Trouble Bleeding Rear Brakes, Rear left one is fine but nothing comes out of rear right Options

[LTom]

I recently overhauled both rear calipers and now i've put them back on they require bleeding. With the help of a friend who did the pedal pushing I first bled the rear left (passenger, uk) caliper which went fine. However the rear right one just will not bleed. Nothing comes out as far as I can tell, not even air. I have taken the bleed nipple off and it is not obstructed, i can blow air through it. What the hell is causing this? I'd really appreciate some help as the weather is grim and my only other means of transportation is a motorbike.

[czwalga]

Why are you bleeding your brakes, did you do something to the system?

If you did, there could be a lot of air in the lines that you arent noticing. Are you bleeding them correctly? Pedal push, open screw, bleed, close screw, release pedal, repeat?

[Special_Edy]

This is part of why its suggested to take a section of hose(preferably clear), plug one end over the brake bleeder nipple, and submerge the other end in a jar partially filled with brake fluid. You will see if air or fluid is going into the jar.

I'd verify that the brake fluid reservoir isnt losing fluid while you attempt to bleed the problem caliper(would indicate a leak) and check the brake line for kinks or bends.

[LTom]

I took the callipers apart and replaced the seals and pistons which is why I have to bleed them now they're back on. I am following that bleeding procedure, yes.

I have connected the bleed nipple to a clear hose but nothing comes out, not even bubbles. Very frustrating. The reservoir does not lose fluid during my attempted bleeds.

I should also note that that the peal goes to the floor every time.

This post has been edited by LTom: Dec 20, 2012 - 1:31 PM

[Nial]

Have you checked the brake line for kinks?

[LTom]

Have you checked the brake line for kinks?

Yeah, there are none that I have found.

Is there any merit to the idea that one circuit is preventing the other from being bled? Tomorrow I was going to try opening both rear bleed nipples at the same time and seeing if that helps. I thought it might be the ABS unit but I couldn't see a bleed valve on that so I guess not.

[Tigawoods]

get some speedbleeder fittings. that will help speed up the process when you go to fill up the lines

[Nial]

It helps to have the ignition on when bleeding brakes with cars that have ABS.

[Galcobar]

Bleeding one port at a time, starting with the port farthest from the master cylinder, is the recommended procedure.

You mention that the pedal stays soft when bleeding. Is it soft when the bleeder ports are all closed, and does it firm up at all with repeated pumping of the pedal with the ports closed?

How are you bleeding the brakes? The Toyota directions, to prevent the system from re-ingesting air, are to use the jar method but with the engine off close the bleeder valve, pump the brake pedal several times to build pressure, and then to release the bleeder valve. Repeat as necessary.

While you were rebuilding the calipers, was the system left open and allowed to drain to the point the master cylinder emptied? If so, you may have to bleed the master cylinder, which requires disconnecting the brake lines.

Often it helps to work backwards. You've already verified the bleeder port is clear. Next step is to verify the caliper is clear, which given its monolithic nature should be simple. I'd also check that the seal on the piston is air tight; if it were twisted, damaged or the lip holding it damaged you could be losing pressure that way.

The final option is a faulty brake booster. This is unlikely, as it would be quite a coincidence for it to fail at the moment you try to reinstall your calipers. However, it's possible and easily tested. If it's not air tight anymore, the system cannot build pressure. First check is with the engine off; depress the brake pedal several times slowly. If the pedal goes down the farthest the first time, but gradually rises after the second or third time, the booster is air tight. The second test begins with the engine running; press and hold the pedal down, then turn turn off the engine. If there is no change in the pedal reserve travel after holding the pedal for thirty seconds, the booster is air tight.

[trdproven]

you could tell if its a brake booster. usually you can test this by pumping on the brakes multiple times and hold, then turn on the car, and then the pedal should sink. I know theres a few other ways. The other way to tell is hard to brake or a leak on the booster you would hear air.

[LTom]

Bleeding one port at a time, starting with the port farthest from the master cylinder, is the recommended procedure.

You mention that the pedal stays soft when bleeding. Is it soft when the bleeder ports are all closed, and does it firm up at all with repeated pumping of the pedal with the ports closed?

How are you bleeding the brakes? The Toyota directions, to prevent the system from re-ingesting air, are to use the jar method but with the engine off close the bleeder valve, pump the brake pedal several times to build pressure, and then to release the bleeder valve. Repeat as necessary.

While you were rebuilding the calipers, was the system left open and allowed to drain to the point the master cylinder emptied? If so, you may have to bleed the master cylinder, which requires disconnecting the brake lines.

Often it helps to work backwards. You've already verified the bleeder port is clear. Next step is to verify the caliper is clear, which given its monolithic nature should be simple. I'd also check that the seal on the piston is air tight; if it were twisted, damaged or the lip holding it damaged you could be losing pressure that way.

The final option is a faulty brake booster. This is unlikely, as it would be quite a coincidence for it to fail at the moment you try to reinstall your calipers. However, it's possible and easily tested. If it's not air tight anymore, the system cannot build pressure. First check is with the engine off; depress the brake pedal several times slowly. If the pedal goes down the farthest the first time, but gradually rises after the second or third time, the booster is air tight. The second test begins with the engine running; press and hold the pedal down, then turn turn off the engine. If there is no change in the pedal reserve travel after holding the pedal for thirty seconds, the booster is air tight.

Thanks for taking the time to write this.

Yes, the pedal stays soft when all the bleeders are closed.

The lines were disconnected for a week while I waited for parts and it is possible that air got sucked into the master. How would I go about bleeding the master?

[czwalga]

I'm not convinced you have no air coming out. When I run new brake lines it takes a while to get any fluid at all out of the bleeder.


Air in the MC should eventually bleed out. My sisters old car, I changed the brake lines, when I went to bleed them the master died. I dont know if it was just the system depressurized or what, but that could be the problem.




Think about it, the MC pushes, with the bleeder open air or fluid will come out. If the MC isn't pushing nothing is going to come out. The brake system really isnt complicated.
It's certainly not a kink in the lines or anything like that, if it was you'd build up pedal pressure. It's either a bad MC or air.

This post has been edited by czwalga: Dec 21, 2012 - 8:19 AM

[LTom]

UPDATE: Problem solved

I opened both the rear bleed valves (with tubes on both going into jars of brake fluid) and left it like that for a few hours after which (with both sides open) I pumped the brakes for a few minutes.

When I tried bleeding the rear right valve on its own after this, bubbles did start to come out (whereas they weren't before). There was a LOT of air in the system and it took a long time for me to bleed each side properly but all is now well and my car is back on the road. For some reason having both sides open and pumping fixed the issue.

Thanks for all your help, I'm sure most of you think I'm a bit slow or doing something wrong and all I can say is that I would think the same in your position but there really was nothing coming out of that right side for a LONG time. I'm posting this update just in case someone has the same problem one day.

Merry Christmas/Happy Holidays/End of the world

[czwalga]

No problems glad you got it solved. It can take a long time go bleed out manually. A good tip is when you open the bleeder screw you can cover it with your finger to tell if there is any air.

[enderswift]

All future brake/clutch bleeding problems solved:

http://www.harborfreight.com/brake-fluid-bleeder-92924.html

I bought this and it is by far the fastest, easiest, and cleanest way to bleed brakes. It doesn't matter if you have abs either, unless its one of those annoying GM units. Oh yea its a one man operation as well