enough to stop a bike. This took the course of an hour and an entire 11oz bottle of brake fluid. No leaks anywhere, just pumping the lever to no avail.

Any ideas what could be the issue?
 

SEAL-rider

Active Member
Sounds like air in the lime. I remember in the start of this thread a check valve bleed screw and power bleeder were recommended. Did you use those? When you rebuilt the caliper did you use a rebuild kit and replace all the rubber parts and polish the pistons?
 

No H2O

Active Member
Sounds like air in the lime. I remember in the start of this thread a check valve bleed screw and power bleeder were recommended. Did you use those? When you rebuilt the caliper did you use a rebuild kit and replace all the rubber parts and polish the pistons?
I installed this speed bleeder screw that doesn't allow air back into the line:
http://www.wildsteedworx.com/index....&cPath=68_173_74_273_320_322&products_id=1652

I didn't use a power bleeder, assuming a power bleeder is the same as a vacuum pump bleeder I can get one easily.

I polished the pistons and replaced all the rubber parts. Two piston seals, two housing seals, and two banjo bolt crush washers. No leaks in the caliper.

I'm worried it may not be air since I used a different colour brake fluid and I watched air exit the line and eventually the new coloured fluid come out of the line with no air so I figure the line at this point would only contain new fluid.
 

No H2O

Active Member
"I polished the pistons"

What did you use to polish the pistons?
I should have said "cleaned the pistons", I used brake cleaner and a towel. Got all the dirt off, they looked new when I put them back in. I don't think it's the caliper, there's no leaks at all from the caliper.
 

No H2O

Active Member
Someone said there's air stuck in one of the banjo bolts and to use a vacuum pump to make the job faster and knock on both the upper and lower banjo bolt while using the vacuum pump, I'll try it and report back.
 

Jersey Big Mike

100K mile club
The other trick is to use a regular bleeder and a big syringe.
Take the cover off the master cylinder and force brake fluid from the bottom of the system UP to the top.
Cover everything and don't use too much force or brake fluid will go everywhere.
 

Mr. Wright

Knows some things
Supporting Member
Someone said there's air stuck in one of the banjo bolts and to use a vacuum pump to make the job faster and knock on both the upper and lower banjo bolt while using the vacuum pump, I'll try it and report back.
The problem is it's an 04. On the 04's the way the reservoir was machined, if the brake fluid is just a little bit low, and you squeeze the brake handle while it is on the kickstand, it will suck air. Bleed the air back out by lightly squeezing the handle. Watch the air bubbles coming up in the reservoir.
 

No H2O

Active Member
The problem is it's an 04. On the 04's the way the reservoir was machined, if the brake fluid is just a little bit low, and you squeeze the brake handle while it is on the kickstand, it will suck air. Bleed the air back out by lightly squeezing the handle. Watch the air bubbles coming up in the reservoir.
and I should be doing this while I'm on the bike so it's not leaning over to the left on the stand, I assume?
 

Rottweiler

Well-Known Member
Supporting Member
The problem is it's an 04. On the 04's the way the reservoir was machined, if the brake fluid is just a little bit low, and you squeeze the brake handle while it is on the kickstand, it will suck air. Bleed the air back out by lightly squeezing the handle. Watch the air bubbles coming up in the reservoir.
Mr Wright is correct. Brings back some bad memories. After bleeding a couples times I turned the handle bars left and just kept slowly pulling the lever for about 5 minutes to no more bubbles.
 

No H2O

Active Member
Mr Wright is correct. Brings back some bad memories. After bleeding a couples times I turned the handle bars left and just kept slowly pulling the lever for about 5 minutes to no more bubbles.
ok so upright on the bike,
handlebar all the way left,
leave everything intact except open the brake fluid reservoir
slowly pull the brake lever
add brake fluid as needed
repeat until no more air coming out of the reservoir
correct?
 

No H2O

Active Member
Mr. Wright must be a genius!
I got on the bike
Turned the handlebar all the way left.
Fluid still wasn't quite level, I had to lean the bike so far to the right to get the fluid level that if I leaned it any more it would have tipped over.
Slowly squeezed the lever and held it, didn't really see any consequential bubbling. I heard a couple squealches and saw a very tiny bubble or two. Had the old lady tap on the upper and lower banjo bolts with the end of a wrench. Still nothing dramatic when looking at the reservoir but next thing I noticed, the lever was firm, then it got very firm, and then it got the firmest it's ever been.
All within 5 minutes.
A brake fluid change on an 04 Ridgeback is going to be a 3 person job:
- One to hold the bike in position (if that person is me I wouldn't be able to do anything else)
- One to fill the reservoir
- And one to pump out the old fluid from the caliper.
Thank you for saving the day
 

Rottweiler

Well-Known Member
Supporting Member
Mr. Wright must be a genius!
I got on the bike
Turned the handlebar all the way left.
Fluid still wasn't quite level, I had to lean the bike so far to the right to get the fluid level that if I leaned it any more it would have tipped over.
Slowly squeezed the lever and held it, didn't really see any consequential bubbling. I heard a couple squealches and saw a very tiny bubble or two. Had the old lady tap on the upper and lower banjo bolts with the end of a wrench. Still nothing dramatic when looking at the reservoir but next thing I noticed, the lever was firm, then it got very firm, and then it got the firmest it's ever been.
All within 5 minutes.
A brake fluid change on an 04 Ridgeback is going to be a 3 person job:
- One to hold the bike in position (if that person is me I wouldn't be able to do anything else)
- One to fill the reservoir
- And one to pump out the old fluid from the caliper.
Thank you for saving the day
Glad to hear you got working

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Rottweiler

Well-Known Member
Supporting Member
Not sure if you need 3 people?
I did with just Me, Myself and I.

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